In this instructable I will show you how to use multiple processes in Simplify3D to print multiple colors with only one extruder.
I prefer this method compared to pausing the print manually and swapping color because I don't end up with a blob of filament where I paused it. I can prime the filament so only the new color comes out the change. Also the extruder could move out of position using the pause method.
I will be using my remixed version of the cover from the Raspberry Pi Zero NPR One Radio project by Adafruit.
If you want to follow along I have posted the files on Thingiverse. http://www.thingiverse.com/thing:1647961
Step 1: Prepare the Design for Printing
First we need to edit the design to have each color we want to be at a different height in the file. I am using Autodesk Fusion 360. But any 3D modeling program should work also.
When adjusting the heights also make sure its a multiple of the layer height you will be using. I will be printing this at a 0.2mm layer height.
I want the base to be brown. Looking at the side profile you can see that I have the base from 0mm to 2.2mm. The next color will be red from 2.2mm to 2.6mm. After that we will use black for 2.6mm - 3mm. Blue will be 3mm - 3.4mm. We then finish off with white for 3.4mm - 4.2mm
Step 2: Add Multiple Processes in Simplify3D
To add the multiple process I just click the add button until I have one for each color. You can then rename them to the color and height ranges if you want. This makes it easier to follow when printing.
Now that you have each process added you can set the start and stop height for each one. In the example screenshot I have red selected. So we tell the process we want to start at 2.2mm and end at 2.6mm
Also make sure to turn off the brim or outline after the 1st process. Otherwise subsequent processes will try to print one out and just be printing in the air.
Step 3: Configure Start Script Gcode Commands
For the first color we want the printer to home all axes. But after that as long as we don't the turn printer off and back on the z axis will not need homing. We modify the start script on all processes after the base to only home the x axis and y axis. The command is G28 X0 Y0
We want these homed because while changing filament between colors we might move the print bed or extruder on those axes by hand
Step 4: Configure End Script Gcode Commands
We also need to change the end commands. We don't want the bed to start cooling down between colors. This could cause our part to become loose on the print bed. We remove the M140 S0 command from the end script. We could also remove the M104 S0 command which turns off the extruder.
We will want these commands in the last color though. Since we are done printing after that.
Step 5: Check Preview
Now that the processes are all setup correctly we can check and see if the print preview looks good. Select all the processes to see the full print. You can also check each process individually.
Step 6: Save Individual Gcode Files and Print
Now that the preview looks good we will save the gcode for each individual color. Click prepare to print and select one color a time. Save the gcode and name it to the color.
Now we print each color going in order from bottom up. After each color is printed we can swap the filament and purge the previous color out before starting the new color layers.
Step 7: Completed Print
As you can see the part came out great. This method allows you more creativity when printing without the hassle of multiple extruders.
Using this method you will be able to see the color changes on the side profile. So take that in to consideration to make sure it is acceptable for your design.