Plastic milling – Recommendations for action from K&B:

1. Fields of application of plastics processing

Nowadays, plastic is used in an extremely versatile way. Plastic is one of the most frequently used and most popular materials worldwide. In addition to companies such as K&B Kunststoffdreherei, plastic processing also takes place in areas of application such as model making, deep drawing or sign engraving, to name just a few. In addition to the milling and machining of plastics, we also use other common methods for processing plastics. Appropriate tools and many years of experience also allow us to work by drilling, cutting, turning, gluing, welding and the like. Certain types of plastic such as rubber are not suitable for contact with a CNC milling cutter, for example, and can therefore only be machined by a cutting process. Compared to alternative machining methods, the milling of plastic has basically neither advantages nor disadvantages with regard to the quality of the end product. Depending on the material composition and the intended use, we choose between plastic processing by milling, punching, turning, cutting and so on. In this article, however, we would like to concentrate on the milling of plastics.

2. Our milling cutter tool for machining plastics

Plastic milling is a type of machining where material is removed (or machined) in order to process the plastic into a finished product. With the aid of computer control, we aim to achieve the highest level of quality in plastics processing by milling. This technique is called CNC milling and is one of the most widely used methods for processing plastics for our company. The milling cutters we use differ, among other things, in the number of axes they have. We process plastic according to requirements, for example, with 3-axis, 4-axis or 5-axis milling machines.

3. Materials usable for plastics processing by milling

For processing by CNC milling, plastic is the third major field of application alongside aluminium and wood. Machining processes using CNC milling involve a large number of plastics. The machining of thermoplastics (soft plastics) such as PVC, which can be easily deformed in contact with heat. In addition, our CNC milling machines are also designed for processing thermosets (hard plastics) and elastomers (flexible or stretchable plastics).

4. Criteria for machining plastics with CNC milling machines

In comparison with alternative materials, such as metal, our plastics have some advantages. Due to the lower density of plastic, the material has less weight and comparatively better sliding properties as well as a higher chemical resistance. Within plastics processing, there are a number of things that need to be considered when milling plastics in order to maintain the quality of the material. When plastics are processed by milling or machining, the heat generated is dissipated via the chip, since conventional plastics have a considerably lower thermal conductivity than, for example, metals. Because plastics have different properties, we process them in contact with CNC milling machines in correspondingly different ways. When milling, we influence the heat input into the plastic by selecting the tools and the corresponding cutting parameters. The clamping of the raw material is just as important when milling plastic. In case of too strong tension of the plastics, it is possible that the material will be deformed before it is machined by the milling cutter and that dimensional deviations will occur after the processing of the plastics.

4.1 Common procedures for milling plastics

Milling plastics requires a high level of technical know-how to maintain the quality of the material. Before CNC milling processes the plastics, an appropriate program is written or a template is used and the correct tools for perfect milling are set up. After the plastic to be machined has been fixed in the milling cutter by means of a vacuum clamping, the CNC machine traverses the programmed contour with the correspondingly programmed tool. Here the plastic is sucked in with the help of vacuum so that the milling cutter can process the material. In addition to this rather modern method, it is of course also possible to clamp the plastic blocks in a more conventional way in a corresponding device. Both techniques are mostly used for machining plastics by 4-axis and 5-axis milling.

4.2 More efficiency in plastic milling

Where there is planing, chips fall! To a certain extent, however, they can also be used further, at least in the field of plastics processing – or do not even have to be created. With the help of the right or more efficient tools and, in parallel, a vacuum clamping method for the plastics. By the combination of these saving measures, we are able to decimate the material loss, when processing plastic with CNC milling, strongly. In other companies in our industry, however, this has been used relatively seldom so far, since the more conventional method of machining (by “clamping” the plastics to a corresponding device) is much simpler and therefore more economical than the vacuum method. The reason for this is that the plastic must first be prepared for the vacuum clamping and the plastic processing processes are thus extended. Depending on requirements and budget, competitors often opt against vacuum clamping and for conventional material clamping.

4.3 Main findings on plastics processing by milling

When processing plastics by CNC milling, a whole range of details must be taken into account. In particular, the choice of the milling cutter and the conditions of a stable mechanics are two of the most important criteria for our work. In order to maintain the material quality with regard to our plastics, our milling cutters work with the highest degree of sharpness and even meet high quality standards.
If you would also like to benefit from our high-quality plastics processing, please let us know your individual request and we will be pleased to prepare a non-binding offer for you!