A set of reliable plastic mold design is mainly reflected in the quality of the formed plastic products (appearance quality and dimensional stability), which is convenient, rapid, concise, and saves money and manpower during processing and manufacturing, leaving room for correction and improvement. It is safe, stable, easy to maintain, and has a short molding cycle, long service life and reasonable mold manufacturing process during injection molding.
01 Main process of factory mold design
The customer provides the product drawing→analyzes the product→confirms the plastic type→confirms the mold material→transfers to the engineering drawing→makes a mirror image by multiplying the shrinkage→perfects the assembly drawing→orders the mold blank→orders the core material for the mold→draws the mold→3D parting→determines the runner /Gating method→Refer to the layout diagram for structural design→Remove inserts→Correct 3D→Engineering drawing (mold core/insert/mold blank/parts)→Make BOM→Proofreading and review.
02 Several aspects that should be paid attention to in design
1) When we start the mold design, we should pay more attention to consider several schemes, weigh the advantages and disadvantages of each scheme, and choose one from them. For the T mold, we should also take it seriously. Because of the time understanding, the reasonable design at that time must have possible improvements after production and use practice.
2) After handing over the design plan, communicate more with the factory to understand the processing process and the situation in manufacturing and use. Each set of molds should have a fixed analysis experience, and the process of summarizing gains and losses can continuously improve the level of mold design.
3) When designing, refer to similar drawings designed in the past to learn from their experience and lessons.
4) The mold design department should be a whole, and each design member cannot work independently, especially in terms of mold design summary conclusions, there must be a unique style.
03 Mold Design Basis
The main basis is the product drawings and samples provided by customers. Designers must carefully analyze and digest products and samples. At the same time, they must check all items one by one during the design process.
1. The correctness of dimensions related to dimensional accuracy
1) Plastic products with high appearance requirements and low dimensional accuracy requirements, such as toys, etc., except for assembly, the other dimensions only need to match well.
2) Products with strict appearance and size requirements
Whether the draft slope is reasonable.
Product wall thickness and uniformity.
Kind of plastic. (Selection of mold steel and determination of shrinkage rate)
Superficial requirements.
Product color.
In general, color has no direct effect on mold design. When the wall of the product is thick and the shape is large, it is easy to produce uneven color; and the darker the color, the more obvious the product defects are exposed.
2. Is there post-processing after the product is formed?
If there are products with electroplating on the surface, and one mold has multiple cavities, it must be considered to set up auxiliary flow channels to connect the products together, and then separate them after the electroplating process is completed.
3. Batch size of products
The batch of products is an important basis for mold design, and the customer must provide a range to determine the number, size, material selection and life of the mold cavity.
4. Injection molding machine specification
5. Other requirements of customers
Designers must carefully consider and check to meet customer requirements.
04 General flow of mold design
1) Analyze and digest the products and samples.
2) It should be known whether the customer has requirements for the specifications of the injection machine to determine the size range of the mold.
3) Determine the number of cavities and arrange them.
4) The parting surface is determined.
5) If there is row position and orthorhombic structure, it should be understood first.
6) Design of gating system
7) Determination of mosaic structure.
8) Ejection and reset system design.
9) Cooling and heating system design.
10) Guiding and positioning device.
11) Determine the mold base and select standard parts.
12) Selection of mold steel.
13) Complete the structural drawing, mold base drawing, and material cutting.
14) Finally, print out the drawing, check it, and submit it to the mold design team leader and supervisor.
05 Mold trial and mold repair
Although the mold design is carried out under the expected process conditions when the molding materials and molding equipment are selected, people's understanding is often incomplete. Therefore, it is necessary to conduct a mold trial test after the mold processing is completed to see the molded parts. How is the quality. It is always found later, and the model is repaired to eliminate errors.
There are many types of defects in plastic parts, and the reasons are also very complicated. There are reasons for molds and process conditions, and the two are often intertwined. Before repairing the mold, it should be carefully analyzed and studied according to the actual situation of the defective phenomenon of the plastic part, and the remedy method should be proposed after finding out the cause of the defect of the plastic part. Because the molding conditions are easy to change, the general practice is to change the molding conditions first, and only consider repairing the mold when changing the molding conditions cannot solve the problem.
You should be more cautious when repairing molds, and you should not act rashly if you are not very sure. The reason is that once the mold conditions are changed, it is impossible to make major modifications and restore the original state.
06 Organize data for archiving
After the mold is tested, if it is not used temporarily, it should completely wipe off the mold release residue, dust, oil, etc., apply butter or other anti-rust oil or anti-rust agent, and send it to the storage place for storage.
From designing the mold to successfully processing the mold and passing the inspection, the technical information generated during this period, such as task book, part drawing, technical specification, mold assembly drawing, mold part drawing, base drawing, mold design specification, inspection record Forms, mold trial and repair records, etc., shall be systematically organized, bound, numbered and archived according to regulations. It seems troublesome to do so, but it is very useful for repairing the mold and designing a new mold in the future.
