[SaskFab]

Hi everyone,

I've lurked here for a while reading countless threads and attempted putting some of the knowledge I've picked up to use building this table. I decided it was time that I had this capability in-house and went ahead with this project. I've got a fair bit of machining and fabricating experience but this is my first foray into the world of CNC.

Travel on this machine is 102" x 54". X and Y motors are 570 oz/in with 8060 drives from Keling. Powered Z will come a little later. Racks and pinions came from Applied Industrial. I tried to keep costs down and I think my total is only at about 2500.

I'll go ahead ahead and bore everyone with photos now...

Thanks for looking!
Marv

[SaskFab]

I'll start with the basic frame. Main rails are 3x3 box tube with 2x2 spreaders. One inch diam adjustable leveling feet. 6203 bearings on eccentric adjusters.

[SaskFab]

Here are some pics of the Y-car and the eccentric pinion shaft adjusters. Y-car rides on 6000 and 6203 bearings. 15 tooth 12 diam pitch pinions.

[SaskFab]

Some pics of machining pulleys for the HTD 5mm x 15mm belts. 60 tooth is 6061, 18 tooth is stressproof steel. The small sprocket was then heat shrunk onto a hub with one integral flange and outer flange staked on.

[SaskFab]

Gantry and Y-car.

[SaskFab]

Paint job (John Deere construction yellow!) and reassembly. I'll grab some more photos and post again soon.

Marv

[SaskFab]

A few more pics of the pressurized control box with Dell 280 built in and the low buck cable carrier setup. I didn't have any luck sourcing any Igus type carrier locally and ran out of time.

[SaskFab]

A few more showing slat details, Y-car and torch holder, gantry drive, and it sitting in place.

I did a few test runs on some lighter material and with the exception of me needing to learn a few things about Mach3 and Sheetcam, everything seems to work great.

It is easily capable of rapids of over 1000 in/min and will accelerate in excess of 200 in/sec^2. Despite being single drive, the gantry is very rigid because of the long X-car bearing spacing and light weight of the gantry itself.

Come on guys, I'm looking for some criticism or some tips... anything!

Marv

[I Lean]

No criticism or tips from me....just wondering what your "cable carriers" are made from? Looks like rubber hose, or something similar?

[Teknition]

Pretty impressive build. You've got some serious fab skills and think outside the box. Im glad you shared making the pulleys for the belt reduction units, that was one of my favorite parts. Very creative cable carriers as well. Only 2 things come to mind that I would have done differently than you. I would have ran the bearings on CRS bar instead of the rectangular tube just for tollerance issues and I would have extended the rail on the short side of the X axis so the short side Y leg could be straight. Seeing it on an angle like that looks a little strange for some reason although I understand why you did it, so the gantry could park out of the way.

Brad

[SaskFab]

@ I Lean,

The larger ones running down the X axis are just 1/2" (5/8" OD) pex pipe. The smaller ones across the gantry are 1/2" nylon air brake hose. I machined spreaders that clamp them together every foot or so out of some UHMW.

They seem to be doing the job and haven't tangled themselves up yet

Ran the first paying job tonight cutting some 5/8" A36. Used size #1 Airco style #263 tip burning propane and cut oxy @ 40 psi and 16 ipm. Pierced 7/8 holes with 35 seconds preheat and 22 ipm. Very impressed with hole and cut quality. Lost cut once when at 18 ipm probably 2 feet into the cut, so I just cut the speed to 16 and tried to be more patient. I think I could have upped the speed on the holes a fair bit, but most of the slugs dropped out on their own anyway, so I left it alone for this job.

[SaskFab]

@ Teknition,

Thanks for the compliments!

I totally agree with you on the CRS vs tube issue. I was in a huge rush as usual and the CRS would have been a bit difficult to get around here. I did take a micrometer with me to the steel supplier and managed to find a length that was exceptionally uniform. I welded carefully and heat shrunk to counteract weld shrinkage in many areas. I also "balanced" alot of the welds to minimize distortion.

I realized after the fact that the angle leg is still dangerously close when loading full sheets and it would have been better to do it as you suggested. Just trying to save a little space, and it didn't really work out that way. Oh well

I did drill a couple dud pulley blanks because the holes are NOT on the pitch circle like some folks on the net claim they are. I finally dug up the right dimensions for the HTD profile and they turned out very well. If anyone is needing the specs just ask. I originally ordered the small flanged ones because of the extra trouble of building the flanges and the cost was low, but after waiting two weeks for them, it turned out that they shipped AT profile instead of HTD I didn't have time to wait so I just made them too.

