Plastic product manufacturers often work intermittently after putting molds into production. During annual production, molds need to be stored for a considerable period of time. Therefore, whether molds can be properly stored during non working periods to avoid accidental damage is one of the important links to ensure that molds reach their expected service life.

1. Establish mold archives

    The molds used in the workshop are exchanged according to production needs. A machine needs to have several or even more than ten sets of molds exchanged and used each year. The frequent exchange and repair of molds should be recorded in detail. And managers are required to keep track of all aspects of the existing molds at all times, and regularly propose replacement mold names, mold spare parts, spare parts details, etc. Therefore, it is necessary to establish a mold archive, whose content is shown in Table 1

Table 1 List of Mold Archives

The establishment of detailed mold archives can regularly provide decision-makers with suggestions for mold repair and maintenance, as well as spare parts processing and procurement plans. Provide reasonable and objective materials when making decisions on mold scrapping and production of replicas. At the same time, the mold is effectively maintained during production and use. Once a production malfunction occurs, it can be quickly resolved in a short period of time to ensure the normal operation of the production line.

2. Repair before storage

If the mold is used for a period of time and needs to be replaced, the raw materials or color masterbatch that are prone to carbonization or residual color lines should be cleaned, and the power and cooling water on the equipment should be cut off in the required order. Measures should be taken to clean up residual cooling water in waterways.
After dismantling the mold, important dimensions should be checked, and mold parts that need to be repaired or replaced should be indicated.
After confirming that the mold is intact and undamaged, it needs to be thoroughly cleaned to check for any residual materials in the mold cavity, and to check for any pulling or collision damage on the clamping surface and slider working surface.
The surface of the cavity should be carefully inspected. When poor exhaust or abnormal surface of the cavity is found, maintenance work such as sandblasting (or etching) can be carried out.
After cleaning the cavity, to prevent rusting, apply machine glycerin. It is best to apply anti-corrosion materials to the surface at room temperature to prevent side effects caused by temperature changes.
The supporting devices of the mold should be organized, and if necessary, some devices can be disassembled, classified and arranged in the box, marked, and placed together with the mold to avoid loss or damage during the loading and unloading process.
Before transporting the mold to the storage location, the residual cooling water in the machine and residual oil in the oil pipe should be cleaned, and then the moving and fixed molds should be fixed with locking plates to prevent arbitrary opening.
The cavity degreasing treatment should be carried out before the mold is reused. The degreasing method is generally to use liquid agents such as trichloroethane and trichloroethylene for cleaning, or acetone for cleaning. However, attention should be paid to fire prevention during use.

3. Storage management of molds

The storage location of the mold should be flat, dry, and clean, making it easy to lift and transport. Small molds can be stored in storage racks arranged in order, while large molds can be placed directly on the cushion. Storage should be classified and divided, and molds that match the same product should be placed together. The storage precautions for molds are shown in Table 2. The specific method of storage varies depending on the actual situation and conditions of each unit, making it difficult to enforce regulations, but the precautions are generally similar.
 

Table 2 Precautions for Storage of Molds

Molds are mostly valued by operators during use, but they are often overlooked during storage. However, in actual production, cases of heavy production losses caused by poor mold storage and storage often occur, and it cannot be ignored.
At present, in most domestic manufacturers, there is no standardized system for mold management, and management methods are formulated according to the size and characteristics of each manufacturer. Small and medium-sized enterprises and large enterprises, as well as professional and non professional plastic factories, have different management methods for plastic workshops. However, in terms of basic practices and expected purposes, there are similarities and differences. Each enterprise should establish a management system based on their own characteristics and actual situation, so that molds can be properly stored in management and achieve the expected service life.

The expected service life of the designed mold is guaranteed in terms of design structure, material selection, heat treatment arrangement, and machining accuracy; On the other hand, effective maintenance and upkeep are required during prolonged use.

1. Regular inspection and oiling
The normal production of molds involves continuous work, with a work cycle ranging from one month to several months. During this period, in order to ensure the batch supply of parts, it is necessary to ensure the uninterrupted normal operation of the mold. During the shift handover, in addition to the handover of the quantity of production products, the operator also needs to have a detailed handover of the usage status of the mold.
The operator who takes over the shift should apply oil to the working surface of the sliding components, especially in high summer temperatures. Each shift should apply oil twice to prevent dry friction and even pulling the working surface.
The mold keeper shall conduct a patrol inspection of the molds in operation in the workshop and promptly handle any abnormal phenomena found. During a period of normal operation, if the shutdown is expected to exceed 24 hours, the surface of the mold cavity should be coated with oil for rust prevention (or sprayed with rust inhibitor). Especially in humid areas and rainy seasons. The moisture in the air can reduce the surface quality of the mold cavity and the surface quality of the product.
The anti rust and corrosion work of the polished cavity is more important. It is not necessary to touch the working surface with your hands casually, but to use absorbent cotton, gauze, and other cloth products to remove dirt.
Even materials with strong corrosion resistance such as stainless steel or S136 cannot ignore rust prevention work.
2. Timely remove excess materials and dirt, and maintain internal and external cleanliness
Every time the product comes out of the mold cavity, it is inevitable that there will be some excess material left in the cavity, gaps, or other parts. Dust and other dirt from the workshop will also adhere to the mold cavity. Therefore, it is necessary to clean the surface of the mold cavity in a timely manner. During continuous work, a small cleaning of dirt and impurities should be carried out once a week, and a comprehensive cleaning should be carried out once a month.