Overcoming common medical injection molding challenges

Your medical device has been designed and your preferred plastic has been selected. The final step is to mold your part, which should be simple. However, even the most seasoned injection molders face molding challenges, including medical device manufacturers.

Although these challenges are common in every industry, defects associated with medical devices require special attention to plastic material selection and part design along with the associated mold design and process parameters.

Medical devices are subject to stringent regulations, specifically FDA and ISO. Defects can seriously compromise the integrity of your final product and their subsequent approval. Fortunately, these challenges can be remedied and even prevented.

Causes of injection molding defects

Attention to detail as well as adhering to best practices can minimize and even prevent molding defects. The root cause of most molding defects can be narrowed down to issues associated with the machine, mold, plastic material and / or the operator.

Be mindful of oversights on these process parameters and considerations:

  • Mold design
    • Mold flow
    • Venting
    • Gating
  • Plastic material
    • Viscosity
    • Hydroscopy
    • Material handling
    • Melting temperature
    • Cooling temperature
  • Temperature settings that are not optimized for the plastic material
    • Mold temperature
    • Melt temperature
  • Pressure at different stages of the medical molding process
    • Injection pressure
    • Holding pressure
    • Ejection pressure

Common medical molding challenges


Illustration of common injection molding defects

Defects can range in seriousness from simple cosmetic blemishes to concerns with the part