{"id":12323,"date":"2026-02-27T01:24:56","date_gmt":"2026-02-27T01:24:56","guid":{"rendered":"https:\/\/hlh-js.com\/?p=12323"},"modified":"2026-03-02T07:17:26","modified_gmt":"2026-03-02T07:17:26","slug":"plastic-tumbling-media-for-aluminum-parts-finishing","status":"publish","type":"post","link":"https:\/\/hlh-js.com\/es\/resource\/blog\/plastic-tumbling-media-for-aluminum-parts-finishing\/","title":{"rendered":"Plastic Tumbling Media for Aluminum Parts Finishing"},"content":{"rendered":"<!-- ============================================================\n     CLUSTER ARTICLE #10 \u2014 WordPress Post Content\n     Title: Plastic Tumbling Media for Aluminum Parts Finishing\n     \u7c98\u8d34\u65b9\u5f0f\uff1aGutenberg\u300c\u81ea\u5b9a\u4e49 HTML\u300d\u5757 \u6216 \u7ecf\u5178\u7f16\u8f91\u5668\u300c\u6587\u672c\u300d\u6a21\u5f0f\n     ============================================================ -->\n\n<style>\n\/* \u2500\u2500 \u94dd\u94f6\u8272\u5de5\u4e1a\u4e3b\u9898 \u2500\u2500 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0}\n.pm-control-card{background:#f8fafc;border:1px solid #e2e8f0;border-radius:6px;padding:16px 18px}\n.pm-control-icon{font-size:20px;margin-bottom:8px;display:block}\n.pm-control-card h4{font-size:14px;font-weight:700;color:#1e293b;margin:0 0 6px}\n.pm-control-card p{font-size:13px;color:#64748b;margin:0;line-height:1.55}\n\n\/* FAQ *\/\n.pm-faq-item{border-bottom:1px solid #f1f5f9;padding:18px 0}\n.pm-faq-item:last-child{border-bottom:none}\n.pm-faq-q{font-size:16px;font-weight:700;color:#111827;margin:0 0 8px}\n.pm-faq-a{font-size:15px;color:#4b5563;margin:0;line-height:1.7}\n\n\/* Cluster links *\/\n.pm-cluster-group{margin:0 0 24px}\n.pm-cluster-label{font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.12em;color:#94a3b8;margin:0 0 10px}\n.pm-cluster-group ul{list-style:none;padding:0;margin:0;display:flex;flex-direction:column;gap:4px}\n.pm-cluster-group ul li a{display:flex;align-items:center;gap:8px;color:#334155;text-decoration:none;font-size:14.5px;padding:8px 12px;border:1px solid #e2e8f0;border-radius:4px;background:#fafafa}\n.pm-cluster-group ul li a:hover{background:#f1f5f9;border-color:#cbd5e1}\n.pm-cluster-group ul li a::before{content:\"\u2192\";color:#475569;font-weight:700;flex-shrink:0}\n\n.pm-section-divider{border:none;border-top:1px solid #f1f5f9;margin:48px 0}\n\n@media(max-width:640px){\n  .pm-stat-bar{grid-template-columns:repeat(2,1fr)}\n  .pm-shape-grid{grid-template-columns:repeat(2,1fr)}\n  .pm-outcome-grid{grid-template-columns:1fr}\n  .pm-surface-grid{grid-template-columns:1fr 1fr}\n  .pm-alloy-grid{grid-template-columns:1fr 1fr}\n}\n@media(max-width:420px){\n  .pm-compound-grid{grid-template-columns:1fr}\n  .pm-control-grid{grid-template-columns:1fr}\n}\n<\/style>\n<h1>Plastic Tumbling Media for Aluminum Parts Finishing<\/h1>\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 INTRO \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<p>Aluminum is the workhorse alloy of precision manufacturing \u2014 light, machinable, thermally conductive, and responsive to a wide range of surface treatments. It is also, in its as-machined or as-cast state, a surface that rarely meets the functional or cosmetic requirements of its final application without some form of mechanical finishing. Machining leaves tool marks. Die casting leaves parting line seams and flash. Stamping and forging leave burrs, sharp edges, and scale. Extrusion leaves die lines and surface roughness from the extrusion die.<\/p>\n\n<p>Plastic tumbling media \u2014 precision-shaped polymer pieces processed in vibratory bowls, centrifugal disc machines, and barrel tumblers alongside aluminum parts \u2014 addresses all of these as-processed surface conditions in a single automated batch operation. It deburrs, edge-radiuses, descales, and smooths aluminum parts simultaneously, without the chemical hazards of acid etching, the dimensional imprecision of hand finishing, or the part-damage risk of more aggressive abrasive tumbling media.<\/p>\n\n<p>This guide is the definitive technical reference for plastic tumbling media applied to aluminum parts finishing: how to select the right media shape and compound for the specific finishing objective, how to set up and run the process for different aluminum alloys and part geometries, how to achieve the surface finish specifications required for anodizing, plating, painting, and assembly applications, and how to troubleshoot the most common problems in aluminum vibratory finishing. For a foundational comparison of tumbling vs. blast media, see: <a href=\"https:\/\/hlh-js.com\/resource\/blog\/plastic-tumbling-media-vs-blast-media-whats-the-difference\/\">Plastic Tumbling Media vs Blast Media: What&#8217;s the Difference?<\/a>.For a broader overview of the full plastic media category, see: <a href=\"https:\/\/hlh-js.com\/resource\/blog\/what-is-plastic-media-the-complete-guide-to-types-uses-applications\/\">What Is Plastic Media? The Complete Guide<\/a>.<\/p>\n\n<!-- TOC -->\n<nav class=\"pm-toc\" aria-label=\"Table of Contents\">\n  <p class=\"pm-toc-title\">\ud83d\udccb Table of Contents<\/p>\n  <ol>\n    <li><a href=\"#al-why\">Why Plastic Media for Aluminum Tumbling?<\/a><\/li>\n    <li><a href=\"#al-alloys\">Aluminum Alloy Guide: Properties That Affect Finishing<\/a><\/li>\n    <li><a href=\"#al-objectives\">Matching Process to Finishing Objective<\/a><\/li>\n    <li><a href=\"#al-shapes\">Media Shape Selection for Aluminum<\/a><\/li>\n    <li><a href=\"#al-compounds\">Compound Selection: Chemistry for Aluminum<\/a><\/li>\n    <li><a href=\"#al-machines\">Machine Types and When to Use Each<\/a><\/li>\n    <li><a href=\"#al-sequences\">Multi-Stage Finishing Sequences<\/a><\/li>\n    <li><a href=\"#al-surface\">Surface Finish Ra Targets by Application<\/a><\/li>\n    <li><a href=\"#al-anodize\">Preparing Aluminum for Anodizing<\/a><\/li>\n    <li><a href=\"#al-plate\">Preparing Aluminum for Plating<\/a><\/li>\n    <li><a href=\"#al-process\">Process Setup and Operating Parameters<\/a><\/li>\n    <li><a href=\"#al-ratio\">Media-to-Part Ratio and Loading<\/a><\/li>\n    <li><a href=\"#al-control\">Process Control: Monitoring and Adjustment<\/a><\/li>\n    <li><a href=\"#al-problems\">Problemas comunes y soluciones<\/a><\/li>\n    <li><a href=\"#al-faq\">Preguntas frecuentes<\/a><\/li>\n    <li><a href=\"#al-related\">Related Guides<\/a><\/li>\n  <\/ol>\n<\/nav>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S1 WHY \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-why\">Why Plastic Media for Aluminum Tumbling?<\/h2>\n\n<p>Aluminum presents a specific set of finishing challenges that plastic tumbling media is uniquely suited to address. Understanding why plastic media outperforms ceramic and steel shot alternatives on aluminum parts begins with the alloy&#8217;s physical properties.<\/p>\n\n<p>Aluminum is soft \u2014 Mohs hardness 2.5\u20133.5 depending on alloy and temper, roughly one-third the hardness of mild steel. This softness is an asset for machinability but a liability in finishing: the same quality that makes aluminum easy to cut also makes it easy to scratch, embed foreign particles into, and contaminate with iron from steel-based finishing media. Ceramic tumbling media \u2014 the most common general-purpose mass finishing media \u2014 operates at Mohs 6\u20139, well above aluminum&#8217;s hardness. The result of ceramic-on-aluminum contact is predictable: surface scratching, smearing at edges, and the risk of ceramic particle embedment in the soft aluminum surface. Iron contamination from steel shot media creates galvanic corrosion sites that compromise any subsequent anodizing or coating.