On 14 May 2013 15:38, Daniel Rogge <dro...@tormach.com> wrote: > Say I've got a drawing of as shaft with two diameters. Diameter 1 is 20mm > +0.0/-.03mm. Diameter 2 is 30mm +.03mm/-0.0mm. If I want to hold the > tolerances using only one tool, I need the ability to apply two different > offsets to the same tool.
There are other ways to do that, though not Fanuc-ways. One option would be to have two different tools in the same "Pocket" with the same Geometry and different wear. This isn't actually possible in LinuxCNC at the moment, as it enforces one tool per pocket, and doesn't understand wear at all. > G43 isn't an accepted Fanuc lathe code, so if you want programs to be > compatible across LinuxCNC and Fanuc machines, you won't be using G43 to > apply two different offsets. I only mentioned G43 for comparison. When using G43 H you have the choice of using a dummy tool or a real tool as the place that the offset comes from. The offsets are not additive in that case, though. > The only reason the wear offset appears to be a 'dummy tool' is that we > happen to store it as a tool due to limitations of NML and the LCNC tool > table. I thought about hijacking U and W offsets for wear, or adding new > fields, but this seemed the most minimally invasive option (and it still has > generated a lot of pushback from the developers!). I'm all for not gobbling > up half the available tools to store wear offsets, but I think it should wait > until the table/NML restructure. My concern at the moment is to not paint ourselves into a corner now, with an eye to the future restructure. If the tool data moves into a key-value store (such as Redis, which was one suggestion) then it would be possible for an one tool to have multiple wear offsets. (which would settle your multiple tolerances issue) In fact, the issue then becomes one of deciding what a tool _is_. I suspect that the answer is that the "tool" is only the number that appears on the "tool-selected" pin, and the pocket is only what appears on the "pocket-selected" pin. I can think of reasons that you might want multiple tools in the same pocket (gang tooling) , and multiple pockets with the same tool (duplicate tools at optimised positions in a long tool chain). I am not sure what the default behaviour would be for choosing which pocket number to broadcast in the duplicate-tool scenario, and in that situation you would probably want the wear offsets to be instance-specific. (And, in fact, it may be too intractable an issue to consider, and better handled by having physically identical tools with different tool numbers) Personally I don't mind this patch going in now, as the whole thing will hopefully be replaced relatively soon. But I would hate for us to have to compromise the new system to suit the limitations of an old Fanuc control. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ AlienVault Unified Security Management (USM) platform delivers complete security visibility with the essential security capabilities. Easily and efficiently configure, manage, and operate all of your security controls from a single console and one unified framework. Download a free trial. http://p.sf.net/sfu/alienvault_d2d _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
