Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Davek0974 on February 06, 2016, 12:18:05 PM
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Been looking at various threads on here regarding the abundant min-mills like the 3020, 3040 and 6040.
Was thinking of taking the plunge but are they really any good or a pile of bits for an upgrade project??
Most likely the 3040 as the 3020 is too small and the 6040 is getting a bit beyond experimental fun spendy spendy :)
Obviously it would be fed by Mach but there seem to be two flavours - a cream unit and a black unit model, any one better than the other, any recommended UK suppliers?
I would like to run aluminium, obviously feeds would be low but can they do it?
Also engraving and sign making etc.
Just wondering.
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IF I remember correctly they are just cheaply put together with cheap chinese electronics and are router type cutters not really what you would class as a MILL.
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Hmph, thats pretty much what i figured, seems they use the nasty 4 channel-on-one-board motor drives and small nema23's with trapezoidal screws.
The bit that threw me was a couple of videos on the 'tube of them milling alu and working pretty well, seems they were modded though but no comment of how or what.
£500 though, can't get 3 motors, 3 drive boards, decent motion guides, some cable chain, some sort of bed and the rest of it for any where near that sort of cash though.
The apparently ballscrew 6040 unit is about £1200 - for £3000 i could get a CNC proper workshop mill! (hardly desktop though :) )
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Dave.... me again haha (turning out to be a right royal PIA....)
I got one of these (1605 ballscrews) .... along with a 64mm spindle mount [just asked for them to swap it at no cost] ..... and a Makita router (note it only comes with a 1/4" collet .... you can use a collet sleeve if you want to use 1/8" bits, but being the perfectionist.... I got the right collet from the US)
http://www.ebay.co.uk/itm/CNC-3040-Frame-Ball-Screw-Alloy-Router-Milling-Mechanical-Kit-Aluminium-Diy-New-/171640434692?hash=item27f6913004
http://www.screwfix.com/p/makita-rt0700cx4-2-710w-router-trimmer-240v/10140 (although I didn't pay that price [they are avail cheaper])
http://www.elairecorp.com/makitaroutercollets.html
Personal choice.... I gave up with spindles ..... seems like a bit of a game of roulette if you end up with a ceramic bearing one or not... plus water cooling it etc sometimes (dependant on size you desire), hence more complexity.
When I get the time I'll be adding a Super PID to it.
http://www.vhipe.com/product-private/SuperPID-Home.htm
What I've done with mine is I'm using the third port of my ESS to drive a separate set of AM882H drives within my same driver control panel (plasma cut for all my various bits, including PC stand and monitor stand [may weld some trolley type wheels on it at some point...])
To be fair I haven't finished the drive case as I'm trying to allow space for whatever THC I end up with in the end [future proof]
Hope it helps.
Intention is to do some PCB work on it .... and aluminium too but we'll see (I've got two proper non cnc mills and a very old lathe and I intend to convert them but time is short).
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Hi Rob,
Looks ok, so that was just a chassis and you fit your own choice of stuff?
I might just wait and build my own or get something more manly to replace the Bridgeport possibly :)
Not sure yet, its just a thought.
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Yup, just a chassis.... I took the decision to buy some trusted drives and motors given I had a bob, power supply etc, and didn't have the space for another drive box.... the plan is to link in the other stuff into the same drive box (hence try to use all the same stepper motors.... [right or wrong])
I didn't think you'd beat a bridgeport... what about converting it? (must have been done)
I wanted something really for PCB's and small stuff, aluminium / wood (kids sort of wall art nothing high precision)...
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Th BP is my favourite machine :) done some ridiculous jobs on her, they have been converted before with ballscrews and servos but they are not really meant for it and the Z axis is particularly tricky to do well. Simple conversion is out as there is way too much backlash.
Something like a bench mini mill might be worth looking at.
The only spares i have are a BOB and a parallel cable ! Not really a deciding factor I think :)
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The best combo of a do everything setup is a fixed gantry bed mill . It can normaly do everything well. Just make teh long axis inline with teh gantry for the smallest package.
