#  Step 2: Holes & Blends 

 



 ##  

  expand\_more  

 
  

 

#### Add channel holes

- Now, we build the holes into the cylinders to get our channels (Insert → Design Feature → Hole).
- Zoom in on one channel as shown in the image below and choose the edge of the extruded cylinder.
- The edge should be highlighted in yellow.

   ![cda-step2-1.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/cda-step2-1.png?itok=o_bKTgAW) 

 

[Click here for larger image](/file_url/474)

- Now enter the data for the channel.
- Set the “Diameter” to 7mm, the “Depth” to 50 mm and the “Tip Angle” to 150°.
- Finalize by clicking “OK”.
- Repeat this process for the left channel.
- The middle channel uses the same procedure, but with a diameter of 3 mm.

   ![cda-step2-2.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/cda-step2-2.png?itok=JfX1tBVm) 

 

[Click here for larger image](/file_url/475)

- To check whether your channels penetrate into the combustion chamber or not, use “Crtl+H” to open the “View Section”.
- Choose the YC-orientation and click “OK”.
- Now, your actuator should look like the figure below. If so, exit the “View Section” (View → Section → Clip Work Section)

   ![cda-step2-3.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/cda-step2-3.png?itok=7GBSpjgB) 

 

[Click here for larger image](/file_url/476)

#### Add edge blends

- Now, we add edge blends in order to smooth the surface.
- This is important, since the silicone has a higher chance to tear where there is an incisive angle.

   ![cda-step2-4.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/cda-step2-4.png?itok=k96H0iZe) 

 

[Click here for larger image](/file_url/477)

- Insert a blend (Insert → Detail Feature → Edge Blend).
- Choose edge separating the horizontal cylinder from the combustion chamber.
- Choose a radius of 10 mm.
- Finalize by clicking “OK”.

   ![cda-step2-8.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/cda-step2-8.png?itok=mfpE353P) 

 

[Click here for larger image](/file_url/481)

- Select the two edges shown below and use a radius of 2 mm.

   ![cda-step2-5.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/cda-step2-5.png?itok=q5Vs4KEg) 

 

[Click here for larger image](/file_url/478)

- Select the edges shown below and use a radius of 1 mm.

   ![cda-step2-6.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/cda-step2-6.png?itok=MRXaW1ff) 

 

[Click here for larger image](/file_url/479)

- The edges shown below should also have a radius of 2 mm.
- Finalize again by clicking “OK”. You now have designed your combustion driven actuator.

   ![cda-step2-7.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/cda-step2-7.png?itok=LyAm9Jz6) 

 

[Click here for larger image](/file_url/480)

### Bibliography

Loepfe et al. (2015) [Contrast Agent Incorporation into Silicone Enables Real‐Time Flow‐Structure Analysis of Mammalian Vein‐Inspired Soft Pumps](/publications/contrast-agent-incorporation-silicone-enables-real-time-flow-structure).

Loepfe et al. (2015) [An Untethered, Jumping Roly-Poly Soft Robot Driven by Combustion.](/publications/untethered-jumping-roly-poly-soft-robot-driven-combustion)

Loepfe et al. (2014) [Design, Performance and Reinforcement of Bearing-Free Soft Silicone Combustion-Driven Pumps.](/publications/design-performance-and-reinforcement-bearing-free-soft-silicone-combustion)

Schumacher et al. (2014) [3D printed lost-wax casted soft silicone monoblocks enable heart-inspired pumping by internal combustion.](/publications/3d-printed-lost-wax-casted-soft-silicone-monoblocks-enable-heart-inspired)

Shepard et al. (2013) [Using Explosions to Power a Soft Robot.](/publications/using-explosions-power-soft-robot)

Stergiopulos et al. (2014) [A Soft Combustion-Driven Pump For Soft Robots.](/publications/soft-combustion-driven-pump-soft-robots)

### Contributors

Michael Loepfe