Reply to Thread

Message:: [QUOTE="ToughCOINS, post: 8049989, member: 20480"]One way to possibly tell the difference would be difficult, but irrefutable. Both scanning and machining equipment can make errors in both directions.  In manufacturing vernacular, tolerances on size and location are bilateral, and can occur in both the positive and negative directions.  Small features, such as the diameter of a dot or the thickness of a line for two examples, may grow when transfer dies are employed, but they cannot get smaller.  This is not true of digitally replicated features. As good as makers of 3D manufacturing equipment try to be, the output from the scan has a +/- tolerance on it, as does the positioning of the cutting tool on the milling machine.  That means the tool may be out of position as much as the tolerance on those 2 pieces of equipment allow. For example, if the scanner output has an accuracy tolerance of +/-.001" and the milling center has an accuracy tolerance of +/-.002", theoretically, the cut surface could be as much as .003" out of position.  That means opposing surfaces (the diameter of a dot or the thickness of a line) could be out as much as .006".  Said differently, the dot / line could be as much as .006" smaller / thinner, or as much as .006" larger / thicker than the scanned feature. That's not to say the surfaces would be out of position at all.  The equipment manufacturer just allows for that much error in the design and manufacture of their equipment.  What's daunting is when one is made to the high side (MMC for GD&T geeks), and the other to the low side (LMC), the tolerances are offsetting, and the end result may in fact be nearly perfect. Still, if measured and found to be smaller than the real thing, it rules out transfer dies and points to digital replication.  It's probably premature to go down this path today, but it may become necessary in the future.[/QUOTE]

Create my FREE Account!

Log in or Sign up

Reply to Thread

Useful Searches