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New Rotary Axis Build

Posted: Sat Nov 26, 2016 2:16 pm
by Mtw fdu
Not sure if this is the right place but administrators please change if necessary.

After a long time thinking and working out how to do this I decided to go ahead and build a rotary axis. Here are some pics.

The first pic is the main plate with the necessary holes for bearing housings and it is mounted to my table at the end.

The next pic is the main plate with a bearing and housing in place.

Next pic is the back of the main plate with all hardware less an XL pulley and belt (waiting to arrive in the mail).

The last pic is my chuck mounted only on a shaft for demonstration purposes. I will be machining a piece of 100mm shaft down to 20mm most of it and also incorporating a backing plate for the chuck.

Need to acknowledge some of you guys for the help I have received.

Jester Thanks for the ideas and pics you sent. Now working with my cnc guy and everything is running now to plan...Cheers!

More pics to come soon.

I will be using my existing Y axis motor connected with a belt and XL pulley to the top shaft and this will be connected to the bottom shaft with a sprocket and chain.


Mtw fdu.

PS My table is only 600 x 600mm (cut table). My tube cutter will only allow up to 500mm length of tube. This is ok because I do not intend to do anything "big" on my table.

Re: New Rotary Axis Build

Posted: Sat Nov 26, 2016 10:54 pm
by Brand X
Good job, keep posting updates. Always interesting to watch a build of someones own design.. Good ideas come out of them for everybody.

Re: New Rotary Axis Build

Posted: Sat Dec 03, 2016 1:24 am
by Mtw fdu
Thanks for your comments Brand X.

Did some more to it and here are some pics.

The first pic is the piece of 100mm shaft material I used for the chuck backing plate and shaft combined.

The second is the shaft machined down to the 20mm I need.

The third is the chuck bolted to the new backing plate and shaft.

The fourth and final pic is the chuck mounted on the backing plate and installed on the bearings.

Should have the rotary axis running tomorrow. Will post more pics and a video of it turning without any cutting.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Sat Dec 03, 2016 5:06 am
by Mtw fdu
1 thing I forgot to ask is how do you earth the rotary axis? Also how do you earth the material being cut? Thinking that the earth lead from the plasma machine will get wrapped up if continuously going round and round.

Thanks in advance.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Sat Dec 03, 2016 7:26 am
by exapprentice
Hi Mtw fdu

Take a look at this video:
https://www.youtube.com/watch?v=d2fscbLNtGU

at about 0.44 seconds in will give you some ideas ;)

Re: New Rotary Axis Build

Posted: Sat Dec 03, 2016 12:22 pm
by acourtjester
I use a flat braided battery cable on mine.
MDF blank supports for tubing cnetering (2).JPG

Re: New Rotary Axis Build

Posted: Sat Dec 03, 2016 4:13 pm
by Mtw fdu
Thanks exapprentice and acourtjester.

Can you show me the other side of that pic you sent please acourtjester? Thanks in advance.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Sat Dec 03, 2016 8:53 pm
by acourtjester
it is hard mounted to the frame so it is also hooked to the plasma return wire (work return wire).
The spring is used to hold tension on the flat braided cable in both directions of rotation.

Re: New Rotary Axis Build

Posted: Sat Dec 03, 2016 9:26 pm
by Mtw fdu
Thanks Jester.

Did some more and got it running. Here are more pics and a video.

https://www.youtube.com/watch?v=HxO4wG-w4J0

Mtw fdu.

Re: New Rotary Axis Build

Posted: Thu Dec 08, 2016 10:09 pm
by Corfabrication
dang, that was some lathe time there.

Re: New Rotary Axis Build

Posted: Fri Dec 09, 2016 12:38 pm
by _Ogre
Mtw fdu wrote:1 thing I forgot to ask is how do you earth the rotary axis? Also how do you earth the material being cut? Thinking that the earth lead from the plasma machine will get wrapped up if continuously going round and round.

Thanks in advance.

Mtw fdu.

we use our table mostly with the rotary head for exhaust tubing
this is how i did our table similar to acourtjester, the other end is attached to a spring
as long as the chuck is tight there is no arcing on the internal parts of the chuck :mrgreen:

Image

we have a ground lug welded to the water pan and work clamp
main ground to a buss bar that has all the earth grounds attached

Image

Image

Re: New Rotary Axis Build

Posted: Fri Dec 09, 2016 1:12 pm
by Capstone
I'm curious if you've gotten far enough in the process to test backlash. It seems from the video that with the heavy chain and gear reduction there's an audible "ka-chunk" that sounds like slop. Hope that's not that case and we'd like to see cutting vids too.

Thanks

Re: New Rotary Axis Build

Posted: Fri Dec 09, 2016 2:40 pm
by Mtw fdu
Corfabrication. Yes that was a lot of machining which had to be done. I took my time with it so I didn't have to start with a new piece.

Ogre. Thanks for your info.

Capstone. That "ka-chunk" is backlash. I still need to make a tensioner for the chain. Have been waiting for my cnc guy with the next step of info he needs to finish my rotary "profile" so I can start cut testing parts. I needed to get as much as I have done so I could tell him what distance a full revolution of the chuck was. I tensioned the chain by hand while rotating with the jogging and it came up to be 50mm.

