#  Make thread grooves 

 



 ##  

  expand\_more  

 
  

 

## Draw helix path

\[[Video: Make helix](http://www.youtube.com/watch?v=NtzGudSc3J0)\]

The thread grooves will be made using the **Swept Cut** feature. First, we have to make the path for the cut to follow, which is a helix. To create this helix, go to **Curves > Helix and Spiral**.

 ![image17 crop marked](/sites/g/files/omnuum4601/files/2024-11/image17_crop_marked.png)

 

Select the bottom face of the actuator, and draw the base circle for the helix, which is 20mm in diameter and also centered at the origin.

 ![image18_crop](/sites/g/files/omnuum4601/files/2024-11/image18_crop.png)

 

 ![image19 2](/sites/g/files/omnuum4601/files/2024-11/image19_2.png)

 

   ![shorterhelix0.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/shorterhelix0.png?itok=zplwYbYw) 

 

Exit the sketch and set the helix parameters.

- Defined By: Height and Pitch
- Constant pitch
- Height: 168mm (2mm shorter than actuator length to leave room for cap)
- Pitch: 3.6mm
- Start angle: 90degrees
- Counterclockwise

If the helix is going in the wrong direction (not surrounding the actuator), then check “Reverse Direction.” The result should look like the image on the right.

Sort   ![shorterhelix1.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/shorterhelix1.png?itok=QclUC9Qq) 

 

   ![shorterhelix2.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/shorterhelix2.png?itok=E7R5jux3) 

 



   ![shorterhelix3.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__960x960_scale/public/sorotoolkit/files/shorterhelix3.png?itok=UZkOsEO9) 

 







#### Swept cut

\[[Video: Swept cut for thread grooves](http://www.youtube.com/watch?v=t-PrrQe8ntc)\]

 ![image24 crop](/sites/g/files/omnuum4601/files/2024-11/image24_crop.png)

 

Now that we have the helix path, we can draw the profile for the swept cut. In the **plane corresponding to the flat face of the actuator’s inner cavity**, make a new sketch.

 ![image28_1](/sites/g/files/omnuum4601/files/2024-11/image28_1.png)

 

Draw a 0.4mm diameter circle, with its center aligned with the outer bottom edge of the actuator.

 ![image25 crop marked](/sites/g/files/omnuum4601/files/2024-11/image25_crop_marked.png)

 

 ![image26_crop](/sites/g/files/omnuum4601/files/2024-11/image26_crop.png)

 

 ![image27](/sites/g/files/omnuum4601/files/2024-11/image27.png)

 

Using **Swept Cut**, use the sketches you just made and define them as the sweep profile and path. This will cut a series of grooves spiraling up the front of the actuator.

 ![image29 swept cut clarify](/sites/g/files/omnuum4601/files/2024-11/image29_swept_cut_clarify.png)

 

 ![image29 1](/sites/g/files/omnuum4601/files/2024-11/image29_1.png)

 

 ![shorterhelix4](/sites/g/files/omnuum4601/files/2024-11/shorterhelix4.png)

 

## Mirror

\[[Video: Mirror for symmetrical thread wrapping](http://www.youtube.com/watch?v=S8zIQGq0lYg)\]

To get the other set of grooves, we can simply **Mirror** the swept cut we just made over the mid plane of the actuator, which corresponds to the Right Plane in this tutorial.

 ![image30 mirror clarify](/sites/g/files/omnuum4601/files/2024-11/image30_mirror_clarify.png)

 

 ![image30 1](/sites/g/files/omnuum4601/files/2024-11/image30_1.png)

 

The result should look like this:

   ![shorterhelix5.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__100x100_scale/public/sorotoolkit/files/shorterhelix5.png?itok=5_yUmxOB) 

 

 ![image 20](/sites/g/files/omnuum4601/files/2024-11/image2_0.png)

 



 

##  Bibliography 

Galloway et al. (2013) [Mechanically programmable bend radius for fiber-reinforced soft actuators](/publications/mechanically-programmable-bend-radius-fiber-reinforced-soft-actuators).

Maeder-York et al. (2014) [Biologically Inspired Soft Robot for Thumb Rehabilitation](https://softroboticstoolkit.com/book/publications/biologically-inspired-soft-robot-thumb-rehabilitation).

Connolly et al. (2015) [Mechanical Programming of Soft Actuators by Varying Fiber Angle](/publications/mechanical-programming-soft-actuators-varying-fiber-angle)

Connolly et al. (2016) [Automatic Design of Fiber-Reinforced Soft Actuators for Trajectory Matching](http://softroboticstoolkit.com/publications/automatic-design-fiber-reinforced-soft-actuators-trajectory-matching)



 

##  Contributors 

Panagiotis Polygerinos

Kevin Galloway

Zheng Wang

Fionnuala Connolly

Johannes T B Overvelde

Harrison Young