New Shop CNC Footprint and Ductwork?

[Leigh Betsch]

I'm in the process of running dust collection ductwork for my new shop. I'm installing my ductwork above the ceiling before the ceiling goes in. I'd like to put in a ceiling drop for a future CNC router. I have a general open floor space of 12' wide x14' long. I don't know what size CNC I'll end up with so its a bit of a guessing game but I figure I'll size for something that can process a full 4x8 panel and go from there. (A few years ago I go interested in building a 8 foot MechMate) Within this space, where would the best place be to locate the ceiling drop? In the center of the space, toward one end, on a side? I watched on video where the guy built a swinging arm that allowed the flex hose to follow the gantry. I think this required the ceiling drop to be at one end. Is this common and required? Any suggestions?

[Jim Becker]

So a typical 4x8 CNC machine will have a physical footprint of about 5' wide by about 10' long, giver or take a few inches either way. For material handling, a typical "ideal rule of thumb" is to have three feet clearance on the sides and enough clearance in the front to be able to load and manipulate material that's the maximum size of the machine's capacity as well as to perform routine maintenance. Many folks get away with less to at least one the sides. My compromise up front is that I have my adjustable height primary workbench in front of the machine, but it will not interfere with the process and sometimes is leveraged to help support the process. (my machine is only 4x4 so I tend to throw a full sheet up and support the "free" end with my bench)

DC location can be direct above the center or so or off to the side, depending on how you decide to support the hose for the moving gantry and spindle. Since you don't know specifically what you will end up with, consider putting in the "drop" off the main line, but capping it right there so you just have to extend it to "the spot" later when you have a more solidified plan. Having the branch installed makes things really easy later since you don't have to disrupt the main or major branch to add the business end of the actual future drop.

You may also want to consider pre-planning for electrical and air for the location; the need for electricity is a give and it can be anywhere between 20a 240v and 40a 240 v for a typical "reasonably priced" 4x8 machine. So if your machine wiring is going "in" the wall/ceiling, pre-plan for a generous conduit that you can pull what you actually need later once you've made your choice and also consider how you'll get air to the machine for both utility use as well as machine requirements for things like gantry assist (takes weight pressure off the Z-axis stepper/servo), automatic tool change (less likely on a personal machine) and utility air for a spindle mounted blower for some applications. No need to fully install, but plan for it and do similar to the DC by putting in the branch, but not extending it all the way.

[eugene thomas]

i would center in opening. gives ya more flexability.

[Leigh Betsch]

Thanks for the input. I put a drop pretty much centered above the future CNC router. It’s 6 ft from the wall and 10 ft from the overhead door. The other two sides are to the open shop, about 6 ft to the slider saw and 10 ft to the metal shop, where I plan to have a plastic slat curtain to separate the two work areas. So I think I’ll be good.

Good point about the air. I hadn’t considered that. I do have overhead electrical planned.

[Jim Becker]

The reason I suggested a generous conduit for electrical is that different machines have different requirements. My 4x4 Camaster with a 1.7 KW spindle requires a 240v 30a 4 wire (dual voltage) circuit. If I had opted for the 3 KW spindle, it would have kicked it to 40 amp. So make it easy to be flexible with that.

[Leigh Betsch]

Where would be the best place for the air line drop. I could bring one down from the ceiling now, before the sheet rock goes on. Or I could add a line on the adjacent the wall. But that would block the aisle. I’m thinking I should stub down a line at the ceiling along side the dust collector hose.
Any thoughts?

[Jim Becker]

If the machine is going to be "out on the floor", I think an overhead connection near a rear corner of the machine makes sense...same for electrical. That lets you avoid doing this, which I had to embrace for my current temporary shop situation for air, power to the CNC, computer, BS and RT and comms to the computer for both Ethernet and HDMI.

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[Leigh Betsch]

Thanks Jim. I very much appreciate your input.