Company News

The surface of the mold is baked and printed bright and has surface flow marks

• 2025-08-02

The surface of the mold is baked and printed bright and has surface flow marks

The surface is baked and printed bright

Phenomenon: The surface of the product is a fine-textured surface. During the molding process, due to the incomplete discharge of gas, it is difficult to improve the brightness of the product surface due to baking, which cannot meet the quality requirements.

Analysis: The mold temperature setting is unreasonable. The pressure setting in the fourth section is too low. The mold has poor exhaust.

1. Features of injection molding machines

Grade: HT120T, Clamping force: 120t, plasticizing capacity: 125g

2. Mold characteristics

Mold ejection number: 1×2, glue injection method: large water outlet (side point injection), ejection method: Ejection by ejector pin and inclined top, mold temperature: 125°C (constant temperature machine)

3. Product physical evidence

Material: ABS+PCHI-1001BN, color: black, product weight (single piece) : 5.68g, nozzle weight: 11.66g

4. Analysis of causes of defects

The mold is a 1×2 casing. The mold flow channel is relatively long. The glue inlet method is point-in glue inlet. The molten material flows to the area near the glue inlet. Due to the slow speed and high pressure, the stress on the product increases, and the baking mark is obvious.

Second: Setting the mold temperature too low is not conducive to the discharge of gas from the mold and may cause trapped gas.

5. Countermeasures

One: Utilize multi-level injection and position switching.

Two: 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 95% of the mold cavity with medium speed and relatively high pressure to prevent the high-temperature molten rubber compound from cooling. The third short fill the mold cavity slowly to completely expel the air inside the cavity, and finally switch to the pressure-holding switching position.

Three: Increase the temperature of the mold.

Four: Add exhaust vents around the parting surface.

Five: Use an eraser to polish the shiny surface.

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

Surface flow marks

Phenomenon: There are flow marks on the surface of transparent lenses during the production process.

Analysis: High speed will cause material melting, intensify shearing, generate high temperatures and be prone to decomposition. The surface of the mold is smooth. If the shooting speed is too fast, flow marks are likely to occur. The position switch is too early.

1. Features of injection molding machines

Grade :DEMAG, clamping force: 50t, plasticizing capacity :80g

2. Mold characteristics

Mold ejection number :1×2, injection method: fan-shaped gate, ejection method: Ejection by top block, mold temperature :100 ° C.

3. Product characteristics

Material: PMMA Color: Transparent Product weight (single piece) : 3.5g Nozzle Weight: 8g

4. Analysis of causes of defects

The main channel of the mold is quite large. The way the glue is fed in is by submersible. The molten material flows to the area near the glue inlet. Due to the excessive speed and the mold

The surface is very smooth, causing high shear which makes the molten material heat up rapidly in an instant, causing the raw material to decompose and produce gas, thus forming flow marks.

5. Countermeasures

One: Utilize multi-level injection and position switching.

Two: In the first section, fill the flow channel to the glue inlet at a relatively fast speed and find the corresponding switching position. Then, in the second section, fill the area near the glue inlet at a slow speed and a very small position. The third section is filled with 90% of the mold control quickly to prevent the high-temperature molten rubber compound from cooling down and forming wavy patterns. 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)