Industry News

How to solve the problems of whitening, charring and deformation of the bone position at the water outlet of the mold

• 2025-08-16

How to solve the problems of whitening, charring and deformation of the bone position at the water outlet of the mold

The nozzle position of the mold is white

Analysis: The water inlet is located on the edge of the product. After the mold is opened, the product slightly sticks to the front mold, causing the water inlet to turn white. The pressure holding at the water outlet is too high. The milky white raw materials used have the particularity of fission color. It is easy to process white during processing.

Characteristics of injection molding machines

Grade: DEMAG, clamping force: 100t, 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: 80°C (constant temperature machine)

(3) Product characteristics

Material: ABS, Color: White, Product weight (single piece) : 4g, nozzle weight: 5g

(4) Analysis of causes of defects

1. The product's glue entry method is direct entry. The nozzle is connected to the product's surface appearance. After the mold is opened, the product adheres to the mold, forming a white pull at the nozzle position.

2. The product is made of ABS milky white material. This material has the special property of cracking color, and it is very easy for the water gate position to turn white after mold opening.

3. Since the scissors cannot cut the water outlet position flat and smooth at one time, the remaining residual material needs to be corrected by hand. Because the water outlet position is not a straight surface but a circle, when correcting the water outlet position, relying on hand to control the roundness of the water outlet position does not match the roundness of the product itself, so it is very easy to have scratches or whitening on the contact surface after correcting the water outlet position.

(5) Countermeasures

1.Under the condition of meeting the quality requirements, carry out process improvement treatment to reduce the holding pressure at the water outlet position and ensure that the water outlet does not turn white after the product is demolded.

2. When the customer or mold conditions permit, shift the position of the product's glue inlet.

3. Provide customers with confirmation and approval in accordance with the current best quality standards that can be achieved.

4. Expose the texture on the bone position inside the product to ensure that the product adheres tightly to the back mold after mold opening and does not turn white.

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

Charring of the mold

Phenomenon: During the production process of the guide frame for electrical product bodies, charring often occurs at the corners.

Analysis: The surface of the mold is highly glossy and it is not convenient for gas to be discharged at the corners. Trapped gas causes the product to burn.

Characteristics of injection molding machines

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

(2) Mold characteristics

Mold ejection number: 1×2, injection method: lap gate, ejection method: Ejection by ejector pin, mold temperature: 95°C (constant temperature machine)

(3) Product characteristics

Material: ABS TV20, color: white, Product weight (single piece) : 11.5g, sprue weight: 2.3g

(4) Analysis of causes of defects

The main runner of the mold is quite large, and the injection port is of the lap type. The surface of the mold is highly bright and located at the corners. Due to the overly fast injection speed, it is not convenient for the gas to be discharged, and the trapped gas causes the product to burn.

(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. Then, in the second section, fill the corner area near the runner at a fast speed and find the corresponding switching position. In the third section, fill the corner area at a slow speed and a very short position. Finally, fill slowly and switch to the pressure-holding switching position.

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

Bone position deformation of the mold

Characteristics of injection molding machines

Grade: Haitian, Clamping force: 80t, Plasticizing capacity: 133g

(2) Mold characteristics

Mold ejection number: 1×2, glue injection method: point injection into the gate, ejection method: push plate ejection, mold temperature: 80°C (constant temperature machine)

(3) Product characteristics

Material: ABS, Color: Black, Product weight (single piece) : 4g, nozzle weight: 5g

(4) Analysis of causes of defects

The fire pattern on the bone position of the mold (rear mold) is not smooth and is still very rough. When the product is fully injection molded, it tightly adheres to the rear mold. When it is ejected, due to the lack of smoothness on the bone position, the product sticks to the rear mold and deforms.

(5) Countermeasures

Perform mold-saving polishing treatment on the rough areas of the rear mold bone position.