CNC machine build log

[asbo]

So as promised I'll be posting pics and blurb as I build my CNC machine.
Its base on this machine, with some modifications. I'll be using threaded rods to drive mine rather than belts and pulleys. I'll also be giving it 3d printing capability. Haven't designed anything for the 3d printing head yet, there's various different types floating around on the web. So if anyone with 3d printing experience wants to suggest anything I'm all ears

Here's the MDF parts I got CNC'd:


Anyway here's what I've been doing for the past 3 days. Please note that I suffer from a long term illness which means I have to rest often, hence it doesn't look like I've done all that much in three days.


Q:how do you drill 6mm holes in the edge of 12mm thick MDF. A:very carefully



Yep pictures of me drilling holes


That's the gantry I suppose you'd call it. It'll sit on rails and move up and down the Y axis. And after building that I nearly passed out, so that was that for today.

[xman]

Very nice work Asbo. I also like building stuff that requires precise measurements and construction but metal is my favorite material to work with but that's because I actually find wood harder to be accurate. Needless to say I am quite enjoying your workmanship on this project. Keep up the pics please because I can assure you, I for 1 am very interested. Also looking forward to see what projects you turn out with this thing when it is complete. I'm presuming when finished you will be using it to make parts and shapes from wood and plastic and not metal or alloy?. If this is the case, maybe an ideal motor assembly may be a "Trimmer" which is actually a smaller version of a router. I have one made by Makita like this-
http://powertoolworld.com.au/shopdispla ... e+Trimmers
It spins at about 10000rpm and does a very fine job on wood or plastic. May be totally unsuitable for what you need or a thinking of using but let me know what you have in mind and I'll keep looking.

[professor_jonny]

yip im intrested in how it turns out im kind of intrested.

id look at fitting a double cut rotary bur to a say 600w die grinder you could chop up metal with that.

you could look at one of those wicked lasers from the us that roll in at 1w and cut plastic quite well.

what do you plan on making with it? styrene molds for metal casting or something?

[asbo]

Thanks xman
Dad's a furniture maker and restorer so there's always free bits of wood laying around. Also all the tools we have a primarily designed for wood working, although there is a bunch of metal engineering stuff my uncle left behind when he emigrated to NZ.
Yep, I'll certainly keep taking pics. Mainly wood, since its freely available, but I reckon it ought to be able to cut aluminium in smallish amounts. I'm going to be sticking some fairly beefy stepper motors on there. The original design recommends 130+ ounce of holding torque. I'll be using motors with 439 ounce of holding torque, more power!
For the spindle I haven't decided yet, the original design is for a dremel, but that seems a bit weird somehow. Why strap a hand tool to a robot when you can give it a dedicated spindle?
I'm thinking something like this CNC Spindle 300W Motor ER11 collect & Mount bracket Set or Router Spindle CNC or maybe even 1.5KW Water-Cooled Spindle Motor for CNC Engraving Inverter Drive VFD (probably not). Then again maybe something like Universal Router / CNC Spindle = CauCau 850 W would be best. I'm not really sure. I don't want to skimp out on the bit that does the cutting but then again I think this one of those rolling projects that'll keep getting changed and added to.

@ professor_jonny ahhh lasers maybe one of them will get added oneday. I'll be making wooden bits and bobs mainly, 3d printing plastic hopefully later on. Metal casting is a bit beyond me.

Anyway I'm off out to the shed now, its time for some fun with bearings

[xman]

Arr OK, something with heaps of balls. Well in that case maybe air powered tools may be a cheap alternative with the added advantage of using the exhaust to blow the saw dust away.

[asbo]

maybe air powered tools may be a cheap alternative with the added advantage of using the exhaust to blow the saw dust away.

You mean pneumatic tools? We don't have a compressor so I don't think I'd go down that route.
I'll probably be adding some sort of fitting to attach a vacuum cleaner hose, don't want loads of dust clogging bits up.

Today's progress:







Didn't get chance to do the bearings.
I could write a little caption for each picture, but I'm out of brain power for today, and I'm sure your all smart enough to figure out what each picture is

[professor_jonny]

Shame you dont live in nz i could supply you a danfoss inverter positioning system you would just need to make an encoder from some halleffect sensors and could use the toothed wheel out of a car distributer for the sencing disk.

i have a lot to do with variable speed drives it is what i do at work

[asbo]

Yep, sometimes I think its a shame I don't live in NZ, then I think of how much my medical bills would be and am glad of the NHS.

I'm not entirely sure what that all means. Is that using 'normal' motors and then a sensor to tell the computer how much its rotated?

Automated farm stuff right?

[Xphazer]

Asbo i must admit that i'm truly admiring this project.
Keep up the good work like that.

