Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: RandomCheese on June 07, 2011, 12:19:22 PM

Title: fixture specific soft limits
Post by: RandomCheese on June 07, 2011, 12:19:22 PM
I am using a small table CNC to make tags for the company I work for.  We have three basic sizes of tag and I have made a single fixture with depressions sized and shaped to hold the tags while they are being engraved.  It works fairly well.  Each location is stored as a separate fixture in the Mill profile (i.e. Fixture 2: G55, Fixture 3: G56, etc.) so this gives me a specific start point for the three most common tag styles we use.  I have to verify that the G-code maximums fall within the designated area for the tags to avoid running the tool into the side of the fixture each time I load a file.  This doesn't take much time and as long as I remember what the dimensions of the tags are, I'm OK.  Next step is to train someone else to use the machine and engrave the tags and I'm less confident in that person's attention to detail.  

I was wondering if there is a way to set up the soft limits so that if the programmed G-code exceeded the programmed dimensions of a particular fixture (or tag) Mach3 would warn the operator that the code exceeded the area available for engraving.  Each fixture could/would have it's own subset of softlimits within the larger set of overall table softlimits.
Title: Re: fixture specific soft limits
Post by: BR549 on June 07, 2011, 01:13:32 PM
OK  Lets see, IF each fixture is unique in location G55 G56 G57 etc AND the fixture is called by the program file G55 G56 G57 etc HOW could it go wrong.

The only way I can see it going wrong is the Operator uses the WRONG fixture number and that is impossible to guard against. You could create a macro the REMIND the OP that the Operation requires the use of TAG styleXX and  fixture #xx (based on what the current fixture # is) and IF he sees it does not match he can abort the operation and start over. It could even be made to acces a page that had the VISUAL picture of the fixture and required tag.

Just a thought, (;-)TP
Title: Re: fixture specific soft limits
Post by: RandomCheese on June 09, 2011, 03:23:21 PM
I don't think I expressed myself clearly.  The fixture locations are marked and programmed.  if the operator can't tell that he/she is at the right fixture, then there's no hope for them.   :)  I'm looking for a way to let them know that the program they've loaded won't fit the fixture they've selected.

The usable table size is quite small, 7.5" X 13.5".   These are set into the "soft limit" locations as there are no safeties on the mill at all.    Each tag-holding depression has a specific fixture setting that denotes the lower left hand corner of the tag as a starting point for that particular tag.  There are currently three fixtures programmed but there is room for and plans to create more.

ex:  Fixture #2 is a 1" X 3" rectangular tag depression .07" deep.  The offset is Xo .5 Yo 1.5 Zo -.355.  What I'd like is the ability to have the program warn me if I try to load G-code that falls outside of X 0.5 to 3.5, Y 1.5 to 2.5, and Z -0.425 when the offsets for fixture #2 are in place.  Fixture #3 is a complex shaped depression 1.75" at its widest point and 2.25" at its longest point, also .07" deep.  The engraveable portion of the tag is approximately 1" x 1.5".  the offset for fixture #3 is Xo .25, Yo 3.25, Zo -.355.  When Fixture #3 is selected/loaded, I'd like a warning if the programmed Gcode falls outside of X 0.25 to 1.75, Y 3.25 to 4.25 and Z -0.425.

Currently, the softlimit warning is only generated if the code compiled exceeds X 0 to 7.5" or Y 0 to 13.5"
Title: Re: fixture specific soft limits
Post by: BR549 on June 09, 2011, 06:32:08 PM
Are are the fixture locations on the table at the same time?? IS this machine dedicated to JUST this process ?

The best thing you could do is when the program is loaded then do an extents travel of the program code at SAFEZ height THAT will tell the OP IF his code exceeds the fixture capacity.

I do that all the time HERE for plasma work. I have a BUTTON that has code to take the program extents and slowly nagivate the table to each corner of the extents of the program code. That way I can be assured that the program will FIT the material on the table.

How do you create the Program code??? Hand coded or CAM. IF CAM just select a material size that represents the fixture size as background then the OP will SEE if his code runs outside of the box when they create the Program code.

IT may be possible to use the program extents to compare against the FIXTURE extents BUT that is just something the OP has to process and use. You would have to write a MACRO to add to the program so do the work AND IF the OP forgets to include the macro call (;-).

Just thinking out load BUT it may be possible to create a switch that when used would process the Gcode against the fixture extents and prevent you from running the code if it exceeds it.

Let me know IF i can be of help, (;-) TP

Title: Re: fixture specific soft limits
Post by: RandomCheese on June 13, 2011, 06:07:29 PM
So far, I've been generating code using the write wizard.  I've also run some tests using stickfont but I haven't found it to be substantially better for my needs than the included write wizard.  My needs are quite simple: text in a specified area.

The concept of a switch that checks the Gcode against the limits of a designated tag sounds like exactly what I'm looking for.  Unfortunately, everything I know about writing Gcode could be painlessly engraved in large block letters on my thumbnail.

I started this project off lookiing for a pantograph.  The Chinese mill and dedicated computer was much cheaper and quite a bit more versatile.  Unfortunately, when it comes to training someone to use it, that versatility translates directly into complexity and that makes training tricky.
Title: Re: fixture specific soft limits
Post by: BR549 on June 13, 2011, 06:46:24 PM
OK I'll whip up something and get back to you to try.

(;-) TP