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G-Code, CAD, and CAM discussions / Re: Cumulative error in YZ
« on: February 26, 2018, 06:47:29 AM »
It was too late for me to edit the previous message, so here is an addendum:
EDIT: I just remembered one experience with a blueprint that was made for me by a customer in Australia on poster board type material. When he rolled the material for shipment in a tube the differential in radii from one side to the other of the material caused a permanent distortion in the drawing (it was shortened linearly). If I had scanned that drawing and used it without referring to and double-checking the longitudinal dimensions the error would have cumulative and I might be chasing after errors/wear in the CNC drive.
Alternatively, I also learned that expensive commercial scanners (like those used to copy blueprints) needed correction factors after the machine introduced repeatable linear errors during the feed process into the scanning bed/strip. It was very expensive for me in terms of time and materials to discover all this.
EDIT: I just remembered one experience with a blueprint that was made for me by a customer in Australia on poster board type material. When he rolled the material for shipment in a tube the differential in radii from one side to the other of the material caused a permanent distortion in the drawing (it was shortened linearly). If I had scanned that drawing and used it without referring to and double-checking the longitudinal dimensions the error would have cumulative and I might be chasing after errors/wear in the CNC drive.
Alternatively, I also learned that expensive commercial scanners (like those used to copy blueprints) needed correction factors after the machine introduced repeatable linear errors during the feed process into the scanning bed/strip. It was very expensive for me in terms of time and materials to discover all this.