The 3 most common production problems in extrusion – part 1

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.


Production problem #1: Product and material changes

A change of product or material is understood as the change from a special product geometry to another geometry, or also the pure change of a raw material or even a colour. Due to the fact that during such a conversation process both technical components (nozzle, tool, cooling section, haul-off, winder, support rollers, etc.) and process parameters (temperatures, speeds, etc.) have to be changed, the avoidance of waste production is usually impossible. While smaller change-over processes are often carried out while production is running, the production must be stopped for major changes.

As a result, product or material changes are time-, personnel- and material- intensive. Especially in large systems, the material change times or the rinsing times of an extruder can often take several hours.

There are therefore different approaches on the market for speeding up product and material change processes.

Technical possibilities for problem solving (examples):

  • Automatically adjustable nozzles
  • Automatically adjustable calibrations
  • Automatically adjustable cooling tanks or cooling sections
  • Use of rinsing materials, use of cleaning granules
  • Use of liquid inks
  • Flow-optimized tools and nozzles
  • Flow simulation and tool or screw optimization
  • Tool coatings
  • Process engineering purging programs, process parameters


Organizational possibilities for problem solving (examples):

  • Execution of SMED analyses
  • Workplace organisation
  • Work design, 5S or 5A
  • Analyses and evaluations of setup procedures
  • Employee training
  • Internal know-how transfer
  • Preheating of tools
  • Production scheduling


Strategic possibilities for problem solving (examples):

  • Batch size analysis
  • Stock
  • Resource costing
  • Production cost analysis and margin analysis
  • Outsourcing / Mergers

We will take up and explain all of the above-mentioned possibilities for optimizing product and material changes on this website in the coming weeks.


Production Problem #2: Staff Availability & Know-how (see part 2 of this article)

Consequences of problems such as demographic change, the general shortage of skilled workers and the frequent need to employ unskilled workers are dealt with In the second part of our article.


Production Problem #3: Robust processes, quality and productivity (see part 3 of this article)

Typical quality problems in extrusion are the content of our third chapter. These include problems such as:

  • Surface quality
  • Beard formation
  • Black specks
  • Blowholes and vacuoles
  • Fluttering of films
  • Sheet travel of profiles
  • Residual stresses
  • Tube end entry
  • Sagging
  • Shark skin
  • Orange Peel
  • Roughness
  • Avoid tempering processes
  • Increase throughput but how
  • Pulsating the extruder
  • Pressure fluctuations
  • Mixing and homogenizing

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