I have been working on a minitech minimill 3 pro. Setting up an automatic toolchanger. I have to say WOW. This machine is a TANK! While not light on the wallet. This thing is amazing.

I got contracted to work a couple bugs(turned out to be a broken wire in the control box) out of the system. Needless to say, This machine run soo smooth. While I didnt have the right spindle to actually do tool changes I improvised. I hooked a small lamp to the collet release relay. And made a video of it running thru the tool changes. Small G code to cut a 1 inch line in X and change tools 5 times. Will post the you tube link. I also wrote some toolpaths to tet the control boxes. Long long 3d code to see if the machine will miss steps ect.

I am totally impressed with these machines.

YouTube - mini3proatc

*EDIT* added what issue was found in the control box wireing.
Also tested the minitech front end of mach 3. We also improved a couple features based around the ATC configuration.

That is amazing!

If you don't mind me asking? How much did it cost you? Ballscrews, linear ways! Wow, great work. What are your actual cutting speeds? I imagine pretty high...Man! I want linear ways and ballscrews!


-Jason

Speed.......
Unfortunately I do not own the machine. I was asked to help solve some issues with it. Come to find out there was intermittent contact with some step/dir wire. Found that some of the wires were actually broken inside the insulation. Re-wired the controller. This is smooth. The machine is setup for micro-fluidics. Really small parts. So I have it setup for higher resolution which limits the top speed. I cut the wood face at 1000 mm`s per minute.

True- I looked up the machine, very expensive. Good for high precision stuff...


But for the price you could get a CNC IH mill!

Dang!!!!!!!


With the the broken wires, what was the issue? What was happening with the machine?


-Jason

jogging was very erratic

In Mach 3 press the down arrow button to jog Y and sometimes Y would move and sometimes Z would go up. very erratic on all jog commands.

True- I looked up the machine, very expensive. Good for high precision stuff...


But for the price you could get a CNC IH mill!

Dang!!!!!!!




This is indeed true - but it is a matter of the right tool for the job. For small parts that require rapid movement, high accuracy and reasonably high spindle speeds, the IH is not the right tool for the job and would be considerably less productive than the Minitech machines.

I totally agree with Mike here. You need the right tool for the right job. A bigger mill could be had for the same price. But sometimes a bigger mill doesnt fit the requirments of the client.

I will say that the technology that is in place on these machines is out standing!
The level of engineering is impressive with this desktop machine. When you are dealing with nano machining and microfluidics this machine is no slouch.

I am shipping out the drive controller today back to the client. But the machine itself gets to stick around for a bit longer. So I will be building another drive box and do some more testing. I am actually excited to try some of this microfluidic machining I have been reading about. As per the agreement with Minitech I will do my best to find any weakness with the machine design under these high tolerance demanding situations. But having talked with some engineers in the industry that utilize these machines. It already is a solid performer! I am guessing that I will be hard pressed to find anything that might or could be improved upon.

You can run them at crazy fast feeds without a problem, depending on materials, cutters etc. I'll normally run mine at 1500 -2200 mm/min with .005" conical cutters in wax. 1/8" end mills, I've had them up to 3000mm/min which is pretty hilarious actually. Takes about 5 seconds to mill a square inch.

Like everyone above mentioned, not designed for big cutters and deep cuts, but they're great for small precision work.

You can run them at crazy fast feeds without a problem, depending on materials, cutters etc. I'll normally run mine at 1500 -2200 mm/min with .005" conical cutters in wax. 1/8" end mills, I've had them up to 3000mm/min which is pretty hilarious actually. Takes about 5 seconds to mill a square inch.

Like everyone above mentioned, not designed for big cutters and deep cuts, but they're great for small precision work.

They are impressively capable little mills for their size. I actually have the "big brother" to this machine (minimill 4) with some mods. Even when it had the Sherline spindle and a 1/2 HP motor, I could cut 6061 Aluminum at 60+ IPM with a .25" bit at .05" DOC(I can double this now with the same machine and different spindle). 400ipm rapids are no trouble with a stepper system, either. Like Fixittt said - they are smooth, efficient little machines - tough to find better in this size IMO.

Can you post a photo of the spindle? Is that similar to the HF spindles from homeshopcnc and keling? (http://www.homeshopcnc.com/HFspindle2.html and http://www.kelinginc.net/CNCSpindleandController.html)

Can you post a photo of the spindle? Is that similar to the HF spindles from homeshopcnc and keling? (http://www.homeshopcnc.com/HFspindle2.html and http://www.kelinginc.net/CNCSpindleandController.html)

My mill has an x2 head on it now(with a completely custom z axis from the bearing block outwards) - sporting a 2HP motor and 2 speed pulley setup and using Tormach tooling with the z-bot power drawbar. No HF spindle on my machine - or were you asking Fixittt?

