On 2014-03-18 01:15, David Bagby wrote: > On 3/17/2014 2:46 PM, Gene Heskett wrote: >> On Monday 17 March 2014 17:23:05 David Bagby did opine: >> >> [snip] >> >> This is not anything that I have ever played with. Why? Because I do the >> majority of my TLO's via a probing touch, and set the corresponding G55-56- >> etc co-ordinate system. > Not to quibble, but just FYI what you described is resetting the Work > Coordinate Z0 location after measuring a tool. > Moving Z0 is really setting a WC offset value for Z. > > That's not the same as setting a TLO value and using G43 to get TLO > compensation done in the control logic as MC moves are converted to MC > moves. > > Both may end up doing what you want depending on how you run the > machine, but they are two separate mechanisms. > > I've noticed over the years that I see guys with wood routers shift Z0 a > lot - they have no clue or desire to know what TLO values or tool tables > or H (or D) registers are or why they'd want to use them. > The opposite tends to be true of mill users - trained machinists learned > about TLO values and tool (D and H) compensation and don't get why > anyone would think of shifting the WC offsets for Z instead.
I have a feeling there are many more untrained machinists using milling machines these days. Most people, I know, including myself, use the Z0 offset manner to work with. The main reason is that many machines do not use fixed tool holders or the user does not have many tool holders and the tool is replaced almost every time it is used. So the offset in the table is pretty much useless. The easy way is to just reference that tool to the material and zero Z there. You will find this is a very common way of working and I do agree with your comments about G43 in general. The choice to use G43 must be that of the user. >> With the lack of a precision tool length to my >> morse tapered collet set, setting a tool length in the table is a total >> waste of time even for collared tools, so I only set the tool radii or >> diameter. >> >> There are quite a few ways to skin this cat in LinuxCNC, but marrying the >> TLO setting of G43 into the tool table value just because you did a tool >> change is not a universally good idea. If you want to use it, and have the >> tool mounting precision to make it work, then put the G43 as the next >> operation after loading the new tool, before lowering it to go back to >> work. >> >> Now, if someone wants to play with the tool table, I can see a lot of >> advantageous utility in making the tool pocket number into a string, like >> ".250in end mill", "3mm end mill" or "5/16in drill" or "Num68 drill", >> something along those lines. >> >> Cheers, Gene > > ------------------------------------------------------------------------------ > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and their > applications. Written by three acclaimed leaders in the field, > this first edition is now available. Download your free book today! > http://p.sf.net/sfu/13534_NeoTech > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > -- Regards /Groete Marius D. Liebenberg +27 82 698 3251 +27 12 743 6064 ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/13534_NeoTech _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
