SC V1 - 3D Printed CND Table Router

I build this machine at the end of 2021, this is actually a project that I was handling during my internship period. Always wanted to post this Instructables to share my experience and hope that it will give you some inspiration if you are building one too. This will be a short Instructables just to get this up for now, I will progressively add more information if you are interested :)

The design is inspired by X-carve and Tuan. I really liked the design of the carriages on these machines as they allow you to scale up and down the machine as you like, having the belt and roller system running the carriages might not be giving you the best precision, but it is quiet and easy to install. Since I use 3D printers, it is a good idea to print the parts with my 3D printers and only purchase those I cannot make.

• 3D printers
• Aluminium profiles (2040, 2020, preferably v-grooves)
• Stepper motors, drivers
• Arduino UNO
• Spindle motors

If you are not familiar with the belt and roller system, it is a system that is commonly used in 3D printers to provide linear motions. Here is a link for you to learn more (https://www.youtube.com/watch?v=eCr1ogUuNPA)

The system I used however is kind of the opposite. The carriages are slotted on the grooves of the aluminium profiles, secured by sets of rollers which allow linear motion along the profiles. The carriages move when the stepper motors turn and move along the fixed pulley. This system makes it possible to build the carriages in one single piece and slide it into the profiles, which means u can extend the profiles as far as you want (theoretically). This same system is used to move the cutting spindle in X and Y axis. The build volume is about 875*875*80mm.

Almost forgot to mention that you also need eccentric nuts to make sure the v shape wheels grip properly onto the profiles, and the idler pulley to ensure the belt is properly tensioned.

The Y-axis profiles sit on the ground, the Y carriage is installed on it, and then the X carriage is installed on the X-axis profiles which sit on top of the Y carriage.

Apparently, while I was doing my research, the V-slot seems to be associated with a company called OpenBuilds, not sure if they invented this system, but it is a brilliant idea and so modular! By the way, finding a V-slot aluminium profile seems to be impossible in Malaysia, if anyone knows where I can get one locally, please let me know. A T-slot profile will work as well, but you will have to sacrifice some grip and power.

The Z axis simply has to move the spindle up and down. The stepper motor uses a belt to turn a lead screw (which is essentially just a threaded rod). The lead screw is connected to a nut block, which moves when the lead screw is turned. The nut block is connected to the Z carriage where the spindle is installed.

The electronics are mainly out of the shelf solution, I got some generic NEMA23 stepper motors and DM556 stepper drives from China. They work great and quietly, but there is not much of the specification I can talk about because there is hardly any documentation I can find. The good news is I have not found them to be super hot during the testing of the machine.

I use the Arduino UNO as the brain of the machine. The firmware I use is the GRBL v1.1, this firmware makes it extremely easy to build a CNC machine like this.

1. Connect your stepper motor to your driver (usually there are 4 poles)
2. Follow the pin diagram in the GRBL github to connect your stepper driver to your Arduino
3. Download serial communicator, the one I use is the UGS (universal gcode sender)
4. Import some G-code file and run the machine

If you are wondering how to generate G-code, Fusion 360 comes with its own CAM you can use for that.

Another thing is the use of limit switches, tho they are optional, I used them to help home my machine. I was experiencing some interference from the stepper motors so I used the optocoupler, and they worked very well.

The final step of the project is to install everything on an MDF board so I can move the machine around. I also made my own waste board with threaded T nuts so I can bolt things down.

There are definitely improvements that can be made to this project. I found that the Z-carriage is constantly twisting about the X-axis while plunging into harder materials. This is caused by the bend of the 3D printed X carriage, together with the tolerances of the v wheels (both on the Z and X axis). Maybe having a shorter X-axis profile, using linear rails instead of v-wheels would help in resolving this problem?

Another problem is the 3D-printed collar nut that keeps the Z carriage in place also breaks constantly, the plunging force from the spindle pushes the lead screw nuts upwards, which exerted force on the collar nut causing it to break.

Although this project only took around 2 months, I definitely learned a lot about CNC and 3D printing. Till next time!