Im on my third rev of my home-built CNC project. My best advice is to make
it much more rigid than you think you need to. I started out with small
slider shafts and now Im up to 7/8 (which you can get surprisingly cheap
at speedymetals). But in my case every rev got considerably bigger. The
first rev was a little 8*11 PCB cutter and it had ¼ sliders, the second rev
grew to 11*17 with 3/8s and the latest rev will be a whopping 20*34, thus
the need for the huge sliders. But definitely err on the side of
over-engineering for rigidity.
The other part that I couldnt afford that I wish I could have was good
linear bearings. I tried many times to come up with my own linear bearing
surface but in the end most of the available torque was spent trying to
overcome the sliders. I still cant afford good linear bearings but my
latest home-brew setup uses small standard bearings (some of which are
spring-loaded). These are a bear to manufacture but will dramatically
increase the quality of the machine.
I am using threaded rod but it makes for a very slow machine. If anyone
here has a line on good inexpensive ballscrews please let me know.
As for electronics I am doing it all myself because I want smart nodes. But
I think the consensus here is probably right spend the money to save the
time.
Drop me a note if you have specific questions.
DougM
_____
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of seth wiley
Sent: Sunday, March 02, 2008 1:10 PM
To: [EMAIL PROTECTED]; Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] home-mad CNC machine project.
sean,
i'm slowly (in my very spare sparetime) working up a small (12"x12"x3") low
tolerance cnc machine for light wood and plastics. it is also serving as a
general teach-myself-cnc project. i chose to go with a pre-config'd
electronics / servos package from keling inc.
(http://www.kelinginc.net/ThreeXCNCPackage2.html). after reading lots of
cnczone entries and doing lots of chipset / board / wiring research, i
figured it's 329$ well spent by saving me time, and it's a pretty complete
set of items for a good price. also, this site has some helpful info on
wiring (http://www.robertguyser.com/). i am next building up the machine
using basic 8020 or minitec extrusions and linear accessories. lovejoy
couplings will round out the basic bom. i'll use whatever i have as a cutter
head - dremel, trim router, etc. it should turn out to be a fairly cheap
machine without eating up too much time reinventing the wheel. cam
environment: emc2 packaged with ubuntu. it was a smooth install and the
forums are great. so, i cannot say that this route is flawless and worked
out yet since i'm still in the process, but i can say that i've spent a
bunch of time running cnc machines, spent lots of time reading everything i
could find on the internet and printed about various diy cnc options. i
think this route seems like a pretty efficient and solid starting point.
i'll let you know how it comes out - if i ever get the time to complete it!
have fun regardless of which direction you choose. good luck.
-seth
On Fri, Feb 29, 2008 at 10:59 PM, <[EMAIL PROTECTED]> wrote:
I was wondering if anyone has ever tried a do-it-yourself CNC project like
this.
http://www.instructables.com/id/Easy-to-build-CNC-Mill-Stepper-Motor-and-Dri
ver-ci/ and this
http://www.instructables.com/id/Easy-to-Build-Desk-Top-3-Axis-CNC-Milling-Ma
chine/ . If so, any pointers or words of knowledge before I dive in?
Also, I'm still looking for some stepper motors to use if anyone has a good
source.. I'm a college student, so I'm obviously broke and starving. So,
inexpensive would be good. Thanks guys.
Sean
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