I registered in this forum last July but have lurked a few more months before that. I've seen how a CNC works and have been eyeing one of the mini-mills but after viewing the posts here and visiting the links, I have decided to try my hand on building one and hoping that the knowledge that I picked up from this forum will help me through. So here goes and it's from somebody who had "0" knowledge on the intricacies of DIY CNC but armed with knowledge picked up from reading posts from the good folks here.
I decided to use what is readily available to me. I have a 1/2" (12mm) aluminium plate that I picked up from a junk shop of which I'll use as the back-bone of the project. It's edges are perfectly square and it can give me a working area of x=30", y=12" and (I decided) z=2" but have the whole yz assembly on the gantry capable of being, repositioned manually, moved up by 4" if needed. This design decision was made because I understood from some posts here that the lesser travel on the suspended assemblies will help in the precision in faithfully reproducing the translated CAD. The repositionable feature is for later on when I decide to use a 4th axis dividing head.
The 1/2" alum. tabletop was strengthened to address the sag (0.5mm) at it's mid-point when a 100 lbs. weight is applied on the center of the table. This was achieved by bolting an aluminium sliding door track around it's perimeter. The table legs which are adjustable for leveling were also bought at the hardware store together with the sliding door tracks as well as the drawer sliders that I plan to use.
Here's the expense break-down for now.
1/2" Aluminium table-top 20.5"W x 43.3 L (from junk shop)=US$17.75
Aluminium hanging sliding door tracks 2-2mtr sections = US$20ea=US$40.00
Aluminium adjustable leveling legs x4= US$36 total
Extension drawer slides, 2 sets for x-axis, 1 each for y&z=US$26
48" Stanley brand aluminium carpenters level x2=US$20
Odds and ends= 1/2"x1"x3' scrap aluminium to make the recieving nuts to lock the sliding door rails aroung the table top and 8mm x 1.25 x 25mm allen recessed head screws x 24pcs. = US$10
Current project total= US$149.75
I bored the tabletop's perimeter for 24 recessed in allen screws to attach the sliding door rails to the bottom of the tabletop for reinforcement and made the 24 recieving nuts from the 1/2"x1" alum scrap (milled the shoulders to fit into the slide's slot the drilled and tapped for 8-1.25mm).
Total man hours so far including the shopping and plan drawing=22 hours  |