It is crucial to comprehend the best practices for CNC machining when designing nylon parts to produce functional, high-quality parts quickly and affordably. It reduces risks, facilitates a more efficient project workflow, and eventually produces positive results.

Tooling and Setup

End Mill Selection:

l Employ end mills featuring a high helix angle of 30° or greater to enhance chip evacuation and minimize thermal accumulation.

l Ball nose end mills are a good option for roughing operations and rounded features.

l Corner radius end mills or flat nose end mills work well for sharp corners and pockets.

Tool Diameter:

l To guarantee a good surface finish and prevent excessive material removal, select tool diameters slightly smaller than the feature width.

l Steer clear of fragile tools as they are more likely to break and deflect.

Fixturing:

l Securely fix the nylon part to avoid movement during the machining process, which could result in imprecise cuts and possible harm.

l When using vacuum fixtures or soft jaws, ensure not damage the nylon surface.

Cutting Parameters

Cutting Speed:

l Modify cutting speeds according to part geometry, material grade, and tool type, starting at a cautious 100–200 m/min.

l To attain a good surface quality, use lower cutting speeds for finishing passes and higher speeds for roughing passes.

Feed Rate:

l To avoid overloading the tool and to guarantee smooth chip formation, maintain a moderate feed rate.

l Roughing passes benefit from higher feed rates while finishing and thin sections benefit from lower feed rates.

Depth of Cut:

l Make shallow cuts (0.5 - 1 mm) to reduce heat generation and enhance surface quality.

l Roughing passes can be performed with deeper cuts, but caution is advised to prevent tool wear and part distortion.

Coolant and Lubrication

Always use coolant：

l Water-based coolants work well when machining nylon.

l Coolant prevents thermal warping and improves finish by lubricating the tool, flushing chips, and controlling heat generation.

l Make sure there is enough coolant flowing through the cutting zone.

Additional Tips:

l Minimize tool dwell time: Refrain from leaving the tool lingering after cuts as this may cause heat stains and cause the nylon surface to melt.

l Roughing and finishing passes: To attain a high-quality surface, separate the roughing and finishing processes.

l Deburring: After machining, nylon parts might need to be deburred to smooth out sharp edges and enhance appearance.