Custom Injection Molding Company | Plastic Injection Moulding Services | Mulan Manufacturing Group Contact@china-plasticparts.com
Author: MULAN -Plastic Molding Manufacturer
When the mold parts have the above-mentioned defects, qualified fastener products cannot be formed, which will inevitably affect the production plan of the enterprise. Preventive measures In order to prevent early failure of injection molds and effectively prolong the service life of molds, injection mold manufacturers mainly take corresponding preventive measures from the following aspects. 1. Mold material Because the cold working mold bears a large unit extrusion force, high-performance mold materials with high strength, good toughness and good wear resistance should be selected; because the working conditions of the punch are more susceptible to eccentric forces than the die , Therefore, the wear resistance of the punch material should be selected higher than that of the die material.
2. Heat treatment The heat treatment of the mold includes: timely tempering after forging of the cold-work mold blank to refine the grain, tempering after rough machining to eliminate stress, and low-temperature tempering for stress relief after EDM and wire cutting. Experience shows that for molds with a diameter of ≤80mm, it is advisable to use bar stock for direct machining without forging, because improper forging will cause defects such as overburning, coarse grains, and segregation. If the quenching cooling rate is too fast and the temperature is too low, the mold is prone to quenching cracks.
If the tempering temperature is too low and not sufficient, the residual stress in the quenching process will not be eliminated, the toughness of the mold will be reduced, and early fracture will easily occur. 3. Mold design The structure of the cold working mold must have sufficient strength, rigidity, reliability and good orientation, but the unreasonable structure of the mold will directly affect the service life of the mold. The working part of the mold should be designed with a sufficiently large fillet radius to avoid stress concentration caused by sharp corner transitions. The width of the ligament should be reasonably designed according to the metal flow to minimize friction, generally between 1.5-3.5.
4. Mold processing In the process of mold cutting, the following measures should be taken: improve the surface roughness, the traces of micro-cracks formed by grinding, and the transition part should be smooth, and the tool marks and small defects cannot be machined to prevent stress during use. Concentration leads to cracks.