Nylon (polyamide) is one of the most demanding materials to grind in the plastics industry. Its combination of high hardness, abrasiveness, moisture sensitivity, and susceptibility to thermal oxidation places demands on a grinding system that few materials match. Yet nylon powder — particularly from PA6, PA66, PA11, and PA12 — commands a significant premium in powder coating, sintering, and additive manufacturing markets precisely because it is difficult to produce to specification.
Nylon powder coating is a multi-billion-dollar market. Applied via fluidized bed or electrostatic spray and then fused in an oven, nylon coatings provide exceptional abrasion resistance, chemical resistance, and low friction — protecting everything from dishwasher racks to automotive underbody components. The powder must meet strict specifications for particle size (typically 60–120 mesh depending on coating thickness), particle morphology (near-spherical for flow, angular for mechanical adhesion), and thermal stability (no yellowing or oxidation during the coating fusion cycle).
Nylon's hardness — Shore D 70–80, with tensile strength of 60–85 MPa — translates directly to grinding difficulty. The material resists fracture and abrades the grinding surfaces. Without proper disc material and cooling, nylon grinding can degrade the powder (oxidation yellowing), wear out the grinder (accelerated disc consumption), or both. The SMF series from Chenxing Machinery addresses these challenges with wear-resistant discs, dual cooling for oxidation prevention, and precision particle size control.
| Parameter | SMF-400 | SMF-500 | SMF-600 | SMF-800 |
|---|---|---|---|---|
| Disc Diameter | 400mm | 510mm | 600mm | 800mm |
| Discs | 2 | 2 | 2 | 2 |
| Vibrating Screen Diameter | 800mm | 800mm | 1200mm | 1200mm |
| Main Motor Speed | 3700 RPM | 3800 RPM | 2950 RPM | 3000 RPM |
| Main Motor Power | 30kW | 37kW | 45kW | 75kW |
| Blower Power | 4kW | 5.5kW | 7.5kW | 11kW |
| Air-Lock Valve Power | 0.75kW | 1.1kW | 1.1kW | 1.5kW |
| Capacity (Nylon) | 60–100 kg/h | 120–220 kg/h | 150–300 kg/h | 250–450 kg/h |
| Dimensions (L×W×H) | 3200×2000×3600 | 3500×2200×3850 | 3500×2200×3600 | 3200×2500×3900 |
| Weight | 1400kg | 1500kg | 1800kg | 2800kg |
Nylon throughput is at 40–80 mesh with well-dried and cooled material. Glass-filled or mineral-filled nylon significantly reduces throughput and increases disc wear. Capacity assumes unfilled, properly conditioned material.
| Nylon Application | Typical Throughput | Recommended Model | Special Consideration |
|---|---|---|---|
| Lab / small powder coating | 50–80 kg/h | SMF-400 | Adequate for R&D and small-batch |
| Medium powder coating / sintering | 100–180 kg/h | SMF-500 | Best balance for specialty nylon powder |
| Commercial powder production | 150–280 kg/h | SMF-600 | For dedicated powder coating supply |
| High-volume glass-filled PA compounding | 250–450 kg/h | SMF-800 | Required for abrasive filled grades |
Nylon's hardness makes it a double threat during grinding: the material resists size reduction and simultaneously wears the grinding surfaces. The SMF series addresses both challenges.
Step 1 — Pre-Conditioning: Nylon is hygroscopic (PA6 absorbs up to 9% moisture at saturation). While moisture does not cause hydrolytic degradation in nylons as it does in PET, moisture-plasticized nylon is softer and tougher — harder to grind. Pre-drying with an STG-U hopper drier at 80°C for 2–4 hours (PA6) or 80–90°C for 4 hours (PA66) dries the material to <0.2% moisture, restoring its hardness and brittleness for efficient grinding.
Step 2 — Metered Feeding: Dried nylon pellets or pre-crushed scrap enter through a screw feeder. Nylon's hardness means the motor draws significant current under load — consistent feeding prevents current spikes.
Step 3 — High-Torque Grinding: The SMF's motor delivers the sustained torque to fracture nylon. The SMF-800's 75kW motor and large-diameter discs provide the grinding surface area and torque required for commercial throughput.
