What acceptance criteria does a good set of molds need to meet? Is your mold good?

Today, I want to explain to you the acceptance criteria of mold products. We mainly analyze the appearance, size and material of the mold. Let’s take a look.

1. Mold appearance

1. Surface defects

Defects are not allowed on the mold surface: lack of material, scorching, white top, white lines, peaks, blistering, whitening (or cracking or breaking), baking marks, wrinkles, etc.

2. Weld marks

Generally, the length of weld marks for circular perforations is no more than 5mm, and the length of weld marks for special-shaped perforations is less than 15mm, and the strength of weld marks must pass functional safety testing.

3. Shrink

No shrinkage is allowed in obvious areas of the appearance, and slight shrinkage is allowed in inconspicuous areas (no dents can be felt).

4. Flatness

Generally, the plane unevenness of small products is less than 0.3mm. If there are assembly requirements, the assembly requirements must be ensured.

2. Mold size

1. Accuracy

The geometric shape and dimensional accuracy of the mold product should comply with the requirements of the formal and valid mold opening drawings (or 3D files). In addition, the tolerance range of the mold should comply with relevant principles. For example, the shaft size tolerance is a negative tolerance, and the hole size tolerance is a positive tolerance. If If customers have special requirements, mold manufacturers can also customize production according to actual conditions.

2. Mold wall thickness

Generally, the wall thickness of the mold is divided into two types: average wall thickness and non-average wall thickness. The non-average wall thickness should comply with the drawing requirements, and according to the characteristics of the mold, its tolerance should be -0.1mm.

3. Matching degree

The surface shell and bottom shell of the mold must match perfectly, and their surface deviation cannot be greater than 0.1mm. In addition, the holes, shafts, and surfaces of the mold products must meet the matching spacing and usage requirements, and no scratching occurs.

4. Nameplate

The text on the mold nameplate should be clear, neatly arranged, and complete in content; the nameplate should be fixed reliably and not easy to fall off.

5. Cooling water nozzle

The raw material of the mold cooling water nozzle is plastic (the customer has other requirements according to the requirements), which is made through counterbore processing technology. The diameter of the counterbore is generally 25mm, 30mm and 35mm, and the direction of the chamfering of the hole is consistent. In addition, the installation position of the cooling water nozzle must comply with relevant requirements and should not protrude from the surface of the mold base, and the entrance and exit marks must be marked.

6. Ejection hole and appearance

The ejection hole size and appearance dimensions of the mold should comply with the requirements of the specified injection molding machine. Except for small molds, only one center cannot be used for ejection.

3. Mold material and hardness

1. Mold base material

The mold base should be a standard mold base that meets the regulations, and its material should have certain environmental adaptability.

2. Performance

Mold cores, movable and fixed mold inserts, movable inserts, diverter cones, push rods, gate sleeves and other parts have good stability and corrosion resistance, and their material properties are higher than 40Cr.

3. Hardness

The hardness of molded parts should not be less than 50HRC, or the hardness of surface hardening treatment should be higher than 600HV.

The above is all about the mold acceptance standards. I hope it will be helpful to everyone.