Moulds are Heart of Precision Manufacturing
What is moulds ? A mould is a tool used to make a shaped item.The use of molds in life is very extensive, and there are many types of them.Although it is only a model, many products are produced based on moulds,which has plastic injection mould and composites compression mould and the role of molds is becoming more and more important.
The mold design is not made out of thin air, but is designed according to certain requirements. Whether it is material, shape, size, and smoothness, it must be completed according to the requirements.
- Mould are shaped tools: A mold is a model shape tool for mass production of identical products. After the mold is finished, inject some materials into it, and then open the mold to get the expected product. The common plastic molds are often iron molds. Inject molten plastic into it, cool it for a while, and take it out to be a molded plastic product.
- Mould is the mother of industry: In addition to the mold itself, it also needs a mold base, a mold base, and a mold core to cause the ejection device of the product, etc. These parts are generally made into a general-purpose type. Known as the “mother of industry”, a mold is a cavity tool with a certain shape and size. It is used in conjunction with various systems or auxiliary mechanisms in the mold to fill various high-temperature liquid materials into the mold cavity. Industrial parts can be produced with a specific shape, size, function and quality.
Mould making is an art that combines precision engineering with creative design. It is the process of creating a cavity or a series of cavities into which a liquid or pliable material is poured to form a product with a desired shape and detail. This process, known as casting or molding, is fundamental to industries ranging from food and packaging to automotive and aerospace.
Historical Significance
The history of mould making dates back to ancient civilizations, where artisans used moulds to create coins, pottery, and jewelry. Fast forward to the industrial revolution, and the role of moulds expanded exponentially with the advent of mass production techniques.
Types of Moulds
There are many types of molds.According to the processing object and processing technology, they can be divided into:
- Molds for processing metals.
- Molds for processing non-metals and powder metallurgy. Including plastic molds (such as two-color molds, compression molds and extrusion molds, etc.), rubber molds and powder metallurgy molds. According to the structural characteristics, molds can be divided into flat punching molds and cavity molds with space. Molds are generally single pieces and produced in small batches.
Classification of molds
There are many types of molds, so we will not introduce them in detail here. We will explain the various types of molds in detail in another article.
Here, we mainly say that according to the different materials being molded, they can be divided into hardware molds, plastic molds, and special molds.
- Hardware molds : including stamping molds (such as punching molds, bending molds, drawing molds, hole-turning molds, shrinkage molds, undulating molds, bulging molds, shaping molds, etc.), forging molds (such as die forging molds, upsetting molds, etc.), extrusion molds, extrusion molds, die-casting molds, forging molds, etc.;
- Non-metal molds : plastic molds, inorganic non-metal molds, sand molds, vacuum molds and paraffin molds, etc.
Among them, with the rapid development of polymer plastics, plastic molds are closely related to people’s lives. Plastic molds can generally be divided into: injection molding molds, extrusion molding molds, gas-assisted molding molds, etc.
Mold composition
In addition to the mould itself, it also requires a mold base, a mold frame, a mold core, and a part ejection device, etc. These parts are generally made into universal types. Mold companies need to expand and refine, and determine product positioning and market positioning based on market demand, technology, capital, equipment and other conditions. These practices are especially worth learning and drawing lessons from for small mold companies, and they should concentrate their efforts to gradually form their own technical and product advantages. Therefore, my country’s mold companies must actively strive to learn from the experience of these advanced foreign companies for better development in the future.
Mold steel material
The most important factors of mold material are thermal strength and thermal stability. Commonly used mold materials: Working temperature Forming material Mold material
<300℃ Zinc alloy Cr12, Cr12MoV, S-136, SLD, NAK80, GCr15, T8, T10.
300～500℃ Aluminum alloy,copper alloy 5CrMnMo,3Cr2W8, 9CrSi,W18Cr4V,5CrNiM, W6Mo5Cr4V2,M2.
500～800℃ Aluminum alloy, copper alloy, steel titanium GH130, GH33, GH37.
800～1000℃ Titanium alloy, steel, stainless steel, nickel alloy K3, K5, K17, K19, GH99, IN100, ЖC-6NX88, MAR-M200, TRW-NASA, WA.
>1000℃ Nickel alloy, copper-based alloy molds, cemented carbide molds.
