Troubleshooting guide for Raffia Tape Extrusion Applications
Raffia Tape Extrusion Troubleshooting
Problem
Probable Cause
Suggested Remedy
Temperature Setting
Temperature setting are crucial parameter for proper plastic processing ,hence one should check temperature controller, thermocouple and solid state relay(SSR)
- when you cold start the machine ,wait for 2hours.
Slippage of material in the extruder
- Contamination of material
- Melt flow index of material much higher in the higher weight material component
- Higher extrusion temperature
1. Check material for contamination
2. Use lower MFI material
3. Reduce extrusion temperature
Film breakage
1. Slippage of material in the barrel
2. Agglomerate formation at feed zone
1.Check for cooling water circulation, reduce feed zone extrusion temperature
2. Reduce extrusion temperature
Film puncher
- Contaminated die lip
- Improper temperature profile
- Clean die lips
- Maintain die temperature profile
Bubbles in film
- Material contains too much moisture
- Too coarse screen
- High level of moisture in masterbatch
- Use drying operation or raise drying temperature
- Use fine mesh screen backed up by a coarser screen plate
- Use drying operation for antistatic masterbatch
Wrinkles in film
- Variation of moisture, film thickness
- Quench tank temperature too low
- Film guide rolls of quench tank not rotating properly
- Adjust die lip, check film thickness
- Increase quench tank temperature
- Check film guide rolls for jamming
Tape breakage
- Contaminated die lip, variation of die gap
- Too high or too low quench tank temperature
- Poor hot plate circulation, high stretch ratio, damaged hot plate surface
- Clean and reset die lips, reduce quench tank temperature
- Optimize hot plate temperature, slightly reduce the stretch
- Check hot plate surface for deposits or serrations caused by running tape and repair it
Low strength of tape
Higher melt stretch ratio at quenching, higher air gap, melt temperature too low, hot plate/oven temperature at lower stretch ratio too low or stretch ratio higher.
Reduce melt stretch ratio, reduce quench tank temperature, reduce air gap, increase hot plate/oven temperature to optimum level, increase stretch ratio.
Elongation of tape
Higher melt stretch ratio at quenching, higher air gap, too low hot plate/oven temperature.
Reduce melt stretch ratio, reduce air gap, increase hot plate/oven temperature to optimum level, increase stretch ratio.
Variation of tape denier
Non-uniform film thickness, variation in spacer thickness variation in first godet speed quadrant, due to open-loop (lack drive) slippage at godet, border pressure roll or damaged rubber component, not working properly or control system.
Adjust die gap and clean die if required, check first godet speed control system, check rubber pressure rolls for damage or replacement, increase hot plate/oven temperature and actual set temperature of hot plate/oven.
Fibrillation or longitudinal splitting of tapes
Contaminated die lips, non-uniform film thickness, blunt cutting blades on spacer rod, particles in film, tape separation too high stretch ratio, higher winding tension, damaged traverse guide of winders.
| Adjust die gap and clean die if required, replace damaged cutting blades, correct film thickness, polish hot plate surface at damaged portion, increase hot plate/oven temperature and reduce stretch ratio, adjust winding tension. |
