[spresv]

Hello!

This is not so much a build thread as the machine is mostly complete and operational, but i wanted to share and document any further development. There are so many people over here with much more experience than me, so i'm open to criticism, suggestions, anything.

A bit of backstory, i started with a chinese 3040 router frame, which was mostly horrible. I started upgrading and reinforcing it here and there but soon realized that it was a lost cause, so i started building a machine from scratch. Goal was to have a machine rigid enough to mill aluminium somewhat reliably, but since i'm a student currently without a job, it had to be as budget minded as possible.

First thought was to make the entire frame out of 80x80 aluminium extrusions, but that thought quickly went away due to cost and the fact that i somehow got it in my head that it wouldn't be rigid enough. So i made a frame from 10mm mild steel plates with a 12mm mild steel top, with holes for mounting a vice or an aluminium t-slot table. The base ended up weighing about 50kg alone. Complete machine comes about 75kg.

Then i adapted the gantry i had made for my previous machine. Double ball screws for the x-axis, 16mm ball screws and 16mm supported shafts all round, coupled with 270oz stepper motors. I'd love to have gone with hiwin rails or something like that, but it was more than double the cost and i really couldn't afford it. Spindle is a generic 2.2kw chinese spindle. Travel ended up being 550mm x 250mm x 125mm.

Now at that point i intended to get the steel frame stress relieved and the top skimmed but the machine shop wouldn't be available for a few weeks, so i couldn't hold myself from assembling and testing it. First impressions are really satisfactory. There is a bit of ringing from the steel frame, but much less than expected. I'll probably be filling the base with epoxy granite, or something to that effect. I've made a couple of samples (like the carburetor mounts you see in the pics), and i'm quite pleased with the result. These were made with a 2 flute 8mm carbide end mill on ~12k rpms, with a 6.8mm depth of cut and 0.65mm width of cut and 1600mm/min feed rate with no chatter. That's not the limit, it's just the first combination i happened to use randomly, and worked good.

Next step is to disassemble the whole thing, get the base relieved and skimmed, put it back together and square everything up for good. I'll then fabricate some sort of enclosure, because i intend to use both mist cooling and flood cooling. I haven't made up my mind if it'lll just be a plain polycarbonate enclosure, so that the flood cooling won't be making a mess, or if it will be a substantially larger double-walled wooden soundproof cabinet. Also, i played around a bit with the VFD's torque boost function, which does make a difference and will definitely be of use, but the spindle gets really hot really quickly, so a proper water cooling system is in order, instead of just a bucket with a recirculating pump.

I'd love to hear your thoughts! Excuse the crappy quality pics, i'll be posting better ones.
Steve

[Jim Dawson]

Very nice build! The machine looks very substantial. Your parts look good also!

[spresv]

Thank you! Only thing that bums me out is that i can't fit some sort of ATC on that spindle. There are some chinese made available of similar shape and size, but they cost a couple of grand and i haven't seen anybody use them, so...

Got parts to build a mist cooling system today, will post pics later.

[spresv]

So, got all the parts needed for a mist cooling system and put it together. I only use one solenoid for the whole operation (later I'll be using two, to have an option to select either mist cooling or just air blast) and I use the air compressor's regulator to a range of 20-40psi. It worked like it was supposed to, but i guess I had higher expectations than I should as even at 40psi it's not enough to blast wet chips away, especially on deep slot cuts. I'll be moving on flood cooling for those as soon as I decide what sort of an enclosure to build. I'm leaning towards huge wooden soundproof one, because firstly I'm really tired of earmuffs, and most importantly, I intend to rent another place (currently everything is at my tiny home workshop) that will be able to fit all my tools, machines and most importantly all my cars. And since it's most probably going to be in a residential area, it can't make a lot of noise.

Other than that, I still haven't skimmed it because I had a lot of demand all of a sudden and I've been milling parts like crazy. Really bugs me that I have to change tools manually, because most of the time the toolchange takes longer than the actual operation, and you can't do anything else.

Has anyone used any of the ATC spindles available, like these ones? https://www.aliexpress.com/w/wholesale-atc-spindle.html I really wonder how hasn't there been more options like there available, are they that difficult to manufacture? One of the few places i've seen selling something like that is blurry customs, but like the chinese ones there's no real feedback of actual use which is far more important for me than the price tag. Anyone any inputs on this?