<\/p>\n\n<p>Plastic tumbling media \u2014 typically thermoset polyester, urea, or melamine compounds at Mohs 2.5\u20134.0 \u2014 operates in the hardness range of and slightly above aluminum. The media is hard enough to cut the aluminum surface progressively, removing tool marks and burrs, while soft enough that it does not embed particles in or mechanically score the aluminum beyond the intended surface finish change. And because plastic media contains no iron or metallic compounds, it introduces no contamination risk for aluminum parts that will be anodized, chemically treated, or used in electrochemically active environments.<\/p>\n\n<div class=\"pm-stat-bar\">\n  <div class=\"pm-stat-card\">\n    <div class=\"pm-stat-value\">2.5\u20134.0<\/div>\n    <div class=\"pm-stat-unit\">Mohs<\/div>\n    <div class=\"pm-stat-label\">Plastic media hardness \u2014 within aluminum&#8217;s processing zone<\/div>\n  <\/div>\n  <div class=\"pm-stat-card\">\n    <div class=\"pm-stat-value\">Zero<\/div>\n    <div class=\"pm-stat-unit\">Iron content<\/div>\n    <div class=\"pm-stat-label\">No iron contamination \u2014 critical for anodizing applications<\/div>\n  <\/div>\n  <div class=\"pm-stat-card\">\n    <div class=\"pm-stat-value\">4\u201316 \u00b5in<\/div>\n    <div class=\"pm-stat-unit\">Ra achievable<\/div>\n    <div class=\"pm-stat-label\">Final Ra on 6061-T6 with fine media + burnishing sequence<\/div>\n  <\/div>\n  <div class=\"pm-stat-card\">\n    <div class=\"pm-stat-value\">60\u201390%<\/div>\n    <div class=\"pm-stat-unit\">Labor saving<\/div>\n    <div class=\"pm-stat-label\">vs. manual hand deburring for equivalent batch production<\/div>\n  <\/div>\n  <div class=\"pm-stat-card\">\n    <div class=\"pm-stat-value\">Months\u2013Yrs<\/div>\n    <div class=\"pm-stat-unit\">Media life<\/div>\n    <div class=\"pm-stat-label\">Plastic tumbling media wears gradually \u2014 not fracture-limited like blast media<\/div>\n  <\/div>\n<\/div>\n\n<div class=\"pm-callout pm-callout-green\">\n  <strong>The anodizing advantage:<\/strong> For aluminum parts destined for anodizing, plastic tumbling media provides two specific benefits over ceramic: it produces a cleaner, more uniform surface that anodizes more evenly (ceramic-finished aluminum can show mottling from surface contamination), and it leaves no foreign particle contamination that would create pitting or coating defects in the anodize bath.\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S2 ALLOYS \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-alloys\">Aluminum Alloy Guide: Properties That Affect Finishing<\/h2>\n\n<p>Not all aluminum alloys respond identically to plastic tumbling media. Alloy composition, temper, and microstructure all influence how the surface responds to abrasive contact \u2014 the rate of material removal, the surface finish achievable, and the risk of smearing or edge distortion.<\/p>\n\n<div class=\"pm-alloy-grid\">\n  <div class=\"pm-alloy-card\">\n    <div class=\"pm-alloy-head\">\ud83d\udd27 6061-T6<\/div>\n    <div class=\"pm-alloy-body\">\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Mohs hardness<\/span><span class=\"pm-alloy-val\">~3.0<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Anodize response<\/span><span class=\"pm-alloy-val\">Excelente<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Notes<\/span><span class=\"pm-alloy-val\">Most forgiving; responds well to all plastic media. Best anodize uniformity.<\/span><\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-alloy-card\">\n    <div class=\"pm-alloy-head\">\u2708\ufe0f 7075-T6<\/div>\n    <div class=\"pm-alloy-body\">\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Mohs hardness<\/span><span class=\"pm-alloy-val\">~3.3<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Anodize response<\/span><span class=\"pm-alloy-val\">Good (slight mottling)<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Notes<\/span><span class=\"pm-alloy-val\">Zinc content causes some anodize mottling regardless of finish. Fatigue-sensitive \u2014 avoid aggressive media.<\/span><\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-alloy-card\">\n    <div class=\"pm-alloy-head\">\ud83d\udd29 2024-T3<\/div>\n    <div class=\"pm-alloy-body\">\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Mohs hardness<\/span><span class=\"pm-alloy-val\">~2.8<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Anodize response<\/span><span class=\"pm-alloy-val\">Poor (copper content)<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Notes<\/span><span class=\"pm-alloy-val\">Softest common structural alloy. Used for deburr\/pre-paint. High copper prevents quality anodize.<\/span><\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-alloy-card\">\n    <div class=\"pm-alloy-head\">\ud83c\udfd7\ufe0f 5052-H32<\/div>\n    <div class=\"pm-alloy-body\">\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Mohs hardness<\/span><span class=\"pm-alloy-val\">~2.7<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Anodize response<\/span><span class=\"pm-alloy-val\">Bien<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Notes<\/span><span class=\"pm-alloy-val\">&#8220;Gummy&#8221; cutting behavior. Use acidic compound to prevent aluminum smear buildup on media.<\/span><\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-alloy-card\">\n    <div class=\"pm-alloy-head\">\ud83c\udfce\ufe0f 6063-T5\/T6<\/div>\n    <div class=\"pm-alloy-body\">\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Mohs hardness<\/span><span class=\"pm-alloy-val\">~2.8<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Anodize response<\/span><span class=\"pm-alloy-val\">Excellent (architectural)<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Notes<\/span><span class=\"pm-alloy-val\">Extrusion alloy. Multi-stage plastic finishing removes die lines for architectural anodize.<\/span><\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-alloy-card\">\n    <div class=\"pm-alloy-head\">\ud83d\udd04 A380 \/ A356 Die Cast<\/div>\n    <div class=\"pm-alloy-body\">\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Mohs hardness<\/span><span class=\"pm-alloy-val\">~2.5<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Anodize response<\/span><span class=\"pm-alloy-val\">Limited (silicon content)<\/span><\/div>\n      <div class=\"pm-alloy-row\"><span class=\"pm-alloy-label\">Notes<\/span><span class=\"pm-alloy-val\">High silicon; uneven surface between skin and sub-surface. Porosity is a risk with aggressive media.<\/span><\/div>\n    <\/div>\n  <\/div>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S3 OBJECTIVES \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-objectives\">Matching Process to Finishing Objective<\/h2>\n\n<p>The media and process parameters that optimize for deburring are different from those optimizing for pre-anodize smoothing, which are different again from those optimizing for pre-plate burnishing. Define the objective first; then select the process.