How did the injection mold cavity damage occur?Its elimination method?
(1) repair of failure of mold bite and damage.
The mold bite has occurred.
A. The parting of the mold is combined with the surface of the molding products. Due to the long opening and closing actions, the edges are obtuse due to extrusion, impact and other reasons.Frequent high pressure injection and ejection, remove the parts, make the working face wear or erode.
B. Hardening treatment on the surface of the contact surface of the sliding parts, the whole part can be put into the water, and the surface of the hardened surface will be exposed to the surface for flame quenching.However, it is better to adopt high frequency quenching for the sliding parts of the sales class, and the diffusion carburizing and nitriding are generally adopted.
C. For the contact surface selection of sliding parts, steel and brass are better than other materials.It is best to add a little bit of molybdenum or copper powder on the sliding surface as lubricant.
D. Generally, the sliding clearance of the mould increases and the guide rod is loose.When forming, due to large pressure on the sliding part, mold deformation or distortion leads to bite mode.Mould rigidity should be increased, deformation should be reduced and fit clearance should be adjusted properly.
The repair of the bite mold.
A. The bite part is cleaned, carefully removed the stuck parts, and sanded the burr with sandpaper.When producing sag, the edge of the sag should be ground into rounded corners so as not to bite the mold again.It can also be used for welding repair after the bite part is removed, but the welding material must be the same, and silver and copper solders can be used.The wall thickness is too thin to be repaired by electric welding.
B. If there is a jamming on the sliding core or sliding surface, it is better to use a small drop, oil stone and sandpaper to polish the light, and when it is stuck, the welding repair shall be adopted.When the corner pin is stuck, because the pin is thinner, it must be remanufactured in most situations. When the card injury is not serious, it can be plated with the plating method.
(2) repair of cavity damage and damage.
The cavity damage occurred.
A. When the plastic part is not taken out, the mold is closed, especially when it is automatically formed, the mold that is most prone to solidification should be equipped with a stripper detection device.
B. When the hard object touches the mold cavity, such as using a screwdriver and other hard tools to remove the plastic parts, the screwdriver touches the cavity surface.After the mold is opened, do not abuse the tool on the mold, causing the hammer, wrench, file and other hard objects to fall into the mold cavity.Each injection molding machine should be equipped with a set of plastic parts that can be left in the mold cavity without damage to the mold cavity, such as brass scraping spoon, brass rod, copper hammer, mace, copper block, etc.
Repair of damage.
A. The method of welding.Welding is suitable for repairing scar weld thickness of 0.1 ~ 0.1 mm, but does not apply to the Angle of repair, adopts brazing is more convenient, when welding the weld alloy with nickel and copper alloy as well: the fix weld brazing suitable thick scar, the momentum brazing is more convenient, silver or brass alloy solder as well.
B. Use the percussion method to repair the surface wrinkles.A small blind hole can be opened on the back of the damaged part of the cavity, then a metal rod is placed in the hole, and a hammer is used to make the damaged surface smooth and smooth.But be careful not to knock too heavy, or easy to crack.
C. The method of caulking.This method is mainly used for local repair the parting surface, can leave the injury with chisels knock about 3 mm, make the dent uplift, tapping point try to stay further apart, tapping range larger, then the part of the uplift in file file, reoccupy oilstone grinding. Sand paper polishing.
D. Method of embedding.This is one of the most commonly used patching methods. The drawback is that it will leave a trace after the repair, and it should be confirmed before the repair that the surface pattern of the plastic parts is affected.The material of the embedded parts should be consistent with the basic material of the mould, otherwise the different shrinkage coefficient will lead to the insertion of the embedded parts and increase the trace of the embedded parts.In determining the location of the embedded parts, the cooling water hole and the screw hole are sometimes involved. Special attention should be paid.
E. Electroplating method.For the wound depth of 0.3mm, it can be repaired with electroplating method. The coating thickness can reach 0.8mm and copper can reach 1mm, but the coating on the corner can not be too thick.The electroplating method is generally used to repair mold cavity damage on the back of plastic parts.