CNC Router New Build

[MikeyC38]

Thanks for the advice Martin and Ross.

I have made a start on some designs after reading through a heap of build logs. Seems that for my size of machine I would be pushing the budget too far to get HIWIN 15mm rails on all the axis. Perhaps I will have to have HIWIN on the Z and build in some upgrade paths for HIWIN on X and Y in the future if I find the machine needs it.

Also thanks for the info on welding problems in regards of accuracy. I think I should be aiming for something similar to this one, in particular JAZZCNC's machines in the second post of this thread http://www.mycncuk.com/forums/diy-cn...ign-build.html

The info on the screws is useful too. I hadn't anticipated the torque required for aluminium, I was worried about whipping. Speed is of secondary concern after the accuracy. I would rather run for 10hrs and be accurate than 5hrs and be sloppy. I will design with pulleys so I can have a bit of choice over it.

I am having trouble finding Aluminium profile with prices listed to get a feel for what is affordable. Are there any preferred suppliers? I need to get a feel for how much I can expect to spend to help with design choices.

Thanks.
Tom.

Hi Pilot Tom
Hope you are getting on well with your design. I have worked up the final drawings and going with Jazz's approach on the use of 80x40 heavy extrusions arranged in an L pattern, with 20mm toolpate for the Z axis and 20mm plate for the gantry sides. After just purchasing a VFD and 2.2kw spindle, it sure is heavy! so stiffness of the gantry is important.

The guys on this forum give honest critical advice which has made the difference in my design and will ultimately save time and money. My buiild will start in a couple of months so watch the build log.

Kind Regards
Mike

[Ross77]

I have worked up the final drawings and going with Jazz's approach on the use of 80x40 heavy extrusions

Ditto on using heavy sections, I bought a job lot cheap on ebay a year or two ago and it was a mix of light and heavy, the light is much weaker and only really any good for display cabs.

Perhaps I will have to have HIWIN on the Z and build in some upgrade paths for HIWIN on X and Y in the future if I find the machine needs it.

If you can, go for the profile rails on the z axis as this is always going to be the weakest section, loaded as a cantilever and also eccentric loading from the weight of the z axis.

20mm plate for the gantry sides.

Ok this is only my opinion and I realise that there are lots of machines thathave been built this way and work fine but to me it is a very inefficient way too do it. The gantry sides are the final link in the chain of transmitting force to the ground so really need to be treated as beams/columns. I would go for using 4040 extrusion with 6mm plates either side, probably the same weight but much stiffer. Again I'm not criticising using plate, it just not the way I would do it.

[davethefixer]

Having nearly finished a build similar to what your describing (mine having a cutting area of 1200X700X200)
Welded box section steel frame (50x50x3)
45x45 heavy aluminum profile frame (on top of box section)
20mm profile rails on all axis
2x1500 2010 ballscrews for x axis, 1x1000mm 2010 ballscrew for y axis, 1x250mm 1605 ballscrew for z axis
20mm side plates (milled with my home made MDF router) (very very slowly)
electrics, stepper drivers x3, (from diy MDF special)
2x nema 34 (for x and y axis) 1x nema 23(from mdf special)
belts and pullys ect. ect ..... a bit over engineered?? oh yes !!! cost...................way more than i had expected (around £2.5k) 5 months to build....
suppliers i got materials from
http://http://aluminium-profile.co.u...KJN990520.html
http://http://www.zappautomation.co.uk/en/
http://http://www.aluminiumwarehouse...php?cart_qty=2
http://http://www.beltingonline.com/...leys-bars-272/
http://http://stores.ebay.co.uk/line...earings?_rdc=1
and a big thanks to iwant1 as his build log was exactly the sort of thing i wanted to build
http://http://www.mycncuk.com/forums...my-head-7.html
hope this helps

[Iwant1]

Dave, last week when you posted pictures of your build, and thought what a neat build, hang on, that looks like mine. Well done for getting so far. I'm still nowhere. At this rate of I'm hoping to find time after July once I tell everyone else to bugger of, no more favors.

How did you get the ali parts machined? Yourself or by someone. Have you tried cutting yet? if so, how does the L gantry hold up to the forces?

Adil

[davethefixer]

Iwant1, it has sucked up a big percentage of my spare time this year, but as my ball and chain cleared off a few years ago telling everyone to bugger off wasnt a problem.
I only got it moving with the spindle attached last sunday and have only v carved a small test peice in wood so havent loaded it up yet.
lots of bits to tidy up, fit some energy chain (maybe make some) for the cables, buy a 75v power supply ect ect (will it ever be actually finished !! i already have plans in my head to iron out all the cock ups i made)
All the ally parts were cut with my first creation the "MDF specia"l although i had bought a 2.2kw spindle for it before i tried to cut ali (see pics) very very very slowly...... 0.5mm deep passes
As i have 4 days off this weekend i will be doing some test runs to load it up a bit, do some calibration and test its repeatability.
On full extention of the z axis the L gantry was rocking at the rear of the L below the Y axis ballscrew so for now i have just drilled a tapped a M6 socket cap through the bottom of the L into the main X axis brearing mounting block.
But all in all i am realy pleased how it has turned out and the speed and accuracy is astounding compared with my first creation
Apart form my "MDF special" i used only used a small pillar drill, hand tools, and a "evolution" sliding mitre saw (that will cut through 20mm ali) all done in a 7 foot square shed
Keep plugging on with your build its well worth it in the end
let me know if i can help in any way

[Ekfer]

Hi Pilot Tom: I also started with a drill press and a miter saw. I added a metal cutting blade to it, purchased files, transfer punchers, taps, transfer screw sets and looked for already made parts that had hole patterns (2, 4, 6, etc, to transfer the hole patterns to my parts and using the screw transfer sets to join them together). I also purchased a 90 degree angle plate, a machinist square, vernier calipers and clamps. with patience and a good plan you can make your machine. Take care.