EMC2 Axis Manual Tool Change

[tomdoyle]

Hi,

I have a bit of a problem with manual tool changes. The program stops at the M6 and raises the Z axis as it should. I would like to be able to use manual control to establish the zero point for the the Z-axis with the new tool. While Emc2 is waiting for the tool change it does not allow manual control of the machine. The only way I have found to regain manual control is to stop the program - the problem here is that it restarts at the beginning of the program. I have added the axis_manualtoolchange.hal link described elsewhere on this forum. All it did was pop up a window with a check box to click when the tool is changed which was no help at all.

Out of desperation I loaded Mach 3 and it did return manual control for tool changes. It also poped up a little box with a warning when it was about to return to the previous location.

thanks,

tom ...

[samco]

You are right. You cannot jog the machine while g-code is paused. This has come up a few times. I don't know How much of a change to emc2 that would require to make possible.

The only thing I can propose is using the tool table and a tool setting switch. You would only have to set the first tool.. Then the rest would be set by the switch.

this is a gcode sample.
http://cvs.linuxcnc.org/cgi-bin/cvsw...e=text%2Fplain

sam

[tomdoyle]

Thanks for the reply. The linux folks have always been more interested in the esoteric aspects of systems so a simple but very important thing like this will probably never be fixed.

tom ...

[samco]

As emc2 is an open-source project.. Patches are always welcome.

sam

P.S.

Others have mentioned
- putting each tool in a different g-code file.
- using 'run from line'

[Dan Falck]

Tom,

What kind of tool holders are you using? Do they repeat when you do a tool change?

Dan

[tomdoyle]

Dan,

I am using ER16 collets in the ER16 spindle on my Taig mill. My work around has been to break up the generated gcode into sections using tool changes as break points.

I do not have an automated tool changer or something like the Tormach tool holders that maintain z when tools are changed.

Thanks to samco I "discovered" the set next line function which should eliminate the need to break the files into sections.

I am still a little concerned with stopping the program and re-starting it from another line. When the program is stopped do carry over codes like G54 persist. I know there were problems related to this when I was breaking the code into sections. Perhaps the program reacts to loading a new file by clearing carry over codes but does not clear them if the program is stopped then restarted from a new line.

All these problems would go away if it was possible to use manual control when the program was stopped/paused.

thanks,

tom ...

[unterhaus]

this does seem like a really nice thing to have, but it needs a programmer that really wants it to implement it.

[Dan Falck]

Tom,

I am lucky enough to have a Quick Change 30 taper tool holding system on my Bridgeport. I can set all my height offsets and then run through the program and just change out the tools (usually endmill holders) with the program paused. I don't have to do any touching off in the middle of the program, because the holders have good repeatability.
You might be able to attach stop collars to some of your cutters to maintain a consistant height offset, if you're having to slip end mills in and out of your ER collets.

Dan

[tomdoyle]

Thanks for the idea of collars on the mills to try an maintain a constant Z tool level. There is another problem with no manual control during pause - A tool breaks or an insert fractures. You hit pause - the spindle is now down and you want to change out the tool and restart the program. Quick change tools with constant Z height will not help as you can not get the tool up out of the work to replace the tool.

Long ago I read that some of the development of EMC was done on etch-a-sketch pads with steppers attached. At the time it seemed to me like a great idea for a low cost trouble free way to debug machine control software. Perhaps the lack of the need for tool changes or broken tools on the etch-a-sketch caused this important function to be overlooked.

[Dan Falck]

Tom,

If you break a tool, then of course you will have to touch off a new one. You need will need to start the program at the appropriate line number to catch back up to where you were. That's how it's done- even on big commercial machines. We have a bunch of vertical machining centers at work (with Fanuc controls) and that's how it's done, when needed.

"Long ago I read that some of the development of EMC was done on etch-a-sketch"

That was just an toy that someone set up for fun. EMC was originally developed by NIST in conjunction with General Motors on a huge horizontal machining center. It has real industrial roots.

If you really have to have this feature, you could look at the source code or maybe hire a programmer to do it for you. Personally, I would just stick with the 'start at line number xxx' and make sure that the G-code program is in a safe spot to use this feature (ie make sure the spindle is at home and you're not going to run it through a fixture or vise).

Dan

[forsalesticker]

Originally Posted by Dan Falck I would just stick with the 'start at line number xxx' and make sure that the G-code program is in a safe spot to use this feature (ie make sure the spindle is at home and you're not going to run it through a fixture or vise). Dan

So I am new to EMC and can't figure out how to get it to 'start at a certian line number. Does someone have instructions on how to do this?

Here is what I am doing.

EMC2
hobby level gantry CNC router (that the chicks definitely dig)
wood router and router bit
3d surfacing operation


so the bit is going back and forth again and again and the gCode is many thousand lines. So I sometimes need to stop the process - and I want to know how to move to a certian point in the file and start cutting from that point. Is this possible?

[Alexthehun]

Simply highlight the line of code where you want to continue and rightclick: you will get the option "Run from here"....