CNC daydreaming

[rabler]

While the rollback has a leg several feet behind the rear axle that lowers to the ground, that requires extending and tilting the bed somewhat. There was a point in this process where the front wheels of the rollback started dancing sideways, close to lifting the front end. Probably could not have come up far as the tractor chain wouldn’t allow that, but illustrates that you have to keep watching everything and not be under or near anything that could shift. We spotted that happening and re-strategized by use of some cribbing.

 

[matthewsx]

Here's a summary of this weekend in pictures. About 9 hours of pretty intense work with skates, cribbing, toe jacks, pry bars, etc. Note the weekend ends with the VMC still sitting on the rollback ramp in front of the door of my shop. About 5pm today I started getting tired to the point where I was thinking "I just want to be done with this". That is not a safe mindset for moving multi-ton machinery. The rollback belongs to the seller. We chained it to the tractor to keep it from rolling downhill on the rather steep shop entrance. He was fine leaving it parked there overnight, or for a couple weeks, whatever works out. Nice to work with people who are easy to work with.

The frame underneath the mill is about 3' wide left/right/ and about 6' front to back. I made the call to put it on the rollback facing rearward to give it the widest stance while being winched up. It was only about 3 miles to move it, all on back roads. Trip was made at about 15 MPH. I was originally planning on renting a tilt deck equipment trailer to haul it but the fellow selling this offered to put it on the rollback given the short trip. I gave him an extra $100 today for his time and effort, a pittance in today's economy, but that was the cash I had on hand.
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We've seen your lathe....

I can't imagine anything less than a full size VMC would be suitable in the new shop you're building. Haas, Fadal, Mazak, etc.

I have a small CNC mill/drill project and I suspect that once you buy a new PM machine and get all the pieces to convert it you will be very close to, or exceeding the price of a full blown VMC. Decent used one can be had which need updated controllers. knee (Bridgeport) type often go for even less $$.

@JimDawson has been an awesome resource for folks on here doing retrofits.

Just make sure when you order power for the new shop you get a lot....

John

Love it when people listen to my totally reasonable advice....

Congratulations, looking forward to seeing it commissioned and put into use

John

 

[matthewsx]

Hey Karl,

The Mesa configuration that I'm looking at is the 6i25 PCIe card with the 7176 breakout card. That configuration costs about $240 when available. Of course when not available price is meaningless. But that combo has seventeen 5 volt I/O pins on the 6i25, plus: The 7I76 is a step/dir oriented breakout with 5 axis of buffered step/dir outputs, one spindle encoder input, one isolated 0-10V analog spindle speed plus isolated direction and enable outputs, one RS-422 expansion port, 32 isolated 5-32V inputs and 16 isolated 5-32V 300 mA outputs. Looks like the Yaskawa servos lean heavily on 10 volt differential signaling for digital, and 10volt analog for the spindle, so this looks like a good match if the servos are configured for step/dir operation.

LinuxCNC's general philosophy is to run a lot of things in software and uses a real-time kernel loop to handle most things. In the original parallel port implementation this was heavily dependent on system latency and corresponding jitter, so a lot of tuning/tweaking the PC config to get low latency was critical. The MESA cards use an FPGA on the card to handle some of the timing, at least at the pulse timing level, which seems to be a significant improvement. A bit of browsing on the LinuxCNC forum doesn't show any special support for the ADLINK card so I think it would end up as a fancy parallel port implementation, with the end result being that the VMC would possibly run slower and/or have more trouble doing smooth operations such as circlular operations. If all that's correct I'm willing to wait a few months to see if the Mesa cards are available.

I believe the Galil controllers are a full motion controller, so they take the front end out of the timing loop to a much larger extent.

At least that's my naive understanding of all of this, perhaps I'm missing something?

I have a Mesa 7i96 that's I bought a few years back for my CNC mill/drill project thats just been languising in a project box. Think it's about time to resurrect my interest in CNC with my new job and all.

John

 

[rabler]

Lost a couple days to a nasty cold (maybe covid?). Gravity wasn’t enough to slide/roll it off. We pulled the skates out for transporting, and I wasn’t willing to get under the downhill side to jack and put in skates, so two skates under the high side. I drilled some holes in the concrete and set three anchors bolts into a shop-made anchor plate. Makes it fairly easy to pull from a safe distance, with the rollback winch still attached to prevent runaway. Only moved it another 4-5 feet today before the remains of whatever sickness won for the day.

