Thread: DIY CNC Help?

Ken described very well how to setup a reciever tank.... BTW I've yet to setup a vacuum table etc on my machine and so far have relied on DIY MiteeBite style excentric clamps for the alloy work I've done and hold down clamps and nailguns for the timber stuff. Yet to do glas and plastics that a vacuum setup would be handy for.

The reason I went with ballscrews is that I had them from some fortuitous dumster diving at work.

My whole machine (98%) is repurposed/discarded/decommissioned gear from Fairfax. The parts dictated the design to a great extent and it would have been a very expensive build without these freebies

Cast epoxy granite construction is basically concrete that uses epoxy as the binder for the silica and granite aggregate. Google Anocast to see examples and check out threads on the CNC zone. We used Anocast to make the large internal drum imagesetters platten at one of my previous jobs.

For the examples shown I'd probably do the arty stuff as cold cast metal or make a pattern and get it cast at a foundry. The large timing belt pulley I'd just buy... why reinvent the wheel.

What I mean by how large of 3d metal work is do you need a full sheet size bed? If not I'd thing converting an older, used mill like say a bridgeport to CNC would be the go for metal work.

You'll need a pretty grunty spindle motor that can be geared down to slow speed for metal work. No way the 2.2 kw chinese spindle I have would do the job.

Everything is a compromise and I doubt it is practical to build one machine capable of doing everything well. Please don't take that as a discouragment I'd love to see such a machine but it would have to be built like the proverbial s**** house
Cheers
Mark

Originally Posted by d0vr

2. Sorry, I'm not sure what you meant by the last part, and what is a huge amount of power?

when you have too install 3 phase power too your shed , if you want to cut steel , you will need 3phase power

a pc , stepper drivers & PSU, , 1.5kw spindle , air compressor/ vacuum pump ( small one ) all add up , you wont run a small 6040 machine off a 10amp power point , with small motors a "full sheet" machine might get away with 2x10amp plugs

Originally Posted by d0vr

Thanks for the tip regarding a fridge vacuum pump,

there the "refrigeration maintenance pumps" they use to suck the air out of the refrigeration pipes before they regas them , not the pump inside the fridge / air conditioner

Hi d0vr
Like you we are thinking of a new build as the current cnc is to small and what we decided was to build two one router 1200x 1200 ( The limit being shed sizes) out of steel tube, With a drop down table for the bigger thing and a 4th axes. The other will be a mill out of epoxy granite 600 x 600, 500 high with a 4th axes also.
Why two? it was decided that the rigidity need for milling would be to much in the router and causing a lose of acceleration and speed. Yes these could be over come with bigger drives but it was just too much power needed
Both will be able to cut wet.

Yes we have milled glass we submerged it under water very slow to cut but next time we will be getting some cutter made for the job this will hopefully speed it up.
Hope this is of help to you.
Wish you the best of luck with your project.

Russell

this is a "nanny state announcement" brought you by Homann and Ubeate

if you start to unscrew the bungs of a " out of date "cars LPG tank "!!!BEWARE!!! the bung could probably knock you out before the area is engulfed in a fire ball ( its ok, you wont feel the pain when you burn )

MAKE SURE ITS "EMPTY" < DEFINITION OF EMPTY IS DISPUTABLE

fill it up with water first too make sure its "empty" is what i did when i found mine on the side of the road ,( service station car park ) believe it or not an empty tank with 12% fumes , is worse than a full one ??? yer ive worked at 3 LNG plants ( EMPTY ANIT EMPTY ) FUMES KILL

out of date LPG tanks , are NOT good for compressed air , and are "time bombs" waiting to happen , a vacuum is different , a full vacuum is -1 bar or -14psi, 28odd hg , even if it fails it wont explode , it will implode , DO NOT USE LPG/BBQ TANKS for compressor bottles, if a peace of the bottle misses you , it will still blow your ear drums out
i think the bottles are rated too 90psi when new ( 10% burst pressure ) so will explode at 900psi ( when NEW )
200bar out of date CIG/ BOC tanks are a different story (2900psi then x 10 to burst pressure ) should never fail at 120psi

Hi D0vr
I am about a km away from you in Alexander Heights. I have a couple of home made machines you can look at and happy to discuss designs with you. Week nights after 6:30pm is the only time I have available so PM me if you want to visit.

Originally Posted by rodm

Hi D0vr
I am about a km away from you in Alexander Heights. I have a couple of home made machines you can look at and happy to discuss designs with you. Week nights after 6:30pm is the only time I have available so PM me if you want to visit.

D0vr
Rod is the man in the know and is only to willing to help anyone out even me.
David

Originally Posted by dj_pnevans

D0vr
Rod is the man in the know and is only to willing to help anyone out even me.
David

well on the top left of the thread is a "pair of scales " click on that and give him a good comment

Sorry for not replying sooner, I seemed to have accidentally unsubscribed to my own thread by clicking the wrong link in an email.

@Mark I would ideally like to be able to cut from full sheets if possible. I would like to be able to make custom computer enclosures from sheet metal. And thank you for your encouragement! At this point, I'm trying to establish how I would achieve it. If it is possible, I will then work out the total cost and decide what I can give up based on the prices. I'm not quite sure what the proverbial s**** house is though, as I don't know what s**** is. :/

@Russell All information helps and thank you for your best wishes! Is there anything complex about implementing a 4th axis that you know of?

@SDS Nanny state announce all you like - those tips aren't things I would of probably considered obvious problems so you possibly saved my life, or at least my hearing. Although, if I did burn to death, it sounds like it would of been painless at least. Just to clarrify though, you are saying that out of date LPG tanks should be okay for use with a vacuum, but not for compressed air, right?

@Rod You're too kind. PM sent.

d0vr
There are two type of 4th axes, common is the wrapped this has z, 4th axes and only x or y depending on your 4th axes alignment.The other is true 4th axes where the job sit on a table below center that swing side to side whilst machining with full xy movement, Google them and you will see.
The first one has plenty of gcode writers out there but the second is some what more complicated and rarer gcode writers, That are affordable.

Russell