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The solution to the problem of the lens length dimension of the mold being too large and the water line being clamped on the side of the middle hole position

• 2025-08-11

The solution to the problem of the lens length dimension of the mold being too large and the water line being clamped on the side of the middle hole position

The length dimension of the lens in the mold is too large

Phenomenon: The length dimension of S02 lens No. 1 is too large

Characteristics of injection molding machines

Grade: DEMAG, clamping force: 50t, plasticizing capacity: 133g

(2) Mold characteristics

Mold ejection number: 1×2, injection method: direct injection into the gate, ejection method: push plate ejection, mold temperature: 75°C (constant temperature machine)

(3) Product characteristics

Material: PMMA, Color: White, Product weight (single piece) : 1.5g, nozzle weight: 4g.

(4) Analysis of causes of defects

1.The dimensions of the two mold cavities do not match, resulting in inconsistent product dimensions.

2. The mold is for 1×2 pieces of products. The size of 1# is relatively large because it was injected under the same molding process conditions, and the dimensions of the two products are not the same.

3. When the size of No. 2 was adjusted to be qualified, a flash occurred at the jaw of No. 1 parting surface, causing the size to be 0.05mm larger. However, when the size of No. 1 was adjusted to be qualified, the size of No. 2 was smaller.

(5) Countermeasures

With the No. 1 cavity remaining stationary, the cavity length of the No. 2 product, which is relatively small in size, was treated with 0.05mm of glue.

Injection molding process table

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

Water lines are clamped on the side of the middle hole position of the mold

Phenomenon: Water marks are prone to appear on the side of the middle hole position during molding.

Analysis: The technician believes that the mold exhaust is poor and requests mold repair. When the injection molding speed is increased, water marks are always present and cannot be significantly improved.

Characteristics of injection molding machines

Grade: Haitian, Clamping force: 86t, Plasticizing capacity: 100g.

(2) Mold characteristics

Mold ejection quantity: 1×2, glue feeding method: submerged glue feeding, ejection method: Ejection by ejector pin, mold temperature: 90°C (constant temperature machine)

(3) Product characteristics

Material: ABS 757 37827, Color: Silver black, Product weight (single piece) : 3.1g, spout weight: 1.8g

(4) Analysis of causes of defects

Due to the thin structure of the product, the depth of the front mold cavity is relatively shallow, and the mold is transported with water separately, the mold temperature is prone to be low.

2. The injection molding speed is relatively slow.

3. The location and travel are unreasonable.

(5) Countermeasures

1. Utilize multi-level injection and position switching.

2. In the first section, fill the flow channel rubber opening at a relatively fast speed and find the corresponding switching position. Then, in the second section, fill the area near the rubber inlet at a slow speed and a very small position. In the third section, use rapid charging to pass through the fusion area of the middle hole position to avoid forming a fusion line. 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.

Injection molding process table

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