Material selection guidance — choose right, save detours
Company Strength
20 Years of Experience
72 Sets of CNC Machines
Precision: ±0.01mm
7-15 Days Fast Shipping
Quality Advantages
No Knife Marks
No Scratches
No Blemishes
No Color Difference
Can CNC Machining of Acrylic (PMMA) Achieve a Mirror Finish?
Yes. Acrylic is one of the few plastics that can achieve a mirror finish directly through cutting. We use single-crystal diamond tools for precision machining, followed by flame polishing or diamond grinding. Surface roughness is consistently controlled within Ra0.4μm, delivering a high-gloss appearance free of scratches or defects, resembling a mirror. No secondary coating is required. For batch production, identical parameters are used to ensure consistent mirror finish quality.
Why Do Acrylic Edges Turn White and Surfaces Get Hazy After Machining?
This is typically caused by excessive cutting heat. Acrylic has low thermal conductivity, so slow feed rates, high speeds, or dull tools cause chips to melt and stick to the tool, resulting in haze and stress-induced whitening. Our approach uses monocrystalline diamond tools with high RPM and small depths of cut, along with air cooling or minimal lubrication to dissipate heat. We leave a 0.05-0.1mm finishing allowance before final machining to prevent heat accumulation on already processed surfaces.
Fine Scratches on Transparent Parts: How Do We Ensure Undamaged Delivery?
Scratches on transparent plastic parts mostly occur during handling rather than machining. We isolate processes to prevent damage: protective films are applied throughout, independent trays prevent stacking between stations, and dedicated fixtures ensure proper positioning. Final inspection is performed under standard light boxes to check each unit's appearance. We guarantee a high-gloss, scratch-free, and flawless finish, not just "imperceptible" defects.
Why PTFE Parts Often Exceed Tolerances After Machining?
PTFE has a low elastic modulus and significant creep; clamping and cutting forces cause deformation and rebound upon release. We employ low-stress clamping (soft jaws or vacuum) and symmetrical layered material removal, with intermediate stress relief if needed. After final machining, parts rest for 24 hours to release stress before final inspection, ensuring batch size consistency within ±0.01mm.
How High Temperatures Can PTFE Withstand? Is It Suitable for Seals?
PTFE maintains long-term usage temperatures from -200°C to +260°C, with higher short-term tolerance. It resists nearly all chemical media and has a friction coefficient as low as 0.04, making it a common material for pump and valve seals, bearing slides, and insulators. For load-bearing conditions, we recommend glass, carbon, or bronze-filled grades, which offer significantly better creep resistance and wear performance.
Yes, drying is mandatory. PEI has a high moisture absorption rate; machining wet material causes hydrolysis at process temperatures, leading to silver streaks, bubbles, and hazy surface defects. We standardize a 150°C drying process for 4 hours or more before machining. Post-machining, we perform stress-relief annealing to prevent stress cracking during assembly or use.
Temperature and cost guide selection. PEI offers long-term service up to 170°C (Tg 217°C), inherent flame retardancy, and lower cost than PEEK, ideal for aerospace interiors, electrical insulation, and medical device structural parts. PEEK withstands long-term temperatures up to 250°C with better chemical and wear resistance, suitable for high-heat, corrosive, or implant-grade applications. For temperatures below 170°C, PEI is usually more economical.
PPS Is Too Brittle: How to Avoid Edge Chipping During Machining?
Use sharp tools with positive rake angles and shallow cuts to reduce cutting forces rather than forcing the material. Glass or carbon fiber reinforced grades are highly abrasive; use CVD diamond-coated or PCD tools, as dull cutters will crush the edges. Additionally, reinforced grades are anisotropic; we align tool paths with material flow direction and maintain uniform orientation in batch parts to ensure dimensional consistency.
PP vs PE: What Is the Difference & Which Should You Choose?
PP offers superior rigidity and heat resistance (mp ~160°C) with good chemical resistance and low cost, making it ideal for chemical tanks, flanges, and pump/valve parts. PE is softer, handles extreme cold better (down to -100°C), and has a low friction coefficient; UHMW-PE delivers 7x the wear resistance of carbon steel, suiting conveyor rails and wear liners. Select PP for rigidity/heat and PE for wear/low-temperature performance.
In low-load, mid-to-high-speed environments with abrasive particle erosion, this is indeed the case. The wear resistance of UHMW-PE can reach approximately 7 times that of carbon steel. It features a low coefficient of friction, non-stick properties, and low operating noise. However, its rigidity and load-bearing capacity are far inferior to steel, classifying it as a wear-resistant but non-load-bearing material. Structural support is required during design to compensate for stiffness.
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