Sorry Mike - Yes I was asking Fixitt - the video looks like it is that style ('that' being the links I posted) and those have caught my interest, though price makes me want to research a lot more, get some opinions, and see what kind of applications they are being used in - The pics Fixitt posted look like work that fits what I would like one for - but wonder if they are capable of less detailed, and more stock removal oriented work (assuming the axis carrying the spindle can handle the loads).

looking at the spindle control

Nakanishi E3000C is the spindle. At lease that is what it says on the control unit for the spindle. Hope this helps

Ok - it's similar, still a brushless high rpm spindle but it's a interchangable system - different spindles can be attached to the motor as opposed to the full cartridge style the ones I've been contemplating. It's got a top of 350W according to what I can make out of the info in press releases and the mfr website (in japanese). Thanks!

yes its an interchangeable setup. Lower spindle housings can be swapped out. Pretty snazzy! One thing I do like about this spindle setup is that the control unit has load monitoring. I like that feature.
30k RPM without air cooling 60k with air.

I cut some of the shoulder off of the wood project with a 1/8th endmill. Took a nice sized cut and pretty deep and the spindle didnt even register the load.

Typically I play with softer materials, but man, I just couldnt help myself....

about 1/3rd the way done.

its just a paw print on the left side and a foot print on the right on a piece of aluminum the size of a domino.

Still Playing........

...and some nice work too! Any chance of a video clip of the machine cutting? :) What resolution is it set at?

I use an NSK E3000 spindle too - they're great with the 1/8" cutters. 1/4" seems a little big for them in Alu, but fine in wood or plastic. I was looking to get the 60,000 rpm ceramic bearing front end for my set (currently using the larger of the two pneumatic collet release spindles) but they put their prices up about 20% a couple of months back :(

Can I ask what were your cutting parameters for that last piece (feed rate, DOC & RPM? What size cutter?)

How will you implement the auto tool change?

Cadmonkey - http://www.nskamericacorp.com/prod_machineTool_e3000.aspx - there's a bit of information on the E3000 spindles, in english! I have a catalogue, if you want to know any specifics.

RC-Monster Mike - can I ask what your resolution on your Minimill 4 is with the rapids at 400 ipm? That's pretty quick :) What spindle are you using now?

Best regards,

Jason

Edit - Mike, sorry - I read your post again & see your spindle info already there!

Jason,
I dont know the exact resolutions. But I got 800 steps per mm. (.9 degree stepper, 10 microstepping)
For that peice I cut, I used a 1/16th ballnose. at 800mm a min, .5mm stepdown 4% stepover

As for the toolchanges, I will need the bottom part of the spindle that is has the air collet release. I think that same one you have. I was testing the function and setting up the XML for the client. To speed up the process of getting ir running.

Even though I don't own one of these machines, I think I know exactly what they are capable of. The bigger one is almost identical to my mill build. I get fast speeds even cutting steels with the right end mills. Good rigidity and excellent accuracy.
I have 14" x 9" x 9" travels. I only use it for production and building other machines so far. Haven't had a chance to play with it much. I did do a couple high precision (for a benchtop) parts. Guitar pickups.
It worked great for those. The screws on yours looked like rolled ball screws. Is that what they come with?
I have ground screws on the mill and rolled on the new lathe. Both are pretty accurate. No backlash on the mill and none I can measure on the lathe.

On the smaller machine, is it built on steel or aluminum? Looks like anodized aluminum, but looks are deceiving.

I am interested in seeing a video too, once you get the controller going again.
Those look like fine little machines.


http://www.cnczone.com/forums/attachment.php?attachmentid=71076&d=1228663102

Did you use Vcarve for the paw prints? I need to spring for that so I will have an excuse to play some. ;) All work and no play just doesn't break enough end mills.

As for the ballscrews, i dont know if they are rolled or what. I believe they can be had in both flavors. The machine is build from aluminum and ample amounts of it!
As for the software used, I used Artcam for the model and toolpath. The reliefs are just some that come with artcam, wanted to spend my time cutting how drawing. Most people create the toolpath in X raster. For this one I was more interested in function of the machine so I created the toolpath in a 45 degree raster so x and Y both moved constantly. Along with Z of course. True 3 axis machining. It was great to watch how smooth the machine cut the material.

"RC-Monster Mike - can I ask what your resolution on your Minimill 4 is with the rapids at 400 ipm? That's pretty quick What spindle are you using now?"

