07-10
Gas assisted injection molding is a special injection molding technology developed on the basis of traditional thermoplastic injection molding technology, which is suitable for special performance req...
Metal insert molding is a manufacturing technique that involves inserting pre-fabricated metal inserts into a mold at specific locations. Molten plastic is then injected into the mold cavity. Once the plastic has cooled and solidified, the metal inserts become firmly embedded within the finished product.
The metal insert that is added can be placed either by hand or by a machine, depending on how precise the plastic part needs to be. This technique can lower the amount of assembly steps needed by adding various metals or materials during the injection molding process.
In injection molding, cracking of plastic products is a headache vexing problem. It's quite common for metal inserts to crack when used with rigid plastics.
This is due to the difference in thermal expansion coefficients between the metal inserts and plastics, with the insert's temperature being much lower than that of the material. The insert can only transfer temperature through the material, but it cools down rapidly. If the cooling rate surpasses the plastic's limit, the metal will crack during mold removal.
Therefore, to avoid this, preheating the metal insert before injection molding is necessary to adjust the thermal expansion coefficient difference between the insert and plastic.