[Teknition]

I was looking thru your pics again and notice something you may want to address. In post #8, pic #3, the acetylene hose looks a but snug at the torch end and will probably kink off after a bit of use. You may want to give it a bit more slack.

One more random thought, not sure if it would be better or not. Since you are using plastic tubing for the carriers, you could split the A/O hoses and cut the nuts off the end. Then run them thru larger diameter pex tube and crimp the nuts back on with new sleeves. 2 advantages of this I can think of are that they would help protect the hoses and also you wouldnt be bending 2 things in different arcs. I think it would add to the flexibility of it.

Brad

Brad

[WSS]

Since you are using plastic tubing for the carriers, you could split the A/O hoses and cut the nuts off the end. Then run them thru larger diameter pex tube and crimp the nuts back on with new sleeves. 2 advantages of this I can think of are that they would help protect the hoses and also you wouldnt be bending 2 things in different arcs. I think it would add to the flexibility of it.
Brad

To further that thought, you could use poly tube inside the pex, it would be protected enough and cheaper. Push locks work good to 120psi (double check each brand) so they are enough for even the hi-speed tips. I used green poly for the oxy and blue for the LP. Poly is also more flexible than the twin O/A hose. Try to put your cut oxy solenoid as far from the torch as possible, this will give you more of a "ease-on" pierce and not tend to throw the hot slag (AKA pierce boogers) as far due to the slow ramp up of pressure. You could use a (oxy cleaned) accumulator to slow the rise too, the down side is the after cut postflow, you will need to dwell and let the psi drop before starting your rapid to next cut, not to mention the loss of oxy. We installed a hi/lo w/ease-on system about a year ago. It really works. The ramp up to cut psi is variable from .5 to 5 seconds. I have generally left it at 2.75seconds. Under 2 seconds and the pierce boogers tend to jump up and hit the sensitive stuff on the gantry (murphy hangs out in our shop).

What thickness are you targeting to cut w/ the oxy?

Nice build.
WSS

[SaskFab]

@WSS,

I considered poly tube for the fuel and oxy, but was thinking it might be more vulnerable to spark damage. After running it for a bit, I think I was worrying for nothing. I've read that long thread about you, millman, and others building the hi/lo systems. Sounds like a great way to do it. I might look into setting up a system like that down the road. At this point, I just needed to get this thing cutting parts and rigged up the torch as you see in the pics.

So far, it's been working great. I'm getting good cut quality for the most part, and part tolerances are great. I've had a lot of bolt holes to do as well, and I'm impressed at the hole quality I'm getting. The only issue has been the preheat time on the first couple holes till the plate warms up. I plugged in an Xbox controller (best use for an Xbox controller yet!) and can feedhold and then resume when it's hot enough to pierce.

I will likely be cutting in the 1/2 to 1 1/2 range most of the time. I'm going to get a Z slide and motor on it shortly as well as plasma w/THC for the lighter stuff. Attached is a photo of some 5/8 I cut yesterday.

Marv

[SaskFab]

Regarding the Xbox controller, I should clarify my previous comment. I can now feedhold and resume while standing right close to the torch, and avoid running back and forth to the keyboard. A much recommended addition if you're running Mach. I really like the variable speed jogging it allows as well.

[MAS]

What I used to do when I have to cut plate was dry run the program and stop it at each pierce point, mark the spot with soapstone. After all were marked I'd get my airdrill and drill starting holes. This takes little time and the main reason I did it was to minimize the heat poured into my parts and my tips lasted quite a bit longer too.

[rexcobey]

hi SaskFab,

nice work i love it...

i wondering how do you control your preheat and piercing, do you have system like the one done by WSS here is the link, also do you have Torch lifter for you system.

thanks

http://www.cnczone.com/forums/attach...6&d=1293149971

[SaskFab]

Hi Rex,

Thanks for the compliments.

I've read about the hi-lo systems and it is something I would like to implement at some point. I really need to get a height controller implemented as well, both for plasma as well as oxy-fuel. I've pretty much figured out how I'll do it for the plasma, but still batting around different schemes for the oxy-fuel.

For the time being, I've been setting a pierce time in sheetcam appropriate for the setup, and when the plate is cold for the first few pierces or if they are far apart, I just feedhold and the resume on the Xbox controller while watching the preheat.

I'll be sure and post an update when I get something figured out.

Marv