A Glossary of Common Terms in Plastic Extrusion

Whether you’re new to custom plastic extrusion or looking to sharpen your technical vocabulary, understanding key terminology can make the entire process clearer and more efficient. From material science to tooling design, the extrusion world has its own language. 

This glossary breaks down the most common terms you’ll encounter during a custom extrusion project. Let’s dive in.

Extrusion

The core manufacturing process in which plastic pellets are melted, pushed through a die, and shaped into a continuous profile. The extrudate is then cooled and cut to length.

Die

A precision-machined metal tool that shapes the molten plastic into the required profile. The die determines the geometry, wall thickness, and flow characteristics of the part.

Calibrator (or Sizing Plate)

A downstream tool used to cool and set the final dimensions of the extruded profile. Calibrators help maintain tight tolerances and prevent warping.

Resin

The raw plastic material used in extrusion. Common resins include PVC, PE, PP, ABS, TPE, and TPU. Resin selection impacts flexibility, durability, chemical resistance, and overall performance.

Additives

Modifiers blended into the resin to improve performance. These may include UV inhibitors, flame retardants, color concentrates, impact modifiers, or anti-static agents.

Melt Temperature

The controlled temperature at which the resin becomes molten and ready for extrusion. Maintaining the correct melt temperature is essential for consistent quality.

Barrel & Screw

The screw rotates within a heated barrel to convey, melt, and mix the plastic resin. Screw design influences melt uniformity, output rate, and processing stability.

Line Speed

The speed at which the extrusion line pulls the profile through the die and downstream equipment. Faster line speeds can increase output but require optimal cooling and control.

Tolerances

The allowable dimensional variation for the final part. Different industries have different tolerance requirements depending on application, fit, and performance needs.

Shrinkage

The natural reduction in size as plastic cools from molten to solid form. Understanding shrinkage characteristics helps ensure accurate die design and final dimensions.

Wall Thickness

The measurement of the material’s thickness in the extruded profile. Wall thickness impacts strength, flexibility, weight, and cost.

Co-Extrusion

A process in which two or more materials are extruded simultaneously to create a multi-layer or multi-color profile. This is often used for added strength, adhesive layers, or aesthetic features.

Tri-Extrusion

An advanced form of co-extrusion involving three materials. This is common for complex profiles that require multiple performance characteristics in a single part.

Cut-to-Length

The process of cutting the continuous extruded product into precise lengths. Automated cut-off systems ensure consistency during high-volume runs.

Secondary Operations

Additional processes performed after extrusion, such as punching, drilling, notching, printing, taping, or assembly. These help deliver a ready-to-use component.

Quality Control (QC)

Inspection performed throughout production to verify dimensions, appearance, material properties, and consistency. QC may include inline checks, sample measurements, and post-production testing.

The Importance of Extrustion Terminology

Having a working knowledge of extrusion terminology makes it easier to communicate your needs, evaluate design options, and collaborate effectively on custom projects. As your extrusion partner, our goal is to make each phase of the process transparent and straightforward, empowering you to bring your product to life with confidence and clarity.

Custom Extrusion with Inplex

Looking for quality custom extrusion products and services? Inplex is one of the leading custom extrusion services in the US and has almost 60 years of experience. We pride ourselves on our ability to put the right talent and technology in place to perform the best possible job for our clients.

We own a 42,000 sq. ft. facility in Naperville, Illinois, that is temperature-controlled and features an environmentally friendly closed-loop water cooling system. If you have specific needs or questions, don’t hesitate to contact us!