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FridgeFreezer

Learning CNC milling, first steps

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Some time ago as something of an extravagant eBay impulse purchase I bought a small Proxxon MF70 with CNC conversion as the "missing link" in my tool collection, figuring with a mill & a lathe you can make anything.

Life got in the way but I've finally dug it out and set it up - as you can see it's small enough to have on your desk which is part of the attraction for learning:

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I downloaded LinuxCNC and am currently running it inside a virtual machine (which is a terrible idea and should not be attempted by anyone) on my indoor PC just to get the hang of it, lo and behold I actually got it to do a thing:

20181222_174555.jpg

 

I'm not about to actually mill stuff in the house as it will throw carp everywhere, but I can at least work out the toolchain before moving to a dedicated PC and moving it all to the shed where mess can be made.

I'm hoping to get a bit of tinkering time over the festive period so will post updates.

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Ooh. I've been thinking about getting something like that at some point, seems more useful than a 3D printer really.

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Coincidentally, I spent yesterday afternoon cnc milling ali parts to upgrade my 3d printer :D

(... and just to give FridgeFreezer a laugh, cos he's seen me do this before, the spring from the mechanism that I spent 3 hours looking for turned out to be sat on top of the circuit board when I turned it on :wacko: Oh well, at least it wasn't shorting the mains this time :ph34r:

Edited by TSD

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My cnc converted mill has a steel tub around it with a polycarbonate front for access. It catches most of the chips and if you fit coolant that as well. Plus it makes a Taiwanese mill look much more serious! With a mill that size maybe you could put it in a large plastic box or something?

I run mach3 because everyone runs mach3 and I've learnt it's much easier to follow a trodden path unless you have the energy to go to anorak levels of understanding. 

Its been fun and I've learnt a lot. I got the hang of aluminium so have moved onto steel. Im using some tool steel backplates to try mill loco wheels. The poor hobby mill really isn't happy and I'm on a whole new learning curve. 

I'd like to cnc convert the lathe sometime too.

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Al - yeah, everyone uses Mach3 but I kinda fancied the challenge of doing it as free and open-source as possible from the ground up.

Ben - it depends what your target is - I've done some 3D printing thanks to TSD's "spare" printer and you can make more complex shapes than a 3-axis mill could manage, but even with the more robust filaments etc. you aren't going to beat a nicely milled aluminium or even nylon bracket.

Dave - now you've upgraded your 3D printer using your mill, are you going to upgrade your mill with any 3D printed bits? :D

 

In other news, I managed to get a shape from Inkscape via PyCam to LinuxCNC to a post-it-note, possibly the least efficient computer printer known to man :rolleyes: but it proves the "other" use of the mill, which is my better half using it for jewellery designs - an ideal fit and it generates a lot of extra brownie points :ph34r:

Oh and I definitely need to fit some limit switches as the first mod!

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Depending what materials you’re machining/engraving, you can easily hook up a vacuum to the end. 

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Yeah, but being a small high-speed mill the spindle's slowest setting is about 5000rpm so something's bound to escape!

Also it's quite noisy for indoors either way round - long-term I'll build a little enclosure for it but that's a glory project for later.

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Sounds like the engraver we had in my old department.... annoying the 5K minimum RPM made it pretty useless for anything other than engraving part numbers :( 

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19 hours ago, FridgeFreezer said:

Yeah, but being a small high-speed mill the spindle's slowest setting is about 5000rpm so something's bound to escape!

Also it's quite noisy for indoors either way round - long-term I'll build a little enclosure for it but that's a glory project for later.

It will be possible to add speed control to slow it down.  However, if you're using small cutters <6mm, 5k rpm isn't far off what you should be running.  People always run mill cutters too slowly with too shallow cuts.  Cranking up both gives you a better cut finish and makes the tools last longer (surprisingly) so long as you have decent cooling (which could just be an air blower).

Si

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On 1/2/2019 at 4:23 PM, simonr said:

It will be possible to add speed control to slow it down.  However, if you're using small cutters <6mm, 5k rpm isn't far off what you should be running.  People always run mill cutters too slowly with too shallow cuts.  Cranking up both gives you a better cut finish and makes the tools last longer (surprisingly) so long as you have decent cooling (which could just be an air blower).

Si

I think the tools last longer because your moving more mm per cut. However I find I can never hit the theoretical speeds without problems like snapping cutters or breaking tips. I think it's because my machine isn't rigid enough for it so I end up with uneven loading etc but I'm no expert at it. 

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It's kinda academic as I'm not running a CNC mill in the lounge no matter what mods it has! :SVAgoaway:

We try to keep tools and stuff in the shed / garage and keep the house relatively normal :ph34r: otherwise it would get out of hand...

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Meh it'd be fine, just get some noise cancelling headphones and you won't even know it's there. 

 

I have learn't that women don't like masses of swarf trodden into the carpet. 

Edited by Cynic-al

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My new 'CNC' project arrived today for work. 

It's a 2013 robot, it can lift 130kg at it's full reach of 3.2m so could probably do an engine change :lol:. It's retired from a BMW standby production line so has less than 5,000 hours, the company we buy off buy in bulk and refurbish. You can buy just the bare robot or they will build a full production cell or anywhere inbetween. I got them to add a 7th axis as a turntable and if I can get the better of it it will use a variety of tools to shape foam. I have a piece of CAM software which will write the paths as native language, then run it through a post processor to add the extra bits, then load onto the robot... hopefully :o

20190111_110131_zpsn1basq91.jpg

 

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OK now you're just showing off, swanky barsteward! :glare: Just a little bit jealous! :angry2:

Would love to see some of your output though.

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Hehe, are we playing top trumps here?

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Well the difference is I don't have to pay for this as it's work :lol:

The concept will be something similar to this but customised to what we need to make

 

 

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I could break so much stuff with one of those!

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LOL.

My favourite I've seen was at an exhibition where they had one chipping a gold ball into a hole. It did it every time. 

ABB do a program called robot studio where you can link robots to get them to do that sort of thing more easily but I'm not that into it. I can do a program that moves to a position, picks something up, puts it down elsewhere and that's about it. 

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