Messages

671

General Mach Discussion / Re: Set Z to zero automatically?Auto tool zero questions

« on: March 31, 2008, 04:55:59 AM »

Hi to all,
I've been following all the developments on this post and have one question about an option that I have not seen yet. Is it possible to call this macro for zeroing the Z axis by means of pushing a pre-programmed button on the device (pendant, joystick, MPG or what have you) that it used for jogging or fine posisioning? Also along the same lines - Could the same be applied for calling the "video window" (from the PlugIn Control) which is used to center the cutter in the X and Y axii? I'm not much of a guru in this area so pardon me if I'm talking nonsense.
Regards
Marten

G'day Marten

Yes the "Auto Tool Zero" script can be called via a Shuttle Pro.  Mach has a plugin for this device.

As far as Joysticks etc.  There are plugins available but I have not used them.

Also any device that uses "KeyGrabber" will do it.

I don't know if the Video Window can be activated by a button press.  I have not tried to do this.

Greg

672

General Mach Discussion / Re: Backlash compensation for a rotary axis ?

« on: March 29, 2008, 07:27:37 PM »

As far as backlash is concerned, I don't know if Andrews program keeps the axis as a rotary axis or converts it to a linear one.

Yes Andrew's little conversion program uses degrees.  It does not simply convert to  linear code.  So as you say the backlash setting stays constant at different diameters.

In my one test so far I set Backlash Speed at 100% and Shuttle Accel. at 0.01 seconds.  I have no idea why it is called "Shuttle Wheel Setting"

Greg

673

General Mach Discussion / Re: Backlash compensation for a rotary axis ?

« on: March 29, 2008, 05:37:32 AM »

I finally got some shed time today so I knocked up a motor mount for the little stepper I temporarily pinched of another machine.

Keen to give it a go I clamped it very dodgy like to the table and "What do you know....It goes!!!!!"

Had to dial in 0.225 degree back lash compensation in Mach3. That amounts to about 0.1mm or 0.004" backlash at 50mm diameter.

Too much backlash to live with but the compensation seems to work OK so far.

I've never done rotary axis stuff before so for a test I used a great little program that bloke called Andrew wrote.

See this link, http://vectric.com/forum/viewtopic.php?t=2920

It takes a gcode file that you have created in 2D and converts it to a rotary axis. Works great.

Anyway as you can see in the pics it all sort of worked as expected. Not bad for a first try.

So I think on the strength of that first try the gearbox should be OK and I will go ahead and set it up properly and make a tail stock for it.

I also need to make another screen set to suit rotary axis work.  Maybe this one will be in flash. 

Greg

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674

Mach SDK plugin questions and answers. / Re: Shuttle Xpress Problem

« on: March 21, 2008, 03:50:00 AM »

You may have already done this.

Delete the plugin and redownload and reinstall.

Greg

EDIT:  I read your post a little more carefully. 

The centre wheel defaults to incremental.  This was changed to be this way after a few of us users requested it.

If you want to use centre wheel as continuous the you need to assign one of the buttons to select continuous/incremental.

My self I can't see the need as the outer wheel already does this.

675

General Mach Discussion / Re: help with auto tool zero macro

« on: March 13, 2008, 05:42:27 AM »

The thing about this zero routine is that you need to adjust the plate thickness to fine tune it.

The measured thickness of the plate is just a starting point to the fine tune.

So with that in mind the line referred to is not needed anyway.

The adjustment of plate thickness is the reason that I have a "Plate Thickness"  DRO on screen.

Also I do not have, as some do, a "Probe Feedrate"  DRO on screen as I prefer this to remain constant.  One less variable.

Greg

676

General Mach Discussion / Re: help with auto tool zero macro

« on: March 13, 2008, 04:34:06 AM »

Whatda

That Zero Macro is the one I posted and is a variation of one that Scott originally posted.

It has been working for me and many others for some time.  Using Printer Port.

However I now have another machine using a NCpod instead of a LPT and it was not working.

Doing really weird things that made no sense.  Fixed it by removing the line that you referred to earlier.

Now working good on the NCpod.

So the moral of the story is that external pulsing devices do not always act the same as the LPT.

Greg

677

General Mach Discussion / Re: Backlash compensation for a rotary axis ?

« on: March 10, 2008, 09:23:47 AM »

Jimpinder

"Do I understand that this circular table, using the angular axis, will move to a new position, and then stand still whilst the other axis go to work on it."

That is not how I envisage using it. I'm thinking that it will rotate as one horizontal axis (X or Y) and one vertical axis (Z) move about.

However I will keep that bicycle idea in mind.

Greg

678

General Mach Discussion / Re: Backlash compensation for a rotary axis ?

« on: March 10, 2008, 02:21:14 AM »

Bill

I went ahead and made a spindle for it.

1" - 10 tpi  which is the size of my wood lathe spindle so my existing chucks etc will fit.

Only one ended though.  I will build a tail stock to suit if it works out.

I have not measured it yet but I think the backlash is going to be a lot better than I thought.


TP

I would not go to so much effort as to rebuild the bearing housings etc. 

For that much work I would go in a different direction. (Harmonic drive)

I'm definitely  not one of the big boys.  Just a carpenter. 


Hood

I have not delved into the backlash compensation settings yet but I will get to that. 

Greg

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679

General Mach Discussion / Re: Backlash compensation for a rotary axis ?

« on: March 09, 2008, 04:51:29 AM »

No mine is just a philosophical viewpoint.

I am not really anti  Mach's compensation, just software compensation in general. (Although I have read a lot of users hassling with it)

In the type of CNC machines which I am interested in I believe mechanical design is the place to tackle backlash.

Just my opinion, not something I want to debate. 

Having said that, on this gearbox, mechanical measures are not practical so I might try it.

Maybe I will be so impressed as to change my opinion. 

Greg

680

General Mach Discussion / Re: Backlash compensation for a rotary axis ?

« on: March 09, 2008, 04:07:01 AM »

Thanks Jimpinder

I know what backlash is.

I would not consider Mach's software compensation a viable option for a linear axis.

But that's just my opinion.  Each to his own hey. 

Greg