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Solutions to the problems of wire clamping, clamping position pull-over deformation and air marks in molds

• 2025-08-12

Solutions to the problems of wire clamping, clamping position pull-over deformation and air marks in molds

The clamping wire of the mold

Phenomenon: The wire clamping area at the weld joint of the product is prone to breakage, and it is difficult to improve the situation by adjusting the machine.

Analysis: As the product is fed in at two points, during the molding process, two streams of raw materials converge, which inevitably leads to the existence of wire clamping. The insufficient toughness of the ABS+PC raw materials causes the product to break at the wire clamping point after molding.

Characteristics of injection molding machines

Grade: HT86T, Clamping force: 86t, plasticizing capacity: 119g

(2) Mold characteristics

Mold ejection number: 1+1, glue injection method: large water outlet, ejection method: Ejection with ejector pins and inclined ejectors, mold temperature: 120°C (constant temperature machine)

(3) Product characteristics

Material: PC HF-1023IM, Product weight (single piece) : 1.06g, nozzle weight: 4.50g.

(4) Analysis of causes of defects

1. The product forms a wire clamp by injecting glue at two points.

2. Poor exhaust of the mold.

(5) Countermeasures

1. Utilize multi-level injection and position switching

2. In the first section, fill the runner opening to the glue inlet at a moderate speed and find the corresponding switching position. In the second section, fill 90% of the mold cavity at a relatively high speed to prevent the high-temperature molten rubber from cooling. In the third section, fill the mold cavity at a slow speed to completely expel the air inside the cavity, allowing the molten material to flow slowly into the cold material area.

3. Add cold material at the wire clamping point to ensure that when the two strands of raw material combine during molding, they still flow outward without leaving the wire clamping on the product's surface.

4. Increase the temperature of the mold surface and raise the temperature of the melt cylinder.

5. Change the ABS+PC raw material to PC raw material with better toughness.

The buckle of the mold has been pulled over and deformed

Auto Mould_Taizhou Jiefeng Mould Co.,Ltd. (jfmoulds.com)

Phenomenon: During the production process of the diffusion air nozzle, there is a poor phenomenon of the corner buckle being pulled over.

Analysis: The molding material temperature required for PC material exceeds 300°C, and the mold temperature exceeds 100° C. The product needs sufficient cooling time before demolding.

Characteristics of injection molding machines

Grade: Haitian 120T, Clamping force: 120t, Plasticizing capacity: 150g

(2) Mold characteristics

Mold ejection number: 1×2, glue injection method: large sprue to point gate, ejection method: Ejection by ejector pin, mold temperature: Front mold 100°C (constant temperature machine), rear mold 80°C.

(3) Product characteristics

Material: PC IR2200 38864 KC1007, color: black, Product weight (single piece) : 19.42g, nozzle weight: 7.14g

(4) Analysis of causes of defects

Due to the structural limitations of the product's clamping position, the clamping position cannot withstand the adhesive force from the rear mold during demolding. Only when the product is completely cooled to the bottom before demolding can its strength be formed.

(5) Countermeasures

1. Utilize multi-level injection and position switching.

2. In the first section, fill the flow channel to the glue inlet at a relatively fast speed and find the corresponding switching position. In the second section, fill the area near the glue inlet at a slow speed and a very small position. The third section should be filled rapidly to 90% of the mold cavity to prevent the high-temperature molten rubber from cooling down and forming wavy patterns and flow marks. In the fourth section, fill the mold cavity slowly to completely expel the air inside the cavity, avoiding trapped air and charring and other adverse phenomena. Finally, switch to the pressure-holding switching position.

Commodity Mould_Taizhou Jiefeng Mould Co.,Ltd. (jfmoulds.com)

Mold air streaks

Phenomenon: Smok-like air patterns occur at the character inserts during the product's molding process, or air pattern rings form at the glue inlet.

Analysis: The technician believes that the mold is trapped with air and requests to increase the exhaust. During the machine adjustment process, if there is no air mark at the glue inlet, the middle character insert will produce a foggy air mark phenomenon, and it will be very difficult for the two places to be completely unified.

Characteristics of injection molding machines

Grade: Haitian, Clamping force :120t, Plasticizing capacity: 150g

(2) Mold characteristics

Mold ejection number: 1×2, glue injection method: fine water gate point gate, ejection method: Ejection by ejector pin, mold temperature: 70°C (constant temperature machine)

(3) Product characteristics

Material: ABS PA757 080201, Color: grayish black, Product weight (single piece) : 6.29g, spout weight: 4.43g

(4) Analysis of causes of defects

1. The product is of the electrical category. The required melting temperature for the material is more than 10°C higher than that of other similar materials. When the material is injected through the point gate, it is prone to gas from shearing and high-temperature decomposition at the injection gate, which may fill the mold cavity.

2. The speed of melting glue and mixing materials should not be too fast.

3. The calibration accuracy of the forming process is required to be high.

(5) Countermeasures

1. Utilize multi-level injection and position switching.

2. In the first section, fill the glue inlet of the flow channel at a relatively fast speed and find the corresponding switching position. Then, in the second section, fill the glue inlet and most of the inlay characters at a slow speed and a relatively fast position to prevent obvious air streaks at the glue inlet and avoid air streaks on the inlay characters. In the third section, fill the mold cavity slowly to completely expel the air inside the cavity, avoiding trapped air and charring and other adverse phenomena. Finally, switch to the pressure-holding switching position.