BP makes ok conversion if you already have one and do not need an ATC OR just lift the Knee instead of the Quill.
Just a thought, (;-) TP
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BPs makes ok conversions if you already have one, There are good Zquil designed drives OR just lift the Knee instead of the Quill.
Just a thought, (;-) TP
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There are 3040`s out there that do in fact have ballscrews. The 4 biggest downfalls of the 3040`s are number 1.......crap tastic drives. Electronics are simply awful. *hint* G540 it*
The Y axis or long axis is slung by 2 unsupported shafts. I have grab my Z and deflect the gantry in both directions. Still have done some fun works on the router.
3rd, and this is really dependent on purchase, but mine came with a fordum flex shaft type spindle. Spindle I put on it was 10 times the price of the machine. Doesnt have to be.
and that brings us up to number 4. Some of the 3040`s have long thin L brackets that tie the end plates and bed together. Top and bottom. Mine got new bottom plates.
Honestly, I have a old be it, high precision Minitech desktop mill. I have more fun playing on the router. Its just FUN.
https://youtu.be/qfqflI_RfQ8
https://youtu.be/4yyFKL-QiQk
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Thanks,
i might just price up my own build to see what it comes out to, I'd want decent motors & drives, twin drive on the long axis with ballscrews probably, maybe HiWin rails. Water cooled spindle of some sort.
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So, searching for design tips here, getting my notepad out...
1605 ballscrews ok? Gives a step resolution of 0.025mm at 5mm/200steps and theoretical speed of 3000mm/min at 5mm/600rpm
Never having used ballscrews, how do i arrive at a motor size easily? No point in throwing massive motors at it if not needed - just increases PSU, weight, cost etc. 2, 3, 4Nm??? Bear in mind I want slaved drives on the long axis. Or do i want a single drive with a fixed gantry & moving bed?
HiWin rails I think are good, based on my Plasma build, would give a very rigid motion system I think, even the small ones are good.
Frame built from Alu or steel? Alu would be a milled, bolt together design much like the 6040's steel could be welded and plasma cut.
Any ideas for a bed/cutting surface?
Feel free to chime in with any tips.
If I'm heading out of the real of Mach3 please tell me and i'll head on over to a machine build forum ;)
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My first ever retro was a clapped out manual Bridgeport, worked well and the Z was fairly easy to do, below is a pic of what I did. If you decide you may want to go that route then I can give you more details of how I did it.
Hood
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Always interested in build details, when you get a chance :)
My BP is in fair condition i think, the table screws are worn as its slack in middle and binds at the ends so its been tightened up to remove backlash, I guess they get pulled and replaced with ballscrews?
Might be worth a thought, thanks
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HIYA DAVE , The first thing YOU have to decide is WHAT TYPE of machine you want to build and exactly what do you expect out of it .
Do you want a router type, a table mill, a knee mill , gantry mill etc etc . Don't worry about anything else until you get that decided ;) .
(;-) TP
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FWIW,
Modified / cnc'd quill feed for the Atlas mill.
Works very well and if really wanted to can quickly release and use the quill manually.
http://www.machsupport.com/forum/index.php/topic,7396.msg127816.html#msg127816
RICH
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HIYA DAVE , The first thing YOU have to decide is WHAT TYPE of machine you want to build and exactly what do you expect out of it .
Do you want a router type, a table mill, a knee mill , gantry mill etc etc . Don't worry about anything else until you get that decided ;) .
(;-) TP
Ah, there goes that logic again ;)
Not sure really, ideally would like the lot - engraving, pcb's, wood carving, making stuff from aluminium, making labels from 2-layer plastic, maybe even bolt the head and bed from my 3d printer on to it:)
Just fancy messing with A: a new machine build possibly, B: increasing my play time with CNC
Probably won't get off the drawing table but seemed a good idea at the time ;)
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The first step to design is to envision it and understand
the requirements for each envisioned task and the specs required to accomlish the task.
So spec out the requirements for each envisioned task.
- max and min size of work/ X/y/z/rotary
- accuracy
- feedrates, spindle speeds, HP, etc
to name a few................
