What issues should be considered in the design of injection molding molds

The problems that should be considered in the design of injection molding molds can be summarized as follows:

1. Understand the flow behavior of plastic melt, consider the resistance and flow speed of plastic flowing in the flow channel and cavity, and verify the maximum flow length. According to the direction of plastic flow in the mold (i.e., the filling sequence), consider the re-fusion of the plastic in the mold and the original air export in the mold cavity.

2. Consider the shrinkage and shrinkage of plastics during the cooling process.

3. Control the crystallization and orientation of plastics in the mold and improve the internal stress of plastic products through mold design.

4. The selection of gate and parting surface.

5. The problem of transverse parting, core pulling and ejection of the workpiece.

6. Cooling or heating problems of the mold.

7. Fahrenheit mold steel said that the relationship between the size of the mold and the injection machine used, including the relationship with the maximum injection volume of the injection machine, the clamping force, and the size of the mold loading part.

8. The overall structure of the mold and the shape of the parts should be simple and reasonable, and the injection molding mold should have appropriate precision, surface roughness, strength and rigidity, which is easy to manufacture and assemble.

First of all, the insert, which he is split out individually, so, the individual is certainly better than the whole workmanship, which is the main thing. Then, where to make inserts, in some places that cannot be processed on the whole, such as deep ribs, even if the electrode is punched out, there is no way to save the mold, if it is made into an insert, it is very convenient to process and save the mold. There are also some places that need to be exhausted during injection molding, because if the exhaust is not exhausted, there may be a lack of glue and the like, so the places that need to be exhausted can also be made into inserts.

There are also some relatively large workpieces, which can also be split into inserts to do, which is easy to process. If the slider, the front core and the back seat can be split into two pieces, the core is the insert, some places have different requirements for the material of the mold can also be made into inserts, such as the mold kernel to do P20, and then some places need to be often inserted and pierced, etc., those places can be made into inserts to strengthen the strength ......These things are all experienced, and it would be good to do more.

Feasibility Analysis of the Final Structural Scheme of the Injection Mold After the feasibility analysis and demonstration of the structural scheme of the injection mold and the optimal optimization scheme, it is not possible to start the design or modeling of the injection mold immediately, because it is also necessary to carry out the expected analysis of the defects of the injection molded part. Because once there is a defect on the injection molded part, the injection mold is unqualified, which will lead to the injection mold cannot be determined to be qualified. In this way, the injection mold has to be repaired or even redesigned.

Until there are no defects on the injection mold after passing the mold test, the injection mold can be judged to be qualified. As we all know, there are many factors that affect the defects on the injection mold, and the factors that affect whether the injection mold needs to be repaired and remade are mainly the defect factors caused by the improper structure of the injection mold. Therefore, it is necessary to analyze whether the structure of the injection mold will produce molding processing defects on the injection molded parts, that is, it is necessary to analyze the expectation of the final structural scheme of the injection mold.

It ensures that there will be no defects in the injection molded parts due to the structure of the injection mold.

Key points of in-mold injection molding.

First, the product cannot have right angles, and excessive radians need to be large.

Second, it is necessary to consider the location of the product inlet.

Third, there are more mold barrels in the mold, and there is no requirement for the size of the barrel.

Fourth, there needs to be electrostatic equipment, so that the mold can better adsorb the mold surface.

Summary. Plastic mold design is based on the correct design of plastic products, and mold design and manufacturing are closely related to plastic processing. The success or failure of plastic processing largely depends on the mold design effect and mold manufacturing quality

1. Parting surface, that is, the contact surface of the die and the punch when the mold is closed. The selection of its position and form is affected by factors such as the shape and appearance of the product, the wall thickness, the molding method, the post-processing technology, the mold type and structure, the demoulding method and the structure of the molding machine. 2. Structural parts, that is, sliders, inclined tops, straight top blocks of complex molds, etc.

The design of structural parts is very critical, which is related to the life of the mold, processing cycle, cost, product quality, etc., so the design of complex mold core structure requires the comprehensive ability of the designer to pursue a simpler, more durable and more economical design scheme as much as possible.

Starting from the simple structure of the mold and the ease of molding, what problems need to be considered in the shape design of plastic parts.

Plastic mold design is based on the correct design of plastic products, and mold design and manufacturing are closely related to plastic processing. The success or failure of plastic processing largely depends on the mold design effect and the quality of mold manufacturing, and the structural elements that need to be thought of in plastic mold design are: 1. Parting surface, that is, the contact surface of the die and the punch when the mold is closed.

The selection of its position and form is affected by factors such as the shape and appearance of the product, the wall thickness, the molding method, the post-processing technology, the mold type and structure, the demoulding method and the structure of the molding machine. 2. Structural parts, that is, sliders, inclined tops, straight top blocks of complex molds, etc. The design of structural parts is very critical, which is related to the life of the mold, processing cycle, cost, product quality, etc., so the design of complex mold core structure requires the comprehensive ability of the designer to pursue a simpler, more durable and more economical design scheme as much as possible.

The size of the plastic parts is small, the precision level of the product is low, and it is required to have good performance, no cracks, bending resistance, and mass production. The mold is designed into a mold and eight cavity structure, and solves the following problems. First, the balance of the gating system multi-cavity mold in the design of the cavity as far as possible to let all cavities at the same time feed, due to the increase in the number of cavities, must be the length of the runner increases, before the melt reaches the cavity, the injection pressure and melt heat will have a large loss, if the runner design is slightly unreasonable plastic parts may produce defects, such as a cavity or several cavities are not satisfied, or the instant full, but there are defects such as poor welding or loose internal tissue, such as increasing the injection pressure, and easy to produce flash.

The design runner adopts a non-balanced arrangement, by setting the size of the gate and the runner, the injection process is adjusted to the value, to ensure that the shrinkage rate of each cavity is consistent, the plastic parts with the highest precision requirements are required to ensure their interchangeability, and the position of the gate is set at the thick end of the plastic part marked as the Y end, which is conducive to flow and shrinkage, and can also avoid welding marks, and the molecule has orientation to meet the requirements of bending without breaking. Second, the design of the cooling system The design principle of the cooling device is to design the cooling device on the basis of not increasing the structure of the mold itself.

Injection molds are not the same as other cavity molds in terms of part molding process, mold material, structure, accuracy, etc., and even very different, but have the common characteristics of "three denses".

1. The manufacturing of plastic injection mold molded parts is a single-piece small-batch production method, and the precision is high and difficult.

2. Ordinary machining methods are still widely used in the manufacturing process, such as turning, planing, milling, grinding and other processing methods.

3. New technology and new technology are quickly replacing ordinary machining in mold cavity manufacturing, such as non-contact profiling device, CAD CAM, CNC coordinate grinding, CNC electrical machining and three-coordinate measurement, etc., which have effectively improved the quality of products.

4. The capital investment in plastic injection mold manufacturing is high, the production cycle of the mold is generally long, and the manufacturing of complex and large-scale cavity molds has specific risks.