[DonFrambach]

What are you guys getting speedwise with a 400oz in stepper and a 1/2-10 acme screw?

I'm getting 75"/min with my 1/2 10 acme lead screws run by 300 oz/in steppers in my small fixed gantry mill that I'm building. I found that I needed to lubricate the screws at the delrin nut to avoid a terrible grating sound. Hope that helps.

[analogman]

So when all is said and done, you will be able to cut 48" wide. What is the length that you will be able to cut without re-fixing your workpiece?

[prcdslnc13]

my cut area is actually about 53x24. I need to change the positioning of the gantry a bit to get the full 24 but thats what it will be. Currently my cutter extend about 2 inchs past the table when im all the way out one direction, but comes up short ont he other side, so I need to move the gantry back farther. Ill look more into that when I have a final router mount. Im going from a 12x18 cut area on my old machine though, so this one seems huge

[prcdslnc13]

[nomedia="http://www.youtube.com/watch?v=evuwxC6j8fE"]YouTube - DIY CNC Router Plexiglas cutting2[/nomedia]

[nomedia="http://www.youtube.com/watch?v=ZLWS3ZCt7_4"]YouTube - DIY CNC Router Plexiglas cutting[/nomedia]

Heres a couple videos of the machine running. Im still not quite happy with the chain drive, and for some reason everyonce in a while my z stalls out ( thats real bad when it thinks it lifted and it did haha) but things are running OK now I guess. Im looking at redesigning the Z now, and a friend of mine and I are working on a rotating lead Nut for the long axis to be driven with a 1/2-10 5 start acme screw. So well see how all that goes.

[prcdslnc13]

Well Its been quite a while since the last update on the machine, but lots has changed and is in the process of changing Heres the break down on the updates:

1) hitachi router out- Bosch 1617 in. This has been a great decision. All around better tool. Completely worth the price difference
2) Chain drive is now incredibly accurate. Turns out my sprocket was slipping on direction changes. New sprocket with thicker hub walls and there for more threads for the set screws plus lots of lock tite= super accurate drive system
3) the table axis has been switched from a 1/2-10 single start screw to a 5 start screw. I also sank the bearing blocks into the table and extended the travel of the axis to use the full 1000mm of the THK rail. I added over 4in of working area by doing that.
At the same time I remove the belt drive. I now have a motor hanging out in space which I was trying to avoid, by I raised my rapids from 60 IPM to 390 IPM with no stalls, by making all of these changes.

Planned changes in the works.

The Z axis has a lot of lateral play. Enough that O-flute bits chatter, bad, and show in the work. So a complete redesign is in the works. Ill post a screen shot of the model below. I will now be using THK 25 rails with the HSR heavy load blocks, it will give me 9" of supported rail Im also moving the lead screw from the center of the axis to off to the left and leaving it exposed for easy maintenance.

I was planning to make the plate that carry's my bearing blocks from .5" aluminum but the only way I have to mill it is my router and in tests the chatter produces and unreliable result, So I will be maching it from .75" HDPE. Please let me know if you have any feed back.

[prcdslnc13]

I cant believe I let my own build log go so long without any updates when Ive done so many updates to the machine. So I guess Ill go in order of what Ive done

Z rebuild- the model I have up above is real now. Except that its made from 1/2" aluminum plate. With THK25 rails and extended blocks. Safe to say the Z-axis movement is the least of my worries now

Gantry Rebuild- I needed to move the gantry back a bit anyway, so I decided to make the entire thing stronger. So I removed the single sheet plywood uprights and replaced them with box section uprights. This allowed me to bolt the gantry to the table in 2 directions. 1-directly through the torsion box and 2 through the side of the torsion box. This made everything incredibly rigid.

Moving table replacement- The original table was double layered MDF. I thought at first that this would be extremely rigid and be a great table. I was wrong haha. I didnt take into account that over time when you put a board with a 36" unsupported span in a situation where its not climate controlled and things press on it, its probably going to sag. So I replaced it with a square tube steel frame a friend and I welded up. Then drilled and tapped a few holes, bolted a spoil board down, surfaced it off and now Im back to a strong flat machine table.

Driver replacement- The probotix drivers have served me great over the last year, but I feel that I would get better performance from a bi-polar parallel configuration as my X and Y axes are very fast pitches, I wanted thermal protection, and the drivers I selected have the possibility of running larger motors down the road. Im now using the KL-5056 drivers and the C-10 BOB. I am still running the 40V 10amp psu from probotix and also I have added their spindle relay to control the router from the pc.

Well I think that is all the updates for now. And now for some pictures! Some are machine updates, and some are projects that have come off the machine as a result of the updates.