[Alantron]

I finished up the other 4 programs (using Inkscape with the gcodetools extension), and milled out a lot of parts today. The machine ran without hitch or issue. The last piece was 1/4" thick aluminum, and it plowed through that in one pass with nary a problem. 4 mm/sec feed speed and 6 mm/sec plunge speed worked fine. I think maybe it would handle it faster, but with only one spare bit, I took it easy. Best quality of cut was made with the spindle at around 15000 rpm. It made the cuts as smooth as glass. I wish I had bought this machine sooner.

1/4" in one pass in impressive. You have a 1500w spindle. Mines an 800. I've been trying 1mm doc 24k rpm and around 750 mm/min and I've been getting broken bits

[JohnDeere630]

1/4" in one pass in impressive. You have a 1500w spindle. Mines an 800. I've been trying 1mm doc 24k rpm and around 750 mm/min and I've been getting broken bits

I think the bit makes all the difference. I started with HSS 2-flute bits, and they seemed to struggle a bit @ 3 mm/sec in 1/8" material. I also discovered that running the spindle too fast ironically caused more chatter in the cut. I run the spindle at 245-260 Hz, which translates to approx 15,000 RPM. Also, what are you using to cool/lubricate the bit and remove the chips? Aluminum is famous for gumming up the bit = instant broken bit.

I just reread your post, and in my humble opinion; not trying to tell anyone what to do, but 750 mm/min is way faster than I would try on aluminum with this small of a machine. I am using a very conservative 180 to 250 mm/min; 180 on the 1/4" stuff. It goes slow, but finishing the job in a single pass with no broken bits is faster in my opinion than fighting with the machine. One good thing about the carbide is that it will snap before it flexes much, preserving accuracy. I also run the bit far up the collet, so only about 1/2" or less sticks out.

I really don't know if my 1500 watt spindle is that much of an advantage over the 800 watt. It'd be interesting to try the same parameters with the 800 watt unit on my machine.....

I may try some thin stainless (18-8 and 304) at some point, just for fun; I would think a 1 mm cut with the right bit and coolant should be doable.

[Alantron]

I have a sprakool midget mister. I may bump up the psi for better chip clearing. My only gripe about this mister is that it's a bit too wet since I run a mdf spoil board for easier clamping.

I'm also using 1/8" single flutes. I bought a China 10 pack and broke 2 so far

I was trying the speeds and feeds because I saw this video
Homemade DIY CNC Series - 1/4 Thick Aluminum Test Bracket - Neo7CNC.com - YouTube

[JohnDeere630]

I use 3/4" plywood for the spoil board, and a Kool-mist mister with just a small amount of liquid, but a good air-flow. The video was interesting, but I don't run my machine nearly that fast.

I also wonder if plunging completely through the material and doing all the cutting on the side of the bit is allowing for an easier time? I'm not an expert, so take anything I say with a grain of salt! ;-)

[Alantron]

I use 3/4" plywood for the spoil board, and a Kool-mist mister with just a small amount of liquid, but a good air-flow. The video was interesting, but I don't run my machine nearly that fast.

I also wonder if plunging completely through the material and doing all the cutting on the side of the bit is allowing for an easier time? I'm not an expert, so take anything I say with a grain of salt! ;-)

I tried adjusting mine to spray less liquid but the adjustment is made at the nozzle and looser means more air less coolant but with the vibrations it loosens to only air. What psi are you running? Also his video says 24k but my spindle makes a lot more noise than that at 24k

[Alantron]

What are you using for CAM?

[JohnDeere630]

What are you using for CAM?

I do my drawings in scaleable vector graphics (*.svg) format with Inkscape, 2D only, and use the gcodetools extension to compile the gcode. I haven't done anything in 3D yet, I don't know what I'd use for that.

Attachment 252886

If the file uploaded correctly, I sent an image of one of my programs ready to be compiled.

[JohnDeere630]

I've got the feed speed up to 480 mm/min @ 20,000 RPM in 1/4" aluminum at this point, and everything went fine. I don't feel the need to try anything faster; no sense in breaking anything. I've taken the liberty of posting some pics of the setup and some of the pieces I've milled.

Attachment 253010 Attachment 253012

I'll post the LinuxCNC settings in the .stepconf file if anyone needs them.

[Alantron]

Full doc? I'm gonna give it a try

[RussellK]

I've got the feed speed up to 480 mm/min @ 20,000 RPM in 1/4" aluminum at this point,.

So that's a single 1/4" DOC pass with an 1/8" single-flute carbide endmill? That is impressive. I haven't done much aluminium with mine but I'll have to try those settings on some and see how I do.

Edit: Heh. Alantron had the same thought...