[asbo]

Thanks Xphazer
Back out to the shed shortly!

[asbo]

Didn't get much done today, just the bottom rail:

Chiselled shallow holes in the side of the MDF for the rail to slot into then added some aluminium brackets. The remnants of the old aluminium caravan are still coming in handy
Also note the two large holes in the side there, they were for bearings used in the pulley system that I will not be using, a case of oops why did I leave them on the drawings?!?

[professor_jonny]

Yep, sometimes I think its a shame I don't live in NZ, then I think of how much my medical bills would be and am glad of the NHS.

I'm not entirely sure what that all means. Is that using 'normal' motors and then a sensor to tell the computer how much its rotated?

Automated farm stuff right?

normal in terms of automation is 3 phase squrell cage motors motors.
you would connect an encoder on the back of the motor and it tells the drive how many degrees it has turned.

the advantage of 3 phase motors is they have bags of torque and can accelerate ver quickly.
the drives have a serial inter face you just connect them together with 2 wires and plug it into your computer

the danfoss drive converts mains to dc stores it in a capicator bank and switches it out with transistors to the motor you have full control of the motor you can even pump dc into the motor to brake it an lock it in position.

[asbo]

@professor_jonny For these home CNC builds, and big factory ones also, everyone seems to use stepper motors. As a result they're easy to get hold of and there's bags of info about them. I think I'll be using these. Or would the things you were talking about be massively cheaper?
I've read up on steppers and I feel I know what I'm doing. If you were here to help in person I'd probably do whatever you suggested though


Here's today's progress. The X axis is on rails!




The bolts here a bit too long so I'll probably replace them with some shorter ones. The next size down that I have are too short though.




Next is the Z axis.

[asbo]

Been feeling rather bad so didn't get anything done for a few days. But on Tuesday I was feeling good so I got the Z axis done:

Note the slight splits in the MDF at the top. Its very solid but I may make a new bit with the machine once its finished.

Now I feel like crap again ohwell.

Yesterday the control breakout board thingy came.

Only cost £8 and I wasn't expecting it to come with the LCD on the top or the blue plastic control pad, so that's two free things I love buying stuff from china

Now I just need to do the Y axis and wait for a few more bits and bobs to come from china. Then save up for the spindle.

[xman]

Sweet bit of control breakout board thingy you got there. Is the display a 4 line X 20 character by chance?. Nearly worth buying that thing from the Chinese to pull apart for bits but don't do that, I want to see what this thing can do, the CNC machine I mean. Grade 5 bolts I see, there not breaking in a hurry. Most people make the mistake of using low strength bolts, cheap bolts on things they build and wonder why they fail. Just I case you fluked the correct bolts, that marking on the head of your bolts.......8.8.....indicates the bolt's strength. I called it grade 5 because it is the closest metric equivalent to the US grade 5. Any decent bolt will have it's rating marked on the head. Any bolt without markings on the head are to be taken as poor quality. Here's a bolt marking chart for an aspiring builders or engineers we may have on the forum. I have a similar chart in my workshop and use it a lot with some of the shit you guys have seen me build. Anyway, looking fine there Asbo. Thanks for keeping us informed.
Bolt Strength Chart-
https://www.boltdepot.com/fastener-info ... Chart.aspx

[asbo]

I took a picture of the LCD on for you xman. Also the pins:

http://i77.photobucket.com/albums/j44/j ... C/pins.jpg It didn't like me embedding that image since its really wide.

I got it from http://www.aliexpress.com. This was a test buy since it was nice and cheap to check its all legit. Took a week and a half with standard free delivery. Not bad I reckon. I've also ordered the motor drivers from there but I've paid a bit extra for DHL delivery since they cost £70, don't want them disappearing. Mind you the sellers don't get paid until you confirm delivery and you get your money back after a couple of months if it doesn't show up. Apparently anyway.
Also there's bound to be some LCD's you'd like on there xman, all sorts of nice stuff. Might be a good source for IDE to SATA adapters.

As for the bolts I didn't really research it, I just though grade 8.8 sounds about right Of course I'd have looked a twit if it was 8.8 out of 100 and they were crap.
Thanks for the chart, I'll actually look it up next time

[asbo]

Got the motors!
They're heavy beasts, each one weighs 1.4KG and has 3.1nm(439 oz in) of holding torque.

[M•O•D]

Wow! Respect!

More, more, more...

[asbo]

Wow! Respect!

More, more, more...

thanks. Should be done in a month or two.... maybe

I still haven't decided which spindle to get. I may even implement its 3d printing capability first.

[asbo]

I'm too tired to write much but here's around 4000 words worth of slightly blurry pictures