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CNC Control of a 3rd party spindle, VFD, and NWA laser

Posted: Sun Jan 19, 2020 1:09 am
by RJGeller
I have seen several inquiries online about CNC control of spindles or lasers, but few responses. I also wanted to use a 220V spindle that had an ER20 collet (1/2” capacity) (which is not offered by NWA) with my Shark, and I wanted my Shark to turn the spindle on and off as appropriate. I also wanted to use a laser attachment, and to have the Shark turn the able to turn the laser selectively on and off as appropriate. And I wanted all this to happen without hacking into the wiring of the control box or the pendant.

We know that the Shark control box turns on the power outlet intended for a router when the GCode calls for the router to be on. So, it seems reasonable that the power outlet for the router could be used as a signal for the spindle or the laser to be on. I think that best practice calls for the cooling pump to be running even after the spindle turns off, to allow time for coolant to continue circulating and cooling the spindle. I also am using a closed circuit cooling system (using liquid-cooled PC components), which may or may not match your circumstances.

Given these planning assumptions, I designed a relatively simple control box to accomplish these goals. The control box uses three relays, a rotary switch, a toggle switch, and a few resistors and diodes. If you are comfortable with basic electrical wiring, soldering, and following a schematic, feel free to adapt the attached files to your needs. Of course, since your situation might be slightly different than mine, your success with the attached is entirely under your own control, and these plans may or may not work for you, and any liability from anything you build remains with you.

As I built this, it has components in 2 separate boxes. The relays and the 110V and 220V power is in a large 2-gang electric box with an outlet in the top of it, into which the laser power supply and the 12V power transformer plug in. The remainder of the connections are made with wiring leaving the box through knockouts with wire protectors on them, plugging into the 110V and 220V wall supplies, the master switch for the entire CNC setup, and connecting to the other box. The second box sits on the countertop in front of the CNC with the rotary switch control and the control from the VFD (which is connected to the VFD itself by a ribbon cable supplied by the VFD manufacturer).

The total parts cost as I built the system was about $100, with most of the parts coming from Amazon. Your cost will vary, depending on what you already have available, where you acquire the parts, and which variations you make in the build.