When should you choose turning over milling for plastic parts?
Plastic parts can be machined in various ways. Two commonly used techniques are turning and milling. Both processes allow for custom manufacturing, but are suitable for different shapes, dimensions, and applications.
The choice between plastic turning and milling therefore starts with the shape of the final product. Is a part round and made from bar stock? Then turning is often the most logical process. Is it a rectangular, larger, or complex-shaped part? Then milling usually offers more possibilities.
Plastic Turning: ideal for round parts
In plastic turning, a round piece of bar stock is placed in a lathe. The material rotates while the tool machines the part step by step. This creates a round product with the desired diameter, length, holes, grooves, or contours.
Plastic turning is particularly suitable for parts such as:
- Bearing sleeves
- Bushings
- Rollers
- Round guides
- Gears
- Cylindrical machine parts
Turning is an efficient way to produce round parts in series. Especially when multiple identical products are needed, the machine can be loaded with multiple bars of material. This allows a larger series to be produced consecutively.
When is turning the best choice?
Turning is usually the best machining method when a part is primarily round. Examples include a bushing with a hole in the center, a roller with a specific diameter, or a gear made from round bar stock.
The main situations in which turning is suitable:
1. The part is round or cylindrical
For round shapes, turning is often faster and more efficient than milling. A lathe is designed to precisely machine diameters, holes, grooves, and round contours.
2. The product is made from bar stock
Plastic turning typically starts with round bar stock. This makes the technique suitable for compact and cylindrical parts. The material is turned to size until the final product has the correct shape.
3. You need multiple identical parts
For recurring or larger production runs, turning offers additional advantages. With a bar feeder, the machine can process multiple bars, allowing production to proceed efficiently.
4. High dimensional accuracy is required
For parts such as bearing sleeves, rollers, and mechanical connections, a good fit is essential. Turning allows for the precise machining of diameters and internal dimensions.
When should you choose plastic milling?
Milling is more suitable for parts that are not primarily round. In milling, the tool moves across the material to create shapes, cutouts, holes, and contours.
Plastic milling is often used for:
- Rectangular machine parts
- Guides
- Sheets with cutouts
- Free-form contours
- Drilled holes and tapped holes
- Parts with beveled edges
- Larger products made from sheet material
Milling offers a great deal of freedom in terms of shape. While a lathe excels primarily in round geometries, a milling machine can perform complex contours and machining operations on multiple sides of a product.
Turning vs milling: The key differences
| Plastic turning | Plastic milling |
|---|---|
| Suitable for round parts | Suitable for rectangular, flat, or complex parts |
| Often starts with round bar stock | Often starts with sheet material or a sawn block |
| Ideal for bushings, bearings, rollers, and gears | Ideal for guides, contours, recesses, and plates |
| Efficient for series of similar products | Flexible for a wide variety of shapes and custom work |
| Focused on diameters, holes, and round shapes | Focused on flat machining, contours, and multiple sides |
Sometimes a combination is necessary
Not every part is completely round or completely flat. A turned part, for example, may still require holes, flat surfaces, or contours that are best created using a milling machine.
In that case, a product can be milled after turning. Turning-milling combinations are also possible, combining turning and milling into a single machining process. This allows a part to be manufactured efficiently without unnecessary extra steps.
From working drawing to plastic part
For both turning and milling, Lakwijk prefers to work based on a PDF working drawing and a 3D model, such as a STEP file. This clearly defines the shape, dimensions, and desired machining operations.
Based on this data, the following is determined:
- Which plastic material is most suitable
- Whether turning, milling, or a combination is required
- Which machine is most suitable
- How the part can be produced efficiently
Even when a complete 3D model is unavailable, in some cases we can work with an existing sample or a technical drawing.
The right machining process for your application
The choice between plastic turning and milling ultimately depends on the part’s design and function.
Choose plastic turning when you need a round part, such as a bushing, bearing, roller, or gear. Turning is an efficient solution, especially for parts made from bar stock and for recurring production runs.
Choose plastic milling when the part is rectangular, larger, or has a more complex shape. Milling offers greater flexibility for cutouts, drill holes, contours, and machining on multiple sides.
Not sure which machining method is best suited for your machine part? Lakwijk will work with you to determine the best material selection, manufacturability, and the most efficient production method. Feel free to contact us.
