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How can the surface dirt, water line inclusion and warping deformation of the mold be solved

• 2025-08-30

How can the surface dirt, water line inclusion and warping deformation of the mold be solved

The surface of the mold is dirty

Phenomenon: During the production process, transparent protective covers often have impurities and dirt at different positions on the product surface.

Analysis: The mold surface is highly bright, and the product is transparent. During the injection molding process, the residual rubber threads in the mold runner are washed onto the product surface, forming impurities and dirt.

Characteristics of injection molding machines

Grade: HT-DEMAG, clamping force :100t, plasticizing capacity :150g

(2) Mold characteristics

Mold ejection number :1×2, injection method: point gate, ejection method; Top block ejection, mold temperature: 100℃ (constant temperature machine)

(3) Product characteristics

Material: PC IR2200N, color: transparent, Product weight (single piece) : 2.5g, nozzle weight: 4.2g

(4) Analysis of causes of defects

The main runner of the mold is quite large, and the glue inlet is made at the diving point. Due to the long cooling time for adjusting product deformation, when the mold is opened, there is slight residual glue on the runner parting surface at the glue inlet position, along with residual glue threads. Additionally, the mold runner does not fit well, resulting in cold residual glue threads that wash onto the product surface, causing impurities and dirt.

(5) Countermeasures

1. The mold runner is smooth, and the front and rear die runner channels are well-matched.

2. Increase the position of the cold material in the main runner to ensure smooth demolding.

3. Clean the surface of the mold irregularly to keep it clean.

Stool mold Manufacturer in China (jfmoulds.com)

The clamping water line of the mold

Phenomenon: During the molding process of this product, water line inclusion is prone to occur at one flat printing position.

Analysis: The positioning effect of this part of the mold is not good. The injection speed and stroke adjustment were not in place.

Characteristics of injection molding machines

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

(2) Mold characteristics

Mold ejection number :1×2, glue injection method: point gate, ejection method: Ejection by ejector pin, mold temperature: 90℃ for front and rear molds (constant temperature machine), 70℃ for row position core-pulling

(3) Product characteristics

Material: PC K3037824, color: white, Product weight (single piece) : 27.1g, nozzle weight: 13g

(4) Analysis of causes of defects

1. Start from the mold to improve the exhaust in this area.

2. Appropriately increase the mold temperature and the melt temperature to improve the melt effect.

3. Locate the position of the molten glue in this part of the product, adjust the position switch properly, and increase the injection speed.

(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, then proceed to the second section

Just fill the area near the glue inlet with a slow speed and a very small position. For the third stage, use a fast speed to fill this part of the product, and for the fourth stage, use a slow speed

Quickly fill the mold cavity to completely expel the air inside, avoiding trapped air and charring and other adverse phenomena. Finally, switch to Song Press Cutting

Change positions.

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

Warpage deformation of the mold

Phenomenon: Warping and deformation occurred in the front shell of the casing product during the production process.

Analysis: The raw materials include glass fiber, which is prone to deformation due to orientation in the flow direction. Post-shrinkage deformation is caused by the release of internal stress in the product.

Characteristics of injection molding machines

Grade: HT-DEMAG, clamping force: 100t, plasticizing capacity :150g

(2) Mold characteristics

Mold ejection number :1 ×1, gluing method: point gate, ejection method: Ejection by ejector pin, mold temperature :120/35℃ (constant temperature machine)

(3) Product characteristics

Material: PC+GF20%, Color: Gray, product weight (single piece) : 4.9g, nozzle weight :5.6g

(4) Analysis of causes of defects

When the product is injected with glass fiber reinforced materials, the glass fibers form an orientation in the flow direction, which is prone to deformation. The glue position of the product is too thin. The design of four-point glue injection leads to excessive internal stress in the product. After mold opening, the stress release causes deformation.

(5) Countermeasures

1. Adjust the temperature difference between the molds before and after.

2. Adjust and increase the temperature of the barrel.

3. Adjust multi-stage injection molding and multi-stage gradual pressure reduction holding.