Solutions for Chip Melting in Injection Molding

In the field of electronic packaging, injection molding is widely used to encapsulate electronic components such as chips within plastic casings. However, chip melting during the injection molding process can sometimes occur, which not only affects the quality and performance of the product but also has adverse impacts on production efficiency and cost control.

Causes of Chip Melting After Injection Molding

1. Improper Temperature Control: During injection molding, the temperatures of the barrel, nozzle, and mold are critical factors. If the temperature is too high, the molten plastic may directly melt the chip during injection. Insufficient cooling time for the molten plastic in the mold can also cause the chip to melt after injection

2. Mold Design Defects: Unreasonable gate design or poor venting in the mold can lead to excessive shear heat or high pressure during injection, which may melt the chip. An improperly designed cooling system in the mold can also cause excessively high mold temperatures, further increasing the risk of chip melting.

3. Ultrasonic Vibration: In some injection molding processes, ultrasonic vibration is used to enhance the flow and filling of the plastic. However, if the power of the ultrasonic vibration is too high or the application time is inappropriate, it may cause localized high temperatures on the surface of the already solidified chip due to high-frequency mechanical vibrations, leading to melting.

4. Material Mismatch: If the injection molding material is not compatible with the chip material, it may also cause the chip to melt during the injection process. For example, some plastics with a high coefficient of thermal expansion may squeeze the chip during injection, causing it to melt.

Baking Solutions

To address the issue of chip melting after injection molding, the following specific steps and precautions for baking treatment are provided:

Pre-Baking Preparation

• Confirm the type of chip material and its baking requirements.
• Select an appropriate baking equipment with a stable temperature control system and suitable capacity.

Setting Baking Conditions

• The baking temperature should be below the melting point of the chip but above the glass transition temperature of the plastic to ensure that the plastic is fully cured without melting the chip.
• The baking time should be determined based on the size, quantity, and baking temperature of the chip to ensure that moisture or volatile substances inside the chip are fully removed.

Baking Process Control

• During the baking process, regularly check the temperature of the baking equipment to ensure stable baking conditions.
• If any abnormal temperature fluctuations are detected, adjust the parameters of the baking equipment in a timely manner.

Post-Baking Handling

• After baking is completed wait, for the baking equipment to cool down completely before removing the chip.
• Conduct visual inspections and performance tests on the chip to ensure that it has not melted, deformed, or been damaged.

Suitable Oven Types

For the baking requirements of chips that have melted after injection molding, the following types of ovens are recommended:

1. Hot Air Circulation Oven:The hot air circulation oven distributes heat evenly inside the oven through a hot air circulation system, ensuring uniform heating of the chip. This type of oven is suitable for baking chips of medium size and quantity.

2. Vacuum oven: The vacuum ovencan remove air from inside the oven during the baking process, reducing the risk of chip oxidation. The vacuum environment can also accelerate the evaporation of moisture, improving baking efficiency. This type of oven is suitable for chips that are sensitive to oxidation or require rapid baking.

3. Nitrogen Oven:The nitrogen oven introduces nitrogen during the baking process to prevent the chip from reacting with oxygen in the air. This type of oven is suitable for chips that are particularly sensitive to oxidation, such as some high-performance semiconductor materials.

4. Programmable Oven:The programmable oven can automatically adjust the baking temperature and time according to the preset program, ensuring the stability and controllability of the baking process. This type of oven is suitable for chips that require precise control of baking conditions.

Post-injection molding chip melting is a complex issue involving multiple factors such as temperature control, mold design, ultrasonic vibration, and material compatibility. Baking is an effective solution. By selecting appropriate baking equipment, setting suitable baking conditions, and strictly controlling the baking process, moisture or volatile substances inside the chip can be effectively removed, preventing the chip from melting again during injection molding. Depending on the specific requirements of the chip and the baking conditions, suitable oven types such as hot air circulation ovens, vacuum ovens, nitrogen ovens, or programmable ovens can be chosen.