Operator Training Courses for Harrel TUBETROL(R) Automated Tubing Extrusion Systems


Plastics extrusion plants seldom can spare the supervisory time to train operator thoroughly on hi-tech extrusion equipment. The result is that a great deal of the savings through automation are lost, because the operators simply do not know how to take full advantage of it.

To help Harrel customers deal with this problem, Harrel offers training courses in its Plastics Extrusion Development Laboratory in East Norwalk, CT, U.S.A, to give operators the hands-on training they need to utilize fully the automation potentials of Harrel Hi-Tech Equipment. Some of the topics covered:

General Principles:

  1. How a screw type pump - an extruder - works. "Stick to the barrel; slip on the screw!"
  2. Control of the extruder parameters: Temperature.
  3. RPM Control
  4. Control of pressure
    • Care and feeding of pressure sensors
    • Pressure control
  5. Melt pumps
    • Why?
    • How they work.
    • Stabilization of throughput compared to extruder used alone.
    • Increase in throughput.
    • Cleaning
  6. Control of the Plastic Flow:
    • Melt temperature control
    • Melt pressure control.
  7. Control of the product -- TUBETROL
    • Automated Control of outside diameter
    • Automated Control of Inside Diameter
    • Automatec Control of layer thickness in coextruded products
    • Automated Control of OD and ID of both bump and stem of bump tubing.



Hands-on Operation of a Harrel Automated Bump Tubing Line

  1. Familiarization with Equipment
    • CP-873 DIGIPANEL Controller
      • Overall System diagram
      • Set points
      • Bump tubing setup screen
      • Display in any of 4 languages
      • Time Machine
      • Trim Procedures
      • Temperature plots
      • Trend plots
    • DIES
      • Importance of separate temperature zone on "snout"
      • SPIRODIES
    • TROUGHS
      • Adjustment of water flow for good uniformity without excessive turbulence.
      • Cooling medium from chiller separate from process water
      • Cleaning of reservoir.
      • Air wipe
    • LASER GAUGE
      • How it works
      • Routine calibrataion
    • PULLER
      • Care of rolls
      • How to replace rollers.
      • Roll spacing adjustment
    • CUTTER
      • Importance of closs fitting bushings.
      • Adjust RPM of knife.
      • Cut counting,
      • Cleaning
      • SAFETY FIRST!


  • Operating the line to make precision bump tubing.