Precision mold processing and manufacturing quality problem analysis

How to distinguish from many aspects in precision plastic mold manufacturing mold quality stand or fall? (1) product quality: product size stability, compliance, roughness on the surface of the products, products material utilization ratio and so on; (2) the service life: on the premise of ensure the quality of the products, the mould can be done by a number of fabrication or production cycles. The use of (3) the mold maintenance: whether to belong to the most convenient to use, easy mold release, production of auxiliary time as short as possible; (4) the maintenance cost, periodic maintenance and so on. Common surface defects are silver surface, bubble, dark, dark spots, surface depression, pieces of black, white, wrinkles near gate and rub marks, bad lustre and table material flow lines or corrugated, uneven color, surface scratch and mixed molten plastic particles, etc. The above all kinds of defects can be avoid by process control and mould design, such as silver and bubble is contained in the melt moisture volatilizes and low molecular volatiles when heated, precipitation at the time of melt molding mobile and elongated, caused by plastic should be fully dry before use, or avoid the melt temperature is too high. Dark lines and spots, the forehead is unequal because of plastic excessively heated, such as feed temperature is too high or the material Jane a stagnant time is too long, so that the dark material oxidation or pigment decomposition. Improper edge horn is black or carbonized exhaust. If the venting is not good, quickly melt filling one cavity to cavity sharp compression, the original air temperature more than plastic carbonization temperature, the gas accumulation in the plastic, carbide should be here to open sufficient exhaust slot can avoid this kind of phenomenon. Gate near white, wrinkles and rub marks are due to the mold temperature is too low, the melt into the cavity cooling too quickly, a into the cavity to form a thin solidification shell, shell in the melt to fill by stretching, white or become muddy due to stress, if the shell is drawn to move or torn, it presents the wrinkles or rub marks, obviously increasing the die WenCai can avoid this kind of disease, reduce the molding when the shear rate, the solidification shell from excessive tension. Corrugated plastic surface mainly USES the small gate during injection molding, should take appropriate measures to avoid them. Precision plastic mould processing and manufacturing when two parts of the surface contact, the convex surface of the summit first contact, so the actual contact area is less than the theoretical contact area greatly. The more rough surface, the smaller the actual contact area, peak pressure will increase per unit area, the convex surface wear is more easily. Even under the condition of a lubricating oil, is because the pressure in contact with the more than a critical value, the oil film tension damage the formation of oil film, exacerbating the surface layer of wear and tear. Under different working conditions, the optimal precision connector mold parts surface roughness value is different. Heavy load cases parts surface roughness value than the optimal light load. Surface roughness profile shape and surface texture of parts processing also has effect on the wear resistance of the, because the surface contour shape and surface texture affected parts processing the actual contact area and lubrication conditions. Precision mould surface layer of work hardening increase the surface hardness of the parts, so that the elastic and plastic deformation on the surface of the reduction, reducing wear and tear, and increase the wear resistance of the parts. But the excessive hardening, can make the surface layer of metal parts brittle, wear will intensify, appear even peeling phenomenon, so the precision connector mold parts surface hardening layer must be controlled within a certain range.