Introduction: How to Assemble and Use Cheap CNC Machine
Have you ever want to have a CNC machine? If you asked me few months ago I would say NO! Why? Because I prefer 3D printers, they are creating things from nothing instead of cutting things from material. But some time ago I was making a pcb with toner transfer method (I don't like it) and I thought that there must be better method for it. I read about other methods like using special UV laminats or just ordering it from manufacturer but one that I was intrested in was milling it. And the time when I can try this method came, but not only. I also tryed other tings with this CNC like engraving text or milling in wood and plastics.
Step 1: What Is CNC?
Computer Numeric Control (CNC) is the automation of machine tools that are operated by precisely programmed commands encoded on a storage medium (computer command module, usually located on the device) as opposed to controlled manually by hand wheels or levers, or mechanically automated by cams alone. Most NC today is computer (or computerized) numerical control (CNC), in which computers play an integral part of the control.
Here is the definition from wikipedia. So in other words CNC means computer numeric control and CNC mill is just controlled by computer. We can use those machines to make mechanical things very precisely.
Step 2: What You Will Need
Originally this Instructable was about a T8 CNC machine, looks like it is no longer available, so here is an alternative 3018 version.
If you want to build something on your own you should also check out my Instructable about DIY Dremel CNC machine. And if you want to build even bigger, more powerful and a bit more profesional CNC you should check out my recent CNC project IndyMill.
If you are just starting especially with a CNC kit like 3018 this instructable will be very useful for you. If you prefer building something on your own you can still learn some basics of CNC machining and short tutorial on milling something for the first time.
Step 3: Main Frame
Frame of this CNC is made out of aluminium profiles which are so simple to build and also looks good.
To start building this frame you need to take all of the aluminium profiles and some screws with special nut (rectangular ones) and using mounting brackets fix every thing together. Make sure to tight everything strongly ( to prevent it from any loosening after some time).
Back bracket of vertical profiles should be at the end of horizontal one (you can see it on the picture above)
Step 4: Y Axis
Now we will assemble Y axis, this axis moves the table. You will need 2 aluminium plates, bearing (like in the photo), and one of stepper motors. Also some screws but not every screw has a label with size so I can't tell you which one exactly, just find one that will fit hole perfectly.
Begin with screwing bearing to one of a plate and stepper motor to the other one. Attach plates to main frame. Stepper motor at the back and plate with bearing in front of frame. With same screws as you mounted main frame. Then you can add coupling to stepper motor.
Sorry that I don't add the photo of the table assembling but I forgot to make them :(
You just need to screw 2 metal plates to table and golden nut to one of this plate. I hope that from photos above you can understand it.
Put 2 poles inside "bearing" (it's not a bearing but just metal ring) of the table and then screw those poles to frame.
Remember to also screw small screws on the bearing and coupling
Step 5: Z Axis
There are some more of assembling of this axis, and I wouldn't write all of that I hope images are enough if you have any questions leave a comment.
Remember about small screws on the bearing and coupling
Step 6: X Axis
You need to screw again 2 plates to frame and motor to one of them and bearing to another one. Plates must be as high as it is possible, it should touch mounting bracket. Before screwing guides to plates you need to put on it Z axis that you made in previous step. Also remember about small screws on the bearing and coupling. You sholud be able to rotate leading screw without any problems (spindle motor and whole Z axis should move) if not check if it is in level.
Step 7: Spindle
You need to mount gold element to spindle with 2 small screws. All tools for milling or engraving you can mount to golden element. This type of montage is not perfect but it is sufficient for such a small CNC
Step 8: Everything Together
This is how everything should looks like. I also find in kit small rubber legs. They are pretty good and thanks to them you wouldn't scratch your desk like I did :)
Step 9: Electronics
24V are for spindle so solder 2 cables to black socket (you need to measure where is + and - in power supply) then connect one of this cables to relay as shown on the image above. Second cable from power supply goes directly to spindle (we just need to disconnect on cable to turn off spindle). Connect 5V of relay to 5V of arduino shield and GND to shield GND. Input from relay to shield SpnEn (spindle enabled).
