Steel Gantry Wood Router

[gavztheouch]

Hello

This is to be my first attempt at building a cnc wood router, Ive been looking to buy a router for a couple of years now but I decided it would be more fun to build one.

Budget is around £2000 with £1000 in reserve.

Not sure if I should use extruded alu for the chassis or go for an all welded steel structure.

Linear bearings will be linear profile rails or supported round rail. Linear profile rails are going to be a good bit more expensive. What are the benefits over supported round rails?

Single drive rods for x,y and z

To be continued...

[acondit]

I would definitely suggest reading through this thread by "Haydn" before you get too far in. There is also one by "oneyaker". These two are probably the best steel router builds that I have seen.

I think that part of the decision whether to build using steel or aluminum extrusion depends on your plans for using the router. I would think that the steel built router could end up being more accurate than the aluminum router, but if you only need +/- 0.010 either is going to be fine. If you are trying to build to achieve +/-0.0005 repeatability like "oneyaker" then I would say steel is probably the better solution.

There is also the question of what you are planning to cut. If you think you might occasionally cut aluminum but mostly wood or mdf type things, aluminum would probably serve fine. If you think you will cut mostly aluminum and occasionally steel, then I would definitely be looking at steel construction (and possibly a mill instead of a router).

I started a welded steel construction router and I wish that I had gone for bolt together construction instead. I got the table built to fairly precise standards but I stopped and built a mdf router to learn more about the whole cnc process before finishing the steel construction router. When I finish the reconstruction of my current mdf router, I may actually cut the steel router table apart and rebuild it using techniques like Haydn used.

Alan

[gavztheouch]

Thanks for the links Acondit, It was after seeing Haydn's machine on youtube that I decided to go down the diy route. I was looking for some info on that machine I should be busy reading up on it tonight

I am concerned about keeping the whole machine square and true, espically with the heat from the welder distorting the frame.

I have access to a large metal cutting laser cutter so that is an option for some of the parts, however its not cheap and may tip me over my budget.

Im not bothered about cutting steel, alu would be a bonus but not my intension, so if i could but wood with reasonable accuracy I would be chuffed.

Anyone else based in Scotland?

[acondit]

Look at my website, go to the Sitemap, click on the link to CNC Router2 (Steel Frame). You can see how I used a precision cast iron angle and a couple bars of 3/4" aluminum to clamp the corner square before welding. However, I would do basically the same thing on a bolt together epoxy bedded joint. I used a machinest's level 0.0001"/10" to level the top rails to insure that everything was not only square but in the same plane.

Alan

[gavztheouch]

After costing up the various parts I decided to buy an old secound hand machine off ebay and retro fit some new electronics. Took delivery of the machine yesterday evening, its an Autograpth Multicutter large bed router ( 4m * 3m) with a vacuum bed and coolent system. Its big downfall is the electronics it was made back in 1988 so a new control system is prob going to be needed, to make it a usefull machine. The z-axis is pneumatic so I plan to convert that to ball screw.

The X and Y axis are both rack and pinion, does mach 3 support a mixture of Rack and Pinion and ball screws?

Pics to follow...

[gavztheouch]

Flatpacked Table

[gavztheouch]

Y axis

[johnmac]

Mach doesn't care. It simply uses steps per unit of measure (metric or inches). You will need servo or stepper drivers that accept step and direction signals (like Geckos).

John

[gavztheouch]

Thanks John, the drivers, servo motors and encoders are almost 20 years old, I can't see myself being able to encorporate them into my mach 3 system.

Would I be able to scrap the old drivers and still use the servo motors and encoder with the geckos.

The motors are made by WestAmp, the model number is MT233 (Eight wires)
The encoder is made by Dynamic Research Corp, Model number: 25-F010-B06-2048-AXZ0







Drivers and Power supplies

[gavztheouch]

What do you guys think about these drives, any good for my motors?

http://www.granitedevices.fi/index.p...vo-drive-vsd-e

[johnmac]

8 wire motors? Are you sure they are servos? They kinda look like servos in your picture, but I've seen 8 wire steppers with encoders.

John

[gavztheouch]

8 wire motors? Are you sure they are servos? They kinda look like servos in your picture, but I've seen 8 wire steppers with encoders.

It may be that all the connectors on the machine are standard and there may not be 8 wires behind the 8 pins on the socket, I shall check it out tommorow. What is the common number of wires for a servo.

Gav