Tip Molding Catheter Defects, Thin Wall Causes and Improvements

Undermolding of catheters during tip molding is usually manifested by thin walls, defects, or shapes that do not fill the mold in the molded portion. The following are some common causes of undermolding and their corresponding improvements:


1. Insufficient thrust:
– If the push force is too low, the material may not be able to fully fill all parts of the mold.

2. Material temperature is too low:
– If the material is not hot enough, its fluidity will be reduced and it will not be able to fill the mold adequately. 3.

3. Inappropriate mold temperature:
– Too low a mold temperature will accelerate the curing of the material, while too high a mold temperature may lead to material degradation or long cycle times.

4. Mold design problems:
– Poor mold design, such as improperly designed runners, inappropriately positioned gates or air traps inside the mold, can affect the mold filling effect.

5. Inadequate material preparation:
– Inadequate drying of the material or the presence of impurities may lead to poor fluidity.

6. Inadequate performance of the injection molding machine:
– Inadequate performance of the injection molding machine, especially its injection capacity and plasticizing ability, can also lead to inadequate mold filling if it is not sufficient to handle the required amount of material.

Improvement methods:

1. Increase thrust:
– Adjust the thrust setting to ensure that the material can be fully molded.

2. Adjust material temperature:
– Increase the temperature of the material to improve its flow.

3. Adjust the mold temperature:
– Optimize the mold temperature to ensure that the material maintains proper flow and cooling rates during the mold filling process.

4. Optimize mold design:
– Redesign the mold to improve the runner system and gate locations to ensure uniform material filling.

5. Ensure material quality:
– Appropriate pre-treatment of the material, such as drying, as well as ensuring the purity of the material.

6. Use the right tip molding machine:
– Select a tip molding machine that can handle the required amount of material and pressure.

7. Tip molding process control:
– Use finer process control techniques, such as closed-loop control, to improve the stability and repeatability of the injection molding process.

8. Specialized Training :
– Ensure that operators have adequate training on how to adjust and optimize injection molding machine and mold parameters.

Through the proper application and adjustment of the above methods, the underfilling problem of catheter tip molding can be significantly improved, thus improving product quality and productivity.

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