1220 × 2440 build

[JAZZCNC]

It seems like The first and maybe most important things to consider are the strength and accuracy of all parts. The two companies I have in mind, I know someone who builds conveyors at one, and i know the owner of the other one. The other company manufactures all sorts of precision parts. There's no doubt in my mind that both of them will be able to achieve the accuracy, they both have decades of fabrication experience each. It's like jazz said though they are always busy so it'll be a case of finalising a design first, then fitting in the welding and fabrication around what they've got going on when I'm ready.

If it can't be done for that price, how much is more realistic Jazz? There's a few machines this kind of size on eBay for 7.5-11.5k with some offering training. I figure if they can sell them for that surely I can build one for less (hopefully, that's usually the case when you DIY as much you can) with the right kind of guidance and outside expertise.

Ok well obvioulsy depends on lots of factors and how good job you want to do but £4k will be more realistic figure and that is doing everything your self, welding machine work for aluminium parts the job lot.
So straight off the bat your backs against the wall if paying these companys or even if working on mates rates you haven't got much room to play with.

Also you'll all most certainly have to buy all the major components ie: linear rails, ballscrews etc from china to do this for £4k- £4.5K.
Here's Little break done for you.

The Linear rails & bearings, ballscrews & end bearings will cost about £2k and that's working on 20mm rails. Really 25mm would be better for long axis. Then throw another £300-400 into things like Timing belts, pulleys, Cable chains, nut's bolts etc.

Frame materials will depend on design but You'll not have any change from £500 and that's working on steel prices at wholesale not retail. By the time throw aluminium into mix for Z axis and brackets etc and you'll be at £750+.
If you use Profile type gantry like I do then will be easily over £1000.

The electronics will cost best part of £1000 to be done properly. That's working on using Closed loop steepers and using Motion control card all done correctly in Steel cabinet. Including all cables relays, e-stops, limit switches etc.
Wouldn't use open loop steppers for machine this size because using slaved motors as there is lot of inertia and easy to loose position. Plus the difference is cost isn't massive so well worth little extra.

So
Rails/screws etc £2000
Rail/screw sundries £400
Steel/Ali £750
Electrics/Motors etc £1000

These prices are not OTT and based off prices I've paid from China so you don't have massive wiggle room. Plus there will be extra hidden costs like paint,Drills etc which could easily account for another £200-300.

So you see £4K soon gets eaten up and that's allowing for someone who knows what there doing and doesn't screw up. Which is very easy to do for resonably experienced builder and almost guaranted for new builder.!!

Regards the Ebay machines then I've yet to see one that is any good for under £10K and most are Chinese machines which have there problems like coming with DSP controllers which expire quickly and limiting to use or cheap nasty electronics which will need some fetteling costing more money still. Most 8x 4 that are any good are between £15K-£20k.

If you expect to spend £5K you'll end up with machine that will last for years cut everything you want and be very reliable. The same would cost you £20K+ to buy.

[HullMark]

5k sounds reasonable to me, thanks for the break down Jazz, that's helpful and exactly what I needed, a ballpark figure ... have you seen CKJCNC on eBay? They seem to be doing a lot of business selling CNC machines, sub 10k plus VAT for the 1325 model (1300 x 2500 x 200 working area). Certainly looks the part, at least to my untrained eye! About 11.5k inc VAT.

[JAZZCNC]

5k sounds reasonable to me, thanks for the break down Jazz, that's helpful and exactly what I needed, a ballpark figure ... have you seen CKJCNC on eBay? They seem to be doing a lot of business selling CNC machines, sub 10k plus VAT for the 1325 model (1300 x 2500 x 200 working area). Certainly looks the part, at least to my untrained eye! About 11.5k inc VAT.

They are just Chinese imports. If you notice they say Orders being Taken. You could import one of these your self for lot less money. Shit loads on Ali express.
https://www.aliexpress.com/af/1325-c...ewCP=y&catId=0

[malcolm01]

5k sounds reasonable to me, thanks for the break down Jazz, that's helpful and exactly what I needed, a ballpark figure ... have you seen CKJCNC on eBay? They seem to be doing a lot of business selling CNC machines, sub 10k plus VAT for the 1325 model (1300 x 2500 x 200 working area). Certainly looks the part, at least to my untrained eye! About 11.5k inc VAT.

Hi Mark
I’ve just finished building an 8x4 CNC. It works ok,
I fitted it with 25mm ball screws on x and y axis and fitted a ready made z axis. The guys above were correct about ball screws whipping or wobbling while running, the y axis is fine, but the x axis has vibration issues. I’m planning on changing the x axis drive to rack and pinion which I’ll be buying from America ready made, I would recommend if your building a machine to avoid ball screws over 1500mm like one of the other guys said.
It will cost around £5k, it did for me, but when you see that thing cutting out your parts you’ll be glad you did it. I love my machine, I hardly cut anything buy hand if I can help it.
Best of luck.
Malcolm, from Ayrshire, Scotland


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[JAZZCNC]

Hi Mark
I’ve just finished building an 8x4 CNC. It works ok,
I fitted it with 25mm ball screws on x and y axis and fitted a ready made z axis. The guys above were correct about ball screws whipping or wobbling while running, the y axis is fine, but the x axis has vibration issues. I’m planning on changing the x axis drive to rack and pinion which I’ll be buying from America ready made, I would recommend if your building a machine to avoid ball screws over 1500mm like one of the other guys said.

Hi Malcolm,

I wouldn't do that to be honest because R&P comes with it's own issues and I'm guessing you mean CNCrouter parts R&P which isn't the best thing in world. Ballscrews can work fine if done correctly.
The trick is to get the screw speed down. So to do this you use pitch that is higher than you need and apply a ratio. I'll guess you used 10mm pitch.?
If you had used 25mm pitch then applied 2:1 ratio you would half your screw speed. The ratio makes it the same as if having 12.5mm pitch so you have little more travel speed still with decent resolution. The ratio also increases your torque so little more grunt.

If you use Fixed end bearings both ends of screw and put under slight tension then you won't have any issues. If you watch the video of the Vertical machine it's using 2525 screws done this way and traveling at 15Mtr/min. In testing I had it upto 25mtr/min and still with little left.

[HullMark]

Malcolm is this all made from the aluminium profile stuff? I would love to hear a run down on the processes you went through to get to this stage.

[malcolm01]

Malcolm is this all made from the aluminium profile stuff? I would love to hear a run down on the processes you went through to get to this stage.

l


Like you I was trying to build this cheaply and myself, made the mistake of building a torsion box as a base. It still sagged no matter how sturdy I thought it was. Then I just followed my instincts and built it. I used aluminium where I could, I’ve stuck in a few pictures, the gable ends of the gantry I had made from a local engineering firm, they cost a fortune.



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