The extrusion of pipes, profiles, sheets, films, solid and hollow rods or other semi-finished products can cause a wide variety of problems that can impair the economic efficiency of the processes. These problems may concern the production itself, but may also have arisen from the market or external circumstances. We will show you the most common causes of errors and offer approaches to avoid them.
(please find also part 1 and part 2 of this article)
Production Problem #3: Robust processes, quality and productivity
“Quality is the problem number three, is that right? Quality is the most important area of all”. You might think.
Of course, quality and robust processes are among the most important aspects of extrusion. Nevertheless, the problems resulting from the areas of employee qualification and process changes often outweigh the actual quality problems. This is often due to the fact that one of the most important maxims is: “Production must run – no matter what it costs!” Motivated by this guiding principle and taking into account limited resources, the topic of “quality and robust processes” is therefore inevitably left behind to a certain extent as long as the product is considered to be “saleable”. The rule often is: “In everyday production, all plants are first of all ramped up and brought to target production speed, quality is important, but the minimum quality is sufficient. If production is running and there’s no trial run anywhere, the “optimization” can be started.” And so it happens that the optimization of the process and the increase of the product quality as well as the resource and energy efficiency comes last…
If there wouldn’t be the failure on machine 10 and the error on machine 15 as well as the necessary maintenance on machine 5… Then it can also happen that the process optimization fails completely…
Situations like this are not uncommon, because only a producing machine generates turnover.
Nevertheless, quality problems and robust processes are of course important issues that we want to address here on this page.
Therefore, these and other topics will be our topics in the next contributions:
- Surface quality
- Die drool
- Black specks
- Blowholes and vacuoles
- Fluttering of films
- Sheet travel of profiles
- Residual stresses
- Tube and entry
- Sagging
- Shark Skin
- Orange Peel
- Roughness
- Avoid tempering processes
- Increase throughput but how
- Pulsating the extruder
- Pressure fluctuations
- Mixing and homogenizing
In addition, to many articles we will provide you with supplementary materials with which you can analyse your processes step by step and exclude possible causes of errors. We use so-called Ishikawa or herringbone diagrams, which enable you to quickly and easily analyse a problem according to the exclusion principle.
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