5mm lead ball screw with 1/10 microsteps using 1.8 degree steppers - 10160 steps per inch resolution (plenty). The steppers are pretty amazingly spinning at over 2000rpms during a rapid move(after acceleration time of .2 seconds) at 400ipm. I actually run the machine at 350 ipm rapids, but have tested it to over 500ipm! It starts missing steps occasionally during rapid moves near 500ipm, but at 450ipm, it doesn't miss a beat in testing - just too fast to catch the occasional programming error(and I have no limits or home switches, either).
The spindle is from an X2 with aftermarket bearings(don't remember where i got them as it was about 1.5 years ago). I rebuilt the z axis from the bearing block out to accomodate this head. Initially, I planned on using the X3 motor, but it didn't have the nuts, so I am using a pretty beefy(17 pounds or so) 2HP 90 volt motor on it(running 110 volts through it). It has a 2 speed pulley system with a jackshaft - I get about 8500 rpms on the "low speed" and run it here 99.9% of the time. It has plenty of torque here. The "high speed" tops out at 13k rpms, but it is frankly a little scary and I don't use this speed. When i need to use an occasional 1/16" endmill, it is a nice option to have available. I also made a 30"x9"x1" thick table to replace the 24"x6"x 5/8" table that came on the machine(which functions nicely as a fixture when placed in the three vises). :)

The Ball screws are kind of a hybrid - they are rolled screws, but the threads are ground. IIRC, the spec'd lead accuracy is .05mm/300mm? Single preloaded nuts with no measurable backlash on any axis. I get about 23.5" travel on X, 11" on Y and 14" or so on Z (about +/-12" usable with the vises on the table).
It is a rather impressive machine for its size. I was fooling around while cutting some clamps the other day(6061 aluminum) and got up to around 120ipm and .05" DOC with no trouble - an errant chunk out of the middle of the stock(about .25" square by .5" thick) got into the tool path with no time to correct - it proved to not be a problem, as the machine(loudly) ripped through and basically disintegrated the chunk without missing a beat! I have had the machine for a couple years and it still manages to impress me. :)

Man this machine is just sooo much fun to play with!!!!!!
Yeah I broke an endmill because I was in a rush. Blemish on the left side, oh well....... OPPS!

As for the toolchanges, I will need the bottom part of the spindle that is has the air collet release. I think that same one you have. I was testing the function and setting up the XML for the client. To speed up the process of getting ir running.

I have a suspicion the air collet release spindles aren't as rigid as the manual change ones - steel bearings instead of ceramic, and different bearing configuration. I'd be very interested on a comparison if you're able, once you have the air collet release spindle?

For this one I was more interested in function of the machine so I created the toolpath in a 45 degree raster so x and Y both moved constantly. Along with Z of course. True 3 axis machining. It was great to watch how smooth the machine cut the material.

I'd like to try that. Any chance you'd consider letting me try your G-code for that one? :) I must find out whether my CAM software will let me do a parallel finishing pass at 45°


5mm lead ball screw with 1/10 microsteps using 1.8 degree steppers - 10160 steps per inch resolution (plenty). The steppers are pretty amazingly spinning at over 2000rpms during a rapid move(after acceleration time of .2 seconds) at 400ipm. I actually run the machine at 350 ipm rapids, but have tested it to over 500ipm! It starts missing steps occasionally during rapid moves near 500ipm, but at 450ipm, it doesn't miss a beat in testing - just too fast to catch the occasional programming error(and I have no limits or home switches, either).

What's the maximum recommended speed for your ball screws - are they 16mm Ø? You must be approaching it! ...limit switches are overrated anyway :)

Best regards,

Jason

What's the maximum recommended speed for your ball screws - are they 16mm Ø? You must be approaching it! ...limit switches are overrated anyway :)

Best regards,

Jason

Yeah - 16mm ball screws. No idea what the rpm limit is, but they are secured at both ends(plastic bushing at non-driven end) so I haven't had any troubles. The X axis would be the issue if there was one, given its length, but I haven't had any troubles. I find that as long as things are written within the machine capabilities and travel limits(part programming), things seldom go wrong. Steppers are forgiving if things go sideways as well - they will miss if you hit the end of travel without ripping the machine apart or blowng a drive.