Step 4 — Critical Cooling: Nylon oxidizes (yellows) at temperatures above approximately 150°C in the presence of oxygen. The SMF's dual cooling circuit — air for chamber ambient, water for disc surface — keeps the grinding zone below this threshold. For nylon, cooling serves two purposes: preventing yellowing (quality) and maintaining the material in its hard, brittle state (efficiency).
Step 5 — Precision Screening: A vibrating screen classifies powder. For powder coating, 60–120 mesh is typical. Oversize returns for regrinding.
Step 6 — Moisture-Protected Collection: Dry nylon powder re-absorbs moisture rapidly. Collection into sealed containers or immediate packaging preserves the dry state.
Feature: Disc tooth geometry and alloy specifically designed for the high hardness and abrasive wear regime of nylon (PA6/PA66/PA12).
Advantage: Nylon is among the most abrasive unfilled thermoplastics. Its hardness (Shore D 70–80) and high tensile strength subject disc teeth to both abrasive wear (material removal) and impact fatigue (micro-cracking from repeated impact). Standard disc materials that serve well in PE or PP service wear 2–4x faster in nylon service. The SMF's nylon-duty disc alloy is formulated for combined abrasion resistance and impact toughness.
Benefit: Disc life of 400–800 hours in unfilled nylon service — versus 200–400 hours with standard discs. For a nylon powder coating supplier producing 5 tons per day, extending disc life from 300 to 600 hours saves 5–8 disc changes per year, each representing 4–6 hours of downtime plus the cost of replacement discs. This single advantage can save $15,000–25,000 annually in combined spare parts and production time.
Feature: Dual air + water cooling that maintains grinding zone temperature below 150°C — the threshold for nylon thermal oxidation in air.
Advantage: Nylon powder that has yellowed during grinding is rejected by powder coating customers because the yellow color indicates thermal degradation that compromises both aesthetics (visible yellow tint in clear or light-colored coatings) and performance (reduced molecular weight, lower impact strength, poorer chemical resistance). A grinder that allows the material to overheat produces powder that is unsellable at full price — or unsellable at all. The SMF's dual cooling prevents any oxidation.
Benefit: White, non-yellowed nylon powder that meets powder coating color specifications. Full market price for every kilogram produced. No customer returns for thermal degradation. For powder coating powder, where price premiums over pellet feedstock are $2–5/kg, every kilogram of saleable powder directly contributes to margin.
Feature: Adjustable disc gap with feeler-gauge precision, combined with interchangeable screen mesh, providing independent control over particle size distribution.
Advantage: Nylon powder coating specifications vary by application: fluidized bed coating uses 60–100 mesh powder (thick, durable coatings); electrostatic spray uses 80–140 mesh (thin, uniform coatings); sintering (SLS, MJF 3D printing) uses 40–80 mesh with tight particle size distribution. The SMF's two-point size control (gap + screen) enables targeting each specification without disc changes.
Benefit: One machine serves multiple nylon powder markets. Fast specification changes (change the screen, adjust the gap — under 15 minutes). Reduced inventory of dedicated machines for different powder specifications.
Feature: SMF feeds from an STG-U hopper drier, establishing a continuous dry-to-grind workflow.
Advantage: Moisture-plasticized nylon is softer and tougher than dry nylon. It absorbs more impact energy through deformation and grinds at 20–30% lower throughput. Pre-drying restores the material to its hard, brittle state, maximizing grinding efficiency. Additionally, dry nylon powder flows better and resists clumping during storage — important for powder coating customers who pneumatically convey and fluidize the powder.
Benefit: Consistent throughput — not the 20–30% variation between humid-season and dry-season operation. Better powder flowability for customers. Reduced risk of nylon powder absorbing moisture and clumping during transit or storage.
Feature: High-load-rated bearing assembly with forced oil lubrication, engineered for the combination of high RPM (2950–3800) and the impact loads of nylon grinding.
Advantage: Grinding hard nylon transmits impact forces through the discs to the main shaft bearings. These forces, combined with high rotational speed, create a demanding bearing environment that degrades standard bearings faster than lower-impact materials. The new bearing design pairs larger bearing surfaces with active oil circulation that removes heat and continuously replenishes the lubricant film under load.
Benefit: Extended bearing service intervals in nylon service. Reduced risk of bearing-related downtime — which in hard-material grinding can escalate from vibration to catastrophic failure faster than in softer-material grinding.
Feature: Integrated automatic feeding, grinding, pneumatic conveying, screening, and oversize return — controlled from a single operator panel.
