Urethane Casting

Making Soft Parts for Robots ( Grippers, Wheels, Rollers)

for this process we will already want a part designed in Onshape in addition to a mold create

Select the hardness (shore durometer)



Select the Hub style

no hub

hard hub

Prep the Mold

    1. Your mold should be sanded smooth to prevent the rubber from grabbing to the mold.
    2. in addition to a smooth mold you want to spray the inside of the mold with a light coating of spray lubricant.

Select the Color

Please only use one pigment when mixing and only use a very small amount (less than 1/4th teaspoon)

    1. add 1/4 teaspoon of pigment to your mixing cup

Mix the resin

    1. based on the volume of your mold pour equal parts of resin A and resin B in to a mixing cup
    2. using a Popsicle stick stir until well mixed and the added color is consistent.

Pour the resin

    1. pour your mixed resin in to the mold while quickly shaking the mold. this will help the resin fill in any gaps and release any bubbles that may have formed when mixing.
    2. if you are adding a hard hub place your hub in as you are pouring the resin.
    3. once your resin has reached the fill line give the mold a last good shake
    4. then place the mold in the corner to cure overnight

Let the resin cure

    1. allow the resin to set and cure over night.
    2. you should be able to remove the part the next day