A customer with a TPE overmolded handle told us that their product had fringes and they wanted us to help them deal with it. What is a "edge"? This is called from Taiwan, there are some will be called so, the book is called "overflow edge", commonly known as burrs, burrs often appear in the overmolded plastic injection molding products of the parting surface or cavity assembly line or hole and other parts, is burrs, burrs, mostly in the mold on the combination of the location of the module. Such as: the parting surface, the aperture of the ejector pin, the matching parts of the slider, the gap of the insert, the aperture of the ejector pin and so on. Flying edge is not corrected in time may affect the product appearance or affect the exhaust in the process of filling the mold; if the flying edge is too large, the debris generated in the process of demolding may remain inside the mold, resulting in cold material products, serious will also make the mold to produce a permanent indentation, if the debris remains in the moving parts, such as the slider, the thimble, etc., it may also lead to the mold movement is not smooth.

　　The main reason for its generation of TPE overmolded handle fretting:

　　A:TPE/TPR material aspect

　　1, whether the viscosity is too high or too low may cause the product flying edge, too low viscosity resin such as paraformaldehyde

　　Solution: Attention should be paid to improve mold precision, reduce mold clearance, improve the clamping force;

　　2, high viscosity resin will cause excessive flow resistance, increase the cavity back pressure in the mold filling process, which leads to mold parting solution: mold gap, and ultimately the formation of fretting.

　　B: injection mold causes:

　　1, the mold closing surface has a gap, mechanical spare parts with poor or parts deformation, inequality may lead to the emergence of burrs; injection molding pressure, speed is too fast.

　　Solution: check the mold, whether there are foreign objects attached to the mold parting surface, resulting in mold clamping is not tight; spare parts are damaged, spare parts are not good with the targeted overhaul.

　　2, reduce the corresponding injection molding process.

　　a) injection pressure is too large, need to reduce or earlier from the injection pressure to holding pressure.

　　b) Reduce the screw forward time and reduce the injection speed.

　　c) Properly reduce the amount of injection molding and reduce the temperature of the melt.