That especially is what I like about steppers. I get about 98% perfect jobs off my mill. The ones that go bad are usually with my head space during setup or my mag chuck releasing from too deep a cut. My fault again.
I have run mine @ 300 IPM on all three axes before with no trouble. I turned it down to about 250 just to be on the safe side. That is plenty fast for rapids. Each job spends 98% of it's time cutting and not rapiding anyway.
I would like to have had the 24" X travel, but @ 14", I still have some extra travel that I don't use. I use 7" of the 9" on Y and I use all the 9" on Z when I have the vise mounted on the mag chuck.
Perfect. ;)

That especially is what I like about steppers. I get about 98% perfect jobs off my mill. The ones that go bad are usually with my head space during setup or my mag chuck releasing from too deep a cut. My fault again.
I have run mine @ 300 IPM on all three axes before with no trouble. I turned it down to about 250 just to be on the safe side. That is plenty fast for rapids. Each job spends 98% of it's time cutting and not rapiding anyway.
I would like to have had the 24" X travel, but @ 14", I still have some extra travel that I don't use. I use 7" of the 9" on Y and I use all the 9" on Z when I have the vise mounted on the mag chuck.
Perfect. ;)

I almost never need the extra travel, either - sure is nice to have when I do need it, though. It is also nice to set up 3 operations in one go on the 3 vises. The tormach quick change is cool, but most of my stuff requires several tools, so minimizing tool changes is important.
I did read your 80/20 mill and lathe threads, Leeway - cool stuff and great work. :)

Made another little video........... The table is moving not the spindle. I promise :)
http://www.youtube.com/watch?v=Xp89hGDqXzs&feature=channel_page

Cube is done..... and still playing

http://www.youtube.com/watch?v=h4f9aBlhaJ0
GO BABY GO!!!!!!

VERY, VERY, VERY NICE !!!!!!!

Think for making those small alu parts it is THE machine.
Nice to see some videos of it.

keep up the good work my friend!!!

What are the speeds and feeds?

i am not going to lie or pad any information here....
I am still learning the feeds and speeds on the aluminum. I cut that with a 1/16th ballnose. Rastered the toolpath 45 degrees to keep 3 axis`s moving at all times. Depth of cut going one way was .020 thou deep. I started over riding the feedrates because i was scared of snapping the endmill. Started off somewhere around 400 mm per minute. 12k RPM on the NSK spindle. Once it go true one full pass it would go back across it to just clean up any scallops. Waste of time if you ask me, but Im still learning, so I would take the clean up pass at 1500mm a min (What the video showed) while it was cutting minimal amounts of material it was not taking anything as far as depth goes. I slowly ramped up the feedrates on the depth passes to over 700 mm per minute. And everything held up fine. I would clear chips in between passes and add a coat of WD-40 to keep chips from welding to the the tool. I did the video to show the speed and accuracy of the machine at blazing speed!
So full cutting speed was .20 in deep, 700 mm per minute at 12K RPM. For argument sake. I think I once had it to 750mm but chickened out. Due to lack of sufficient real world knowledge and experience. But even at that speed, I was cutting aluminum faster then my maxnc would cut wax.

It will take you some time to zero in on just the right speeds for your machine I think.
That is a good way to do it though. You use the over rides. Bump up the speed when is seems too slow. You can't increase DOC this way, but you can spindle and feeds.

I just replaced the factory bearings on my machine. They were on an X2. The new bearings and proper installation has really improved the performance of my machine. I can now cut better and faster. I will use my regular codes and just bump up the feed rates to see how much better.

ever see something done on youtube that you just have to/want to try yourself? I first seen a model like this cut in aluminum on a you tube video and was so intrigued. After a long search, I was able to find a STL file (Thanks again HARRY) And of course the performance of the minimill 3 pro was beautiful.

Material : Delrin
Size 1.5 inches tall.
Cutter 1/16th ballnose

That looks great. I just bought and have been fooling around with Vectric's Cut3D. It can do things like that on a 3 axis machine. You would have to size it right to maintain the correct proportions in it though.
I milled one side of the marlin file out of some mahogony. It turned out pretty good. I just wanted to see what kind of finish I would get. Nice and smooth.
The details were getting to brittle though in wood. The whole marlin was only about 1.25" tall. My bit was too large as well @ 5/32".
I have a block of aluminum I will try it on eventually when I get more playtime. ;)

Nice, nice, nice!

I didn't realize it was so dinky, I thought it was @ 3-4" tall.

Yea it looked like it was a few inches big. Beautiful work.


What was your stepover rate?


-Jason

rough pas was pretty high step over, finish pass was really really small. like 3%

Oh ok nice. Did you Cut3d for the programming? I assume you didn't since you used the 4th axis.

I'm trying to obtain a nice smooth finish on curved pieces. I'm using a 1/8 ball mill and had 5 % stepover, maybe I need to get a smaller ball-nose or maybe even a better one, the one from grizzly that I got stink. At least the regular end-mills did.

-Jason

Hmmmmm, I'm getting much better results with a 5% finish pass with a 1/8th cutter. I meant to say I was using a 3/16 cutter in my earlier post. Much better results. Can even do better with lower step. But the program will run about 4 hours now....


-Jason