New build with recycled parts on a ridiculous budget 120cm*60cm work area

[Desertboy]

Hi, welcome to my first cnc milling machine build (Although not my last I hope) I have a little experience with cnc as I built and use a reprap, I'm just upgrading it from a mendal to a I3 graber when the frame ever arrives from the Ukraine but if you have a cnc machine you can make your own for a lot cheaper. I've been able to score quite a few bits over the last 6 months for nothing except my time and a lot of hard work lol.

I set myself some ambitious goals for my first build.

1. 120cm*60cm work area (Or close as I can get) ***plan has changed 120cm*80cm***
2. Capable of milling aluminium, ply and mdf
3. Be better than if I bought an Xcarve
4. Build it for almost no money although I will if I have to I hope to build this for under £300, I think the spindle will be the most expensive thing as I can't reclaim one of them.
5. Work on Arduino or Raspberry Pi electronics, Arduino is better as I have a spare one and have been using it with cheapo stepper drivers to test the nema motors I recover.

I haven't cad the machine just winging it but will cad the mounting plates for the bearings and the z axis.

Supported rail 25mm I've now cut it down to 2*1.4m lengths for the Y and 1*70cm length for the X so will only have one support on the x which does worry me but the supported rail was free so it's being used, price for 8 bearings from china was £42 delivered through ebay.com (Was more expensive on ebay.co.uk).

Aluminium extrusion 9cm*4.5cm heavy duty profile I have another 2 lengths this long with different profile they are even more chunky and wider) all the lengths are 3.5-3.6m. I also have the t nuts, bolts, angles etc. Price £0 but 1 days very very hard work removing them from the machine. I was allowed to keep em for free as I saved them 1 days work doing it themselves. There was a lot of toolsteel, tool aluminium on that machine.

I have 2 of these one with stepper will grab a pic later. The motor is crazy small for this thing, far too heavy for a z axis as is but did consider selling them on ebay or converting one to a z axis by stripping it down, weld a frame out of steel box section and remount everything in a smaller profile scrapping the 4cm solid aluminium lol. They weigh over 20kg at moment. Would be excellent start to a mini milling machine on it's own as a moving bed but if I do rebuild one as a z axis put a proper nema 23 on it. These cost me a day's pay I flipped a coin with the gaffer over these heads I got them free tails he docked me a day's pay to keep them and I lost lol. Not including this in build cost though yet as I might not use them.

I have 2 nema 23's that work at the moment have powered them up with a ramps 1.4, steppers and ardunio combo one of them makes a whining noise (It's the bigger one) but I think this might be related to 12v from the ramps board at moment. I intend to convert the ramps board to 24v (Lots on reprap forums about this). I bought the cheapest combo of ramps, steppers and arduino on ebay, just over a £10 all in. I expect to have to change some of the capacitors but the mosfets don't matter. So will be using the x carve software at start but will look into the alternatives, I like the arduino though because it's cheap ;)

I've sent the aluminium for cutting today so tomorrow I can pick it up and assemble the frame and fit both the y axis supported rails and the single x axis one but my bearings were only shipped from China this morning so can't do much more on the frame until it comes will be looking for more nema motors as I want a matched pair on the y axis. Always looking for stuff of course so plans might change if I come across bigger sildes, ballscrews, etc. I can start on the Z axis as well and I should probably get a spindle sorted if going to order from China.

My intention over the next 6 months is to collect enough to build a proper 8*4 one which I'll spend a lot more money on a decent spindle.

I intend to belt drive the X&Y I think it's called belt an pinion that I want to use but not sure how I do it yet. I expect this build to take me 4-6 weeks to complete to me carving but who knows.

Total cost so far is £62 including cutting the aluminium, a few days of hard work and swearing and a lot of spanners, alan keys and torx have been snapped along the way.

Wish me luck

[Desertboy]

I made last minute design change it's now going to have a working area (Hopefully) of 1.2m*0.8m also trying to sort 2 slides for the other axis. The frame you see the long bits are 150cm and the short lengths are 100cm, width of extrusion is 4.5cm*9cm (It's the heavy duty profile).

Not for the first time I'm waiting on China post lol but at moment seems really good got arduino mega in 11 days, capacitive sensor took 14 days and my heated bed for the 3d printer was 16 days so seems a good time to order.

I am going to reinforce with steel angles before I put it together properly so the corners are more for alignment than anything else, I have considered having the frame welded I can get it done free ;)]

Just can't afford it at moment but eyeing up ballscrews in case I can sell a kidney ;) so we're still looking at belt drive at moment which works well as all my nema 23's have cogs permanently mounted on them.

I will buy a new nema 23 for the z axis (Unless I find one with a shaft) so I can mount it easily to the ballscrew.

I realise I can recover proper stepper drivers 4amp+ from the machines so will upgrade the drivers as and when but (If I can) will still use an Arduino to drive them.

[Desertboy]

Already budget is out the window ha ha ha.

I bought a pair of 1.5m of linear rails with 4 blocks and a 1.4m ballscrew with couplings, mounts, etc.

Spend is ~£250 now but will need to buy 2 900mm ballscrews for the x axis and need to sort z axis but I think I can do that cheap.

That will then leave a router/milling spindle but lol lets get the X,Y & Z working.