Will post more video and pics when I get to the next stage.

Thanks again guys.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Fri Dec 09, 2016 2:50 pm
by acourtjester
I did not see any backlash with mine but I did use a smaller chain (#35)
https://www.youtube.com/watch?v=mDO9sx8NiPA
https://www.youtube.com/watch?v=rz7nVt1EvX0
spindle alignment (7).JPG

Re: New Rotary Axis Build

Posted: Thu Dec 22, 2016 3:43 pm
by Mtw fdu
Still waiting to get my "profile" from my cnc guy. Can't do anything until I have this.

He is now starting to annoy me with false promises of sending it to me. :x :x :x

Mtw fdu.

Re: New Rotary Axis Build

Posted: Mon Dec 26, 2016 8:07 pm
by Mtw fdu
Jester...or anyone else that may know...

Somewhere in Mach 3 there is a chart to use to convert steps per mm/inches from flat plate to round tube. I cannot find it so can someone please point me in the right direction? Thanks in advance.

I am still having trouble with my cnc guy not sending me my profile so I need to do it this way.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Mon Dec 26, 2016 11:36 pm
by motoguy
Mtw fdu wrote:Jester...or anyone else that may know...

Somewhere in Mach 3 there is a chart to use to convert steps per mm/inches from flat plate to round tube. I cannot find it so can someone please point me in the right direction? Thanks in advance.

I am still having trouble with my cnc guy not sending me my profile so I need to do it this way.

Mtw fdu.


Here:

https://www.machsupport.com/forum/index ... ic=16260.0

or here?

http://www.machsupport.com/forum/index. ... 315.0.html

Re: New Rotary Axis Build

Posted: Tue Dec 27, 2016 1:59 am
by Mtw fdu
Thanks motoguy.

This is what my cnc guy sent me about 2 months ago.



1) Switch the Y motor output pins to the A axis output pins

2) insert the Y motor tuning values into the A axis

3) Make sure that A is set as rotary

4) change the A steps per so that you get an acurate angular movement - IE
360 degrees = 1 rotation

Go to this website and download Gcode ripper

http://www.scorchworks.com/Gcoderipper/gcoderipper.html

make the gcode for your part in Bobcad

Open the Gcode in Gcode ripper

Convert to rotary



Is this another way of doing it as well?

Thanks.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Tue Dec 27, 2016 11:22 am
by acourtjester
personally I go for the simple method I switched my X motor cable (X on my table) to the rotary stepper motor. Then ran the axis calibrations on the tube diameter I would be cutting with a paper taped around its diameter to calculate the distance moved by the X axis.
Remove the paper and cut the tube perfectly.
I’m no rocket scientist but I did work at the Kennedy Space Center many years ago. :lol: :lol:

Re: New Rotary Axis Build

Posted: Tue Dec 27, 2016 1:02 pm
by tcaudle
With an extra motor and driver and the Rotary XML, screens and POSTS the software does all of that for you . There is a calibration macro with screen inputs to get the correct ratio for the rotary axis. Then you just input in the Screen the pipe diameter and it does all of the calculations . Its all done in linear units and not degrees of rotation. You lets you draw the shapes in 2D and it (mathematically) wraps the 2D around the pipe for you

You can also look at the Rotary Plasma Plugin for SheetCAM. The way you do the rotary and drivers is up to you . It defines "A" as the defautl rotary but you can change it in the POST to be another axis. Having the extra motor and driver affords you the option to do square tube cutting too.

Re: New Rotary Axis Build

Posted: Tue Dec 27, 2016 4:39 pm
by Mtw fdu
Thanks guys for your input.

I decided to use my existing y motor axis to run my rotary because it was the cheapest and easiest way to go. I cannot get in touch with my cnc guy as he is not answering any emails or telephone messages so it looks I am going to have to wait until he decides to do the right thing and send my profile. That way he has done everything that needs to be done.

I just thought I could do the adjustments but it still seems complicated to me to tackle it.

I will keep you guys updated as I go.

Thanks again.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Wed Jan 04, 2017 4:43 am
by Mtw fdu
Did a little bit more to my rotary axis.

Cut and installed a chain tensioner to the top and bottom shafts as well as mounted my earth cable (braided copper) to the chuck shaft for earthing it together.

Still have not yet heard from my cnc guy.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Tue Jan 10, 2017 7:11 pm
by Mtw fdu
Finally...I got my profile from my cnc guy.

Will do all the change overs and setting the ports and pins and motor tuning over the next few days and will post up some results after testing. And some more video as well.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Wed Jan 11, 2017 5:50 am
by Mtw fdu
Had some spare time to work on my rotary axis.

Have done everything to setup Mach 3 apart from how do I make sure A is set as rotary? Do I just make sure it turns when it is suppose to or is it more complicated than that. I am going by what my cnc guy sent me a few posts up (Number 3 on the list).

I will be testing tomorrow (Australian time).

Thanks in advance.

Mtw fdu.

Re: New Rotary Axis Build

Posted: Wed Jan 11, 2017 10:41 am
by acourtjester
Why not setup a separate Mach 3 profile for the rotary operation so when you want to use it you would just start that profile.
Any changes in steps or speed could be in the separate profile.