Classification of gate system
Based on the different types of pouring systems, plastic molds can be divided into three categories:
Large sprue mold
The runner and gate are on the parting line, and are demolded together with the product when the mold is opened. The design is simplest, easy to process, and the cost is low, so many people use the large sprue system. The plastic mold structure is divided into two parts: the movable mold and the fixed mold. The movable mold (mostly the ejection side) moves with the injection molding machine, and the fixed mold is generally inactive at the injection end of the injection molding machine. Because the fixed mold part of the large sprue mold is generally composed of two steel plates, this type of structural mold is also called a two-plate mold. The two-plate mold is the simplest structure of the large sprue mold.
Fine sprue mold
he runner and gate are not on the parting line, but are generally directly on the product, so an additional set of sprue parting lines must be designed. The design is more complicated and the processing is more difficult. Generally, the fine sprue system is selected depending on the product requirements. The fixed mold part of the fine sprue mold is generally composed of three steel plates, so this type of structural mold is also called a “three-plate mold.” The three-plate mold is the simplest structure among the pinhole molds.
Hot runner mold
The structure of this type of mold is basically the same as that of the pinhole mold. The biggest difference is that the runner is in one or more hot runner plates and hot nozzles with constant temperature. There is no cold material demolding. The runner and gate are directly on the product, so the runner does not need to be demolded. This system is also called a no-sprue system. It can save raw materials and is suitable for situations where raw materials are expensive and product requirements are high. It is difficult to design and process, and the mold cost is high. The hot runner system, also known as the hot runner system, is mainly composed of a hot runner sleeve, a hot runner plate, and a temperature control box. Our common hot runner systems are single-point hot runners and multi-point hot runners. The single-point hot runner uses a single hot runner sleeve to directly inject the molten plastic into the mold cavity. It is suitable for plastic molds with a single cavity and a single gate; the multi-point hot runner uses a hot runner plate to branch the molten material into each branch hot runner sleeve and then enter the mold cavity. It is suitable for single-cavity multi-point feeding or multi-cavity molds.
Design and Engineering
The design of a mould is a delicate balance of art and science. It involves:
- CAD/CAM Software: Utilized to design the mould digitally, ensuring precision and efficiency.
- Material Selection: The choice of material for the mould can affect the product’s quality, durability, and production cost.
- Tolerances: The allowable limits of dimensional variations in the mould, critical for the fit and function of the final product.
Ejection Systems: Mechanisms to remove the finished product from the mould without damaging it.
Innovations in Mould Making
With advancements in technology, mould making has seen significant innovations:
- 3D Printing: Enabling rapid prototyping and the creation of complex mould designs.
- High-Performance Materials: Such as P20 and H13 steels, which offer better wear resistance and heat stability.
- Computer Simulation: Software that simulates the mould filling and cooling process to predict and prevent defects.
How to choose mold material
In selecting the material of the mold, the customer’s usage needs and manufacturing costs are mainly considered.
In terms of usage requirements
General users will focus on high hardness and wear resistance, which is closely related to heat treatment. If the heat treatment is not done well, the hardness requirements will not be met. If the brittleness is too high during the heating process It is also possible to cause the mold to explode and rupture when heated, so the heating process is also critical.
In terms of manufacturing cost
This kind of fine processing and manufacturing cost also occupies a large proportion.The selection of materials must pay attention to the heating performance to avoid wasting materials and increasing the manufacturing cost.
Attention points for main parts of the mold manufacturing
First of all, pay attention to the grinding of the surface and interior of the mold;
Secondly, when processing the mold, pay attention to the wire cutting process, because the diameter of the wire is small and the difficulty is relatively high, so special attention should be paid to it;
Finally, it is necessary to pay attention to avoid injury to the eyes caused by the heat generated by the spark when the electrical appliance is working.
After all processing is completed and the final inspection is passed, the complete mold is considered a success. In order to ensure the quality of the mold, we should choose a regular professional mold manufacturer.
Environmental Considerations
Mould making is also becoming more environmentally conscious with the use of recyclable materials and energy-efficient processes. The industry is moving towards sustainable practices, reducing waste and the carbon footprint.
Moulds are the silent architects of the products that populate our world. As the manufacturing industry evolves, the role of mould making becomes even more pivotal. It is a field that demands precision, creativity, and an unwavering commitment to quality. The future of mould making promises to be as dynamic as the products it helps create, with technology and innovation continuing to push the boundaries of what is possible.
Molds are various molds and tools used in industrial production to obtain the desired products by injection molding, blow molding, extrusion, die casting or forging, smelting, stamping and other methods. This tool is made up of various parts, and different molds are made up of different parts. It mainly realizes the processing of the shape of the article by changing the physical state of the formed material.
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