Die-casting Mold Maintenance

This article is a simple article, suitable for small and medium-sized enterprises, based on basic mold maintenance and maintenance. The specific mold management lean method and the application of PDCA tools will be shared in the advanced chapter.

Die-casting mold is the main process equipment for die-casting production. Whether the die-casting production process can be carried out smoothly depends largely on the rationality and technological advancement of the die-casting mold structure. It is also the most important part of the three major elements of die casting production.

The quality of mold use directly affects the life of the mold, production efficiency, and product quality and is related to the cost of die casting. For the die-casting workshop, the good maintenance of the mold is a strong guarantee for the smooth progress of normal production, which is conducive to the stability of product quality. Furthermore, it reduces the invisible production cost to a large extent and thus improves the production efficiency. According to the problems encountered in actual production, let’s discuss how to improve the mold’s maintenance.

1.Die-casting Mold Management

In the process of mold management, what most people say is quite simple and understandable, but it is very difficult actually to do it. We need to do our due diligence to implement it and do the work well. The storage of molds should be consistent with accounts, drawings, files, etc. The molds cannot be disassembled and stored to avoid the loss of parts, and the molds that have not been used for a long time should be regularly treated for rust prevention. The new mold should be treated with stress relief as much as possible within the specified period to prolong its service life.

A. Create a mold resume card

When a new mold enters the factory, a complete mold resume card should be established, which is equivalent to the identity certificate of the mold. Fill in the relevant information about the mold in the resume card, which is an important reference for future maintenance and maintenance work.

B. Mould accessories file

Structural parts need to be recorded in detail for each pair of molds in the file. And the wearing parts need to be marked. Next, create a consumables inventory list. When inventory is insufficient, replenish inventory in time to avoid production delays due to lack of spare parts.

C. Make mold sign

Make a permanent sign for the mold and install it in a prominent mold position. The sign’s content should include the size of the mold, the weight of the mold, the mold number, and the manufacturer.

D. Storage of molds

For the mold after production, the specific storage location should be specified, and the fixed-point storage meets the 6S management requirements. At the same time, there must be management kanban and mold information descriptions. Finally, make the mold placement clear at a glance, reducing the time to find the mold.

E. Maintenance guide

Formulate mold management regulations in advance. include:

  • Mold Maintenance Essentials
  • Instructions for mold maintenance work
  • Mold maintenance records
  • Mold maintenance list

Mainly explain the main content and parts of maintenance, problems that occur, and maintenance methods and standards.

2.Maintenance of Mold

Mainly explain the main content and parts of maintenance, problems that occur, and maintenance methods and standards.

A. Parting surface

It is better to clean the parting surface of the mold, and it is better to clean the parting surface twice per shift. To ensure that the mold can ensure the fit of the movable and fixed molds of the mold when the mold is closed and effectively reduce the flash burr.

Use a copper hammer to avoid damage to the mold.

B. Cavity surface and interior

Clean the inside of the mold cavity, and grind the mold strain and hot crack parts. Remove the parts that stick to aluminum. Use a coating machine to repair the mold. According to the surface roughness required by the mold, select the appropriate welding material. After repairing, it is necessary to check the mold fit.

C. Matching degree of movable and fixed die

When the mold is maintained and repaired, it is necessary to use red powder to check the fit of the movable and fixed molds and internal inserts. Prevent the mold gap from being too large to affect the product quality and mold sealing effect.

D. Fit degree of the vacuum mold

After checking the fit of the vacuum die casting mold, it is necessary to seal the mold’s inserts to ensure the mold’s sealing effect and prevent product quality problems.

E. Cooling system

Check the mold cooling system for damage. Check for leaks in the water fittings. If the inside of the pipeline is blocked, clean the pipeline. Check the condition of each valve. To check the sealing effect, parts with high pressure and cold spots need to be disassembled. High-density grease should be smeared during installation, mainly to lubricate and seal. At the same time, the mold cooling pinhole and the cooling pin must have a special one-to-one correspondence to prevent installation errors from affecting product quality during installation.

F. Ejector rod and reset rod

When the mold is repaired and maintained, it is necessary to check whether the ejector pin is bent or damaged. If found, it is necessary to replace the new thimble in time. When installing the thimble, apply high-density grease to lubricate and seal. The tail of the ejector rod and the reset rod should be marked with corresponding symbols to avoid wrong positions.

G. Vacuum die casting mold seal

The requirements of vacuum die-casting molds are higher to check the fit of the movable and fixed molds and check the sealing effect of the parting surface and the inside of the mold cavity to prevent quality problems such as air leakage. In addition, the top plate and cooling system parts need to be properly sealed. When it is found that the sealing strip is aging, it should be replaced in time to avoid air leakage during production and cause serious losses.

H. Mold inspection table

Every time you maintain and repair the mold, you need to do a careful inspection, find a problem, and solve it in time. The mold inspection table is mainly for the inspection of each part of the mold after use, and it mainly records whether there is any abnormality in the mold at that time and how to deal with it.

3.Influence of Peripheral Equipment On Mold Life

A. Temperature control island

Influence of external cooling cycle of temperature control island on mold life. The temperature control island is mainly composed of a pure water machine, chiller, intermediate water tank, fine core point cooler, and high pressure die cooler.

The entire mold cooling system uses pure water to ensure water quality, and the entire circulation system is independently closed. There are two ways of cooling water: normal pressure and high pressure, and both have an intermittent cooling function.

The opening and closing of the mold cooling water are controlled by the signal provided by the die casting machine. The influence of the external cooling system on the die-casting mold is great, and the influence on the quality of the product is also crucial

B. Mold temperature machine

In the process of starting production, the mold must be preheated to prevent the occurrence of cracks caused by the sudden encounter of hot metal liquid in the cold mold, such as preheating the mold with a mold temperature machine.

The commonly used mold temperature machine adopts internal indirect heating. The resistance wire is used to heat the protection device first, and then the oil temperature rises. The indirect heating method increases the heating speed due to the increase of the surface area and does not produce impurities to pollute the purity of the oil. It can also reduce consumption.

C. Coating machine

The coating machine can be used to repair the surface defects of the mold to prevent cracks and mold sticking effectively. The coating machine is mainly used to repair the mold to form a certain dense surface layer on the surface of the mold, which can effectively prevent the molten metal from sticking to the mold, erosion, and mold cracking. T

The coating precision is high, and the coating thickness of the mold surface can be from several microns to several millimeters. At the same time, the coating machine can also effectively improve the service life of the mold and reduce the cost of the mold.


In short, mold maintenance is to play the role of “cure the disease, and strengthen the body without the disease.” Through the usual maintenance of the mold to extend the service life of the mold, thereby improving the quality of the produced products, reducing the scrap rate, improving production efficiency, and reducing costs. At the same time, do the following:

  • In the process of maintenance, repair, and maintenance, a principle must be mastered, and it is absolutely not allowed to change the size of the mold without permission.
  • Do a good job of maintenance according to the company’s “Mold Repair Maintenance Management Regulations.”
  • For wearing parts such as ejector rods, cores, etc., should be carefully checked for bending, cracks, etc., if any, replace them in time.
  • Polish the mold to minimize the wear and tear on the mold caused by polishing.
  • All moving parts of the mold, joint parts, screws, etc., should be lubricated and rust-proof.
  • The mold management personnel supervise the maintenance status at any time and pay attention to other management details. Keep maintenance records for inquiries.