About a month ago, Dan Royer from Marginally Clever Robots contacted me about making a vacuum gripper for his jigsaw puzzle solving pick-and-place. I made him 4 different sized suction grippers, that when paired with some source of a vacuum, can stick to objects. This guide covers how to make them.
- PLA/ABS filament
- Silicone Caulk
- Ecoflex silicone (Any type will do, I used 00-50)
- Small zip-tie
- 1/4" barbed connector OR 1/8" tubing
- Flush snips
- 3D printer
- Vacuum source (you can use a designated vacuum pump or just your mouth)
Step 1: 3D Print the Molds
There are four sizes for the grippers. All grippers are 20mm tall.
- 7.5mm OD
- 10mm OD
- 12mm OD
- 15mm OD
Print two mold pieces and a core of a given size with 10% infill and 3 shells.
Step 2: Sealing the Mold
Assemble the mold by placing the core in between the two outer mold pieces and clamp it at the bottom. Make sure the core is centered. Take the silicone caulk and apply it to all the creases of the mold. Let it cure for about an hour.
Step 3: Casting the Mold
Mix up a small amount of whatever Ecoflex you are using. Ecoflex uses a 1A:1B ratio, meaning there should be an equal amount of both parts of the mixture. Mix it thoroughly and then drizzle it into the opening of the mold. Let it cure for about 4 hours.
Step 4: Demolding, Clean-up and Connection
Once the silicone has cured, peel away the caulk. Use the screwdriver to pry apart the mold. Grip the core from the bottom and pull it out of cast. Use the flush snips to cut off any excess flash. Now connect either the 1/4" barbed connector or the 1/8" tubing.
Step 5: Use
To grip something, press the cup of the gripper against a flat surface that it can form an airtight seal with and apply the vacuum.