China connector mold materials encounter problems

Introduction to commonly used materials and properties, commonly used materials for insulators

Usually there are: PBT, NYLON, ABS, PC, LCP and other materials, but in principle, materials with better flame resistance are used.

A.PBT material:

Generally, PBT material is added with 20-30% glass fiber, which has the ability to resist cracking, impact, and electricity. It has good wear resistance, low friction coefficient, good self-lubricating effect, and good oil and chemical resistance. It has good dielectric strength under high temperature and high humidity. Its shrinkage rate is between 0.6% and 3.0%, and its temperature resistance is about 230℃. Good formability and flame resistance. It is a commonly used rubber material for connector products.

b.NYLON66, NYLON6T, PC, LCP materials:

Its shrinkage rate is 1.0%-0.3%, and its temperature resistance is higher than PBT. Commonly used NYLON66 has a temperature resistance of 260℃--280℃, NYLON6T has a temperature resistance of 280℃--300℃, and LCP has a temperature resistance of 290℃--320℃. However, it has high water absorption and is generally used for products with high temperature resistance and less PITCH (such as SMD, HOUSING, PLCC, etc.)

C.ABS material:

It has good impact toughness, oil resistance, wear resistance, easy molding, good hardness, good rigidity, and temperature resistance of about 100°C. It is generally used in auxiliary products in connectors.

2. Common defects and causes of injection molding

Common molding defects include the following: black spots or black liquid on plastic parts, rough surface, overflow, incomplete plastic molding, bubbles or burnt, deflated shapes, stitching lines or plastic parts shrinking in the mold, etc. . The main reasons are divided into three parts: factors of the injection molding machine, factors of the mold, and factors of the rubber material.

3. Composition and performance of connector contacts

Joint material: The metal joint material of the plug is generally brass, but when the number of plugs and pulls is extremely high and the life span is long, phosphor bronze, beryllium copper, etc. can be used. The following is a summary of the current types of copper materials in the industry and their

Solutions to common plastic mold problems

Plastic product processing--Methods to prevent mold cracks

Causes of cracks in molds.

1-1. Insufficient mold rigidity

1-2. Stress concentration at the edges and corners of the mold cavity

2. Related knowledge

2-1. The wall thickness design of the mold is an important parameter in the mold design. Strength calculation (simple calculation of pure tension) is performed to ensure the necessary thickness of the mold. In addition, additional grooves are added to utilize the overall rigidity of the mold.

3-2. Stress concentration is easy to occur when processing the edges and corners of the mold cavity, and cracks are also prone to occur here. Therefore, the edges and corners must be processed into a shape with a rounded corner R.

3. Solution

3-1. Process the edges and corners of the mold cavity into a shape with rounded corners R, and process the mold parting surface into a grooved shape to strengthen and enhance the rigidity of the mold.

4. Due to differences in materials;

4-1. There is no special reason.

Plastic product processing--Methods to prevent mold sticking and bending

1. Causes of sticky bending in molds

1. Insufficient mold rigidity

2. Due to the injection pressure mold