Brief explanation of the plastic extrusion process…


 

The die and development process  begins with a detailed accurate part drawing, defining all dimensions and critical tolerances. Material selection is important as different materials require different die design and after forming equipment such as vacuum calibrators. For example dies for acrylic will not work for extruding polyethylene and so on. Die design and manufacturing of dies requires qualified and experienced toolmakers who possess a comprehensive knowledge of various plastic materials and their unique characteristics.

 

Once dies have been completed a die test is performed. This involves attaching the die plates to the extruder and setting up the the downstream equipment and fixtures. Some materials require that the extrusion travel through chilled water, some materials can be cooled with air alone and some require a combination of both. In many cases in order to control dimensions and shape, the extrusion once leaving the die exit plate must enter a vacuum chamber or sizer.  The extruder must now be filled with the plastic resin and brought to a specific temperature and pressure. before the process begins. 

 

Now the extrusion process  begins which entails setting extruder temperature, adjusting line speeds and setting correct vacuum in the calibrators. Now the plastic can exit the dies and travel down the line where it is inspected for drawing compliance. In many cases the die will need to be modified or remade in order for the part to match the drawing. In this case another die test must be performed.

 

When the profile meets the print requirements, the die testing phase is finished. The part is now submitted to the customer for approval. Now that we have the extrusion data to meet the print, we can set up and run production orders.

It is important for the customer to leave ample time for the development process.