Injection Mould Manufacturing

Today, we are going to share some basic common sense in our injection mold manufacturing process.

Since the 1980s, the molds have been developed all the way. Some friends around are talking about injection molds, hardware molds, from time to time. You may ask: What it is the injection mold? Mold is not only the mother of industry, but also the foundation of life. Life is happy, but we can't forget the basics. We must know what this is an injection mold. A simple description is a device for producing a (usually large batch) plastic part or product by forming the cavity(s) formed by the assembly, shaping the desired shape of the article.

The old saying goes: If the upper beam is not straight, the lower ones will go aslant., the mold is a tool for forming and processing, and it is like the lower beam, so it requires accurate size, smooth surface, reasonable structure, high production efficiency and easy automation. It also has to be easy to manufacture, high in mold life and low in cost. Also consider that the design meets the process needs, economically reasonable, etc. The design of the mold structure and the selection of parameters must consider factors such as rigidity, guiding, unloading mechanism, positioning method, gap size, etc. The wearing parts on the mold should be easily replaced. There is also a need to consider the rationality of the five factors: product structure, cavity, pouring, ejection, and cooling. In order to increase productivity and reduce runner casting loss, a multi-cavity mold can be used, that is, multiple identical or different articles can be simultaneously completed in one mold. The production of molds is generally one-piece, small batch production, and the manufacturing requirements are strict and precise.

Therefore, sophisticated processing equipment and measuring devices are often used. So what kind of machinery do we use for cavity machining? CNC machining pockets are often used, but temporary technology, cavity corners or too small structures cannot be processed directly. Then the engraving machine processes our electrodes, and the electrodes are clamped to the EDM machine to discharge and etch some small corners of the mold. This is also called the EDM machine. Usually, the mold structure is complicated, and the setting method is also selected. Some structural positions are split to facilitate precision machining, and a precision grinding machine is indispensable. The CMM measuring machine and projector are the precision measuring equipment commonly used in the injection mold manufacturing.

After the injection molding manufacturing process is finished, a lot of knives or patterns and sand marks will leave on the surface of our mold. After the injection, the corresponding products will appear on the surface of the product, which is also the principle of genetic inheritance. So we need to do the surface treatment of the mold, called grinding and polishing. The surface grinding and polishing of the cavity is generally performed by electric or pneumatic tools, with various grinding, polishing wheels and abrasive powders, or by ultrasonic grinding, extrusion honing, chemical polishing etc,.

Molds are precision tools that are expensive and mold life must be as long as possible. The normal failure modes of the mold mainly include wear and rust, collapse and fracture, and bonding, and the failure modes of the molds for different purposes are also different. The way to improve the life of the mold is mainly based on the application conditions, reasonable selection of mold steel and determination of heat treatment specifications. Selecting materials with high strength at the use temperature can prevent collapse; increasing the hardness of the mold can reduce the wear rate; higher toughness and fatigue resistance, as well as eliminating the hardened layer and machining residual stress of the electrical processing, can hinder the generation and development of cracks, Prevent cracking. Surface treatment, lubrication and selection of mold materials with good adhesion resistance are important measures to extend the life of the mold. In addition, reasonable operation is another way to eliminate abnormal failure and slow down normal failure.