Production process

The rotation process for the production of plastic parts

We are the experts when it comes to the process of rotation.

The objective of the method is to give plastics the form required, using rotation that is operated by machine. Thereby, state-of-the-art rotation machines that are controlled by computer process the raw material.

The procedure in detail –the finished plastic part in just four steps

First, a pre-weighed quantity of plastic powder is placed in half of a thin-walled, hollow metal mould, which is mounted on a mould carrier of the processing machine (rotating arm). Then the tool parts are interconnected and sealed.

The tool is moved into the oven and brought into biaxial rotational motion by the rotating arm and the rotary plate. In the oven, regulated heat from the outside penetrates the mould wall. The material inside the tool is heated continuously, the material particles fuse at the hot mould wall and form a new layer, the moulding wall.

After the material has been melted and consolidated to form a wall, the machine enters a new stage and moves the tool to a cooling station. The temperature sinks below the crystallisation point due to air, water mist or direct contact with the water. At the same time, the rotating process continues, preventing the melted plastic from leaking out of the mould.

After sufficient cooling the machine moves to the next step and the tool is placed in the so-called demoulding and loading station in which the finished tool is finally taken out.

The result of the procedure: light, robust and high quality

The results are a major achievement – light weight, robust material and appealing appearance – all at a fair price. Please contact us if you have any questions of a procedural nature or regarding our offer!

Advantage of the process

Highest efficiency and precision: the advantages of the rotation procedure

The rotation procedure is highly efficient. The precise, computer-controlled rotation plants are predominantly used for high-volume production of parts.

The advantage: the almost pressure-less manufacture makes the products almost completely tension-free. This means the final product remains tolerant in respect of pressure and shock. In addition to that, the product has a very light net weight. The low use of tools permits the manufacture of low-volume series below 500 pcs. to medium-sized series of 10,000 pcs. per year.

Since we always want to guarantee the high quality of our final products, we use finely ground plastic powder as our raw material. The plastic powder is available in different variations and is available according to the desired colour and shape. Our raw material portfolio includes PE, PA6, PA12, PP, PVC and XPE.

Product advantages

Top quality at reasonable prices

The rotation procedure is not only efficient, but also makes economic sense – the cost of moulding is lower than the costs for other procedures (deep drawing, blowing method or injection moulding). Shape changes can be carried out at reasonable prices and fast.  A low after-treatment is a further advantage.


The final products speak for themselves – tension-free, seamless, and corrosion-free parts; shockproof and impact-resistant PE. In brief: a high-quality product that withstands any pressure and extreme temperatures. In addition, the integration of metal and plastics components is possible without problems.  Regarding design and colour, there is nearly no limit to your imagination – the plastics powder offers a wide range of variations.  The low net weight of the final products is a further important advantage.

Our extras:

Our rotation system is at your disposal with several extras. These include carrying out fire testings, radiation crosslinking of the parts (stiffening), a complex geometry with insert parts and prepared mounting points that are rotated into the material by threaded bushes.

Furthermore, Köver has its own maintenance facilities which make it possible to remedy certain damages to the tools on site as soon as possible. As a consequence, in the event of smaller problems, we are able to guarantee the reduction of downtime and assure a delivery capability as quickly as possible.

Design information

Individual assistance from beginning to end

Köver is your right partner for rotation-moulded components. From development through to construction and manufacture: we offer more than the standard service in the  sector.

Whether it is the realization of new concepts or the optimization of already existing drafts, with our experienced engineers your wishes are in the best hands. We convert individual concepts into reality and use the most modern 3D-CAD engineering applications for the manufacture of our products.

Optimal adaption to achieve economic efficiency 

Mouldings, mill robots, support means and milling devices: all operating means that are used during the creation process are tailored perfectly in advance according to the 3D design data of our customers.  For example: for after-treatment we simulate the milling programme of the robot in advance – based on the data provided.

The advantages of this methodology are obvious. Even before production starts we can see if problems will occur during the milling process. Thereby, we acquire knowledge that flows into the moulding process at the same time. This means minimal expenditure of time with maximum efficiency during the production process. Mistakes are effectively and permanently prevented.