plastic mold

on the mold its called ejector pins and/or ejector sleeves.

on the part its called witness lines, marks

download gif image and view animation in your browser

  1. Step 1:

    standard ejector pin

  2. Step 2:

    stepped ejector pin

  3. Step 3:

    ejector sleeve

  4. Step 4:

    ejector pin in sleeve

  5. Step 5:

    blade ejector pin

  6. Step 6:

    core pin

  7. Step 7:

    ejection process showing why witness marks appear

  8. Step 8:

    ejecting part