Troubleshooting guide for Printing of Film Applications
Printing of Film 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.
Abrasion- Cylinder wear
- Poor dispersion
- Foreign matter
- Excessive blade pressure
- Corrosive ink
- Regrind the ink
- Filter ink
- Reduce blade pressure
- Consult ink makker
Adhesion- Ink or varnish does not bind to each other or to the substrate
- Improper thinner used
- Ink film not cured
- Improper ink used
- Consult ink maker for proper thinner
- Increase oven temperature
- Consult ink maker
Blocking- Ink adheres to back of the web in rewind
- Too little oven temperature
- Thinner used is too slow for press speed
- Trapped solvent
- Web too hot when rewound
- Excessive rewind pressure
- Check oven temperature if necessary
- Use fast evaporating thinner
- Use proper solvent ratio
- Reduce web temperature, use chill rolls
- Adjust web tension
Mottled Print- solid areas have variation in colour intensity grainy pattern
- Viscosity too low
- Cylinder too deep or cylinder worn
- Improper rubber roller pressure or rubber roller is damaged
- Solvent evaporation is not good
- Increase viscosity with fresh ink
- No immediate solution replace cylinder
Offset on idler roller- printed image transferring to idle roll
- Ink drying too slowly
- Ink viscosity too high
- Oven temperature too low
- Use faster thinner blend
- Reduce viscosity
- Increase oven temperature and air velocity
Pinholes- small uncoloured holes in printed area
- Rough or contaminated substrate
- Ink fails to flow out
- Contaminated ink
- Increase impression pressure
- Reduce viscosity, retard ink drying in the cells of the cylinder
- Discard ink
Rub or Scuff- Dried ink rules off printed product
- Ink improperly dried
- Wrong ink for the job
- Increase oven temperature and air velocity
- Consult ink maker
Screening or mottle effect- Ink not flowing out-define pattern of cells walls
- Ink viscosity too high
- Cylinder worn or cell too wide
- Ink starvation
- Reduce viscosity with recommended reducer
- Remake cylinder
- Increase ink flow (raise the ink pan)
Static- hairlines of ink starting from printed area occurring in random directions
- Ink viscosity too low
- Static in the web
- Raise the viscosity with fresh ink
- Use static charge eliminator (Antistatic bar)
Striation- Wavy print pattern in direction of web travel
Ink viscosity too low
Raise the viscosity with fresh ink
