[Woody97038]

Hi guys,
I just finished building a CNC router of my own design. I am a woodworker and cabinet maker. I chose what I thought were the best features from several different designs. I'll make a more detailed post on a dedicated build thread. It has 1/2" 2 start lead screws powered by (4) 340 oz/in steppers (2 on the y axis). It has 2 NO limit switches on each axis. The controller is a TinyG with a 24 v power supply. For now, I'm using my laptop, but I plan on a permanently installed pc in the control box area. It also has a 120v relay that is triggered from the spindle control on the tinyg. The router is a Bosch 1617evs.

I spent the weekend wiring everything up and setting up the tinyg. I had it finding it's limits and setting the 0 point. I was able to run some test files with the router off. When I triggered the relay and turned the router on the tinyg would lose it's usb connection and shut down. I would have to reset the tinyg to re-establish the connection. I think I know what might be the problem. All of the control cables and the router power run parallel in 2 pieces of drag chain for over 10 ft. I stripped the shielding on the stepper control cable, but I havn'e grounded it yet. I'm pretty sure I'm RF interference from the router.

Opinions?

[Biggs427]

Have you tried to power your router without the relay? Try to manually power on the router and see if the USB connection holds.

[fretman_2]

Nice looking machine!

[109jb]

I use GRBL, which is also a USB microcontroller arrangement for machine control and have found a few things relevant to your situation.

1. Looking at your USB cable I can tell it is a "small" one and is likely cheap. Invest in a good quality "thick" USB cable that has ferrite beads at both ends which will help cut noise and connection dropping. There is definitely a difference when it comes to USB cables. Also get the right cable instead of using the adapter like you have.

2. I located the microcontroller and Steeper drives within a steel enclosure to provide shielding with no 110V AC within that box.

3. The stepper cables are grounded at the box enclosure end.

4. The limit switch wires are CAT 5 wire I had lying around with the shield also grounded to the box. I also have 0.1uF capacitors from the limit pins to the ground pin on the microcontroller.

I have found these microcontrollers work great but they are definitely susceptible to noise issues. Enclosures, shielding and noise filtering need to be used for reliability.

[Woody97038]

Thanks for the advice 109jb. I will upgrade my usb cable. It was what we had laying around. I grounded the stepper cable shielding. I really don't want to replace my limit switch wires. Hopefully the new usb cable will help. will help. I have the day off, so I will get it today and report back.

[RickMc]

How big is the table? Did you use lead screws or thread rods for each axis and what size?

Thanks