<\/p>\n\n<div class=\"pm-outcome-grid\">\n  <div class=\"pm-outcome-card\">\n    <div class=\"pm-outcome-head\">\u2702\ufe0f Deburring<\/div>\n    <div class=\"pm-outcome-body\">\n      Removal of machining burrs, die cast flash, and stamping burrs from edges and through-holes. Preferential material removal from thin cross-section projections.\n      <div class=\"pm-outcome-params\">Coarser plastic media \u00b7 Alkaline compound \u00b7 Higher amplitude \u00b7 30\u201390 min \u00b7 Wet<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-outcome-card\">\n    <div class=\"pm-outcome-head\">\ud83d\udcd0 Edge Radiusing<\/div>\n    <div class=\"pm-outcome-body\">\n      Progressive rounding of sharp machined or stamped edges to a controlled radius. Required for fatigue life improvement, assembly safety, and consistent coating thickness at edges.\n      <div class=\"pm-outcome-params\">Medium media \u00b7 Neutral compound \u00b7 Controlled amplitude \u00b7 60\u2013180 min \u00b7 Measure radius at intervals<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-outcome-card\">\n    <div class=\"pm-outcome-head\">\u2728 Surface Ra Reduction<\/div>\n    <div class=\"pm-outcome-body\">\n      Reduction of machining surface roughness to a target Ra for coating adhesion, sealing, or cosmetic appearance. Progressive with cycle time and stage count.\n      <div class=\"pm-outcome-params\">Fine plastic media (multi-stage) \u00b7 Acidic or neutral compound \u00b7 60\u2013240 min total<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-outcome-card\">\n    <div class=\"pm-outcome-head\">\ud83c\udf1f Pre-Anodize Finishing<\/div>\n    <div class=\"pm-outcome-body\">\n      Preparation for uniform, cosmetically consistent anodize. Requires clean, contamination-free surface with controlled Ra \u2014 not too rough, not scratched.\n      <div class=\"pm-outcome-params\">Fine cylinder \u2192 ellipse \u00b7 Acidic brightening compound \u00b7 Target Ra 16\u201332 \u00b5in<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-outcome-card\">\n    <div class=\"pm-outcome-head\">\ud83d\udc8e Pre-Plate Brightening<\/div>\n    <div class=\"pm-outcome-body\">\n      Highest-quality preparation for decorative nickel, chrome, or bright anodize. Requires sub-microinch Ra and highly uniform surface free of micro-scratches.\n      <div class=\"pm-outcome-params\">Multi-stage: deburr \u2192 fine smooth \u2192 burnish \u00b7 Final Ra target 4\u20138 \u00b5in<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-outcome-card\">\n    <div class=\"pm-outcome-head\">\ud83e\uddf9 Pre-Assembly Cleaning<\/div>\n    <div class=\"pm-outcome-body\">\n      Removal of machining oil, coolant residue, and light contamination. Gentle process \u2014 surface cleaning only, no material removal required.\n      <div class=\"pm-outcome-params\">Very fine plastic or burnishing media \u00b7 Alkaline degreasing compound \u00b7 15\u201330 min<\/div>\n    <\/div>\n  <\/div>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S4 SHAPES \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-shapes\">Media Shape Selection for Aluminum<\/h2>\n\n<p>Each media shape provides a specific pattern of contact that determines where material is removed, how aggressively edges are addressed, and whether the media can reach internal features. Shape selection is driven primarily by part geometry and the location of features requiring finishing action.<\/p>\n\n<div class=\"pm-shape-grid\">\n  <div class=\"pm-shape-card\">\n    <span class=\"pm-shape-icon\">\ud83d\udd3a<\/span>\n    <div class=\"pm-shape-name\">Pyramid \/ Tri-Star<\/div>\n    <div class=\"pm-shape-best\"><strong>Best for:<\/strong> Complex CNC aluminum with internal corners and narrow slots. Three edges reach 90\u00b0 internal corners.<\/div>\n    <div class=\"pm-shape-avoid\">Avoid: Very fine-pitch features<\/div>\n  <\/div>\n  <div class=\"pm-shape-card\">\n    <span class=\"pm-shape-icon\">\u2b21<\/span>\n    <div class=\"pm-shape-name\">Straight Cylinder<\/div>\n    <div class=\"pm-shape-best\"><strong>Best for:<\/strong> General-purpose aluminum deburring and Ra reduction. Best flow, uniform coverage, most economical for high-volume work.<\/div>\n    <div class=\"pm-shape-avoid\">Avoid: Deep blind holes (lodging risk)<\/div>\n  <\/div>\n  <div class=\"pm-shape-card\">\n    <span class=\"pm-shape-icon\">\ud83d\udd37<\/span>\n    <div class=\"pm-shape-name\">Angle-Cut Cylinder<\/div>\n    <div class=\"pm-shape-best\"><strong>Best for:<\/strong> Aggressive deburring of aluminum die castings with heavy flash. Excellent on through-holes and cross-drilled features.<\/div>\n    <div class=\"pm-shape-avoid\">Avoid: Polished \/ pre-finished surfaces<\/div>\n  <\/div>\n  <div class=\"pm-shape-card\">\n    <span class=\"pm-shape-icon\">\ud83d\udd39<\/span>\n    <div class=\"pm-shape-name\">Wedge \/ Trihedron<\/div>\n    <div class=\"pm-shape-best\"><strong>Best for:<\/strong> Inside diameters, counter-bore lips, recessed pockets in aluminum housings.<\/div>\n    <div class=\"pm-shape-avoid\">Avoid: Very small holes \u2014 must size correctly to prevent lodging<\/div>\n  <\/div>\n  <div class=\"pm-shape-card\">\n    <span class=\"pm-shape-icon\">\u26aa<\/span>\n    <div class=\"pm-shape-name\">Sphere \/ Ball<\/div>\n    <div class=\"pm-shape-best\"><strong>Best for:<\/strong> Final burnishing stage for pre-plate brightening. No sharp edges \u2014 pure compressive\/rubbing contact for brightest aluminum surface.<\/div>\n    <div class=\"pm-shape-avoid\">Avoid: Parts requiring burr removal<\/div>\n  <\/div>\n  <div class=\"pm-shape-card\">\n    <span class=\"pm-shape-icon\">\ud83d\udd36<\/span>\n    <div class=\"pm-shape-name\">Angle-Cut Triangle<\/div>\n    <div class=\"pm-shape-best\"><strong>Best for:<\/strong> Sharp internal corners and narrow slot edges in precision aluminum components.<\/div>\n    <div class=\"pm-shape-avoid\">Avoid: Open parts with no geometry for corners to contact productively<\/div>\n  <\/div>\n  <div class=\"pm-shape-card\">\n    <span class=\"pm-shape-icon\">\ud83d\udca0<\/span>\n    <div class=\"pm-shape-name\">Ellipse \/ Ovoid<\/div>\n    <div class=\"pm-shape-best\"><strong>Best for:<\/strong> Pre-plate and pre-anodize final smoothing. Gentle rocking contact \u2014 lower edge pressure than cylinder, less micro-scratching risk.<\/div>\n    <div class=\"pm-shape-avoid\">Avoid: Heavy deburring (insufficient cutting action on thick burrs)<\/div>\n  <\/div>\n  <div class=\"pm-shape-card\">\n    <span class=\"pm-shape-icon\">\ud83c\udffa<\/span>\n    <div class=\"pm-shape-name\">Cone<\/div>\n    <div class=\"pm-shape-best\"><strong>Best for:<\/strong> Countersink edges, tapered bore openings, threaded feature lead-in chamfers in aluminum.<\/div>\n    <div class=\"pm-shape-avoid\">Avoid: Flat-bottomed features (cone tip cannot contact flat)<\/div>\n  <\/div>\n<\/div>\n\n<div class=\"pm-callout\">\n  <strong>The lodging test before production:<\/strong> Before running any new media shape with a new part, load a representative sample at the correct ratio and run for 5 minutes at normal amplitude. Stop and inspect every feature for wedged media. A shape that lodges at the test stage will lodge in production \u2014 change media size (larger, so it cannot enter the feature) or change shape entirely before committing to a full production run.