workpiece touchoff getting lost (v2.6.4)

andypugh wrote: I don't think this is a bug, as such. More a wrong-assumption by the default F360 Post-processor.
On my machines (with repeatable tool holders, BT30) the code is correct and it works properly too.

is that because your machine has an auto toolchanger?

bschiett wrote: is that because your machine has an auto toolchanger?

Manual, but repeatable. So the tool-table is useful.

I still actually tend to run one program per tool, though.

Well, this is getting to be a repeatable problem, as far as i can see (and read), there are several posts on this forum, all pertaining to the same thing : fusion 360 !
Also, using other cam software is a must, but blaming Linuxcnc for errors caused by said software is a no no ( further up in this post and on several occasions on other posts).
Back on topic:
I do not use f360, but from what i gather here, the problem is in the f360, in that that you have done several passes for a job, with different tools, and if you always get the same 2mm error, i am sure of the above, as the second or third tool in the fusion360 is 4mm smaller or bigger in diameter set in f360 tool table for that job (roughing? fine? de bur?.
Please do check that, and let us know how it goes, as this is just an educated guess.
Regards,
Tom

tommylight wrote: Well, this is getting to be a repeatable problem, as far as i can see (and read), there are several posts on this forum, all pertaining to the same thing : fusion 360 !
Also, using other cam software is a must, but blaming Linuxcnc for errors caused by said software is a no no ( further up in this post and on several occasions on other posts).
Back on topic:
I do not use f360, but from what i gather here, the problem is in the f360, in that that you have done several passes for a job, with different tools, and if you always get the same 2mm error, i am sure of the above, as the second or third tool in the fusion360 is 4mm smaller or bigger in diameter set in f360 tool table for that job (roughing? fine? de bur?.
Please do check that, and let us know how it goes, as this is just an educated guess.
Regards,
Tom

Right now it's not sure where the problem is - it could be on the side of fusion 360 and its tool library/post processor, it could be on the side of linuxcnc having a problem with the particular sequence of g codes at the start of my program (m6 t1 and g43 related) ... or it could be myself who doesn't understand what the correct order is to load a program, do a toolchange and touch off.

I'm pretty sure my tool table has all the offsets set to zero, as I already checked that last week. I haven't inspected the table on the command line with vim but will do that just to be sure.

maybe the problem is that i do a tool change without first doing something like m6 t1 on the MDI prompt? up to now what i do is start the software, home the machine, load my program, touch off and start, and click continue when the dialog pops up asking for tool 1.

Just a thought: Fusion CAM does like to leave some material on the part for a finishing pass. You have to remember to clear that option if you are not using one.

andypugh wrote: Just a thought: Fusion CAM does like to leave some material on the part for a finishing pass. You have to remember to clear that option if you are not using one.

i am aware of that, I don't use finishing passes

i opened my tool table with vim on the command line - there are no offsets set for X, Y or Z:

T3 P3 D4 ;4mm end mill 25mm flute
T4 P4 D10 ;10mm end mill 25mm flute
T5 P5 D3 ;3mm twist drill
T1 P1 D10 ;10mm end mill 25mm flute
T10 P10 D10 ;10mm end mill 26mm flute/70mm shoulder/110m total
T11 P11 D2 ;2mm twist drill
T12 P12 D10 ;10mm chamfer tool 90deg
T15 P15 D4 ;4mm end mill alu 21mm flute
T14 P14 D4 ;4mm single pt thread mill 1.3mm flute
T16 P16 D4.2 ;4.2mm twist drill metal
T17 P17 D6.8 ;6.8mm twist drill metal
T18 P18 D1.8 ;1.8mm twist drill metal or carbide

Check the tool table in fusion360.

tommylight wrote: Check the tool table in fusion360.

This shouldn't be the problem unless Fusion has been told to apply tool offsets. (I don't actually know if Fusion can be told to apply tool offsets)

andypugh wrote:

tommylight wrote: Check the tool table in fusion360.

This shouldn't be the problem unless Fusion has been told to apply tool offsets. (I don't actually know if Fusion can be told to apply tool offsets)

I do not know that either, but it sure looks like it, and from the looks of it it is doing the first pass with a 6mm diameter tool and the second with 10mm, or vice versa, as it was not mentioned if the error was +2mm or -2mm.
Then again, all cam software have settings for tools and tool offsets and tool types.