For a general machine you end up with comprimises in how you will apply machine usage. If it satisfies YOUR needs that is all that matters.
BUT
A general machine that does everything rather poorly is just
useless!
FWIW,
RICH
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Here's a picture of a machine that seems to do everything the guy wanted and more. IMHO, it's way overbuilt and could likely take a 1/2" cutter and 2hp motor but the accuracy form his tests stand up at about 0.1mm repeat which i think is pretty good.
I was pondering over a fully welded unit from 5 or 6mm plate, 4mm wall box section, plasma cut details, similar to my Plasma table but heavier and smaller - the tools used would be limited to 1/4" more likely 3mm or 1/8" and less so the forces in these machines when cutting must be pretty low, from reading it seems engraving and pcb stuff etc has practically no counterforce due to the microscopic tools.
Still undecided, but things i have picked up and noted...
1610 screws on X&Y
1605 screw on Z
3.1Nm motors seem perfectly adequate
The two Y screws can be driven from one motor and a long belt but I dislike that idea due to belt stretch etc and would use slaved motors again I think.
A heavy, rigid frame and gantry.
A bed that resists downward forces etc.
Motion controller - UC100 etc.
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The first step to design is to envision it and understand
the requirements for each envisioned task and the specs required to accomlish the task.
So spec out the requirements for each envisioned task.
- max and min size of work/ X/y/z/rotary
- accuracy
- feedrates, spindle speeds, HP, etc
to name a few................
For a general machine you end up with comprimises in how you will apply machine usage. If it satisfies YOUR needs that is all that matters.
BUT
A general machine that does everything rather poorly is just
useless!
FWIW,
RICH
Fully agree, but considering people are making stuff on these dodgy chinese 3040/6040 machines proves a point that, with a little more engineering and better components, a workable unit could be made. With a little more £££ an excellent unit could be made I think.
These water-cooled spindles seem to come in kW sizes and 1.5 - 2.2kW is about the limit it seems, ER11 Collets etc
I think it would be very hard to build a machine that is worse than the £400 import lumps, or even equal, getting far better should not be unattainable.
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Hmmm.......
Make it a little bigger with a built in drip pan allowing for removable spoil board / metal bed.
May as well add ability for a future plasma capability!
RICH
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LOL, having seen what it does now, I would never want to mix plasma with any sort of other machine :) Two totally different beasts here - plasma needs massive acceleration and speeds unto around 9000mm/min (45A system) and machining needs more rigidity at the expense of speed and acceleration.
Cutting figures -
3mm single flute tool,
5000 series aluminium,
1mm depth of cut,
Pocket milling ( a hard task),
10,000 rpm,
323mm/min cut speed - way lower than plasma
Cutting force - 8Nm - plasma would be zero (unless you like torch diving :) )
So there is no comparison really apart from both being CNC.
Drip pan is a good idea to allow for some sort of coolant, spoil board can be simply mounted on whatever rigid bed is used.
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Bridgeport would be a better route if intending to do metals only but if wanting to do wood then I would think a gantry style router would be the best option. It would also be able to do non-ferrous metals if built rigid enough but wouldn't be much use at steels/stainless etc.
Regarding the feeds and speeds you quoted, seems slow to me, I never use single flute cutters but even using one I would be expecting double that feedrate at least and much bigger DOC as well, then again it all boils down to the rigidity of the machine I suppose.
Hood
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dont dismiss the cheap stuff. Flimsy but a great way to learn cnc and a platform to build/rebuild from.
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direct answer to your thread title/question - I wouldn't really regard any of those you list as mills. They're all routers really whatever their quality or lack of.
I saw a comment once on the uk site which I think sums things up quite well. It went something like: "Any router will eventually scratch its way through ally - that's not to be confused with milling though".
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^ Ok, so I totally LOVE THAT QUOTE!
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Bridgeport would be a better route if intending to do metals only but if wanting to do wood then I would think a gantry style router would be the best option. It would also be able to do non-ferrous metals if built rigid enough but wouldn't be much use at steels/stainless etc.