\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S5 COMPOUNDS \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-compounds\">Compound Selection: Chemistry for Aluminum<\/h2>\n\n<p>In wet vibratory finishing, the liquid compound actively participates in the surface chemistry \u2014 it removes fine aluminum swarf, prevents redeposition, adjusts pH to control surface chemistry, and in burnishing applications creates a bright, uniform surface. Compound selection for aluminum has specific requirements different from steel or brass finishing.<\/p>\n\n<div class=\"pm-compound-grid\">\n  <div class=\"pm-compound-card\">\n    <h4>Alkaline Degreasing Compound<\/h4>\n    <span class=\"pm-badge pm-badge-blue\">pH 8\u201311<\/span>\n    <p style=\"margin-top:8px\">General cleaning compound. Removes machining oil, coolant, and light oxide. Must be &#8220;aluminum-safe&#8221; \u2014 highly alkaline compounds (pH &gt;12) etch aluminum rapidly. Check for &#8220;non-etching&#8221; designation.<\/p>\n  <\/div>\n  <div class=\"pm-compound-card\">\n    <h4>Neutral Burnishing Compound<\/h4>\n    <span class=\"pm-badge pm-badge-high\">pH 6.5\u20137.5<\/span>\n    <p style=\"margin-top:8px\">Mid-range finishing compound for standard deburring and Ra reduction. Lubricating film reduces friction while allowing controlled abrasive action. Good for standard anodize preparation.<\/p>\n  <\/div>\n  <div class=\"pm-compound-card\">\n    <h4>Acidic Brightening Compound<\/h4>\n    <span class=\"pm-badge pm-badge-med\">pH 3\u20135<\/span>\n    <p style=\"margin-top:8px\">Dilute acid (citric, phosphoric, or proprietary) that deburrs, cleans, and creates a bright micro-etched surface ideal for anodize or plate. Essential for gummy alloys (5052). Monitor pH to maintain effectiveness.<\/p>\n  <\/div>\n  <div class=\"pm-compound-card\">\n    <h4>Corrosion-Inhibiting Compound<\/h4>\n    <span class=\"pm-badge pm-badge-blue\">pH 7\u20139<\/span>\n    <p style=\"margin-top:8px\">Contains organic inhibitors to prevent water staining and surface oxidation between finishing and subsequent processing. Essential for parts that will sit before anodizing. Removed in anodize pre-treatment.<\/p>\n  <\/div>\n  <div class=\"pm-compound-card\">\n    <h4>Pre-Plate Bright Compound<\/h4>\n    <span class=\"pm-badge pm-badge-med\">pH 4\u20136<\/span>\n    <p style=\"margin-top:8px\">High-performance acidic compound for the final burnishing stage before electroplating. Contains brightening agents and leveling surfactants. Used with sphere or ellipse media. Short exposure \u2014 prevent over-etching.<\/p>\n  <\/div>\n  <div class=\"pm-compound-card\">\n    <h4>Dry Compound (Powder)<\/h4>\n    <span class=\"pm-badge pm-badge-silver\">Dry process<\/span>\n    <p style=\"margin-top:8px\">Burnishing powder for dry vibratory finishing where water contact is undesirable. Less effective than wet compounds for Ra reduction. Suitable for light cleaning and burnishing only.<\/p>\n  <\/div>\n<\/div>\n\n<div class=\"pm-callout pm-callout-warn\">\n  <strong>Never use steel or general-purpose ceramic compounds on aluminum:<\/strong> Compounds formulated for steel are often pH 11\u201313 to prevent rust \u2014 these will visibly etch aluminum, especially 5xxx and 6xxx series alloys. Always use compounds explicitly rated for aluminum. If the product data sheet does not state aluminum compatibility, confirm with the supplier before use.\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S6 MACHINES \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-machines\">Machine Types and When to Use Each<\/h2>\n\n<div class=\"pm-machine-wrap\">\n  <table class=\"pm-machine-table\">\n    <thead>\n      <tr>\n        <th>Machine Type<\/th>\n        <th>Best Aluminum Application<\/th>\n        <th>Ventajas<\/th>\n        <th>Limitaciones<\/th>\n        <th>Typical Cycle<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr>\n        <td>Vibratory Bowl (round)<\/td>\n        <td>General deburring, Ra reduction, pre-anodize finishing of small-to-medium parts. Most versatile machine for aluminum.<\/td>\n        <td>Gentle action; low part damage risk; easy loading\/unloading; 1\u201350 ft\u00b3 sizes<\/td>\n        <td>Slower than centrifugal; large parts limited by bowl diameter<\/td>\n        <td>30\u2013180 min<\/td>\n      <\/tr>\n      <tr>\n        <td>Vibratory Tub (linear)<\/td>\n        <td>Larger aluminum castings, extrusions, and machined housings up to 24 inches long.<\/td>\n        <td>Accommodates longer parts; continuous or batch feed; high capacity<\/td>\n        <td>Less uniform action at edges than round bowl; higher part-on-part risk with long parts<\/td>\n        <td>30\u2013120 min<\/td>\n      <\/tr>\n      <tr>\n        <td>Centrifugal Disc Finisher<\/td>\n        <td>High-volume small aluminum components: machined hardware, small die castings, turned parts.<\/td>\n        <td>5\u201320\u00d7 faster than vibratory; excellent consistency; tight cycle times<\/td>\n        <td>Higher part-on-part collision risk; not for thin-wall or fragile aluminum; higher capital<\/td>\n        <td>5\u201330 min<\/td>\n      <\/tr>\n      <tr>\n        <td>Centrifugal Barrel<\/td>\n        <td>Precision aluminum parts requiring tight Ra specification and controlled edge radius. Aerospace, orthopaedic.<\/td>\n        <td>Highest consistency; very uniform media pressure; excellent Ra control<\/td>\n        <td>Smallest batch size; highest capital cost per unit capacity; slower loading<\/td>\n        <td>20\u201360 min<\/td>\n      <\/tr>\n      <tr>\n        <td>Drag \/ Spindle Finisher<\/td>\n        <td>Individual high-value aluminum components: turbine blades, medical devices, optical housings.<\/td>\n        <td>Each part individually fixtured; best for complex 3D geometry; most controlled process<\/td>\n        <td>Very low throughput (1 part per cycle); expensive fixturing; not economical for volume<\/td>\n        <td>3\u201320 min per part<\/td>\n      <\/tr>\n      <tr>\n        <td>Barrel Tumbler<\/td>\n        <td>Robust aluminum parts, simple deburring, low-volume operations where cycle time is not critical.<\/td>\n        <td>Lowest capital cost; simple operation<\/td>\n        <td>Highest part-on-part damage risk; slowest and least consistent; not for precision aluminum<\/td>\n        <td>60\u2013480 min<\/td>\n      <\/tr>\n    <\/tbody>\n  <\/table>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S7 SEQUENCES \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-sequences\">Multi-Stage Finishing Sequences<\/h2>\n\n<p>The highest-quality aluminum finishing results are rarely achieved in a single process step. Most applications requiring cosmetically consistent surfaces for anodizing, plating, or Class-A appearance use a defined multi-stage sequence where each stage accomplishes a specific finishing objective, and the output of each stage is the correctly prepared input for the next.<\/p>\n\n<h3>Sequence A: Deburr-to-Anodize (Most Common)<\/h3>\n\n<div class=\"pm-seq-flow\">\n  <div class=\"pm-seq-step\">\n    <div class=\"pm-seq-left\">\n      <div class=\"pm-seq-dot\" style=\"background:#334155\">1<\/div>\n      <div class=\"pm-seq-line\"><\/div>\n    <\/div>\n    <div class=\"pm-seq-body\">\n      <h4>Heavy Deburr<\/h4>\n      <p>Remove all machining burrs, die cast flash, and sharp edges. Target: burr-free edges with initial Ra reduction from as-machined condition.