Hi Guys, I'm trying to apply a screw compensation file to the X axis on a waterjet running LinuxCNC 2.64
The screw is about 94 inches long and has some major deviations in pitch. All together the maximum error is about 0.150 over the length of the screw and that is if the scaling is set so the screw pitch is perfect in the center of the screw. At the left end of the screw towards the home position, the screw the pitch is short but then the screw pitch changes from being short to being long towards the right end of the screw. The error data was put into a screw comp file named xaxis.txt and the file type switch was set to "1". LinuxCNC is trying to use the x axis data since ball bar testing results change significantly if the X axis screw comp is enabled or disabled. However the screw comp is not effectively correcting the screw. We may have bad screw measurement data, or else I am wondering if the screw is simply too bad to correct? The Y axis screw on the machine is about 45 inches long and has an an accumulating error across its length of about .040. I put the data into a file and called it yaxis.txt. When running a ball bar test on the machine the Y axis comp is very effective and the y axis error is extremely low. Here is a graph of the x axis data file for the x axis screw. This data is being used with a type 1 screw comp switch in the ini file. http://pasteboard.co/21pTrBBa.jpg Has anyone seen any issues with LinuxCNC when trying to correct a screw that is this far off ?? This screw is brand new and was purchased from Flow Waterjet to rebuild an older Flow waterjet machine. This screw was very expensive, yet it seems to be a very low quality screw. I talked to Flow about this one time and they said that they use a laser interferometer to load a screw correction file into their controls whenever they replace a ball screw. Thanks, Dave ------------------------------------------------------------------------------ Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San Francisco, CA to explore cutting-edge tech and listen to tech luminaries present their vision of the future. This family event has something for everyone, including kids. Get more information and register today. http://sdm.link/attshape _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