 

[extropic]

Very nice. and safe progress on the unload.

I hope you feel 100% soon.

 

[BGHansen]

Lost a couple days to a nasty cold (maybe covid?). Gravity wasn’t enough to slide/roll it off. We pulled the skates out for transporting, and I wasn’t willing to get under the downhill side to jack and put in skates, so two skates under the high side. I drilled some holes in the concrete and set three anchors bolts into a shop-made anchor plate. Makes it fairly easy to pull from a safe distance, with the rollback winch still attached to prevent runaway. Only moved it another 4-5 feet today before the remains of whatever sickness won for the day.

I'm sure your wife more than supports your cautious and safe approach! I've done some pretty stupid things that could have ended very badly. Unfortunately, my wife was the witness to one of them; she doesn't let me forget it!

Bruce

 

[matthewsx]

You

Lost a couple days to a nasty cold (maybe covid?). Gravity wasn’t enough to slide/roll it off. We pulled the skates out for transporting, and I wasn’t willing to get under the downhill side to jack and put in skates, so two skates under the high side. I drilled some holes in the concrete and set three anchors bolts into a shop-made anchor plate. Makes it fairly easy to pull from a safe distance, with the rollback winch still attached to prevent runaway. Only moved it another 4-5 feet today before the remains of whatever sickness won for the day.
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You’ll get it done. Stay safe, stay healthy.

John

 

[rabler]

@matthewsx said: You’ll get it done. Stay safe, stay healthy.

Still a bit off at the tail end of whatever was ailing me, but well on the mend. Mill is off the rollback, inside the door of the shop, with the door closed. It still needs to make the trip across the shop to it's resting place near the rear of the shop with the other large machines, but I can do that without the worry of rain and humidity in the shop. Now that it is sitting on solid concrete rather than tilted precariously on a rollback deck, I can put the third skate under it to make it relatively easy to roll. And the previous owner can have his rollback truck back.

Any good post (even a few sithy posts) needs a picture, so here's a bit of a closer view of the floor plate, come-along, and chain. The orange fiberglass stick is convienent for sliding things under the mill while keeping body parts at a somewhat safer distance. The rod in the bottom right almost out of frame is handy for turning the skates, their angle needs to be tweaked every few feet.

 

[rabler]

I'm sure your wife more than supports your cautious and safe approach! I've done some pretty stupid things that could have ended very badly. Unfortunately, my wife was the witness to one of them; she doesn't let me forget it!

Bruce

My wife is often my co-conspirator in stupid things, although between the two of us we usually manage to avoid the least safe of those. I'd be in trouble without her!

 

[rabler]

The VMC has finally reached its intended destination, and is off the skates and back on the leveling feet. The chip tray on the right side is a little tight with the wall but it does come out. That's not going to be an issue for a while. I left plenty of room around back to work on the electronics. For now it is on the project list. First thing is to move my big granite CMM table/surface plate back into position. Then I'll need to run conduit w/ 3Φ to it to even test the old controller. I probably could boot that with just 220/110 if I wanted to jury rig something. I'll need to enhance my RPC to actually fully power this thing. I have a 20HP idler right now, probably will add a second idler, either 10 or 15HP, and stage them.

I did get a full image backup of the hard drive of the Acramatic 2100 controller, and I can loopback mount that on my linux box to check out the files. That was an 80GB hard drive apparently installed in 4/2004. The original drive was a 1.6GB hard drive, which had bad sectors, but I also backed up/recovered all but 8kB of that drive, those sectors wouldn't read. But at least I have copies of those. I'm not totally set on converting it to LinuxCNC if I can get the original controller working. It even has an ethernet card, almost certainly 10Mb since it has a BNC jack on it for thinnet in addition to an RJ-45 port. Of course a truly brave sole could try to install an old 32 bit Linux on the original controller, but linuxcnc drivers for the existing cards would be a challenge. I have not been able to find documentation on the internals of a Siemens Acramatic Controller, although I have not tried exhaustively.

Anyhow, I think it looks appropriate with the other 5000lb+ machines, modern technology offset by the little hand crank drill press on the divider wall. For now I'm back to scraping in my straight edge and working on the 12" rotary table automation.