Use these drawings if you are building Raw 1.5 CNC DIY kit 100x100cm. If you are building the machine with loose parts, then our other drawings apply!
You will find both video instructions as well as illustrations on this page. One tip is to open another browser tab with the same page so you can switch windows to see both video and illustrations.
The Video instructions can be found further down the page.
Step 9 not required for this machine
Note, some Windows computers, cant find the comport, if that is the case then you need to install a new driver. Search on Google for “Arduino ch340g driver” and find one that suits your operating system
We will use Estlcam but you can use any software compatible with arduino. Go here to see whats avalible https://github.com/grbl/grbl/wiki/Using-Grbl Or search for Grbl software.
To install and setup Estlcam (click on images for closeup and then return by clicking back arrow on your browser)
NOTE, we use drv8825 Stepper Motor Drivers wich is stronger and can handle 1/32 microstepping, so the setting below “Steps per revolution” should be 6400 and not 3200!
We are done! Remember that the belts can’t be too tight or the motor axle can be damaged, the machine might also stall if the belts are too tight.
Read my article on how to cut with the best results, there is a lot to think of to get a good result.
Back to School
We use so many different settings, belt, lead screw or racks in different sizes so I will put out a tutorial for you so that you can calculate this yourself.
If you use Arduino and GRBL the math is different to Estlcam or Mach3 for example, lets start with GRBL that asks for a PER mm number:
GRBL (Estlcam settings below this article but read this as well to understand what we are looking for)
A typical stepper motor has 200 steps PER revolution. These are known as FULL steps or 1.8° per step.
A Raw machine has a HDT3 or HTD5 timing belt which means that they have a pitch of 3mm or 5mm. Pitch is the distance between two tops or bottoms of the timing belt/racks or the distance between threads, if you use leadscrew as we do for the Z-axis.
If you want to calculate a leadscrew then the math is simple just add the pitch of the leadscrew 3mm and divide it with 200 (stepr per revolution) and the number we will put as a value in GRBL (The settings in GRBL call for a PER mm number) for example is:
200/3 = 66,66666666666667 steps to make something travel 1mm
For timing belt we need to calculate how many teeth the pulley has and multiply it with 3 or 5 depending on the pitch, so for a 5mm pitch and 16 teeth (5×16) , then it will travel 80mm/rev
So the math is :
200/80= 2,5 steps to make something travel 1mm
Micro stepping (Estlcam for exampl
CNC shield with the A4988 Drivers uses 1/16 micro stepping when all jumpers are activated , which means each step is divided into 16 microsteps.
A typical stepper motor has 200 steps PER revolution.
200 steps x16 micro steps = 3200 total steps/rev So the value “steps per revolution” in Estlcam is 3200. If you use other drivers that has 32 micro steps that value would be: 200 steps x32 = 6400.
“Distance per revolution” is what your machine will travel per revolution so for a HTD5 belt (5mm pitch) with a pulley that has 16 teeth that distance would be 16×5=80mm
-HTD3 with a pitch of 3mm would be 16×3=48mm
-Lead screw with a pitch of 3mm will travel 3mm per rev and that would be 3mm
The same math applies for Mach 3 but we need to extend it some more
Mach3 or other software’s asks for how many steppes it takes for something to move 1mm, so let’s do the math with the lead screw that has a pitch of 3mm (it travels 3mm per rev) We use 16 micro steps setting on the drivers for the z-axis so the math is basically,
1600/3 = 533,3333333333333 steps to make something move 1mm (again, if your thread is different, then the divider number will be different)
533,3333333333333 is the number I put into Mach.