There is a series of perfect production processes in the production process of silicone rubber products, from product design to R & D, to mold development, raw material processing, production process and quality inspection. Today we will talk about the production process of silicone rubber products:


What is a sample model?


All silicone rubber products must be made before making silicone mold, through the mold can develop new products. Now, let's introduce our mold.


Sample mold is also called hand plate mold. When confirming the cooperation is to print samples, the sample, 2D drawing or 3D drawing are required first. If you provide a template, you will copy the data according to the template and get the 3ddrawing. If the 3dchart is provided, it is more convenient. The master of the mold room will program and open the mold according to the 3ddiagram provided by the customer. Usually, the sample opening mold is first for confirmation, and then the large die is opened for mass production after confirming that there is no problem.


The sample mould of mobile phone sleeve is generally 1 to 2 points. When the sample is much, the sample mold will open 4 points. The sample model plays a role in confirming the initial sample, which turns the drawing file into the physical object. Because silicone rubber is elastic, the product produced does not necessarily match the drawing. At this time, a sample model should be opened and samples shall be punched to let the guests confirm. If there is a problem with the sample mold, it is also relatively simple to modify the mold at this time, and the modification time is short and the efficiency is high. Every time the mold is opened, the mold repair must be confirmed by proofing, that is to say, confirm the mold. When the product development meets the requirements of the guests, the mold is confirmed.


Raw materials of sample mould


The sample mould is generally used for steel materials. The size of the template is determined by the size of the product. Formwork with length * width * height of 300mm * 300mm * 30MM is usually used.


Time of sample mold making


The length of the sample mold is determined by the complexity of the product structure. Generally, the simple products usually take 2-3 days from programming to processing; It's about 5-7 days for the complex. The more complex the product structure, the longer the opening time.


The benefits of sample opening


First, the number of holes in the sample mould is small, the use of the template is less, and the processing time is short, so the cost is relatively small and the efficiency is high. Secondly, the sample opening mold can bring other benefits, such as the first time the product structure is not confirmed, and it is convenient to modify the mold, and repair it


After the change, we can check the sample immediately, which shortens the time. In addition, because of the low cost, the risk of opening sample mould first can be reduced. If the large die is opened directly, the sample cannot be confirmed for the first time. When the modified die is used to produce the product, many quality problems will be brought. In this case, the mold will only be repaired worse and the more difficult it is to be repaired is not conducive to production. So, the first thing to confirm the product is to open a sample mold. If you confirm that there is no problem, you can open the large mold at once. In this way, there are few quality problems in the products produced.


The important steps before mould making


The first problem to consider when making the mould of silicone rubber products is the selection of raw materials of the mould. According to the quality, quantity, structure of the product, the material selection of the die is determined. The selection of die is a very important part in the whole process of mold making. The material selection of the mould needs to meet three requirements: first, the mold meets the requirements of wear resistance, strength and toughness; Secondly, the mold meets the process requirements; Thirdly, the mold should meet the requirements of economic applicability.


（1） Mold meets the requirements of conditions


1. When the wear-resistant blank is deformed in the mold cavity, it flows and slides along the surface of the cavity, which causes severe friction between the surface of the mold and the blank, which will easily lead to the failure of the die due to wear. Therefore, the wear resistance of the material is one of the most basic and important properties of the die. Hardness is the main factor that affects the wear resistance. Generally, the higher the hardness of the die parts, the smaller the wear, the better the wear resistance. In addition, the wear resistance is also related to the type, quantity, shape, size and distribution of carbides in the material.


2. The conditions of the strong and ductile die are mostly very bad, some of them often bear the larger impact load, which leads to brittle fracture. In order to prevent the die parts from breaking suddenly, the die should have high strength and toughness. The toughness of the die mainly depends on the carbon content, grain size and microstructure state of the material.


3. In the process of fatigue fracture performance, fatigue fracture is often caused by the long-term effect of cyclic stress. The results show that the fatigue fracture is characterized by the impact fatigue fracture, the contact fatigue fracture and the bending fatigue fracture. The fatigue fracture performance of the die mainly depends on its strength, toughness, hardness, and the content of inclusions in the material.


4. High temperature performance when the temperature of the mold is high, the hardness and strength will decrease, which will lead to the early wear or plastic deformation of the die and failure. Therefore, the die material should have high tempering resistance stability to ensure the mold has high hardness and strength at temperature.


5. Some die are in the state of repeated heating and cooling during the process, which causes the surface of the cavity to be subjected to tension and pressure, causing surface cracking and peeling, increasing friction, hindering plastic deformation, reducing the dimension accuracy, and thus causing die failure. Cold and hot fatigue is one of the main failure forms of hot working die. It is suggested that these dies have high cold and hot fatigue resistance.


6. Some mould with corrosion resistance, such as plastic mold, are decomposed and precipitated with HCI, HF and other strong corrosive gases due to the presence of chlorine and fluorine in the plastic, which erodes the surface of mold cavity, increases its surface roughness and aggravates the wear failure.


（2） The mold meets the requirements of process performance


The manufacturing of die usually needs forging, cutting and heat treatment. In order to ensure the manufacturing quality and reduce the production cost, the material should have good malleability, cutting processing, hardenability, hardenability and grindability; It should also have small oxidation, decarbonization sensitivity and quenching deformation cracking tendency.


1. The forging property has low deformation resistance, good plasticity, wide forging temperature range, cold crack and low precipitation of carbide.


2. The temperature range of spheroidizing annealing is wide, the hardness of annealing is low and the fluctuation range is small, and the spheroidization rate is high.


3. The cutting capacity is large, the tool loss is low and the surface roughness is low.


4. The oxidation and decarbonization sensitivity are good in oxidation resistance and slow decarburization, insensitive to heating medium and have little tendency to pitting.


5. After quenching, the surface hardness is uniform and high.


6. After hardenability quenching, the deeper hardening layer can be obtained, and the quenching can be achieved by using the mild quenching medium.


7. The deformation cracking tendency of quenching is small, the shape warping and distortion are slight, and the abnormal deformation tendency is low. The conventional quenching cracking sensitivity is low, and it is not sensitive to quenching temperature and workpiece shape.


8. Grindability


The grinding wheel has small relative loss, large amount of grinding without burn limit, which is not sensitive to the quality and cooling conditions of grinding wheel, and is not easy to cause grinding injury and grinding crack.


（3） Mold meets economic requirements


In the selection of die, the principle of economy must be considered to minimize the manufacturing cost. Therefore, on the premise of satisfying the performance, the lower ones are selected first, and the alloy steel is not used for the carbon steel, and imported materials are not required for domestic materials. In addition, the production and supply of the market should be considered in the selection of materials, and the selected steel should be as few and concentrated as possible