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Measuring the 0.5mm wall calibration cube I noticed that it was longer in one direction than the other. Anyone know what might cause this? I do remember reading something about delta printers having troubles with circles. I wonder if it's related?

theverant wrote:Measuring the 0.5mm wall calibration cube I noticed that it was longer in one direction than the other. Anyone know what might cause this? I do remember reading something about delta printers having troubles with circles. I wonder if it's related?

It's actually pretty common for all printers, it points to a problem with the geometry, something not perfectly square, how much are they out by, I wouldn't expect anything better than 0.1mm.

When I first built my printer I didn't put a whole lot of time into making sure each tower was the exact same distance, big mistake. The result was that the items I printed out were slightly parallelogram shaped. It wasn't until I went back and redid them that things started coming out square. I only have a pair of vernier style calipers here, but now all of my square shaped objects come out square and I can't see any dimensional difference between sides. Very accurate now.

Av8r RC wrote:When I first built my printer I didn't put a whole lot of time into making sure each tower was the exact same distance, big mistake. The result was that the items I printed out were slightly parallelogram shaped. It wasn't until I went back and redid them that things started coming out square. I only have a pair of vernier style calipers here, but now all of my square shaped objects come out square and I can't see any dimensional difference between sides. Very accurate now.

what do you mean by each tower being same distance?

~*Brian

The distances from the X tower to the Y tower, Y to Z, Z to X. You need to get all of those as close to the same as possible.

No matter what I tried. Just getting the rails flush with the cut outs wasn't good enough, at least with the parts I got. It was off about 0.080. For mine it took filling down one cut out on the base, and slotting the holes to pull a rail further out on another to get the distances all the same. A lot of work, but worth it if your trying to make precision parts.

Right now I'm trying to print out some prototype parts for a customer. It's a ring with about 160 holes in it. The ring diameter is 122mm +0.1/-0.3. I drew it to 122 and it consitantly comes out to 122 +/-0.1. Pretty damn good for a machine squirting molten plastic out of a 0.35mm hole.

Av8r RC wrote:The distances from the X tower to the Y tower, Y to Z, Z to X. You need to get all of those as close to the same as possible.

No matter what I tried. Just getting the rails flush with the cut outs wasn't good enough, at least with the parts I got. It was off about 0.080. For mine it took filling down one cut out on the base, and slotting the holes to pull a rail further out on another to get the distances all the same. A lot of work, but worth it if your trying to make precision parts.

Right now I'm trying to print out some prototype parts for a customer. It's a ring with about 160 holes in it. The ring diameter is 122mm +0.1/-0.3. I drew it to 122 and it consitantly comes out to 122 +/-0.1. Pretty damn good for a machine squirting molten plastic out of a 0.35mm hole.

Considering that the distances between the rails are fairly large and the tolerances are very small what in your opinion is the best way to measure these? I'm getting closer to starting my build and need your type of input. I'm really not sure
what I could use to measure within thousands of an inch over a large span. Any help would be appreciated.

Carl

I used a tape measure. I hooked the hook in the slot and spanned it over to the adjacent rail. I used the beginning of the radius on the corner as a reference point. You could make a mark on the tape measure and compare it to the others. I work in 0.001's everyday at work so I have an eye for small distances like this.

EDIT: You also want to measure at the top and bottom. Double and triple check it.

Thanks for the pictures, it helps to see how you did it instead of just reading it.
Much appreciated.