Advantage: Nylon powder coating powder production is a continuous, specification-driven operation. Manual adjustment of feed rate or screen management introduces variability that shows up as out-of-spec particle size distribution. The SMF's automation maintains consistent parameters.
Benefit: Consistent powder quality, batch after batch. One operator manages multiple units plus other production tasks. Continuous throughput through breaks and shift changes.
Feature: Complete negative-pressure enclosure from feed to collection with air-lock discharge.
Advantage: Nylon dust is combustible and creates a cleanliness issue in powder coating production where cross-contamination between colors or materials is unacceptable. The sealed design contains all dust and prevents ambient contamination.
Benefit: Clean facility. Reduced cross-contamination risk. Compliance with combustible dust standards. Suitable for food-contact nylon powder production where cleanliness is audited.
| Nylon Type | Characteristics | Pre-Drying | Mesh Target | Recommended Model | Notes |
|---|---|---|---|---|---|
| PA6 (unfilled) | Hard, abrasive, hygroscopic (up to 9% moisture) | 80°C, 2–4 hrs to <0.2% | 60–120 | SMF-500 / SMF-600 | Most common for powder coating; good grindability when dry |
| PA66 (unfilled) | Harder than PA6, higher melting point (255°C vs 220°C) | 80–90°C, 4 hrs to <0.2% | 60–120 | SMF-600 / SMF-800 | Higher abrasion than PA6; SMF-800 recommended for volume |
| PA11 / PA12 | Softer, lower moisture absorption | 80°C, 2–3 hrs | 60–120 | SMF-400 / SMF-500 | Premium powder coating material; grinds easier than PA6/66 |
| PA6/66 Glass-Filled (30% GF) | Highly abrasive | 80°C, 2–4 hrs | 40–60 | SMF-800 exclusively | Disc life 150–300 hours; inspect discs after every 100 hours |
| PA6 Mineral-Filled | Moderately abrasive | 80°C, 2–4 hrs | 40–60 | SMF-600 / SMF-800 | Mineral filler increases abrasion; SMF-800 for production |
| Nylon Regrind / Recycled | Variable quality | Mandatory — condition varies | 40–80 | SMF-600 / SMF-800 | Pre-screen for contaminants; magnetic separation essential |
Pre-dry all nylon. Even if it has been stored in sealed bags, nylon equilibrates with ambient humidity. Drying restores hardness for grinding and prevents post-grind moisture absorption.
Pre-chill if ambient >30°C. Nylon softens as temperature increases. Pre-chilling dried nylon (storing in air-conditioned space) provides additional thermal headroom for the cooling system.
Magnetic separation is mandatory. A CJ magnetic frame captures tramp metal that would otherwise damage discs and contaminate nylon powder — critical for powder coating where metal contamination causes coating defects.
Package powder immediately. Dry nylon powder absorbs moisture from the air within hours. Package into sealed bags or containers directly from the collection point.
Nylon's abrasiveness comes from its molecular structure. The polymer chains are held together by strong hydrogen bonds between amide groups, creating a material with high hardness (Shore D 70–80), high tensile strength (60–85 MPa for unfilled grades), and high surface energy. When a grinding disc impacts nylon, the material resists deformation and instead transmits the force back into the disc surface — effectively grinding the grinder. This is fundamentally different from PE or PP, which absorb impact through deformation and cause less disc wear. The SMF's wear-resistant disc alloy is formulated to withstand this abrasive load, extending disc life to 400–800 hours in unfilled nylon versus 200–400 hours with standard disc materials.
The optimal particle size depends on the coating method. For fluidized bed coating — where preheated parts are dipped into a fluidized powder bed — 60–100 mesh (150–250 microns) is standard. The coarser powder provides good fluidization and builds thick (250–500 micron) coatings in a single dip. For electrostatic spray — where charged powder is sprayed onto a grounded part — 80–140 mesh (105–180 microns) is preferred. Finer powder charges more uniformly and produces thinner, smoother coatings. For selective laser sintering (SLS) 3D printing, 40–80 mesh with a narrow size distribution is required for consistent layer deposition. The SMF's adjustable disc gap and interchangeable screen mesh accommodate all of these particle size targets.
