new cnc

[Ben-bee]

Hi guys, ive been reading a lot of stuff for the past few months from this forum, as im looking to get a cnc. The main use will be to cut 18mm Baltic birch ply, I may use it to cut other materials but birch ply will be the material. Ive set aside a budget for the new machine which will be able to cut 1220mm by 2440mm sheets.

This is were the fun begins...

Ive been reading a lot of the build logs on this forum and it is very evident, some core skills are needed for a machine of this size, like welding and metal machining skills. Which sadly I do not have, ive all ways been a wood only guy lol... Having to get a lot of the machine made for me would push the cost well up, which is not an issue, but would I be better off purchasing a ready to go machine or getting one built for me, or having a go my self.

The main jobs I plan to do is mainly simple rebating of panals, and cutouts, plus the occasional logos.

whats your thoughts on the route I should go.... thanks in advance....

[Clive S]

Ben Welcome to the forum. Why don't you start by using something like Sketchup and submitting a drawing of what you would like to achieve. It needn't be expensive to have the steel frame welded up at a fab shop. Don't be worried about the drawing the good folk on here will keep you on the straight and narrow for you to have a good machine.
It would help if you stated your budget as well. I take it that you have read through some of the build logs to get an idea of the general way to go. Good luck. ..Clive

[Ben-bee]

Thanks Clive, cad is the easy bit for me lol, I have a reasonable budget, im not looking for bare bones cheap, as this will be used for production. from a design point, the table is not a big issue to design, ive read a lot of very helpful threads and different views, which were all very informative. One thing that puzzles me is the way to go in options for movement of parts, ive read a fair few threads in regards to ball screw single and double motor options, belts, gears etc but not many seem to use rack and pinion, on a few machines (non diy) a lot opt for rack and pinion. is this due to complexity's to build, or just ott. Which would best suit my needs for a wood cutting cnc, Mainly Baltic birch ply. simple sheets cutting and rebating to a depth of 5mm.... Im looking for a quick machine, full 3d carving etc I would like to have a go, but my main use is for the machine to help speed up, what I currently do, which is build and design speaker cabinets, the occasional logos route'd into boxes etc..

[Ben-bee]

Hi guys, ok after a bit more research, ive come up with 3 options,

buy second hand

import a new machine (china)

or go and build some thing....

below is a very ruff cad drawing of what im thinking of...

http://www.mycncuk.com/attachment.php?attachmentid=14869&stc=1
not a detailed drawing but a ruff design.

[Ben-bee]

hi-win rails, and rack and pinion drive.http://www.mycncuk.com/attachment.php?attachmentid=14870&stc=1

[Ben-bee]

again 2 x hi-win rails with rack and pinion

http://www.mycncuk.com/attachment.php?attachmentid=14871&stc=1

[GEOFFREY]

Hi Ben, welcome to the forum. If you have access to a decent 3 phase supply, I think that you could do a lot worse than look for a reasonably priced used commercial machine. Many of this type of machine will have a vacuum bed and a tool change facility and are very robust. Good luck with whatever you decide. G.

[Ben-bee]

I only have single power, I can wire into the fuse board, giving 32 amps or 64amps, the cable to my workshop from my house is rated at 64 amps.... this rules out a fair few commercial machines. The space for a bigger commercial machine is also an issue. max height is 2.2 meters and not much bigger than the drawing above 3 meters by 1.5..

[Ben-bee]

im fairly happy about building a vacuum bed. simple 6 section mdf bed.

[Clive S]

Hi Ben
It would help if you put some dimensions on your drawing. Some vac pumps are quite big Hp I believe. Clive

[routercnc]

If I understand your dwg correctly I would put the hiwin rail on the TOP of the section. This gives natural vertical spacing of the gantry, provides a nice way to connect it to the bearings, and gives you the option of epoxy leveling the surface to get the bearings level with each other (LH and RH side).

Do you know how much vertical clearance and travel you want between the spindle and bed? It looks very close at the moment so you may need to make the side sections deeper to raise the gantry. Don't commit to the side bits until you have drawn the Y, Z and spindle and got the top/bottom travel worked out as this will dictate the X rail height to a degree.

[Ben-bee]

thanks for the replys guys,

suction bed, yes ive seen some pumps need a lot of power, I was looking at the option of using a small pump or a hoover.

rails, the plan was to mount the rails and the rack and pinion on the side of the left and right main frame.