1. How to prepare a pre-drying procedure before ABS processing?

Pre-drying prior to molding is needed to achieve high quality molded parts. The drying process is to force the moisture out to the surface of plastic pellets and then take it out by hot air. Factors to be considered include grades and initial moisture content of the pellets, flux and humidity of inlet air, retention time, etc. The most key factors are as follows:
¡@(1) The inlet air must be dry enough so as to carry out the moisture to a maximum.
¡@(2) The temperature of pellets must be high enough so as to shorten the pre-drying period, but
¡@¡@ not too high to clog the pellets.
¡@(3) The retention time must be long enough to remove the moisture.

Typical drying conditions for different grades are :
General purpose grade 80-90¢J 2-4hrs
Flame retardant grade 75-85¢J 2-4hrs

2. Why molding defects happen?

Please check following factors carefully:
¡@(1) Mold design
¡@(2) The function of Injection machine
¡@(3) Structure design of the product
¡@(4) Molding conditions
¡@(5) Material selection
¡@(6) Operational errors
¡@(7) Operation environment
Examples of molding defects are: sliver streak, flow mark, black streak, dull gloss, weld mark, short shot, shrink, warp, poor mold release, flash, bubble, crisp, crazing, etc.

If you have any Injection molding problems, please contact our sales representatives.

3. Typical extrusion problems usually are as follows:

¡@(1) Flow mark (parallel)
¡@(2) Flow mark (vertical)
¡@(3) Waviness mark
¡@(4) Surface sink
¡@(5) Silver speck
¡@(6) Roughness
¡@(7) Dull gloss
¡@(8) Color unstable
¡@(9) Thickness unstable
¡@(10) Shrink and warp

If you have any extrusion problems, please contact our sales representatives.