TROUBLESHOOTING - ROTATIONAL MOULDING Problem ...
TROUBLESHOOTING - ROTATIONAL MOULDING Problem ...
TROUBLESHOOTING - ROTATIONAL MOULDING Problem ...
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<strong>TROUBLESHOOTING</strong> - <strong>ROTATIONAL</strong> <strong>MOULDING</strong><br />
<strong>Problem</strong> Probable Causes Suggested Remedy<br />
Poor release from<br />
mould<br />
• Lack of release agent<br />
• Improper release<br />
agent<br />
• Localised Degradation<br />
of polymer<br />
• Improper design of<br />
the mould<br />
• Insufficient cooling of<br />
the mould<br />
• Apply more<br />
release agent<br />
• Reduce<br />
temperature<br />
and/or heating<br />
time<br />
• Modify mould<br />
design<br />
• Increase cooling<br />
time<br />
Warped moulding<br />
• Sagging of hot plastic<br />
• Collapse due to<br />
vacuum formation<br />
• Excessive shrinkage<br />
• Reduce oven<br />
temperature<br />
• Vent mould<br />
• Shorten cycle time<br />
• Select proper resin<br />
grade<br />
Discoloured moulding<br />
• Polymer degradation<br />
• Decrease oven<br />
temperature<br />
and/or time<br />
Bridging of powder in<br />
mould thus resulting in<br />
poor flow<br />
• Poor mould design<br />
• Improper rotation<br />
• Modify the mould<br />
design<br />
• Select the proper<br />
grade<br />
• Modify rotation<br />
ratio and / or<br />
speed<br />
Pin holes, bubbles,<br />
rough inner surface<br />
• Maximum<br />
temperature attained<br />
by polymer too low<br />
• Increase cycle<br />
time<br />
• Increase oven<br />
temperature<br />
• Select proper<br />
grade<br />
• Dry mould before<br />
charging<br />
• Reduce wall<br />
thickness<br />
• Provide venting<br />
Poor Impact resistance • Cooling rate is too • Check venting in<br />
Reliance Industries Limited, Maker Chambers IV, Nariman Point, Mumbai. 1
slow<br />
the mould<br />
• Increase cooling<br />
rate<br />
Excessive flash<br />
• Poor parting line<br />
• Remake parting<br />
line<br />
• Check venting<br />
Long oven cycles<br />
• Oven temperature<br />
too low<br />
• Oven capacity<br />
insufficient<br />
• Moulds shielded<br />
• Increase oven<br />
temperature<br />
• Increase air<br />
circulation<br />
• Avoid shielding of<br />
the mould<br />
• Select proper<br />
grade<br />
Reliance Industries Limited, Maker Chambers IV, Nariman Point, Mumbai. 2
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