When manufacturing profiles (with hollow chamber structures), the design of the vacuum calibrations and the post-cooling represents a challenge. The number of calibrations, the geometry, the materials and coatings used, the vacuum control, the temperature control and much more must be optimally tailored to the product, the material and the […]
Process Knowledge
18 posts
In the extrusion of pipes, cables, profiles and many other semi-finished products, immersion cooling tanks or spray cooling tanks are used in which the hot extrudate is introduced and cooled with cooled water. Both the immersion cooling tank – in which the extrudate is completely submerged in a water bath […]
The choice of the right extruder size is based on many different factors and can have a decisive influence on the achievable product quality and also on the achievable productivity of the production. General statements are often not correct and must therefore be thoroughly questioned before they are implemented in […]
The processing behavior and the achievable product properties of plastics can change enormously depending on the residual moisture content of the polymer raw material. In most cases, too high residual moisture leads to problems, but in some cases quality problems or processing problems also occur due to too low residual […]
Extrusion dies should ideally be designed and coated in such a way that production can be carried out without any interruption for cleaning. This aspect is already taken into account in the design of the flow paths, in the selection of steels and coatings as well as in the selection […]
As already mentioned in the previous article, it is always advisable to optimally parameterize the temperatures of the extrusion cylinder to avoid production problems and to ensure economical and productive production. Optimizing cylinder temperatures while production is running is not an easy task and is therefore often avoided due to […]
Today’s extruders usually have several different heating (or heating/cooling) zones, which can be individually parameterised with regard to the desired temperature. The temperature control of the extruder is essential for the achievable product quality as well as for the productivity of the plant. Nevertheless, in practice it happens very often […]
In plastics processing, quality problems are often caused by the presence of angel hair, impurities or dust. Angel hair can be recognized as very fine, hair-like plastic threads that can be formed during material transport. Dusts are fine solid particles of different sizes and can be made of plastic, but […]
When extruding profiles, the maximum production speed is one of the most important factors for the calculation af a quotation. If the production speed is assumed to be higher than the real production can be in practice, this can mean high losses for the extrusion plant and represents a high […]
Extrusion cylinders are generally divided into smooth barrel extruders (conventional extruders) and grooved extrusion cylinders (grooved barrel extruders, helibars, etc.). The differences between the different systems lie, as the name suggests, in the design of the extruder barrel. While the conventional extruder has a completely smooth cylinder, a grooved system […]
In order to achieve a high product quality, additives are added to the raw materials, which cause a change or improvement of the product properties. Nowadays plastic products are often used in areas where the use of pure plastics would be unthinkable. After the melting zone of the extrusion screw […]
The term “assistance system” refers to electrical, information technology or mechatronic systems (e.g. a software, a car) that provide the user with assistance in a current real situation or even actively intervene in the operating process and carry out actions in the background. As virtual assistants (e.g. in the […]
The screw of an extruder is considered as the “heart” of the machine and can have a significant influence on the achievable product quality, the achievable maximum throughput and the efficiency of the production plant. There are different basic concepts of screw design, which have different advantages and disadvantages. In […]
In addition to the width of a film and the profile tolerance, the flatness is considered as one of the most important quality criterions. Good flatness refers to film products with a high planarity, also a low tendency for sagging areas or bulges. The flatness of a film is an […]
In different extrusion processes, curvature (or bowing, sabre-running, katana effect, etc.) represents a major quality problem and is often difficult to get a grip on. The cause of the curvature is almost always an inhomogeneous thermal situation of the product during cooling and can often be greatly reduced or completely […]
The collapsing of pipe ends is one of the most common problems in the extrusion of pipes and occurs especially when high production speeds are used on the production lines. The reasons for the geometric shape deformation are internal stresses. The reduction of the problem is often possible with simple […]
Collapsing of pipe ends is one of the most common problems in the extrusion of pipes and occurs especially when high production speeds areused on the production lines. The reasons for the geometric shape deformations are internal stresses. The reduction of the problem is often possible with simple means. […]
Different extrusion tool concepts can be used for the extrusion of rotationally symmetrical semi-finished product geometries (e.g. pipes, hoses, jackets, blown films, blow molds). Typical applications are the use of spiderleg dies, screenpack dies, heart curve but also the use of spiral mandrel distributors. From a price point of view, […]