FabricationInstructions

Created 22th September 2017 By John Lin, Updated 19th June 2018 by Liyu Wang

Overview

This is how to make an OpenRoach from materials to finish.

Gather and Size Materials

Material	Quantity	Dimensions
PET	1	11"x14"x.003"
1.9 Oz.Ripstop Nylon	2	11"x14"
Posterboard	4	11"x14" x0.175"
Thermal adhesive	10	11"x14"
Delrin	1	0.125" (T)
Pololu #994	2
Pololu #1086	1
Zumy Board	1
Blue 3d Printed Base	1
DRV8833 Dual Motor Driver Carrier, Pololu #2130	1
⌀ 3 mm rod	2	25 mm (L)
Flat head brass rivets	4	.125" x .5"
7.4 V Li-Po Battery	1
Time belt SDP-SI A 6Z16M077030	2

Make sure you have the correct AutoCad Files from the OpenRoach webpage. They should be the .dwg files.

Fabricate Parts

Fabrication of the OpenRoACH uses desktop fast-prototyping techniques such as laminating, laser cutting and 3D printing.

For laminating and laser cutting, here is an illustration showing how the steps are to be done in order. The lightning bolt symbolizes a laser cutting step. Note that the order of steps 2, 3, 4 may be switched. It is only ordered in this way for the time-saving purpose.

If you are using a laser cutter similar to Versa Laser 200, make sure you have the right settings for laser cutting as below.

Step ID	Material	Power	Speed	PPI
2	1 layer of paperboard + 1 layer of thermal adhesive	30	3	1000
7	2 layers of paperboard + 1 layer of PET + 1 layer of nylon + multiple layers of thermal adhesive	85	2	1000
-	Delrin	80	.2	1000

I. Body and leg transmission bar:

1. Take the two poster boards and laminate each poster board with a thermal adhesive sheet with the adhesion side to the poster board.

2. Laser cut the poster board. Make sure you cut them mirrored as they are positioned in the illustration above i.e. one with posterboard side up and the other with posterboard side down on the laser cutter.

3. While step 2 is being done by the laser cutter, take two thermal adhesive seats and laminate with the ripstop nylon.

Example Below:

4. Then take two thermal adhesive seats and laminate with the 0.003 PET. Now you should have all the pieces needed before you laser cut.

5. Laminate the Nylon and the PET together.

6. Use the metal pins to organize the cut parts, remove the white sheet from the other sheets revealing the thermal adhesive. Then layer the pieces as such: Top poster board, Nylon, PET, bottom poster board. Laminate it all together.

7. Complete the final laser cut. You can remove the excess material and you should be left with the example below.

II. Legs:

• The same steps as the body but there is no PET layer or step 4 as the legs do not need to stretch.

1. Take the poster board and laminate 2 poster boards with the thermal adhesive sheet with the adhesion side to the poster board.

2. Laser cut the poster boards with the correct settings. They will have to be mirrored because they are opposite sides of the body.

3. While step 2 is being done by the laser cutter, take two thermal adhesive sheets and laminate with the ripstop nylon.

5. Laser cut the Nylon with the appropriate settings.

6. Use the metal pins to organize the cut parts, remove the white sheet from the other sheets revealing the thermal adhesive. Then layer the pieces as such: Top poster board, Nylon, bottom poster board. Laminate it all together.

7. Complete the final laser cut. After removing the excess, there is an example below.

III. Laser cut leg transmission bar and pulley-flange coupler with Delrin

IV. 3D print the motor mounting base and pulley-flange hybrids.

Assemble

IMPORTANT: Before assembly, bend the kinetic flexure locations from around 180 degrees so that the flexures will work. Otherwise, after the OpenRoACH is assembled, then it may not run because some parts are not bending. If the flexures cannot bend, you must go back and fabricate another set for a working OpenRoACH.

Starting with the shafts of the roach, wrap the laser cut out below so they resemble the ones below.

Now, assemble the two pieces of flange-pulley structure with superglue applied between the two pieces.

Press the rivets into the 3D printed gears as shown below.

Make sure to solder the wires to the Pololu Motor before starting this step!

Attach the rivets, Pololu Motor with the newly assembled shaft along with the Timing Belt. M

So now attach the new shafts and two motors to the 3D printed base on top of the base platform.

Repeat until the other side of the motors, shaft are attached to the board.

Now below is a series of photos to attach the sides and the top of the laser cut pieces over the base and connect them with slits and such. There is not a lot of instruction. Perhaps a video in the future will be provided.

Attach the base firmly to the bottom base with screws.

Now hot glue the bottom of the base with a popsicle stick such that the hot glue itself will be parallel with the bottom of the base. You should be done with the base now. YAY!

Now, super glue places where it looks like it needs structural support as shown below but don't accidentally glue a joint which was supposed to move.

Pics

And now, time for FEET! Congratz on getting through the hard part!

Start by wrapping the joints around the loopholes.

After you fully assemble the 6 feet shown below, attach them to the OpenRoach. NOTE: The two different ones are for the middle.

Now, more super glue! (For structural support and not for fun)

Now, the front, middle and back legs should be attached.

Notice how the middle legs have a cut open side so it does not hit the popsicle stick on the base.

Now that everything is attached below is a wiring diagram and all the electronics on OpenRoACH to 1.1.

Thus, below is finalized OpenRoACH.

Congratz on finishing! Please provide feedback on this guide!

In addition, attaching the line scanner, there is a guide back on the Main page here.

Version history

Wishlist

Possibly future Camera or QR Code scanner