Plastic CNC Machining for Custom Delrin Gear Parts

This plastic CNC machining project involved a custom Delrin/POM toothed component used in medical equipment. Approximately 100 parts were CNC machined for export.

The component measures about 270 × 270 × 5 mm, combining a large diameter with a very thin cross-section. Fine teeth run around the full outer circumference, while three curved cutouts remove material between the outer ring and central hub. The center also includes a main bore and several smaller locating or mounting holes.

For this part, the machining challenge was not simply producing a flat plastic profile. The process needed to account for the fine repeated teeth, thin 5 mm body, reduced stiffness after the internal cutouts, and repeatability across a 100-piece production run.

CNC machining provided a practical route for producing these custom Delrin parts directly from the customer's CAD data without dedicated molding tooling.

Project Details

CNC Machining Fine Teeth Around the Full Circumference

The outer edge is the defining feature of this component.

Instead of a simple circular profile, fine teeth extend continuously around the approximately 270 mm diameter. This creates hundreds of repeated small features that need to follow the geometry defined in the customer's CAD model.

For custom plastic gear machining, cutter selection depends on the actual tooth geometry. The tool needs sufficient access to produce the required profile without unnecessarily increasing machining time.

The center of the part also contains a main bore and several smaller holes. Their locations relative to the outer toothed profile are important to the finished component and are machined according to the customer's technical drawing.

This combination of outer teeth, center bore and locating features makes the component quite different from a conventional CNC machined plastic plate or housing.

The Challenge of a 270 mm × 5 mm Delrin Part

Part thickness has a major influence on the machining approach.

At approximately 270 mm in diameter and only 5 mm thick, this Delrin component has a high diameter-to-thickness ratio.

A thin plastic workpiece needs suitable support during machining. Excessive clamping force can influence the part, while insufficient support may allow movement during cutting.

The three large curved openings make this more important. As these areas are removed, the amount of material connecting the center hub and outer ring is reduced, changing the stiffness of the component.

Workholding and machining sequence therefore need to be planned together.

For CNC machining thin plastic parts, maintaining a stable workpiece can be just as important as generating the correct toolpath.

Delrin, POM and Acetal CNC Machining

Delrin is a widely recognized trade name associated with POM (polyoxymethylene), an engineering plastic also commonly called acetal.

POM is frequently selected for mechanical components because of its combination of:

• good machinability;
• low friction;
• wear resistance;
• dimensional stability;
• useful mechanical strength and stiffness.

These characteristics make it suitable for gears, rollers, guides, bushings, spacers and other moving or locating components.

Engineers and buyers may use different material terminology when sourcing these parts. Common searches include Delrin CNC machining, POM CNC machining, acetal CNC machining and CNC machined POM parts.

For production, the exact material grade is confirmed against the customer's drawing or material specification.

Low-Volume CNC Production of 100 Plastic Parts

A one-off prototype and a 100-piece production run create different manufacturing priorities.

For approximately 100 parts, the machining setup needs to locate each thin disc consistently. The fine tooth profile is repeated across every component, while the central bore and smaller holes need to maintain their specified positions.

Tool condition also becomes more relevant as production continues.

The objective is therefore not to make 100 individual prototypes, but to establish a repeatable low-volume plastic CNC machining process for the complete batch.

For engineering teams that need tens or hundreds of custom plastic components before higher-volume production, CNC machining can also avoid the initial investment and design commitment associated with dedicated molding tooling.

Custom Plastic CNC Machining for Medical Equipment

Medical equipment can contain many machined engineering plastic components beyond external housings.

Depending on the equipment design, these may include plastic gears, rollers, guides, spacers, insulating components and other mechanical parts.

YS Precision provides plastic CNC machining services for customer-designed components based on 3D CAD models and 2D technical drawings.

Materials we machine include:

Delrin/POM, PEEK, PEI, PTFE, Nylon, ABS, PC and PMMA.

For a component like this, manufacturing review focuses on the actual engineering requirements—material grade, tooth geometry, part thickness, bore locations, quantity and critical dimensions.

Sourcing Custom Delrin or POM CNC Parts?

If you are looking for a plastic CNC machining supplier, Delrin machining supplier or custom POM parts manufacturer for prototype or low-volume production, YS Precision can review your project from the supplied engineering drawings.

For an accurate quotation, please send:

3D CAD + 2D Drawing + Material Grade + Quantity + Critical Tolerances + Surface Requirements

For toothed or gear-type components, please include the complete tooth geometry and identify any critical bores, locating holes or mating dimensions.

We support overseas engineering and purchasing teams sourcing custom CNC machined plastic parts from prototypes to repeat low-volume production.