<\/p>\n      <div class=\"pm-seq-params\">Angle-cut cylinder or triangle plastic media \u00b7 Alkaline degreasing compound \u00b7 Standard amplitude \u00b7 30\u201360 min<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-seq-step\">\n    <div class=\"pm-seq-left\">\n      <div class=\"pm-seq-dot\" style=\"background:#475569\">2<\/div>\n      <div class=\"pm-seq-line\"><\/div>\n    <\/div>\n    <div class=\"pm-seq-body\">\n      <h4>Ra Reduction<\/h4>\n      <p>Progressive surface smoothing from post-deburr Ra to target pre-anodize Ra. Removes coarser texture left by Stage 1 and produces more uniform micro-topography that anodizes evenly.<\/p>\n      <div class=\"pm-seq-params\">Fine plastic cylinder or ellipse \u00b7 Acidic brightening compound \u00b7 45\u201390 min \u00b7 Rinse between stages<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-seq-step\">\n    <div class=\"pm-seq-left\">\n      <div class=\"pm-seq-dot\" style=\"background:#64748b\">3<\/div>\n      <div class=\"pm-seq-line\"><\/div>\n    <\/div>\n    <div class=\"pm-seq-body\">\n      <h4>Final Rinse and Inspection<\/h4>\n      <p>Thorough rinse with clean water removes all compound residue and aluminum swarf. Do not allow parts to dry with compound film. Inspect for any remaining burrs before transferring to anodize.<\/p>\n      <div class=\"pm-seq-params\">DI water preferred for anodize-bound parts \u00b7 Transfer within 4\u20138 hours \u00b7 Handle with clean gloves only<\/div>\n    <\/div>\n  <\/div>\n<\/div>\n\n<h3>Sequence B: Full Pre-Plate Brightening (Highest Quality)<\/h3>\n\n<div class=\"pm-seq-flow\">\n  <div class=\"pm-seq-step\">\n    <div class=\"pm-seq-left\">\n      <div class=\"pm-seq-dot\" style=\"background:#1e3a8a\">1<\/div>\n      <div class=\"pm-seq-line\"><\/div>\n    <\/div>\n    <div class=\"pm-seq-body\">\n      <h4>Aggressive Deburr<\/h4>\n      <p>Full burr removal with coarse plastic media and alkaline compound. Target Ra at end of stage: 60\u2013120 \u00b5in.<\/p>\n      <div class=\"pm-seq-params\">Angle-cut cylinder, coarse \u00b7 Alkaline compound \u00b7 30\u201345 min<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-seq-step\">\n    <div class=\"pm-seq-left\">\n      <div class=\"pm-seq-dot\" style=\"background:#1d4ed8\">2<\/div>\n      <div class=\"pm-seq-line\"><\/div>\n    <\/div>\n    <div class=\"pm-seq-body\">\n      <h4>Medium Smooth<\/h4>\n      <p>Transition from coarse surface texture to medium-smooth. Removes Stage 1 media marks, uniformizes surface topography across all part faces.<\/p>\n      <div class=\"pm-seq-params\">Fine cylinder or ellipse \u00b7 Neutral compound \u00b7 45\u201360 min \u00b7 Rinse between stages<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-seq-step\">\n    <div class=\"pm-seq-left\">\n      <div class=\"pm-seq-dot\" style=\"background:#2563eb\">3<\/div>\n      <div class=\"pm-seq-line\"><\/div>\n    <\/div>\n    <div class=\"pm-seq-body\">\n      <h4>Fine Smooth<\/h4>\n      <p>Aggressive Ra reduction using finest available plastic media with acidic brightening compound. Target Ra: 16\u201332 \u00b5in. No visible machining marks under 10\u00d7 inspection.<\/p>\n      <div class=\"pm-seq-params\">Very fine plastic cylinder or sphere \u00b7 Acidic brightening compound \u00b7 60\u201390 min \u00b7 Rinse<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-seq-step\">\n    <div class=\"pm-seq-left\">\n      <div class=\"pm-seq-dot\" style=\"background:#3b82f6\">4<\/div>\n      <div class=\"pm-seq-line\"><\/div>\n    <\/div>\n    <div class=\"pm-seq-body\">\n      <h4>Burnish<\/h4>\n      <p>Final compressive burnishing with smooth spherical plastic media and pre-plate brightening compound. Achieves sub-microinch Ra. Surface appears semi-bright to bright.<\/p>\n      <div class=\"pm-seq-params\">Plastic spheres or ellipses \u00b7 Pre-plate bright compound \u00b7 30\u201360 min \u00b7 Transfer to plate line immediately after rinse<\/div>\n    <\/div>\n  <\/div>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S8 SURFACE FINISH \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-surface\">Surface Finish Ra Targets by Application<\/h2>\n\n<div class=\"pm-surface-grid\">\n  <div class=\"pm-surface-card\">\n    <div class=\"pm-surface-stage\">As-Machined Baseline<\/div>\n    <div class=\"pm-surface-ra\">63\u2013250<\/div>\n    <div class=\"pm-surface-unit\">\u00b5in Ra<\/div>\n    <div class=\"pm-surface-desc\">Typical turned or milled aluminum. Tool marks clearly visible. Starting point before any tumbling.<\/div>\n  <\/div>\n  <div class=\"pm-surface-card\">\n    <div class=\"pm-surface-stage\">After Stage 1 Deburr<\/div>\n    <div class=\"pm-surface-ra\">32\u2013125<\/div>\n    <div class=\"pm-surface-unit\">\u00b5in Ra<\/div>\n    <div class=\"pm-surface-desc\">Burrs removed. Surface uniformized. Suitable for powder coat (industrial) or primer.<\/div>\n  <\/div>\n  <div class=\"pm-surface-card\">\n    <div class=\"pm-surface-stage\">Standard Anodize Ready<\/div>\n    <div class=\"pm-surface-ra\">16\u201332<\/div>\n    <div class=\"pm-surface-unit\">\u00b5in Ra<\/div>\n    <div class=\"pm-surface-desc\">2-stage finish. Clean, uniform surface. Clear or color anodize will be cosmetically consistent.<\/div>\n  <\/div>\n  <div class=\"pm-surface-card\">\n    <div class=\"pm-surface-stage\">Architectural \/ Cosmetic Anodize<\/div>\n    <div class=\"pm-surface-ra\">8\u201316<\/div>\n    <div class=\"pm-surface-unit\">\u00b5in Ra<\/div>\n    <div class=\"pm-surface-desc\">3-stage finish. Consistent, smooth surface for premium architectural or consumer-facing anodize.<\/div>\n  <\/div>\n  <div class=\"pm-surface-card\">\n    <div class=\"pm-surface-stage\">Pre-Electroplate<\/div>\n    <div class=\"pm-surface-ra\">4\u201316<\/div>\n    <div class=\"pm-surface-unit\">\u00b5in Ra<\/div>\n    <div class=\"pm-surface-desc\">4-stage burnish sequence. Sub-microinch for nickel \/ chrome plate. Surface appears bright.<\/div>\n  <\/div>\n  <div class=\"pm-surface-card\">\n    <div class=\"pm-surface-stage\">Bearing \/ Sealing Surface<\/div>\n    <div class=\"pm-surface-ra\">4\u20138<\/div>\n    <div class=\"pm-surface-unit\">\u00b5in Ra<\/div>\n    <div class=\"pm-surface-desc\">Maximum quality burnish + profilometer verification. Consistent Ra matters more than absolute value for sealing.