Here is a look at my first CNC machine. It is still a work in progress but it is coming along nicely. I am actually using it to build itself.
I'll start with a picture of the machine at it is now, and then start at the begining.
Here is a look at my first CNC machine. It is still a work in progress but it is coming along nicely. I am actually using it to build itself.
I'll start with a picture of the machine at it is now, and then start at the begining.
Umm, what picture?
Bob
"Bad decisions make good stories."
Whoaaa, it's invisible, too !!
"I'm tryin to think but nothin happens" - Curly Howard
Take your time...no big deal !!!
Just wanted to bust your chops a little...:cheers:
Where can I get that clear coat....it works real good!
Jeff
"I'm tryin to think but nothin happens" - Curly Howard
Here is the concept drawing for the first prototype. I decided that I wanted a CNC router made of 8020 extrusions, but to keep the cost of mistakes to a minimum I decided to build the router out of MDF first as a prototype.
Here is the design I settled on. You will see ideas from an assortment of different machines, mostly gleaned from other builders websites.
The X and Y axis are driven by #25 roller chain. The Z axis is lead screw. The steppers are 475 oz. with matching drivers from Keling Inc.
Linear guides are V-bearings on aluminum angle.
Here is the first machine. It worked quite well.
The router is a Porter Cable 690. I was ale to cut MDF and plywood at 60 ipm and aluminum at 3 ipm.
The first machine worked well enough to help build the second.
Here is a look at the new machine as it was going together.
The gantry is 80/20 extrusion (40-8016 ) carried by legs cut from 1/2" 6061. The carriage and Z axis are guided by V-bearings on V-rails from Pacific Bearing. Their V-rails are hardened steel and are embedded in aluminum extrusions. The bolt right onto the 80/20 extrusion. The V-bearings are mounted on either concentric bushings or eccentric busings for preload adjustment. I tighten the eccentric bushings until I can just barely roll the V-bearing by hand. There is no play in the setup at all.
This table is made of MDF with the aluminum angle as bearing guides because I was not sure if the gantry legs would be stiff enough not to flex. Now that I know the legs are stiff enough to support the gantry with no flex I am going to build a new table out of 80/20.
I am considering filling the 80/20 table with epoxy granite to add weight, but I will wait until after the table is built to see if it is necessary.
Hi, I will be very interested to see how you like the V bearings. I am considering them for a project as well. What size did you end up using ?
So far I like the V-rails and bearing very much. They are less expensive than most linear rail and bearing combos. I paid $9.99 each on ebay for the bearings. The rail was about $60 for a 48" IVT from Pacific Bearing. The rail bolted directly to the 80/20 extrusion.
They are self centering, and the preload is very easy to adjust. They are also very easy to clean and lubricate.
I don't have the exact specs in front of me, but they are about 1" in diameter and are sized for a 3/8" shaft. The bushings are sized for a 6m bolt.
I have seen a few commercial machines that use them, including shopbot.
J
Even though I have been watching this site for about a year I am just now getting time to put together my first table. Your design looks like something that would not break the bank but be very functional for a first timer. The majority of my planned work is in wood so I do not think I would need something strong enough to handle metal. Biggst problem is where to start. Your unit looks great.
Virtually all those bearings, regardless of the manufacturer, have the same specs. And the bushing have a 1/4" hole, which is larger than 6mm. You might want to check that, as using 6mm may allow the bushing to move a bit. Although, if they're eccentric, and you have them tight, I guess they can't.I don't have the exact specs in front of me, but they are about 1" in diameter and are sized for a 3/8" shaft. The bushings are sized for a 6m bolt.
Gerry
UCCNC 2017 Screenset
http://www.thecncwoodworker.com/2017.html
Mach3 2010 Screenset
http://www.thecncwoodworker.com/2010.html
JointCAM - CNC Dovetails & Box Joints
http://www.g-forcecnc.com/jointcam.html
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
There are a lot of great ideas out there. I got most of my ideas from Build Your Own CNC Router Machine.
As far as where to start. Start with the spindle. Pick a spindle that is appropriate for the work that you want to be able to do, and then design the machine to carry it over the cutting area that you need.
I would suggest not using MDF as a building material. Use a good quality harwood pllywood, or better use MDO.
Good luck.
jharvey
thanks for the info. I actually have an older fixed base variable speed router that I just rebuilt with new bearings and shims. It has a bit of weight to it, but for accuracy and torque I don't think I will find anything better to start with. Now to start planning table size and all the other good stuff.
I like that zeroing jig, good idea