Yes. PA6 and PA66 have similar grinding characteristics: both are hard, abrasive, and require effective cooling to prevent oxidation. PA66 is slightly harder (higher melting point, higher tensile strength) than PA6 and causes marginally more disc wear — expect disc life to be 10–15% shorter in PA66 than PA6 at the same throughput. The SMF-600 and SMF-800 are both well-suited to PA66. For operations grinding both types on the same machine, thorough cleaning between grades is recommended: PA6 and PA66 have different melting points (220°C vs 255°C), and mixing them in powder form can create melt inhomogeneity in the coating fusion cycle.
Nylon yellowing during grinding is caused by thermal oxidation — a chemical reaction between the polyamide molecules and atmospheric oxygen, accelerated by elevated temperature. The reaction creates conjugated double bonds (chromophores) that absorb blue light, giving the material a yellow appearance. The threshold for noticeable yellowing is approximately 150°C in the presence of oxygen, and the reaction accelerates exponentially with temperature. The SMF's dual cooling maintains all grinding zone surfaces below this threshold. The water cooling circuit, which extracts heat directly at the disc surface (the hottest point in the system), is the primary defense. For nylon powder coating applications where color is critical, cooling effectiveness directly determines product quality and sellable yield.
Glass-filled nylon (typically 30% glass fiber) is one of the most abrasive materials processed on disc pulverizers. The glass fibers, with a Mohs hardness of approximately 6.5 (comparable to feldspar), act as an aggressive abrasive against the disc surface. In 30% glass-filled PA6 or PA66, disc life is typically 150–300 hours — roughly one-third to one-half of unfilled nylon disc life. For glass-filled nylon, the SMF-800 is the only recommended model: its larger disc diameter provides more wear material, and its 75kW motor provides the torque to overcome the higher grinding resistance. Spare disc sets should be kept on hand, and discs should be inspected every 100 operating hours. The investment in an SMF-800 with spare discs is justified for operations that must grind glass-filled nylon regularly.
Yes. PA12 (polylaurolactam) is the premium nylon for powder coating and sintering applications, prized for its low moisture absorption (0.25% vs 9% for PA6), excellent chemical resistance, and low coefficient of friction. Compared to PA6 and PA66, PA12 is softer and grinds more easily — throughput is typically 10–20% higher than PA6 at the same settings, and disc life is longer. The SMF-400 or SMF-500 is usually sufficient for PA12 powder production unless very high volumes are required. Because PA12 powder commands a significant price premium ($15–30/kg for powder coating grades), the precision and consistency of the SMF's particle size control is particularly valuable — every kilogram of out-of-spec powder represents a significant revenue loss.
Dry nylon powder is hygroscopic and will absorb moisture from ambient air, reaching equilibrium within hours to days depending on humidity. Prevent post-grinding moisture absorption through three measures. First, package powder immediately after grinding — do not store in open containers. Use sealed, moisture-barrier packaging (aluminum-lined bags, sealed drums with desiccant). Second, if powder must be stored temporarily, use sealed containers with desiccant packs and store in a climate-controlled area with relative humidity below 30%. Third, for nylon powder coating customers, deliver with a certificate of analysis that includes moisture content — this provides confidence that the powder was handled correctly and has not absorbed moisture during transit.
Step 1 — Define Your Nylon Requirements: Type (PA6/PA66/PA11/PA12), application (powder coating, sintering, compounding), target mesh, and throughput.
Step 2 — Select Your SMF Model: Use the model selection and nylon processing guide above. For glass-filled or mineral-filled nylon, the SMF-800 is strongly recommended.
Step 3 — Contact Nicole for a Quote: Provide your nylon type, throughput, and mesh target. We will confirm the optimal model, pricing, lead time, and spare parts availability.
Step 4 — Install and Start Producing: Installation, commissioning, and operator training are included. Spare disc sets are available for immediate shipment alongside the machine.
For complete nylon powder coating production, Chenxing Machinery also supplies high-speed mixers for pigment and additive blending, STG-U hopper driers for pre-drying, CJ magnetic frames for metal protection, and SML water-cooled chillers for enhanced cooling. For alternative configurations, explore the dual disc pulverizer PNMF-Pro series.
Contact Chenxing Machinery Today:
Contact Person: Nicole
Phone / WhatsApp: +8615951187228
Email: ceo@cxsljx.com
Company: Zhangjiagang Chenxing Machinery Co., Ltd.
Website: www.chenxingmachinery.com