Putting together controls for a CNC router

I've had the hankering to do some more woodworking for a while, and have a few projects that are well suited for a CNC router. Coming to terms that I do not have room for a larger CNC mill at the moment, I've opted to go for a CNC router that is just barely small enough to fit onto an existing bench in my shop.

I was torn between building one and buying one (with Chinese imports being the only thing in the budget at the moment), and had been leaning towards what is known as the 6040 type (roughly 60cm x 40cm) when on a whim I tried searching ebay for a 6060 size. I saw one called a KL6060 from Automation Technologies for a decent price, and decided to do a little bit of research on it. Dumb luck, they were on sale on their website for $899, making the price all that much more desirable and actually less expensive than the level of home-built that I was considering.

They get mixed reviews, with the consensus generally seeming to be that they are plenty stiff for wood, but the choice to use unsupported round rails for the x-axis makes it lacking in the aluminum machining department (which is something I'd like to do at some point, but the primary mediums will be woods and plastics). Getting the router and considering it a good starting point for use with wood, and eventually modifying it to use profile rails on at least the flimsy axis still put me well ahead of a similarly built router from most other sources. The other big use for it that does not rely on any real rigidity is as a CNC laser - just a 2W for now, primarily for wood burning.

The router was sold as a barebones kit of sorts, with no spindle or controls, which is the point I am at now. Along with the router, I got a 2HP 24,000RPM spindle and a single to 3-phase VFD. For the controls I'm going with a Gecko G540 due to both its reputation and my familiarity with it as I used one on my mini-mill conversion. For a laser driver, I went with a unit from Jtech Photonics that allows for PWM control of the laser through Mach 3.

While the general control components are all sourced, getting things into a convenient to use and safe package is where I need some feedback and information. With my mill, I got everything together knowing that I would most likely be the only person using it, so making any kind of friendly interface or panel was of no real concern to me. I know what order to turn things on and how they all interact. For the router, my wife will be running it quite a bit, so I'm a bit more concerned with friendliness and safety than I was on the mill.

Near the top of the list, is a circuit that keeps the system powered down in the event that power is lost and restored, and needs a manual reset opposed to the tools just firing up when power is re-applied. I've used power failure systems in controls at work before, but was hoping there were some simpler options than a relatively expensive module that integrates with a PLC, and everything that I am familiar with was for 3-phase use. Anybody have any suggestions on a good way to accomplish this?

All of my CNC experience so far is with my converted mini-mill. Are there any special items on a physical control panel that those with experience using purpose built commercial CNC machinery would find "needed"?

So, long story for what worked out to short questions.

Thanks

Having recently finished a similarly equipped (but much larger footprint) cnc router build, I figured I could offer some support, but your questions actually relate to something I considred but also haven't fully realized.

I bought a cheap computer tower and gutted most of the inside, stuffed my PSU, VFD, and some wire busses with my 220v going in and splitting to separate 110v services.

Because of the size of the machine my g540 is on a gantry side frame, it moves! thats so I diddn't have to run 30+ extra feet of control wire through a massive cable chain.

Because the vfd and psu were in a computer case at one point I stuffed a micro atx motherboard from an old pc in there, but I remember why I stopped using that pc, the mobo randomly crashes... so for now im running a separate computer controller.

But in a full size pc case it is possible to fit everything reasonably well, for low cost.

As for power reset, I haven't thought about it much other than needing e-stops and power in general, and so your talking about what I think is sortof built in.

If I hit start on the master on/off switch my lights and cooling pump turn on, g540 comes on in a fault mode unless mach3 is already active on and talking to it, and the vfd gets juice but in the default rest mode. If the machine is running and I hit the e stop on the master, that all turns off save the oc running mach... and hitting start again is a new start for the g540 and vfd. I have set per ate switches if I want to toggle the lights or cooling pump off for any reason. but the big thing is the vfd doesn't auto spool up or anything.

As mentioned I have mach 3 on a computer on a whole separate circuit from the cnc so it'll stay on if I kill the machine with the e-stop, but if so, it looses talky talky with the g 540, then it goes into emergency as well, so even if the g540 and vfd come back on, you have to hit reset in mach 3 to use anything.

If I were to trip the 40amp breaker at the panel, i recall the switch on the cnc will automatically reset to off, as if I'd pounded the stop... so maybe that's what you're looking for? A 220v capable master power/e-stop that toggles off without juice?

If you think that would help I can look on amazon for the part.

Are you running one of the "chinese" liquid cooled spindles? I run liquid cooling on my spindle and also havit it pasthrough a heat sink for the g540. I highly enjoy that setup. Doesn't help my steppers but sure keeps the g540 cool as cucumbers

What I found is actually nice and simple, just took figuring out the right terms for Google to not laugh in my face.

Essentially use a relay to switch it's own control voltage so if the power is lost, the coil de-energizes and requires a manual kickstart from a momentary switch to begin again. Have that control voltage also be shared with the relays for everything else. The e-stop I have wired into the 120VAC which powers the 12V transformers. Kill that, and every relay opens, including the feeds for the laser and VFD power supplies, and requires both the e-stop to be reset and the start button to be manually pushed.

http://i1374.photobucket.com/albums/...psgx0rome8.jpg

http://i1374.photobucket.com/albums/...psqqn1bghf.jpg

Yeah, it is one of the Chinese water-cooled spindles. Not planning on doing any auxiliary cooling with the loop, but my bench is located about 3 feet away from my sump pit in the basement, and I have an emergency water powered sump pump installed that runs from municipal water in case the power to the regular one is lost, so I have a nice source handy for it. Was actually thinking about putting a secondary heat exchanger right into the sump pit as it stays full of cold water pretty much all year (very wet property).