It all started about 2 to 3 weeks ago . I decided i was going to try to attempt to build a CNC machine out of whatever i had laying around trying to keep costs down. So i started doing some reading and research , looking at different web sights and soon decided , that was more work than i needed to do . So i started to look into the kit option and stumbled across OpenBuilds web sight. So I joined the openbuilds community and I have been reading thru the forums and looking at a lot of the build ideas . I came across the OX Metal build which i really like except i want it 1500 mm x 1500mm but #1 the longest lead screw available in the store is 1000mm and #2 using a lead screw over 1000mm can result in whippin , which i don't want. anyway my thought train has went something like this . i'm going to build the OX Metal CNC (But i need the 3d printed parts for it) so i started looking at an inexpensive 3D printer to do them because it would cost 45 to 50 bucks to have them done so kick in another 100 or 120 or so i can buy a 3d printer and print my own + i'd have a 3d printer then too. Then i started to think the main core mechanical structure of a CNC and a 3d printer are pretty much the same ie.rail structure , stepper motors . where they differ mostly is electronics ( power supply , control boards and heads ie. 3d printer heads as opposed to router) and as far as the leadscrew issue i want to use rack and pinion(faster than leadscrew more stable than belt and gear at that length due to stretch) So what i am thinking is a OX Metal build with rack and pinion and some way to quick change the work head and electronic(some kind if plug in). By the way i think this is and awesome community with a lot of fantastic peeps. PS all thoughts and ideas welcome.
to get you started you can cut the plates out of mdf... Rack and pinion are the way to go for a bigger machine. 1500mm is pretty big, might want to consider how to stiffen it up so you don't get too much flex. have fun! Bob
R&P is what I have in mind , from what i have read on a span that long lead screw is to slow and can whip , belt has to much potential for stretch and backlash .
Have a question out there. I am starting to make jewelry and i need to cut sheets of sterling silver no more than an 1/8 thick. Largest piece of plate would be 6"*8" can someone recommend a machine or project that would fit my needs, Thanks
I use 1/2"-10 5 start lead screws at 1500 mm and have had great luck with them. They move 1/2 inch for every rotation. They are available from McMaster Carr. I easily cut 1/4 inch plywood at 4000 mm/min in one pass, aluminum at about 700 mm/min, and I have surfaced wood at 6000mm/min at 1 mm depth with a 3/4 inch bit and the screws do not whip. The screw is also very accurate. I figured out what the steps/mm were for the screw and when I sent it 1000 mm it was dead on. I did not have to make numerous attempts at calibrating, so these screws are a viable option if you want a cheaper route than rack and pinion.
The C-beam Plate maker is the way I went. available here on OB site (I'm not associated in anyway) . you will need to set it up and add a router or spindle, power supply and control board. I feel like a water jet and laser systems would be much more expensive
