Honeywell CS071AE User Manual page 12

Description of Problem
Plastic sheet sticks to the plug.
Excessive sheet sag.
Sag levels vary from sheet to
sheet.
Billow height or depth is
varying.
TROUBLE-SHOOTING GUIDE
Possible Causes
• Poor material distribution.
• Plug temperature is too hot.
• Wrong material is being
used for the plug.
• Sheet heated too hot.
• Poor hot strength on the
plastic material.
• Sheet area too large in
relationship to the depth of
draw.
• Sheet temperature varying.
• Improper use of regrind.
• Sheet temperature is uneven. • Check oven for drafts.
• Vacuum or air leaks in the
billow box or seal edge.
• Air pressure or vacuum
volume too great for the size
of billow box.
Possible Corrective Action
• Check the sheet for uneven
thickness.
• Check for uneven heating.
• Decrease the plug temperature.
• Cover the plug with an insulative
material.
• Use mold release on the plug.
• Change the material to an
acceptable material.
• Cover the plug with an insulative
material.
• Decrease cycle time.
• Decrease heater temperature.
• Select a different material.
• Use screening or shading to reduce
the heat in the center of the sheet.
• Change forming techniques.
• Check for drafts in the oven.
• Check for power variations.
• Melt index of the plastic is erratic.
• Avoid mixing regrind with various
melt indexes.
• Avoid using regrind that has little
rheological life left.
• Control the quality of the regrind.
• Check heating elements for power
variations.
• Check heating elements for proper
operation.
• Screen the oven to control
temperatures in given areas of the
sheet.
• Check the seal in the billow box.
• Reduce the vacuum volume or air
pressure to cut down the sensitivity
of the billow. (Widen the
processing window)
• Put in a sag eye in the billow box.
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