Steel Gantry Wood Router

Hello :rainfro:

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...

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

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?

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

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...

<center>
<a href="http://s59.photobucket.com/albums/g282/Gavztheouch/?action=view&current=Tablemain.jpg" target="_blank"><img src="http://i59.photobucket.com/albums/g282/Gavztheouch/Tablemain.jpg" border="0" alt="Photobucket"></a><br /><br />
</center>

Flatpacked Table

<center>
<a href="http://s59.photobucket.com/albums/g282/Gavztheouch/?action=view&current=Yaxis.jpg" target="_blank"><img src="http://i59.photobucket.com/albums/g282/Gavztheouch/Yaxis.jpg" border="0" alt="Photobucket"></a><br /><br />
</center>

Y axis

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

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

<center>
<a href="http://s59.photobucket.com/albums/g282/Gavztheouch/?action=view&current=P1030659.jpg" target="_blank"><img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030659.jpg" border="0" alt="Photobucket"></a><br /><br />
</center>

Drivers and Power supplies

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

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

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

Quote:

---

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

I don't have any experience with servos, but I think there are only 2 for the motor, and 4 for the encoder. Thats the reason I questioned the 8 wires. You may be correct about the unused pins.

Looks like your going to have a nice machine.

John

Just checked my motors, I have 5 wires on the motor (2 black 2 red and 1 earth) and 6 on the encoder? Is there any reason these motors and encoder will not work with the Granite Devices driver (VSD-E) or a similer Gecko Drive

I don't know anything about the Granite product, but you can download a PDF of the Gecko driver at their web site www.geckodrive.com. You will probably need to know which wires do what on the encoders.

The only reason I know anything at all about servos is I have given some thought on changing my steppers to servos. :confused:

John

Ok, it appears that Both Gecko and Granite devices are both limited to 80v while my motors are 140v. :violin:

Due to the weight of the machine im not sure I would get away with smaller motors that would run at 80V?

Could I gear the motors down to make the load easier and half the max speed?

Managed to test both motors with a 12v battery, so far so good they both turn smoothly.:)

Next step is to test the encoders then directly mount them onto the shaft at the rear of the motor. The flanges on the encoders are much to big too fit the mounting bracket on the motor so I will need to make up some reducers mounts to make them fit. The challenge is going to be keeping the two shafts running parallel with each other.

Luckly the two shafts both measure 6mm which seems to be a common size and couplings seem to be easily found, although prices seem to vary massively like $140 for a 6mm to 6mm coupling?

Will these Maplin brass coupling be up to the job? Its the brass inline connectors on the link below.

http://www.maplin.co.uk/module.aspx?moduleno=9335



Video of the motor test.

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/f2l6Jqs8_M8&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/f2l6Jqs8_M8&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

Here are some more pictures of the machine, now semi built in my own workshop.<br />
<br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030696.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030695.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030691.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030690.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030689.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030688.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030687.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030686.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030684.jpg" border="0" alt="" /><br />
<img src="http://i59.photobucket.com/albums/g282/Gavztheouch/P1030682.jpg" border="0" alt="" />

This machine was finished shortly after the last post in this thread. I have been running it with a 2hp bosch router and granite device servo motor drives.

I would like to upgrade my old router for a second hand spindle in the 5hp range. How flexible are spindle motors in terms of coupling them with various different VFD's. Will most VFD's power any spindle or are they specificly built for each other. Im am assuming kw ratings need to be matched or at least the vdf can not be rated higher than the spindle.

Cheers

The VFD can be rated higher than the spindle, as you tell the VFD how much current to supply.
As long as the frequency and voltage match, it should most likely work.