John's Alu Profile build

[Evengravy]

This morning two custom ballscrew nut mounts arrived from the CNC service, they came out really well so I followed on to test fit these and the newly welded (ahem) brackets.

With a little to and fro to swap parts out I'm glad to say it all fits as well as I can expect, and boy does the thing feel much more solid now.



I had to massage the brackets a little on the corner to give some wiggle room by adding chamfer the corner of the L to give a millimeter or two clearance.



I'm now just awaiting the new anti-backlash couplers to mate the motors to the new screws and this part should be done. It's been a bit of extra work, but so far I can feel the improvement and I'm glad that I took it on.

If everything goes smoothly then I'll be removing these steel brackets and adding some more internal welds just to beef them up a little before painting them black and refitting. I'll need to start designing the table soon, I may be back to get some advise from you all when I get around to that part.

[Mister Mills]

Hi John, It's looks great. In relation to the resonance you are experiencing in the Y axis are you running the machine with the Y axis unmounted to a surface or base? Do you only experience this when running the machine with the spindle on or off? Your selection of steps per revolution will also come into play with resonance as I myself experienced something similar. Endless tweaking and trying different combinations of steps per rev and mucking about with acceleration and deceleration settings got rid of it for me. Where are you based in Ireland? Liam.

[Evengravy]

Hi John, It's looks great. In relation to the resonance you are experiencing in the Y axis are you running the machine with the Y axis unmounted to a surface or base? Do you only experience this when running the machine with the spindle on or off? Your selection of steps per revolution will also come into play with resonance as I myself experienced something similar. Endless tweaking and trying different combinations of steps per rev and mucking about with acceleration and deceleration settings got rid of it for me. Where are you based in Ireland? Liam.

Hey, thanks. Currently no base, I'm still considering the best approach for building the base at the moment. Some are quite unconventional lets say but I want to run high flow flood coolant for milling aluminium so I'm going to think about liquid capture etc. I'm going to try and CAD design some ideas over the weekend. I'm a bit limited with the current lockdown in sourcing what I would need anyway so no stress just yet. The vibration was really just coming from the screws themselves without the spindle running, which weren't great quality and not straight either. So, partly crappy ball nuts with lots of friction and play, partly non straight ballscrews plus a coupled hollow cavity = resonance. I'm not too concerned with the resonance part, that's in my field of expertise (I'm an acoustics/audio specialist) more concerned with the smoother motion that the new screws will provide plus hopefully less play (I'll need to measure that again today). I intend to fill the Y rails with either sand, pea gravel or epoxy granite to get rid of that resonance. I'll probably go cheaper options first and see where it is. I can measure the natural resonant frequency pretty easily and try to tune around it too. I'll keep those points in mind for sure though on tweaking, thanks for that.

I'm based in Donegal buddy, you?

[Mister Mills]

I'm down in Co Meath for my sins.... Yes the Lock Down is a bummer but I believe we will be let out gradually from the 18th... Plenty of time to do design work! I forgot to ask what the cutting area of your setup is? It's a decent build for sure. I would 100% recommend flood coolant doing any serious metal machining or mist for lighter work otherwise you will get a pain in your ass replacing cutters! I settled on rack and Pinion after trying belt and lead screw. Both turned out to be disasters.No way I could afford 2.8 Meter Ball screws!! My Rig has been sitting idle for 2 years and only recently am I getting the Itch to start playing again.. The only bonus of the lock down!. Feel free to give me a shout it your stuck with anything. I have made shit load of mistakes building my setup but you live and learn and it may help you from falling into some of those pit falls!!!

[Evengravy]

Ah. Thanks a lot for that. Aye coming from a belt driven build too so something more stiff is in order this time. Yep the rack and pinion sounds like a perfect solution for that size (that's a big machine, jealous) this one has a cutting area of around 1100mm x 750mm ish but should be big enough for my needs. I do a lot of aluminium work and bits of hardwood so don't need anything too large. You never know i might go for an 8x4 machine down the line.

[Mister Mills]

Bigger machine needs a lot more space to be usable. This is my downfall. I may well downsize her and go for a 4 or 5 axis design. I'm getting the Itch !!!!!!!!!!!!!!.

[Evengravy]

Bigger machine needs a lot more space to be usable. This is my downfall. I may well downsize her and go for a 4 or 5 axis design. I'm getting the Itch !!!!!!!!!!!!!!.

I've had a smaller machine than mine for quite a few years, with a cutting footprint of roughly 500 x 380mm and have not found that to be too limiting generally speaking, so didn't want to go too large. If I were to go 8x4 I think I'd go vertical like Jazz's to save space and help with chip clearing. I want to leave some room in my workshop for some other bits too. I acquired an old CNC lathe (EMCO) that I'm upgrading and I'd like to build a small plasma table at some point (maybe 2x4). We'll get this one done firstly anyway.

A rotary axis would be great, if you could pull off a 5 axis design I'd be very interested to see that come together.

[Mister Mills]

I may well downsize to 1m x 1 m or 1m x 1.2m. Seriously Don't have the room and no real need for the full size setup. It took me 6 months to build the Big girl! and if I am to be honest I don't know why I went so big. The joy for me was building her but she has never had a full sized sheet of anything on the table!!!!!!!. If I go 1 x 1.2(Cutting) I will arrange it so I can slide a full size sheet into and through her to save cutting it into several smaller pieces. I have a few smaller ball screws that might fit the new proposed dimensions and I would prefer to use those instead of the R&P. This time round I will Catalog the build :). I have some holiday time booked in 2 weeks so I might start the strip down then. Fingers crossed!

[Evengravy]

Ah here. It never ends. But I bet the next one you build will be better. My first one was an mdf abomination, second much better, and this much much better (so far) we'll see what happens. I'd never go away from propper linear rails again though, anything else is just a false economy in my book as you spend so much time messing you'd be better to buy something made for the job upfront and save the hassle.

I've been busy planning the base, but work is busy atm so I won't update just yet. Bits and pieces are on route but ill post info soon to that end.

[Mister Mills]

I totally agree about the rails. Mine came from a salvaged Bisse industrial cnc router. Top quality parts. Budget usually decides @ 3 meters long! I'm going to try and sell my 50W 600x500 laser cutter/engraver so that might help with the proper rail requirement. Doing a check list at the moment and I have everything I need. Says me as I blindly walk into this project. No doubt there will be something missing when I get to that point of" Shit I forgot about that! .
The size will be dictated by the ball screws i have (they came from a Salvaged Datron cnc machine) top notch. The 5 axis setup is really something I would like to do but I will start with 3 and keep the other 2 in mind when doing the new re-design. Good luck with the new base and be sure to post some photos.