This chapter will go over 3d printing the parts needed for the SwerveBot.
Printing the swerve modules is a bit tricky as they require dimensionally accurate prints. If the gears are slightly too large, they will not run smoothly and if they are slightly too small they will slip. Before you begin, you need to look up the instructions on how to calibrate the X, Y, Z and Feed for your specific printer. This will give you the best chance for success.
I now going to list groups of parts and what settings I use to print them.
Swerve Module Parts
The following are the parts that needed for a single Swerve Module. You will need to build four Swerve Modules.
Layer height 0.3mm, no support
I print the following set of parts using a 0.3mm layer height and no support. They should be printed oriented as shown:
Note that when you print the Base part that has the text on the bottom (i.e. BaseWithInserts.stl) you may need to slow down the first layer speed so that the text will adhere properly to the print bed. For that part I usually set the first layer speed to be 1/3 of normal.
Inserts vs Imbedded nuts
When we need to attach screws we can either use threaded inserts which are inserted into the parts after printing using heat or we can imbed nuts into the parts when they are printed. The advantage of embedding the nuts is that you do not need to add the inserts after printing. The disadvantage is that you must pause the print to insert the nuts.
In the above set of parts, the Base and Upper Support have two STL files, one designed for inserts and the other designed for embedded nuts.
Printing the ones with inserts is straightforward. However to print the versions with embedded nuts, you will need to create your G-Code files with commands to pause the print so that you can insert the nuts. I am using UltiMaker Cura for my slicer and the following is the procedure to create the G-Code file for the Upper Support. If you use a different slicer, you will have to figure out how to do it, but it will probably be fairly similar to this.
Note that this piece has two different imbedded nuts so it will require the printer to be paused twice.
First import the piece and slice it using a 0.3mm layer height. Then use the tool that allows you to see the layers and move it down until you find the top of the smaller 4-40 nuts.
Here we can see layer 10 is the top of the nut because layer 11 covers it. This means that we need to pause the print a layer 10.
To do this, choose Modify G-Code option for the Extensions menu:
Then choose the Pause at height option:
Then set the Pause Layer to 10. Also you will need to choose the correct Method for your printer. My printer needs to use the M25 G-Code command to properly pause the printer.
Then find the second pause point for the 8-32 nuts:
Here we see that I need to pause at layer 13.
Now add that layer to your Pause at height list:
Now when you print the file, the printer will pause at layer 10. At this point you should insert the two 4-40 nuts and then resume. The printer will then pause at layer 13 and you should insert the two 8-32 nuts.
The Base also has two sizes of nuts so will require two pauses. Note that the pause points might be different so you should determine them in the same way as for the Upper Support.
Layer height 0.2mm, no support
The following parts should be printed using a 0.2mm layer height. If you print them in the orientation shown below, you will not need supports.
Out of this set of parts, the Large Steering Gear requires inserts. As before there is a Large Steering Gear with Nuts that you can use to create a part with embedded nuts. This part has only one type of nut so there is only one print pause that will be needed.
Layer height 0.2mm, support required
The following parts need generated support. I recommend using Tree Supports, but your milage might vary.
Robot Parts
This section specify how to print the remaining parts for the robot.
Layer height 0.3mm, no support
The two Power and Pi Panels shown below should be printed using 0.3mm layer height with no support:
Each of these panels also come in a version with imbedded nuts. The Power Panel only uses 8-32 nuts so has a single pause while the Pi Panel has both 8-32 nuts and 4-40 nuts and requires 2 pauses.