CNC Router under construction

[George Carlson]

Today was a milestone, I got the gantry erected. So the Y and X axis are pretty much in place. This machine was designed to operate at very high accuracy. I want to be able to mill printed circuit boards as well as normal woodworking. Since I have a hobby machine shop, I also wanted to be able to do a limited amout of aluminum milling with the machine.
This machine will have a 2.2KW water cooled spindle. Movement range of 48.5x27x5. The gantry can be moved forward to allow the machine to work over the end of the table. This will be used milling dovetails, tenons, and end drilling.
The deck will be made of 1/4" 6061-T651 plate. This will greatly increase the strength of the machine. I will make a table of MDF and T-Slots as the work surface.

[Bruce Page]

Looking good George. How long do you think it will take to complete? What control software will you be using? I am just getting my toes wet with WinCNC, it seems very capable.

[Dennis Ford]

Nice looking frame and gantry. Home-built CNC is fun.

[Frank barry]

Hi George

it looks nice

is it a kit?and what do you expect your total cost to be ?

[Mike Heidrick]

Make a welded base for it. Looking like your mechanical is coming right along.

[George Carlson]

I currently have a Chinese 6040 machine that I have done some modifications to. It's a very strong and precise machine. In that machine I run Mach3, as I will with the new machine.
I'm building this from scratch. The ballscrews and ball slides are from China. I have a smaal machine shop with a Bridgeport, a couple of lathes, and about 40 years experience in designing and building machines, so I'm luckier than most.
The base will be frabricated from 2" square- 11ga steel tubing. Like most of my other machines, this will have casters to make it easy to move around. I suspect I'm about a month away from having it completed.
My total cost should come out around $2K, but I have a lot of material and parts left over from other projects in past years.

[George Carlson]

The Z-axis is complete. A 1.5KW spindle is currently in the mount, but I plan to go to a 2.2KW spindle with an ER20 collet. The Z-axis has 5" of travel. I put the linear bearings and ballnut on the fixed plate, just the opposite of most. But this allowed me to keep the linear bearings as close as possible to the spindle nose.
z axis complete.jpg

[Mitesh Aegis]

Looking to good, very nice. very effective idea.

[George Carlson]

I'm just about ready to start the wiring. Then I'll build a spoilboard with T-tracks in it. The name Robo-Chop came from a CNC plasma I started to build about 25 years ago. I never finished it. It was much more difficult to get affordable motion control components back then. rc-table1.jpgrc-table3.jpg

[Gary Hair]

That's one beautiful machine! Just one question - why did you go with a single drive on the X axis? I would be very concerned about racking when you are at the extents of the Y axis.

[George Carlson]

The drive is for driving the stage, the linear bearings are for alignment. If you have two separate steppers driving two lead screws, and rely on the leadscrews for alignment, it is unlikely that the stage would ever be square. This is because there is no guarantee that both stepper motors will step the same way at power up. I've seen machines designed using the dual lead screws and steppers, but it is usually done to save money on quality linear guides, not for precision. There's an old saying, "The man with two watches never knows what time it is." Using a single stepper and a drive belt to synchronize the leadscrews is actually a better than two steppers.

[George Carlson]

It's finished. I made a "Catch and Release" sign for out neighborhood lake this morning. There's still a little tune-up that needs to be done to Mach3, but that should be easy. The screen is an ELO touch screen, so I shouldn't have to use the keyboard very often. The electronics (including computer) are in the cabinet at the end. The cabinet is pressurized with air drawn thru the large automotive filter under the cabinet. I did this with my last machine, and the electronics has stayed clean for the past year.
finished.jpg

The table is 56x31.5". The travel is 48.5x27x5". I am currently using a 1.5KW spindle. I may change this out for a 2.2KW unit in order to get the larger collet size. Notice the vertical table on the end. The gantry can be repositioned so that it over hanges the end. This will allow me to cut dovetails and do other work on the ends of a board. I've never seen this on a CNC Router before.

[Scott Shepherd]

Looks great George! Well done. Just a word of caution- careful with that touch screen. We don't run Mach 3, so it might be different, but with the Shopbot, when it's running, if you touch any key on the keyboard, it stops the machine and retracts the Z axis. I put a touch screen in and thought I'd be thrilled with it until I opened the doors in the spring and flies came on. They were attracted to that thing like a magnet and every time they'd land on the screen, it would stop my machine! I put a fan in front of it to keep them off, but after a very short time, I removed it. Stupid flies

Your machine might not stop when touched, but they WILL land on spots on your screen that do matter, so be careful.

[Jim Underwood]

Wow. That's a nice build.

[George Carlson]

When running Mach3, it is common to switch screens to watch different parameters, so Mach3 is not sensitive to key entries (except for space and esc). Touch screens can be purchased with different technologies depending on your needs. This screen uses SAW, surface acoustic wave, technology. It requires a pretty firm press. The resistive screens behave much the same. But there are IR scanned screens that would certainly pickup a fly. You could do some interesting artwork in the MDI (teach) mode.