Regarding the feeds and speeds you quoted, seems slow to me, I never use single flute cutters but even using one I would be expecting double that feedrate at least and much bigger DOC as well, then again it all boils down to the rigidity of the machine I suppose.
Hood
BP would get in a tizzy trying to get up to wood speeds i think :) Also dries all the oil out of the ways :(
The cut speeds i quoted, in my ignorance, taken direct from an online CNC speed/feed calculator so I won't say correct or not.
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dont dismiss the cheap stuff. Flimsy but a great way to learn cnc and a platform to build/rebuild from.
I nearly bought one so I'm not dismissing them as such but after spending a whole day Sunday reading stuff on them, I think I can make a far better unit myself.
That last picture looks to be Alu maybe 5mm thick??
What sort of settings were you running there??
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direct answer to your thread title/question - I wouldn't really regard any of those you list as mills. They're all routers really whatever their quality or lack of.
I saw a comment once on the uk site which I think sums things up quite well. It went something like: "Any router will eventually scratch its way through ally - that's not to be confused with milling though".
Yeah fair enough, mill is an exaggeration, multi-purpose machine maybe?
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Like i mentioned earlier if you want a great do everything machine build a fixed gantry mill . It can do everything to a point.
(;-) TP
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Also very easy to convert to a 5th axis machine (;-) I know you want one (;-)
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Like i mentioned earlier if you want a great do everything machine build a fixed gantry mill . It can do everything to a point.
(;-) TP
So that would be fixed gantry and moving bed?
Assume bed moves in 1 axis and the other axis is carried on the fixed gantry?
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Also very easy to convert to a 5th axis machine (;-) I know you want one (;-)
\
5?
having enough getting to grips with three :)
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4 axis is fun. 5 axis is expensive.
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Like i mentioned earlier if you want a great do everything machine build a fixed gantry mill . It can do everything to a point.
(;-) TP
Thinking a little more, a fixed gantry/moving bed puts the motion for the bed in the dirt/coolant zone, ok on a big machine but probably dodgy on a small unit??
I was looking at an X/Y gantry with the rails mounted way up under the gantry so no side support columns on the gantry.
Dredging through the suppliers on Aliexpress, it looks like I'll get 3 sets of 600mm 1610 screws/nuts/supports and some 1m long HiWin's and just build the machine around the motion, it's far cheaper than getting custom lengths and easier than machining the ends of the ballscrews myself.
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Both dependant on the overall size of the machine but…
A moving gantry machine can have a much smaller footprint.
A fixed gantry machine can have a lot less mass on the Y axis.
There are many other for’s and against’s for each design so it perhaps all comes down to personal preference. ;)
Tweakie.
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Yeah, got that, space is very important so will be leaning towards moving gantry.
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Thoughts during tea break....
My want is for a general purpose machine - wood, alloy, plastic, engraving, carving, milling, working envelope maybe 400mm x 500mm.
Now, I see plenty of builds with 100's of kg of steel in them, but for such small cutters, is it really needed or is it "just the norm" ?
Picture if you will, no box-section, use maybe 15mm x 150mm or 20mm x 150mm aluminium to make a shoe-box structure - 4 sides and a base (base can be thinner i think).
Mount 15mm HiWin rails to the tops of the long sides, 2 carriages on each side. Mount 1610 ballscrew on outer side of longer sides.
Make gantry base to span the opening, deep enough to take two carriages suitably far apart, drop plates down from ends to fix ballscrew nuts to - it would be an inverted U shape.
Build gantry as required from base up to hold Y axis and Z axis and brace down to base of gantry at rear.
Basically just build the whole thing from a slab of alu and screw it together suitably.
Probably just hogwash, but can you really get that much counterforce etc from such a small tool???
As i say, just thoughts, no bank balances were damaged during this process ;)
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Scrub all of that, bad idea ;)
Been chatting to a builder that sells these things and got enough help to get going now.
Motion control...
Stick with parallel or go with my feeling of using something like a UC100 motion controller???