<\/div>\n  <\/div>\n<\/div>\n\n<div class=\"pm-table-wrap\">\n  <table>\n    <thead>\n      <tr>\n        <th>Final Application<\/th>\n        <th>Target Ra (\u00b5in)<\/th>\n        <th>Stages Needed<\/th>\n        <th>Final Stage Media<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr>\n        <td>Powder coat (industrial)<\/td>\n        <td>32\u2013125<\/td>\n        <td>1 (deburr only)<\/td>\n        <td>Angle-cut cylinder<\/td>\n      <\/tr>\n      <tr>\n        <td>Liquid paint (automotive \/ consumer)<\/td>\n        <td>16\u201363<\/td>\n        <td>1\u20132<\/td>\n        <td>Fine cylinder + neutral compound<\/td>\n      <\/tr>\n      <tr>\n        <td>Standard anodize (clear or color)<\/td>\n        <td>16\u201332<\/td>\n        <td>2<\/td>\n        <td>Fine cylinder + acidic compound<\/td>\n      <\/tr>\n      <tr>\n        <td>Architectural \/ cosmetic anodize<\/td>\n        <td>8\u201316<\/td>\n        <td>2\u20133<\/td>\n        <td>Fine ellipse + brightening compound<\/td>\n      <\/tr>\n      <tr>\n        <td>Hard anodize (Type III)<\/td>\n        <td>16\u201332<\/td>\n        <td>2<\/td>\n        <td>Fine cylinder \u2014 note: hard coat amplifies Ra ~2\u00d7<\/td>\n      <\/tr>\n      <tr>\n        <td>Nickel or chrome electroplate<\/td>\n        <td>4\u201316<\/td>\n        <td>3\u20134<\/td>\n        <td>Plastic sphere\/ellipse + pre-plate bright compound<\/td>\n      <\/tr>\n      <tr>\n        <td>Sealing \/ gasket interface<\/td>\n        <td>16\u201332<\/td>\n        <td>2<\/td>\n        <td>Fine cylinder; Ra consistency more important than absolute value<\/td>\n      <\/tr>\n      <tr>\n        <td>Bearing surface \/ sliding interface<\/td>\n        <td>4\u20138<\/td>\n        <td>3\u20134<\/td>\n        <td>Fine plastic + final burnish; validate with profilometer<\/td>\n      <\/tr>\n    <\/tbody>\n  <\/table>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S9 ANODIZE \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-anodize\">Preparing Aluminum for Anodizing<\/h2>\n\n<p>The relationship between plastic tumbling media finishing and anodizing is one of the most important topics in aluminum parts finishing, because the surface condition delivered by the finishing process determines the cosmetic quality and consistency of the anodize layer in ways that the anodizing process itself cannot correct.<\/p>\n\n<h3>Why Pre-Anodize Surface Condition Matters<\/h3>\n<p>Anodizing is an electrochemical process that converts the aluminum surface into aluminum oxide (Al\u2082O\u2083) in a controlled acid bath. The anodize layer grows from the aluminum surface outward and inward simultaneously \u2014 roughly half the thickness penetrates into the original aluminum, half builds above it. This growth mechanism means that every surface feature present before anodizing \u2014 every scratch, tool mark, smear, contamination spot, and Ra variation \u2014 is faithfully reproduced and often optically amplified in the anodize layer. Scratches visible at 10\u00d7 magnification before anodize become clearly visible to the naked eye after anodize on cosmetic parts. Aluminum swarf smeared onto the surface by ceramic finishing media shows as dark spots in the anodize \u2014 different oxide growth rate, different shade.<\/p>\n\n<h3>What Plastic Tumbling Media Provides for Anodize<\/h3>\n<p>The combination of fine plastic tumbling media and aluminum-specific acidic brightening compound produces a surface that is: uniformly Ra-matched across all faces with no patchwork zones from different cutting operations; free of directional tool marks that telegraph through thin anodize; free of iron contamination from media that would create dark spots in the anodize bath; and clean of machining oil and coolant residue that would cause adhesion failure or uneven coating.<\/p>\n\n<h3>The Pre-Anodize Timing Window<\/h3>\n<p>After plastic tumbling media finishing, transfer freshly finished aluminum parts to the anodize facility within 4\u20138 hours of completing the tumbling process and final rinse. Do not handle bare finished aluminum surfaces with ungloved hands. Package in clean poly bags or VCI paper if there will be any delay. For best results on architectural or cosmetic anodize, use deionized water for the final rinse \u2014 hard water minerals deposit on the aluminum surface and create white haze after anodizing.<\/p>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S10 PLATE \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-plate\">Preparing Aluminum for Plating<\/h2>\n\n<p>Electroplating aluminum requires a specialized adhesion layer (typically zincate treatment or electroless nickel strike) between the aluminum and the electroplated deposit, because aluminum&#8217;s native oxide layer prevents direct electrochemical bonding. The plastic tumbling media preparation for plated aluminum must therefore deliver a surface that is clean, uniformly Ra-matched, and free of any contamination that would cause the zincate adhesion layer to form non-uniformly.<\/p>\n\n<p>Non-uniform zincate leads to plating adhesion failures \u2014 blistering, peeling, and picture-framing (poor adhesion at part edges) \u2014 that are expensive to diagnose and correct after plating. The four-stage burnishing sequence (Sequence B) is the minimum pre-treatment for decorative electroplating on aluminum. The final Ra target of 4\u201316 \u00b5in is necessary because thin decorative plates (nickel at 0.0002 inch, chrome at 0.0001 inch) conform precisely to the substrate surface, and every imperfection in the substrate appears as an imperfection in the final plated surface.<\/p>\n\n<div class=\"pm-callout pm-callout-blue\">\n  <strong>30-minute timing window for pre-plate aluminum:<\/strong> Transfer parts from the final burnishing rinse to the plating line&#8217;s first pre-treatment tank within 30 minutes. Freshly burnished aluminum re-oxidizes within seconds in air. Parts that sit for hours between finishing and plating require additional etching at the plating line that may compromise the Ra achieved in finishing. Have the plating line pre-treatment sequence ready before the final tumbling stage completes.\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S11 PROCESS SETUP \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-process\">Process Setup and Operating Parameters<\/h2>\n\n<div class=\"pm-table-wrap\">\n  <table>\n    <thead>\n      <tr>\n        <th>Par\u00e1metro<\/th>\n        <th>Light Deburr \/ Clean<\/th>\n        <th>Standard Deburr + Ra<\/th>\n        <th>Pre-Anodize<\/th>\n        <th>Pre-Plate Burnish<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr>\n        <td>Media type<\/td>\n        <td>Fine plastic cylinder or ellipse<\/td>\n        <td>Medium plastic cylinder or angle-cut<\/td>\n        <td>Fine plastic cylinder \u2192 ellipse<\/td>\n        <td>Fine plastic \u2192 plastic sphere<\/td>\n      <\/tr>\n      <tr>\n        <td>Media-to-part ratio (volume)<\/td>\n        <td>5:1 to 8:1<\/td>\n        <td>3:1 to 5:1<\/td>\n        <td>5:1 to 8:1<\/td>\n        <td>8:1 to 12:1<\/td>\n      <\/tr>\n      <tr>\n        <td>Compound type<\/td>\n        <td>Alkaline degreasing<\/td>\n        <td>Neutral or alkaline<\/td>\n        <td>Acidic brightening<\/td>\n        <td>Pre-plate bright (acidic)<\/td>\n      <\/tr>\n      <tr>\n        <td>Machine amplitude<\/td>\n        <td>Low (50\u201360% of max)<\/td>\n        <td>Medium (60\u201375% of max)<\/td>\n        <td>Low-medium (50\u201365%)<\/td>\n        <td>Low (40\u201355% \u2014 gentle burnish)<\/td>\n      <\/tr>\n      <tr>\n        <td>Cycle time<\/td>\n        <td>15\u201330 min<\/td>\n        <td>30\u201390 min<\/td>\n        <td>45\u2013120 min per stage<\/td>\n        <td>30\u201360 min (final stage)<\/td>\n      <\/tr>\n      <tr>\n        <td>Water temperature<\/td>\n        <td>Ambient<\/td>\n        <td>Ambient or 100\u2013110\u00b0F<\/td>\n        <td>Ambient (acidic compound more effective cool)<\/td>\n        <td>Ambient to slightly warm<\/td>\n      <\/tr>\n    <\/tbody>\n  <\/table>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S12 RATIO \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-ratio\">Media-to-Part Ratio and Loading<\/h2>\n\n<p>The media-to-part ratio \u2014 ratio of media volume to part volume in the machine \u2014 directly controls finishing rate, uniformity, and part-on-part damage risk. At low ratios (below 2:1), insufficient media between parts causes direct part-on-part contact. For aluminum, which is soft and easily dented, this creates impact marks worse cosmetically than the original surface condition. At high ratios (above 10:1), the process becomes gentler but slower \u2014 ideal for burnishing, but inefficient for deburring.