How To Repair Zinc Alloy Die Casting Mold

How To Repair Zinc Alloy Die Casting Mold

1. Data of formed parts and molds

Mold maintenance must first be familiar with various technical data of formed parts and the causes of unqualified formed parts, including shape, size, raw material characteristics, accuracy requirements, effect of special surface, etc. Be familiar with the structure and working principle of the mold, assembly relationship and the whole manufacturing process. However, since it is difficult to express the nonconformities of many parts clearly in drawings and words, the maintenance personnel must visit the site in person, inspect the site and observe the final parts, and master the first-hand materials of nonconforming products. Secondly, check the mold and disassemble the damaged parts, clean the parts and check the blanking size.

2. Cause analysis of mold damage

The damage causes are analyzed according to the mastered materials, the general causes are:

– Wear. It can be divided into natural wear and abnormal wear. Special attention should be paid to abnormal wear.

– Crack. Most of them are abnormal damages, and the causes can be divided into four aspects:

a. Operational reasons.

b. Causes caused by mold installation.

c. Cracks caused by mold design, manufacturing, alignment and repair.

d. Crack damage caused by workpiece material. Through the analysis of the causes of damage, on the one hand, targeted can be achieved in the repair, on the other hand, prevention should be given priority to, and the mold should be used reasonably to minimize abnormal damage.

3. Preparation of mold maintenance process route specification

Generally speaking, there are many reasons for waste products, such as their own materials, forming process, mold failure and so on. Here we mainly discuss the mold repair process of waste products caused by mold failure.

After finding the specific cause of damage, conduct process analysis, clarify the maintenance object and purpose, suit the remedy to the case and determine the maintenance scheme. For the formed parts with unreasonable structural design or poor manufacturability, it is necessary to change the structure and improve the process performance. If some parts are damaged, worn, deformed and invalid, they shall be replaced, repaired and spliced, and the machining benchmark mode, allowance and assembly correction shall be correctly selected. In combination with the actual production capacity, maintenance cycle and product batch of the enterprise, formulate the general repair steps, reasonably divide the processes, and attach the schematic diagram of processing and clamping when necessary. The method is simple, economical and practical. Various methods vary from person to person It mainly depends on the accumulation of long-term work experience. Finally, the process documents are compiled into procedure documents.

4. Parts maintenance and processing

There are great differences between maintenance parts and processed parts. Maintenance is generally local replacement and repair. Usually, the machining datum is selected according to the local size and matching relationship, and the forming is matched to meet the local assembly relationship. If it is a forming surface, the datum shall be selected according to the actual size of the forming surface for processing. The approximate method is as follows:

Replacement of individual parts

Process and shape according to the part drawing, and make corresponding adjustment and repair according to the matching relationship of the parts in the zinc alloy die casting mold, because the mold has certain wear and deformation after being used for a period of time, which is also the difference between repair and new manufacture.

Surface preparation and finishing

If the forming surface has special requirements, it can be polished and trimmed Then the surface treatment is carried out by mechanical method. For the formed surface depression, corner collapse and crack damage are not serious, corresponding materials can generally be used for repair welding. Then the repair welding surface shall be processed and formed. In addition, if the forming is not complex, the falling surface method can also be used for processing.

Inlay and mosaic

For complex formed parts, when local parts are seriously damaged, worn, deformed and invalid, if the whole part is replaced, it will take time and labor, especially when the maintenance cycle is not allowed, local repair must be carried out. In this case, inlay and inlay processes are often used. Corresponding measures are taken according to the damage degree of parts. This process method is also the most commonly used and efficient method.

5. Assembly

The mold is assembled by many parts. The assembly accuracy is the main content of the quality index. It is a necessary condition to ensure the mold work. Therefore, the maintenance worker must be familiar with the structure of the whole mold and the requirements of the parts during the assembly process, and understand which are the fitting dimensions, which are the datum plane, which are the fitting surface and forming surface, etc. For the parts and components that must be repaired, a certain trimming allowance shall be reserved according to the original assembly relationship, and the adjustment, trimming and cooperation shall be carried out in an orderly manner according to the order. Finally, the final assembly and mold test are qualified, so as to complete the repair of the whole mold.

6. Quality inspection during maintenance

In addition to the precise geometric dimension requirements, the shape and position tolerance requirements of the parts of the mold are also high, so they should be checked in the manufacturing process of the whole mold. However, because the mold maintenance is only partial repair, the involved area is not large. In the repair and processing stage of general parts, each process is self checked by the operator, and some complex single formed parts that need to be replaced are checked by the inspector according to the process. In the fitter assembly stage, assemble according to the assembly drawing and self inspect the assembly quality. After the self inspection is qualified, it shall be handed over to the inspector for inspection, so as to complete the maintenance process of the whole mold.