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 […]
Spiral mandrel distributors are among the most powerful extrusion tools for the production of pipes, films, hoses and bottles and are available in a wide range of variants on the market. Spiral mandrel distributors can be used for various production processes and a good design of the spiral mandrel distributor […]
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 […]
Blocking of films is the most frequent cause of complaints about films. In some light cases, the problem is only a slight quality defect, but in more extreme cases it leads to large quantities of rejects, as entire rolls have to be disposed of on which blocking has occurred. […]
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 the course of the current trends towards Industry 4.0 (smart factory), the availability of as much process information as possible is one of the first necessary steps. Process information, machine control parameter and sensor values are generally available to a large extent, but it is often not easily possible […]
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 […]
Due to the poor thermal conductivity of thermoplastics, residual stresses (tensile and compressive residual stresses) are build up in the walls of the product during cooling processes after extrusion. Deformations and distortion of the products often result from the residual stresses, whereby the presence of the residual stresses becomes visible. […]
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 extrusion, plastic granulate is plasticized by converting mechanical energy into thermal energy. The mechanical energy required for this (torque and rotation of the screw) is generated with the aid of electric motors, i.e. from electrical energy. The additional heaters often only contribute a small part to the overall energy […]
Voids/blowholes/vacuoles are frequent quality problems that can occur especially in the manufacture of thick-walled products. Although the cause of this problem is well known, it is often difficult and time-consuming to avoid it. When cooling plastics from melt temperature to ambient temperature, the specific volume or density of the plastic […]
During extrusion, the plastic is heated from the ambient temperature level to an elevated temperature level (usually >180 °C) so that the materials melts and becomes plastically deformable. After forming the product (film, tube, profile, rod, etc.), the product is cooled down to ambient temperature to achieve dimensional stability. Thus, […]
In extrusion, the temperature distribution inside the product is a very relevant value whose knowledge can contribute to understanding a variety of effects or problems. However, measuring the internal temperature of an extruded product is difficult in most cases, because in a continuous process such as extrusion (with sometimes very […]
The term Industry 4.0 or Smart Factory is on everyone’s lips. But what is hidden behind this term and what does it mean for the plastics processing industry? What opportunities and chances arise from this and what risks does this “trend” entail? The industrial revolution began with the use […]
Plastics – material of the 21st century Plastics belong to the group of polymers. A polymer is an organic material and consists for the most part of carbon and hydrogen. Polymers are big molecules that have the shape of a chain (chain molecule) in which a great many identical subunits […]
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 […]
In the processing of plastic, additives offer the possibility of changing the properties of polymers and adapting them to a corresponding task. A distinction is made between additives that have an influence on the process ability of the plastic and additives that have an influence on the product properties. Frequently […]
10 possible causes for die drool and solution approaches The formation of die drool during extrusion is a frequently occurring problem whose development cannot yet be clearly explained to this day. Die drool formation refers to deposits in the area of the nozzle exit, which are initially perceived as a […]