Troubleshooting guide


Downsizing is a frequently used solution to a number of processing problems caused by shot capacity being too large. However, downsizing reduces residencly time and increases injection pressure. It also forces you to use a longer stroke which will give you better process control. If you think downsizing could help you, please Contact a General Plastex representative or call 1-800-777-4719 .

Common Problems and Where to Look for Solutions

Processing problems could have many different causes or a combination of causes. Since screws and barrels are one of the key components in any processing machine, replacement or changes in their design could help your machines run more efficiently. Here are some things to look for:

Look For:

  • Poor screw design
  • Wrong compression ratio
  • Need mixing device on screw
  • Improper L/D
  • L/D is too short
  • Need mixing device on screw
  • Poor screw design
  • Wrong compression ratio
  • Improper heat profile
  • Worn screw and barrel
  • Poor root surface
  • Misaligned valve seating
  • Improper heat setting
  • Long residency time
  • L/D is too long
  • Worn valve
  • Worn barrel
  • Injection unit too small
  • Improper heat setting
  • Poor seating surface on face of screw
  • Check ring travel
  • Too much injection pressure
  • Injection unit too large
  • Improper cushion