What Points Should Be Paid Attention To In The Design Of Injection Mold?

Do you know what needs to be paid attention to in the design of injection molds? Next, I will tell you the main points that need to be paid attention to.

Product wall thickness

1. All kinds of plastics have a certain range of wall thickness, generally 0.5 ~ 4mm, when the wall thickness exceeds 4mm, it will cause too long cooling time, shrinkage printing and other problems, you should consider changing the product structure.

2. Uneven wall thickness will cause surface shrinkage.

3. Uneven wall thickness will cause pores and weld marks.

Rib

1. Reasonable application of ribs can increase product rigidity and reduce deformation.

2. The thickness of the reinforcing rib must be ≤ (0.5~0.7)T product wall thickness, otherwise the surface will shrink.

3. The single-side slope of the rib should be greater than 1.5° to avoid top damage.

fillet

1. If the fillet is too small, it may cause stress concentration of the product, resulting in cracking of the product.

2. If the fillet is too small, it may cause stress concentration in the mold cavity, resulting in cracking of the cavity.

3. Setting reasonable rounded corners can also improve the processing technology of the mold. For example, the cavity can be directly milled with R cutter to avoid low-efficiency electric machining.

4. Different rounded corners may cause the movement of the parting line. Different rounded corners or clear corners should be selected in combination with the actual situation. What are the basic points of injection mold design?

Opening direction and parting line

At the beginning of the design of each injection molding product (Shanghai Mold Design Training School), the mold opening direction and parting line must be determined first to ensure that the core-pulling slider mechanism is minimized and the influence of the parting line on the appearance is eliminated.

1. After the mold opening direction is determined, the product's ribs, buckles, protrusions and other structures are designed to be consistent with the mold opening direction as much as possible, so as to avoid core pulling and reduce stitching lines, and prolong the life of the mold.

2. After the mold opening direction is determined, an appropriate parting line can be selected to avoid undercuts in the mold opening direction to improve appearance and performance. Shanghai mold design training

Draft angle

1. Appropriate demoulding slope can avoid product pulling (garbage). The demoulding slope of the smooth surface should be ≥ 0.5 degrees, the surface of the fine grain (sand surface) should be greater than 1 degree, and the surface of the rough grain should be greater than 1.5 degrees.

2. Proper demoulding slope can avoid product top damage, such as top whitening, top deformation, and top breaking, which are the basic requirements for injection mold design.

3. When designing products with deep cavity structure, the slope of the outer surface should be greater than the slope of the inner surface as much as possible, so as to ensure that the mold core does not deviate during injection molding, obtain a uniform product wall thickness, and ensure the material strength of the product opening.

hole

1. The shape of the hole should be as simple as possible, generally round.

2. The axial direction of the hole is consistent with the mold opening direction, which can avoid core pulling.

3. When the length-to-diameter ratio of the hole is greater than 2, the demoulding slope should be set. At this time, the diameter of the hole should be calculated according to the minor diameter size (entity size).

4. The length-to-diameter ratio of blind holes generally does not exceed 4. Anti-hole needle punching

5. The distance between the hole and the edge of the product is generally larger than the hole size.

Precision of injection molded parts

Due to the unevenness and uncertainty of the shrinkage rate during injection molding, the precision of injection molded parts is obviously lower than that of metal parts, and the dimensional tolerances of mechanical parts cannot be simply applied. Appropriate tolerance requirements should be selected according to standards. my country also issued GB/ T14486-93

"Dimensional Tolerance of Engineering Plastic Molded Plastic Parts", the designer can determine the dimensional tolerance of the part according to the requirements of the plastic raw materials used and the use requirements of the part according to the regulations in the standard.

At the same time, it is necessary to determine the appropriate design tolerance accuracy based on the comprehensive strength of the factory and the design accuracy of peer products.

Deformation of injection molded parts

Improve the rigidity of the injection molding product structure and reduce deformation. What are the basic points of the injection mold design? The mold design should avoid the flat structure as far as possible, and reasonably set the flanging and concave-convex structure. Set reasonable stiffeners.

buckle

1. The buckle device is designed to be shared by multiple buckles at the same time, so that the overall device will not fail to operate due to damage to individual buckles, thereby increasing its service life, and adding rounded corners to increase strength.

2. The tolerance requirements for the relevant dimensions of the buckle are very strict. If there are too many undercut positions, it will easily cause damage to the buckle; on the contrary, if there are too few undercut positions, it will be difficult to control the assembly position or the combination part will be too loose. The solution is to reserve a way to modify the mold and add glue easily.

Taizhou Minghuang Plastic Mold Co., Ltd. is a professional Plastic Crates Injection Molds Manufacturers. If you need it, you can click the official website to contact us. We are willing to answer more information for you.