<\/p>\n\n<div class=\"pm-table-wrap\">\n  <table>\n    <thead>\n      <tr>\n        <th>Application \/ Part Type<\/th>\n        <th>Recommended Ratio<\/th>\n        <th>Raz\u00f3n<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr>\n        <td>Robust die castings, heavy deburr<\/td>\n        <td>3:1 to 4:1<\/td>\n        <td>Higher contact rate; casting tolerates vigorous action; throughput priority<\/td>\n      <\/tr>\n      <tr>\n        <td>Machined aluminum housings, standard deburr<\/td>\n        <td>4:1 to 6:1<\/td>\n        <td>Balance of speed and part protection; typical starting ratio for new applications<\/td>\n      <\/tr>\n      <tr>\n        <td>Thin-wall aluminum extrusions<\/td>\n        <td>6:1 to 8:1<\/td>\n        <td>Thin walls distort easily; high media ratio cushions part-on-part contact<\/td>\n      <\/tr>\n      <tr>\n        <td>Pre-anodize smoothing, precision parts<\/td>\n        <td>6:1 to 8:1<\/td>\n        <td>Gentle progressive action; avoid any impact marks on anodize-bound parts<\/td>\n      <\/tr>\n      <tr>\n        <td>Pre-plate burnishing, high-value parts<\/td>\n        <td>8:1 to 12:1<\/td>\n        <td>Maximum part protection; gentlest action; parts too valuable to risk any contact damage<\/td>\n      <\/tr>\n      <tr>\n        <td>Small precision turned parts (&lt;25 mm)<\/td>\n        <td>8:1 to 15:1<\/td>\n        <td>Very small parts at low ratio tumble erratically and impact each other; high ratio stabilizes movement<\/td>\n      <\/tr>\n    <\/tbody>\n  <\/table>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S13 CONTROL \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-control\">Process Control: Monitoring and Adjustment<\/h2>\n\n<div class=\"pm-control-grid\">\n  <div class=\"pm-control-card\">\n    <span class=\"pm-control-icon\">\ud83d\udccf<\/span>\n    <h4>Ra Measurement<\/h4>\n    <p>Measure surface Ra at defined check intervals (end of each stage or every 30 minutes). Record at the same part location each time. If Ra is not decreasing at expected rate, check compound pH, media condition, and machine amplitude before extending cycle time.<\/p>\n  <\/div>\n  <div class=\"pm-control-card\">\n    <span class=\"pm-control-icon\">\ud83e\uddea<\/span>\n    <h4>Compound pH Monitoring<\/h4>\n    <p>Check pH at shift start and midpoint of long cycles. Acidic brightening compounds are consumed during processing \u2014 pH rises as aluminum dissolves, reducing effectiveness. Top up per manufacturer protocol. Log pH trends over time.<\/p>\n  <\/div>\n  <div class=\"pm-control-card\">\n    <span class=\"pm-control-icon\">\ud83d\udce6<\/span>\n    <h4>Media Wear Monitoring<\/h4>\n    <p>Measure media piece dimensions monthly. Replace when dimension has reduced more than 30% from original \u2014 smaller pieces lodge more easily and provide less effective edge radiusing. Top-up with 10\u201320% fresh media to extend charge life.<\/p>\n  <\/div>\n  <div class=\"pm-control-card\">\n    <span class=\"pm-control-icon\">\u26a1<\/span>\n    <h4>Machine Amplitude Check<\/h4>\n    <p>Verify amplitude at shift start with calibrated vibration meter at the bowl rim. Amplitude drift from worn eccentric weights or spring fatigue changes the contact energy and alters Ra reduction rate. Service when amplitude varies more than \u00b110% from qualified value.<\/p>\n  <\/div>\n  <div class=\"pm-control-card\">\n    <span class=\"pm-control-icon\">\ud83d\udca7<\/span>\n    <h4>Water Quality<\/h4>\n    <p>For pre-anodize and pre-plate applications, use deionized or reverse-osmosis water for compound dilution and final rinse. Hard water leaves calcium and magnesium deposits that show as white haze after anodizing. Target &lt;50 \u00b5S\/cm conductivity for final rinse on anodize-bound parts.<\/p>\n  <\/div>\n  <div class=\"pm-control-card\">\n    <span class=\"pm-control-icon\">\ud83d\udccb<\/span>\n    <h4>First Article Inspection<\/h4>\n    <p>Inspect the first parts removed after one complete cycle: check burr removal completeness, Ra match to target, absence of part-on-part damage marks, and no media lodging. Document results vs. the qualification baseline before committing the full batch.<\/p>\n  <\/div>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S14 PROBLEMS \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-problems\">Problemas comunes y soluciones<\/h2>\n\n<div class=\"pm-table-wrap\">\n  <table>\n    <thead>\n      <tr>\n        <th>Problem<\/th>\n        <th>Most Likely Cause<\/th>\n        <th>Soluci\u00f3n<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr>\n        <td>Aluminum smearing on part surface (gray\/dark smudges)<\/td>\n        <td>Media too aggressive for alloy softness; compound pH too high; insufficient compound flow allowing swarf re-deposition<\/td>\n        <td>Switch to finer plastic media; change to acidic brightening compound that keeps aluminum swarf in suspension; increase compound flow rate. Critical for 5052 alloy.<\/td>\n      <\/tr>\n      <tr>\n        <td>Part-on-part impact marks (dents, scratches)<\/td>\n        <td>Media-to-part ratio too low; machine amplitude too high; batch overloaded<\/td>\n        <td>Increase ratio to minimum 5:1; reduce amplitude 10\u201315%; reduce batch load by 20%. Add separator media (non-abrasive plastic pieces) for delicate parts.<\/td>\n      <\/tr>\n      <tr>\n        <td>Media lodging in part features<\/td>\n        <td>Media piece size too small relative to feature opening; incorrect shape for geometry<\/td>\n        <td>Increase media piece size so it cannot enter the feature; change to a shape designed not to lodge. Verify with lodging test before production run.<\/td>\n      <\/tr>\n      <tr>\n        <td>Inconsistent Ra across part faces<\/td>\n        <td>Complex geometry creating unequal media contact on different faces; cycle time insufficient<\/td>\n        <td>Extend cycle time; use a combination of two media shapes with complementary geometry reach. For critical parts, use drag\/spindle finishing for individual part control.<\/td>\n      <\/tr>\n      <tr>\n        <td>Burrs remaining after full cycle<\/td>\n        <td>Burrs too large for media cutting action; media too fine; amplitude too low<\/td>\n        <td>Increase amplitude; extend cycle time; switch to angle-cut cylinder shape. For very large burrs, hand-remove gross flash before tumbling.<\/td>\n      <\/tr>\n      <tr>\n        <td>Water staining after rinse (white film)<\/td>\n        <td>High mineral content in rinse water; parts allowed to dry slowly in still air<\/td>\n        <td>Use DI or RO water for final rinse; dry with compressed air immediately after rinse; add dilute citric acid rinse step before final DI rinse if staining persists.<\/td>\n      <\/tr>\n      <tr>\n        <td>Mottled appearance after anodize despite good pre-finish<\/td>\n        <td>Iron contamination from non-plastic media contact; fingerprints on finished parts; 7075 alloy variability<\/td>\n        <td>Verify no steel tooling contact after tumbling; handle with clean gloves only; evaluate alloy batch consistency. 