Post does not output c axis rewind when using polar coordinate HAAS SL-20T

[Anonymous]

Hi Guys,

we have been struggling on this problem for a while and we really need a solution. here is the problem :

We are using adaptive contour to make a pocket in a shaft with our C axis live tooling on our SL-20T HAAS Lathe ( we are currently using the ST-15 mill/turn post-processor). The problem we have is that the post-processor does not generate a C axis rewind when reaching the C axis encoder limit. The only ways the post-processor can do it is if we do not use polar coordinate.  BUT (correct me if I'm wrong) I cannot have a cutter compensation if we use the standard C axis positioning...

your help would be much appreciated!

thanks !

[Anonymous]

At the end of G-code, after G113 (polar coordinate cancel), add  ......

G113

G0 G28 H0.

[Laurens-3DTechDraw]

That is a nasty limitation of the Haas controller you have found there.

Yeah, the post doesn't know the actual C-axis value so it doesn't force a rewind. Yet indeed you can't use cutter comp with XZC output. So you have gotten yourself in a bit of trouble there. Might the best way be to split up the operation into multiple operations?

[Anonymous]

Thanks for your answer. For now, this is what I am doing ... I know that I have around 20 turns of c axis before being to the max... so I check that all my operations do not make more than 20 turns ....  But this is honestly not the solution i would like :'D

[Laurens-3DTechDraw]

It seems it's 8280 degrees to be exact.

I'm thinking if there is a clever way to work your way around this.

Is there many rapids in the toolpath? (which on the machine has to become high feed in G112 but you probably get what I mean)