| Barry's misc CNC stuff
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I've always wanted a CNC mill / router even before they existing commercially.
With the desire to automate my prototype PCB drilling I hooked up a Digital Group Z80 system to some steppers in about 1979 but never got good slides or ball screws.
Many other life driven things distracted me from going further at the time. Also AutoCad had not been invented. On May 9, 2005 that changed when a buddy who has wanted my big TIG welder finally wore me down. I knew that he had a PC Board router frame and motors so I started pushing him. He finally said something like "I don't really want to get rid of the PCB machine but I've got this gantry with steppers..." so we traded. | |||
 gantry and computer2.JPG | |||
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The gantry is a solid commercially built (techno-isel) system with cast verticals and extruded aluminum t-slot deck and frame.
The work area is about 12 X 12.
It has good slides and ball screws driven by steppers (yuck on the steppers)
(I have servos and Gecko drives waiting anxiously for installation)
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 stepper power supply.JPG | |||
| The electronics were late 1980's vintage in a nice rack mount box.
It had a built in processor with some off-the-wall language.
My buddy had some command line DOS software that he tried to demo and it didn't work.
So after rolling the welder out and sending him on his way I ripped the cover off the box to find a full length 16 bit XT style board mounted inside.
Inputs came from outside terminal board from a 50 pin ribbon cable.
The outputs from the CPU also went by a 50 pin ribbon to a motherboard that the three stepper drivers plugged into.
I removed one of the motors and took the box, motor and cables upstairs to the electronics lab.
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| With a little snooping around I found the signal lines to the drivers. Step and direction as suspected.
Applying a signal from the generator ran my one axis motor.
A little more studying revealed that if I plugged the mother board cable into the terminal block cable,
all of the signals that I needed to run the machine would come out on th back of the box ! (not in a real neat order, but routed to Weco screw type terminals !)
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 re-wiring.JPG | |||
| In preparation for the receipt of the XYZ machine or thinking about putting motors on the Bridgeport I had been looking at CNC programs that run on the PC.
I had messed with TurboCNC which sends it's signals out the parallel port. So I hooked the obvious together and went back to the basement.
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 TurboCNC.JPG | |||
| Within about an hour I had G-code driven XYZ action.
Another hour had the acceleration tuned and a Dremel mounted (well, sort of mounted) on the machine.
Some double sided tape, a hunk of aluminum sheet and I was making chips!
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Since then I've milled the side off of a RotoZip and made a little more solid mounting. Because with TurboCNC I had random slew of the tool to the extremes after a program break (and it was a DOS program), I changed the control program to DeskCNC with the 2nd Generation controller. | |||
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I needed to test the airflow in a pump project that I'm working on so I drew a few grills in AutoCad and exported the dxf files to cut them out. After having success with PCB material and plexiglas, I also made one up out of aluminum. | |||
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Naturally, I've used the machine with solid carbide PCB bits to route and drill PCB's. | |||
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Under the title of "kids don't try this at home" I've also cut some small steel parts on the machine. I used my water bottle to provide coolant and chip removal but I probably won't do much more steel on this machine as 30,000 RPM is a little fast and a coolant system is not in the picture for the future of this poor little thing. | |||
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Now that I have the system worling well I use it for all kinds of cutting jobs. Below I'm cutting and scribing some tubing to make up some PCV clips. I still don't have a good way to get 3D profiles into G-code. | |||
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I had the small cover part made by Laser SL out of Somos. Since I have a model part and .stl file, I'll be working on perfecting a system to make it's duplicate on my machine. For this prototype, I modeled the cover, clip and PCB assy in IronCAD (I know it's odd, but its FAST) | |||
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- - - more to come - - - |
