Extruder Controller Explained

Whether your industrial operation makes PVC pipes or foods such as cereal, pet food, etc., an extruder controller can be used to control heavy-duty extrusion machines.  Understanding how extrusion equipment works as well as how the devices that control them operate can help you find the right motor control products when you need to make a purchase.

Extrusion equipment is used to create various types of objects by pushing material through a pre-set die with a fixed cross-sectional setting.  Some extrusion equipment can melt, pressurize and homogenize plastic materials.  Pipes, carpet fibres, filaments, vinyl siding, films, strands, sheets, etc. can be moulded through these types of machines.  The process for extrusion (based on the desired end product) may include winding, spinning, rolling, blowing into film, folding, and other possible applications.

How an Extruder Works

The solid plastic, or resin, is fed continuously to a heated chamber where it is compressed and melted, then pushed out of the chamber at a constant rate and through a pre-determined die.  As it cools, the plastic solidifies with a cross section that matches the pattern of the die.  Dies are created in such a way so the melted plastic flows in a precise manner to get the desired shape.

A feedscrew within is used to carry the plastic along. This feedscrew is driven by a motor or drive that relies on appropriate speed and torque control to get quality results.  No matter what type of extrusion process is used, speed control is essential to assure that an adequate amount of resin is being fed into the heat chamber.  It’s also crucial that even pressure is maintained so the flow will remain consistent.  The extrusion machine should have good response to changes in torque while keeping a steady speed for high friction loads.  This challenge can be met by using a high quality extruder controller.

Whether using an AC or DC motor/drive for the extruder, there are various extruder control products that can handle basic and advanced control algorithms.  The ElitePro by Carotron, Inc. is one example.  It uses a high speed Digital Signal Processor (DSP) with five additional co-processors that can handle critical speed timing functions.  It also features external and keypad communications.

DC Drives for Extrusion Control

DC drives/motors have been used for many years to power extrusion equipment although newer AC motors are being developed to fit this need as well.  Dc motors and drives have wide ranges for constant torque speed.  They are simplistic in design and some DC drives can easily be retrofitted for existing DC motors.  These also come in smaller sizes but with larger horsepower ratings.

For those who use an extruder machine and need to upgrade their extruder controller to a new one, replacing the control instead of the entire motor can save time and money.  A sales engineer can assist you in finding the right product for your needs and how to purchase and install a new extruder control product.

*Note: If you have an extruder drive retrofit opportunity, we have full motor and drive nameplate data available and can get an answer to you more quickly!