[JohnDeere630]

So that's a single 1/4" DOC pass with an 1/8" single-flute carbide endmill? That is impressive. I haven't done much aluminium with mine but I'll have to try those settings on some and see how I do.

Edit: Heh. Alantron had the same thought...

Bear in mind that this is 3003 H22 alloy, I don't know if 6061 is softer or harder. I'm no metallurgist. I think the kool-mist makes a big difference too. I also don't know how this would work out for a pocket/blind hole; I am completely penetrating the work-piece.

[Alantron]

For some reason I wanna say diamond plate cuts easier but don't quote me on that. None the less 1/4" doc is impressive with a cheap China 1/8" endmill especially on a machine like this

[JohnDeere630]

For some reason I wanna say diamond plate cuts easier but don't quote me on that. None the less 1/4" doc is impressive with a cheap China 1/8" endmill especially on a machine like this

You may very well be correct. I'm cutting some 3/16" 6061 T6 later tonight; I'll see how that goes....

[Alantron]

You may very well be correct. I'm cutting some 3/16" 6061 T6 later tonight; I'll see how that goes....

Very nice let us know. You linked the endmills you bought before right? I may try your supplier next time around

[JohnDeere630]

I just finished up the escutcheons from the 3/16" 6061, and everything worked fine. I was using 9 mm/sec plunge speed and 8 mm/sec feed speed. I wound up running the spindle pretty close to full speed, and I had to increase the airflow a bit to clear the chips vs. the 3003 alloy.

I think I made a mistake earlier...I was cutting the 1/4" plate at 6 mm/sec, not 8; pretty slow, with plenty of air and kool-mist.

[JohnDeere630]

New update...I just finished up cutting some ovals out of 1/16" 304 (I think, maybe 18-8) stainless steel. I think I have either a miracle bit or a miracle machine, because it cut it without a problem @ 5 mm/sec feed speed with the spindle wide open, and a steady stream of kool-mist solution with only enough airflow to clear the chips. Made a very clean cut...almost mirror bright with almost no burring. I ordered 10 more of those bits. Anyone thinking about one of these machines, BUY IT! The $12,000 unit I used at New Balance didn't do anything any better, and in fact, was twice as noisy as this one.

[Adverse Effects]

sorry but i dont believe one of these 6040 units cut SS
A:- cleanly
B:- accurately

with out major mods

[JohnDeere630]

sorry but i dont believe one of these 6040 units cut SS
A:- cleanly
B:- accurately

with out major mods

I guess there is no reason anyone would have to believe me or not, it makes no difference to me one way or 't other. I have no reason to lie, nor to argue about something so trivial, so I won't. I've gotten a lot of useful information here, for which I'm thankful to all who contributed. Good luck and may the blessings of Ceiling Cat be upon you all!

[handlewanker]

Hi, I read all the posts as I'm designing a 300 X 250 router....gone to the model build stage now.....and am getting quite envious of your achievements with this machine.

With the stainless cutting ability, I have to wonder how it would handle mild steel, and if it only allows a depth of cut of 1mm X 9mm cutter diam then that is really something to have "in your tool box"......LOL.

It would be interesting to see how the carbide edge holds up on stainless with that cutter speed, noting that the cutter end for 1mm will be the part that wears out first.

It's almost sacrilege to have to sharpen the whole length of the cutter when in most cases the first mm or so takes all the wear.....so with the prospect of the need for a tool and cutter grinder or person doing that and costing accordingly, would it be more economical to just grind the end mm or two off the cutter carefully by hand and also the end face with back cutting relief to reclaim it at the same diam.

I've done this with some HSS cutters that were much the worse for wear on the ends only when cutter grinder facilities weren't available.

The majority of the time the full length is only used to do a clean up after the depth is reached and only takes small amounts of material off.
Ian.

[JohnDeere630]

@Handlewanker, In retrospect, I wouldn't recommend stainless, my good bit is pretty chewed up now. It had cut a lot of aluminum, and only about 8-10" of stainless. I plan to swap it out before I do any more work. Mild steel may be a different story. An oil bath instead of kool-mist, and a slower RPM may also be indicated for ferrous metal. I think the machine is plenty capable, and the 1500 spindle seems to have plenty of grunt, also. It really comes down to matching up the proper bit, lube, and feed speeds. People that have to tear around the work like an Indy car are going to be disappointed, this is no 5 hp Bridgeport. OTOH, take it slow and easy and you'll have better results.

Also, as I should have been stressing all along, YMMV. I am posting what I have done, but make no guarantees for anyone else. I am not affiliated with the outfit(s) that make these machines in any way, nor do I receive any free stuff for favorable reviews. Had this been a piece of crap, I'd have said so. I merely wish to contribute some information back to a place that I have already received a lot of good advice from.