7075 inherently shows some anodize mottling \u2014 set appropriate acceptance criteria.<\/td>\n      <\/tr>\n      <tr>\n        <td>Ra target not achieved within expected cycle time<\/td>\n        <td>Media worn below effective cutting size; compound depleted; amplitude drift; starting Ra higher than expected<\/td>\n        <td>Check media size vs. wear limit; measure and replenish compound; verify amplitude calibration; measure starting Ra \u2014 variation between production lots significantly affects finishing time.<\/td>\n      <\/tr>\n    <\/tbody>\n  <\/table>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 S15 FAQ \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"al-faq\">Preguntas frecuentes<\/h2>\n\n<div itemscope itemtype=\"https:\/\/schema.org\/FAQPage\">\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">Can plastic tumbling media be used on aluminum parts with anodize already applied?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">Plastic tumbling media can be used on anodized aluminum for very light cleaning and burnishing, but it cannot remove or significantly modify the anodize layer. Anodize (aluminum oxide, Al\u2082O\u2083) has a Mohs hardness of approximately 9 \u2014 far harder than any plastic tumbling media. Plastic media can only polish the surface of the anodize and remove light contamination. If you need to remove anodize for rework or re-anodizing, chemical stripping with sodium hydroxide or phosphoric acid solutions is required. For simply restoring gloss or cleaning an anodized surface without removing the coating, fine plastic burnishing media with a neutral or mildly acidic compound is appropriate and effective.<\/p>\n    <\/div>\n  <\/div>\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">How do I prevent impact marks when finishing cosmetic aluminum parts in a vibratory bowl?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">Part-on-part contact marks on aluminum are prevented through three techniques used together: first, maintain a media-to-part ratio of at least 5:1 \u2014 sufficient media between parts prevents direct contact; second, use separator media \u2014 non-abrasive plastic pieces mixed into the batch to physically space parts within the media mass; third, reduce machine amplitude to the minimum that still achieves the required finishing action, since higher amplitude increases part velocity through the media and therefore impact energy when contact occurs. For very high-value parts where any mark is unacceptable, drag or spindle finishing \u2014 where each part is individually fixtured and drawn through stationary media \u2014 eliminates part-on-part contact entirely at the cost of lower throughput.<\/p>\n    <\/div>\n  <\/div>\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">What is the difference between plastic tumbling media and ceramic tumbling media for aluminum finishing?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">The fundamental difference is hardness and contamination risk. Ceramic media operates at Mohs 6\u20139, far above aluminum&#8217;s Mohs 2.5\u20133.5. This hardness mismatch means ceramic media cuts aluminum aggressively \u2014 faster deburring, but greater risk of scratching, smearing of aluminum into surface features, and ceramic particle embedment in the soft aluminum. Embedded ceramic particles create pitting and adhesion problems in anodize baths. Plastic tumbling media at Mohs 2.5\u20134.0 cuts more gently and uniformly, with no particle embedment risk and no iron contamination. For aluminum parts destined for anodizing, plating, or cosmetically sensitive finishing, plastic media is almost always the correct choice. Ceramic media may be justified for rapid rough deburring of robust die castings where speed is the priority, with plastic media used in subsequent stages.<\/p>\n    <\/div>\n  <\/div>\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">How long does plastic tumbling media last when processing aluminum, and when should I replace it?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">Plastic tumbling media life in aluminum finishing is measured in months to years \u2014 far longer than blast media which fractures per cycle. Media wears gradually as pieces reduce in size through contact with parts and other media. The wear rate depends on compound aggressiveness (acidic compounds accelerate media wear), machine amplitude, and part hardness. Replace media when average piece size has reduced by 30\u201340% from original dimensions \u2014 at this point, pieces lodge more easily in part features, provide less effective edge radiusing geometry, and deliver inconsistent results. The practical production signal: if cycle time must be increased significantly to achieve the same Ra target as before, check media wear first. Top-up with 10\u201320% new media periodically to extend the charge before full replacement is needed.<\/p>\n    <\/div>\n  <\/div>\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">Can I use the same plastic tumbling media for both aluminum and steel parts?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">Using the same plastic tumbling media for both aluminum and steel parts is strongly inadvisable for any aluminum that will be anodized, plated, or used in a corrosion-sensitive application. When plastic media processes steel parts, microscopic iron particles from the steel surface transfer to and become embedded in the media pieces. When that same media then processes aluminum, iron particles transfer to the aluminum surface, creating galvanic corrosion sites and anodize adhesion problems that appear as dark spots, pitting, or mottling. Maintain dedicated media sets for aluminum and for ferrous metal processing and never cross-contaminate them. If your operation processes both materials, the investment in separate media charges protects product quality in a way that shared media cannot \u2014 and aluminum, being softer than steel, wears media less aggressively, so the aluminum-dedicated media set will last significantly longer.<\/p>\n    <\/div>\n  <\/div>\n\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Plastic Tumbling Media for Aluminum Parts Finishing Aluminum is the  [&#8230;]<\/p>","protected":false},"author":1,"featured_media":12333,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[62,177,138],"tags":[],"class_list":["post-12323","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-material","category-resource"],"_links":{"self":[{"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/posts\/12323","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/comments?post=12323"}],"version-history":[{"count":3,"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/posts\/12323\/revisions"}],"predecessor-version":[{"id":12404,"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/posts\/12323\/revisions\/12404"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/media\/12333"}],"wp:attachment":[{"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/media?parent=12323"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/categories?post=12323"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hlh-js.com\/es\/wp-json\/wp\/v2\/tags?post=12323"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}