We can see many thin-walled injection molding things in our lives, so what are the common problems in thin-walled injection molds? Next, let’s learn about it with the editor of Aojie Mould.
common problem:
6. Raw edges
Causes: The joints between male and female molds often occur, due to poor mold clamping, or improper processing of the corners of the mold surface, often due to insufficient clamping force, high material temperature and pressure, etc.
Mold correction: re-clamp the mold
Improvement of injection molding: increase clamping force (check whether the tonnage of the injection machine is sufficient), reduce material temperature, reduce injection pressure, reduce holding time and lower holding pressure, etc.
7. Deformation
Causes: slender parts, thin-walled parts with large areas, or larger finished products with asymmetrical structure due to uneven cooling stress or uneven ejection force during molding
Mold correction: correction of the thimble; setting of tensioning pins, etc.; if necessary, the male mold is added with a bite to adjust the deformation
Improved injection molding: adjust male and female mold temperature to reduce holding pressure, etc. (The adjustment of small part deformation mainly depends on the pressure and time, and the adjustment of large part deformation is generally based on mold temperature)
8. Unclean surface
Causes: The mold surface is rough. For PC materials, sometimes due to the high mold temperature, there are residual glue and oil stains on the mold surface Mold correction: cleaning the mold surface, lighting treatment
Injection improvement: lower mold temperature, etc.
9. Pull white
Causes: It is easy to occur at the thin-walled corners of the molded product or the root of the thin-walled RIB. It is caused by poor force during demolding, improper setting of thimble or insufficient draft angle. Mold correction: increase the R angle at the corner; increase the demolding angle; increase the thimble or increase its cross-sectional area; the mold surface is polished; the thimble or the inclined pin is polished Injection improvement: reduce the rate of fire, reduce the injection pressure, reduce the holding pressure and time, etc.
10. Die
Causes: It is manifested as poor demolding or mold damage, drawing, mainly due to insufficient draft angle or rough mold surface, and molding conditions are also affected
Mold correction: increase the draft angle; polish the mold surface; add/change the pull pin when sticking to the female mold surface, pay attention to the horn Φ diameter when feeding the horn, and add biting to the male mold
Injection improvement: reduce injection pressure, reduce holding pressure and time, etc.
11. Stoma
Cause: Transparent finished PC material is easy to appear when molding, because the gas is not exhausted during the injection molding process, improper mold design or improper molding conditions will have an impact
Mold trimming: increase the exhaust, change the gate (increase the gate), the PC material runner must be polished
Injection improvement: strict drying conditions, increase injection pressure, reduce injection speed, etc.
Post time: Aug-27-2021