Soft Gripper Fabrication Guide


Important Considerations:

Difficulty: Beginner  
Min. Age: Age 10  
Time:  3 Hours  
Est. Cost per 20 Students: $20  
Component Category: Actuator  
Control Category:  Pneumatics  
Essential Learning: Mold Making & Casting  
Safety Equipment:  Lab Gloves, Aprons  


The Soft Gripper Fabrication Guide is a beginner level instructional guide for the introduction of soft robotics within the home or classroom. This soft gripper is made to have four legs that are inflated to pick up an object very gently, highlighting it's special suitability for delicate tasks. The gripper reinforces the principals of soft robotics through building molds with everyday materials and troubleshooting a pneumatic system.

Supporting Documents:

This page provides the Soft Gripper Fabrication Guide, a template for building the mold and a bill of materials for all of the necessary equipment and supplies. These can both be download using the "DOWNLOAD" button to the left. 

Overview of Materials:

  • Cardboard
  • Fabric
  • Glue & glue gun
  • Scissors
  • Silicone elastomer 
  • Tape
  • Thread
  • Tubing 
  • X-Acto knife


  • Students should begin this activity with a prior knowledge of the basics of soft robotics and be able to understand basic vocabulary associated such as with terms like actuators, sensors, controls.
  • A basic understanding of pneumatics used within soft robots is also recommended. 

Essential Learning Objectives:

Students will learn to construct a gripper mold using cardboard, tape and hot glue. By creating the two part cast for this mold, students will learn how materials layered together facilitate the movement of this actuator. Once the gripper is finished, students will test their prototype by inflating the gripper and observing its movement. Lastly, students will evaluate the final device, troubleshooting the pneumatic system and brainstorming possible solutions if needed.  

Construct Mold Create Two Part Cast Evaluate Final Result


Overview of Steps:

The following is an overview of the steps associated with the guide. For more details regarding each step and for a copy of the documents this overview references please download the fabrication guide using the "DOWNLOAD"  button above. 

step_6.png The Gripper mold is made of traditional cardboard, laminated with clear packing tape and assembled with hot glue to seal the corners and to ensure there is no leakage when molding. 
pouring_graphic_new.png The molding process is conducted in two parts. The first layer is cast with silicone to the first line halfway up the cardboard mold. Once filled to this point the elastomer must cure completely before proceeding. 
template_2_placing_new.png A piece of acetate is placed on the first cast layer to define the pneumatic channel within the gripper. The acetate allows the elastomer to flow around it without adhering, establishing an inner channel.
pouring_final_graphic_new.png The second cast layer is cast over the acetate and fills the gripper mold to the top of the cardboard. This completes the silicone casting.
string_step.png A piece of fabric is placed on top of the uncured silicone. This will prevent the top of the gripper from stretching, causing the gripper to close underneath around an object. This second layer is cured completely after the fabric is placed. 
step_24.png The cured gripper is de-molded and tubing is placed into the gripper at the level of the acetate. A syringe is then attached to the tubing, completing the pneumatic network. 

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