12V are for steppers. Solder 2 cables to black DC socket and connect those cables to screw terminal on arduino shield (make sure you connect good + to + and - to -! This is very important!). Motors are connected to goldpins next to stepper motor driver. There are small text x axis, y axis, z axis you need to connect them as shown on the photo above. If you have any problems see some of next steps (called problems). If you have any questions about connection or anything else feel free to ask.
Step 10: Organizing Cables
To organize cables I used cable wrap or something like that I don't know if this is propper name for this. And after it the whole CNC started to look so good. There are no any free cable! Everything are inside those cable wrap. Looks great :)
Step 11: Software
You just need controller for sending gcode to your machine. On gearbest site you can find link to software provided by producer but my antivirus alert me that this is malware. Fortunately normal grbl controller works great with this machine. I had download soft from here:
I downloaded .exe file and installed it on my computer but if you want you can download .zip and unpack it where you want.
This is very simple program but it gives you possibility to mill everything. You can also move your machine with buttons. In the right down corner you can choose how many mm machine schould move every click so if you set 1 and click right arrow your machine will move 1mm to the right, if you set 100 and click left arrow your machine will move 100mm (10cm) to the left. Be carefull, if you put your machine to the max positions and still try to move it you can destroy it.
Step 12: Solving Some Problems
Here I will write about some problems that I had with this machine. They wasn't big but it is possible that you also face with something like this so here you can read how to fix them.
1. Machine moves in opposite direction:
You need to disconnect motor rotate the connector 180 degree and connect it, just change order of cables.
2.When I send command to move 10mm it moves just 5mm
This is problem that I have on Y axis, at the beginning I haven't any idea what can be wrong but after few minutes I relized that motor on Y axis must have 400 steps/rev (Z and X axis motor are 200 stpes/rev). all the motors in kit should have 200 steps/rev but one of them have 400 and I dont know why. Remember that if you have this motor you can mount it anywhere else (on Z, X or Y axis). How I fixed it? Because normal motor have 800steps/mm, motor with 400 steps/rev must have 1600 steps/mm. In grbl controller you need to send command: if this motor is on X axis:
if this motor is on Y axis:
if this motor is on Z axis:
Then everything should works fine.
I didn't found any other problem if you find one and you have solution for it write to me and I will add it right here. If you find and don't know how to fix it leave a comment and I will try to help.
Step 13: First Use
Above you can see how I mill N and PCB. But firstly you should try it manualy.
Remember about safty, this is not a toy, keep it away from children and be carefull while milling!
So firstly connect power supplys (24V to spindle and 12V to controller) then connect USB cable. Open grbl controller, find your machine and click connect. You need to wait few seconds until machine will print all informations. Then you can write F30 (F means feedrate and 30 is value) at the beggining don't try larger feedrate as if something goes wrong. Slowly get closer to material using arrows (don't get too deep!) and start milling. Remember to turn on spindle! And try to mill a rectangle or something else.You can try larger or smaller feedrate but be careful as you can break bit. You can also try with different bits, in kit you can find just 3 engraving bits (perfect for making pcb) I found some other bits in my dremel like grinder, you can see them on images above.
Step 14: Easiest Way to Engrave
After playing with manually moving your CNC it's time to make something more usefull. Right here you can find very simple text to gcode converter:
You can write whatever you want and mill it.
How to mill?
Start by mounting your material (wood, plastic, laminat for PCB) on the machine move your machine with arrows in grbl controller to get to the 0 point. To perfectly find 0 point of z axis you should go as close as you can to the material on the Z axis then loose your bit and screw it again, it should touch material. Click zero position to let the machine now that this is point 0. After downloading gcode form site find it and add those 3 lines at the beggining:
<p>M03<br>N5 G90 N6 F30</p>
Now you can click choose file find your gcode file and click start. Be carefull while milling and watch machine all the time when you will see that it is going to hit i.e. table immediately disconnect USB cable.
Step 15: What I Have Made
Since I got this CNC machine I had made some PCB, most of them just for testing but also one for my useless machine. PCB's are very good, and if I compare it to thermotransfer method milling is much better. I had also milled something in plastic and wood you can see photos above.
Step 16: How to Mill a PCB