[Desertboy]

Bought 2 1m ballscrews now so I have

A strong aluminium frame 1.6m*1m made with heavy duty profile
2 supported rail 25mm slides (With new bearings) will cut to 100cm
2 linear rails with sliding blocks (HWin) 1500mm long with 4 blocks
1 Ballscrew 1400mm long RM1605
2 ballscrews 1000mm RM1604
The fittings for the ballscrews, motor couplings, etc.
Most of a z axis (25mm smooth rod & bearings, 20mm ground ballscrew travel 20cm) I will need to decide how much travel I need and cut down and machine to fit.
2 nema 23 motors (I have these working)
Arduino Uno, CNC shield
Nema 23 mounting plates
Probably more stuff


The budget has been taken outside like old yellow and a bullet has gone in it's head. I am now working on a budget that I bought an xcarve (Which I was seriously considering but in the end decided I could build something a lot better for a lot less and also the satisfaction of building your own and of course I have a lot more wiggle room for upgrading.

Now is the waiting game as I ordered cheap ballscrews from China to get it working (C7) this will be fine I'm sure for my first cnc. When I get some cash in (I already have some jobs for the cnc I outsource at moment.) I will upgrade the ballscrews, cover the frame in 5mm steel (The Y axis will get only 3mm to keep weight down). I also will swap the 2nd hand supported rail for new from zapp.

I now need a spindle but totally wiped myself out financially.

I have some work for this machine so when it does work I will use the money made to upgrade the machine (Looking at slides, ballscrews and electronics also encase frame in steel) and I need to build an 8*4 which will be for wood based products only.

[Greeny]

Looking like you're powering forward with the parts. She'll be cutting in no time ��

1605 &1604 ballscrews might be problematic though.
You're going to have to gear them to spin very quickly to get any reasonable feeds for cutting mdf/wood.
You may experience problems with whip:
On the 1605 1400mm the calculated critical speed is about 1000rpm which equates to 5m /minute.
On the 1604 1000mm the calculated critical speed is about 2000rpm which equates to 8m /minute.

You may be happy with those feeds or may able to exceed the critical speeds, but just wanted to highlight it.


Cheers

[Desertboy]

Hi Greeny thanks for the reply,

This is my first CNC so making it up as I go along. I have a job to do with this machine (At moment I sub contract but am tied into a contract so have 3 months to finish this if I choose to fullfill it myself.) when it's done I intend to build an 8*4 rack and pinion machine for ply and beef this up to do harder materials. Mostly aluminium but occasionally a steel bracket (Mostly building more machines for me personally). I'm somewhere between home user and pro but I get a real kick out building it and am interested in the automation ;)

Like everyone on here I want at least 6 machines in the end 5 of them I will build ;)

3d printer (Already have)
cnc miller/router
cnc router 8*4
laser cutter
vacuum former (Have vacuum pump and air tank)
decent vertical wall saw

[Greeny]

Hi Desertboy,

Sounds good.
All the best with your build, will be watching with interest.

Cheers

[Desertboy]

Greeny out of interest how would you have drive this?

Also for 8*4 how would you drive it? I was thinking R&P for 8*4.

Originally I was going to try and drive this belt and pinion but I knew I was building something special so ballscrews seemed the only choice I want a very capable machine and I'll build the 8*4 for speed and production as 90% will be ply/mdf style products or real wood.

[Greeny]

Although i have a lot of experience using big cnc machines, I don't really have the building experience to offer good advice,
but as long as you bear that in mind here's what i would be looking into if i was thinking about a machine that size.

A ballscrew for the 4ft axis , either a 2010 or 2020. Nema 23 3nm.
The 8ft axis probably 2510 or 2520 fixed ballscrew with 2x rotating ballnuts and 2x nema23.
I would personally only consider R&P if budget can't stretch to rotating ballnuts as they are pricey.

Here's a few relevant threads you might like to peruse.

http://www.mycncuk.com/threads/3340-...n-ideas/page14
http://www.mycncuk.com/threads/10219...tart-8x4-build
http://www.mycncuk.com/threads/10865...concept-review

Hopefully someone with more building experience will chip in.
Cheers

[Desertboy]

China post is working efficiently at the moment the bearings came! 11 days from ordering! And we had no post since Friday so might have been quicker!


They slide super smooth after adjustment very happy with them making me rethink the supported rail for a larger machine as it's a lot cheaper than hiwin style rail and the accuracy will be fine for my purpose.


Hopefully the ballscrews which only went out today will be as quick ;) They will get import tax I'm sure. I've ordered a lot from china recently and a few things were over the limit but just but these screws are over £250 so bastards will screw me.

My 1.5m Hiwin rails came as well today ;) (Like xmas but better because it's stuff I actually want) I think the Hiwin rails are too small 15mm for the purpose but they were cheap and a decent length 1500mm with 4 carriages so I've gone with them to get it working and will get something more suitable in the near future. Will work exclusive wood based products until I change these and if I really need to do aluminium just doing it very slowly with a low cut height.


I'm already thinking though I should have spent another £150 on top and got 2 1.5m supported rails as I have 8 bearing blocks and the supported rail is stupid strong. (The printer I took it off have a sliding carriage that was over 400kg's and powered by a puny nema 23 lol.)