resolution error?

[KarmaJon]

I am having significant resolution errors regarding automeasuring.

The machine automatically measures my piece as being 33.95" long by 5.44" wide. The actual piece is 34.30" wide by 5.634 inches wide. Errors by hand micrometer notwithstanding, this descrepency seems rather significant.

Auto Measured Difference
33.95" 34.300" - 0.350"
5.44" 5.634" -0.194"

I will call CW when they are open. but I was just wondering if somebody had some idea where I may look.

PMS... That having been said, I have worked on more than my fair share of Mori Sekie's and Fanucs (automated machinery), and I am suprised that somebody had the "Spheroids-of-sufficient-volume" to attempt to make an automated machine for the home hobbyist. It's construction is a simple elegance, and THAT requires a LOT of work. Hat's off and good luck to LHR! I'm a guitar maker, and I'm going to push this baby to it's limit!<grin?<can't wait for the probe!>

[KarmaJon]

Ok, I had a belt break. It ran into the side of the machine. Perhaps the rubbing was the cause of the resolution error measuring the length.

[Jeff_Birt]

Don't forget it is opticaly locating the board edges (in the X adn Y axis) and its perception of what constitutes an edge can be hinderd by board defects, very dark wood, or a dirty board sensor. The small roller in the front of the machine is teh board position sendor for the X-axis, any board defect on this part of the board could cause problems too.

A better test for resolution in the X-axis might be to manully jog the board by a certain amount referring to the LCD readout and then to meausure the actual displacment of the board.

[KarmaJon]

I'll do that when I get the new belts. I can't believe it's only 10 bucks for a pair of them! Yeah, it wasn't the best piece of wood that I used to test the measuring skills of the machine. The Y axis had high repeatability, I think the x-axis issue could have been related to the belts. Oh, well, I have a week or so to figure that out before my probe comes! YAY!

[KarmaJon]

Ok, got my new belts today. X-axis repeatability is HIGH, however, not accurate.

I repeatedly get a measurement of 28.68 for a board that truly measures 29.5". I'll try different length boards to see if it's an offset problem versus a scaling problem.

I was taught that repeatability is more important that accuracy, now the question is how to correct for the inaccuracy!

[KarmaJon]

Ok, I've tried several different pieces of wood, and some pretty good solid stuff, too!

There appears to be no ryhme or reason, no offset OR scaling error, and this baffles me!

I'll call CW, but I'll try to keep the thread alive so that whatever my answer may be, others will find something useful from it.

[Malfunction]

keep us posted

[KarmaJon]

A better test for resolution in the X-axis might be to manully jog the board by a certain amount referring to the LCD readout and then to meausure the actual displacment of the board.

Ok, I'll volunteer as the most inept person in the forum. How do you make this thing jog? I can't seem to do it.

[BobHill]

Jon,

Jogging is done width wise with up and down arrows on the LCD keyboard, and length wise with the left and right arrows. You can only jog when the message area tells you that you can.

Bob

[KarmaJon]

How do I get it to let me jog?

The only place I can find to jog is to jog a piece into place when I carve a pattern. I'm trying to jog it while I get a readout of distance traveled so I can check for accuracy.