Matter Control help - prints not proportional

[pholley]

I just tried using Matter control for the first time today. It seems awesome and looked like it was doing a terrific job.

However, the parts are not proportional to the stl drawings. What I mean for instance is that the calibration cube is not square. It comes out a rectangle.
I tried a part with circles and they come out oval.

Am I missing some mystery setting? Has the EEPROM corrupted in the Orion? For now I'm back to repetier, but I would like to use Matter control.

thank you for the help.

[pholley]

OK, my repetier print has done the same thing. How do I get my printer to print the correct size in both axes?

[gestalt73]

ok, so we know it's mechanical.

It's an Orion, so normally you wouldn't have these build issues, but here is what I'd check.
Your print is either being elongated or squished along an axis of the print, so it's going to be one of the following:
- belt is too tight and is binding
- belt is too loose and is slipping
- delta arm(s) are binding

Sometimes you can feel for which tower/belt/delta arm pair is giving you grief by turning the machine off and moving the effector around.

The fun part, is unless you remember the orientation your part was printed in, and have a set of digital calipers to measure, you may not know if your print is being elongated along an axis, or squished along an axis.

Sometimes people will suggest that you rotate the part 45 or 90 degrees and reprint it to see if it's the model or not. also to verify which tower the deformation points to.

[pholley]

What I've tried so far...

I checked the belt tension and the cheapskate adjustments and everything is nice and tight, but the print came out exactly as before.
When measuring with calipers, the size of one large hole should be 15mm diameter, but is 14mm x 13mm oval shaped.

I'll do another calibration run with a known cube. But it looks like the printer is not printing 1:1

update:
Before I adjusted the cheapskates, they were a tiny bit loose. But after tightening, the prints come out exactly (measured with caliper) with the same deformity. The belts seem just right.

I will try to print the cube in a couple different orientations. I will also try printing multiple cubes simultaneously in different orientations.

[geneb]

If you've got the aluminum u-joints, I suspect one or more of them have begun to bind on the metal rod they pivot on.

g.

[pholley]

BINGO! I took the arms off the axis in line with the problem and one of the metal parts is indeed binding.

I'll try fixing it now and see how that works out.
Can I get replacements or is there a way to keep this from happening?

Many thanks to geneb.

update: It is seized. I'm in trouble. Need this working for school. Last two weeks of school start on Tuesday.

[guanu]

spring clips: http://seemecnc.com/collections/parts-a ... nts-6-pack" onclick="window.open(this.href);return false;
molded acetal u-joints (no longer metal so no metal on metal binding): http://seemecnc.com/collections/parts-a ... nt-sold-ea" onclick="window.open(this.href);return false;
axles (also a new coated style): http://seemecnc.com/collections/parts-a ... ock-6-pack" onclick="window.open(this.href);return false;

all of these items are sold in a quantity to replace all the parts, if you got one of each, it is enough to replace all u-joints, axles, and sping cliips (depending on how old your machine is you may not have the spring clip style)

Guanu

[pholley]

Yahoo! Lowe's 1/8" brass rods - 2 for $3.
Brass+aluminum= much happier interface.

[Eaglezsoar]

Yahoo! Lowe's 1/8" brass rods - 2 for $3.
Brass+aluminum= much happier interface.

Good find!
You may also follow guanu's advice and buy the parts he listed. Long term the acetal u-joints are much better.
I agree that aluminum on brass is better than aluminum on steel but anytime you are working with dissimilar metals in contact with each other corrosion will occur.
See http://en.wikipedia.org/wiki/Galvanic_corrosion" onclick="window.open(this.href);return false;

[pholley]

Prints are coming out fine now! Thank you for the help.

Strangely I found that only the top joints were getting tight. The ones around the hot end were as loose as ever. I will replace these as well just to be sure when I get a chance. (oh yeah. In three weeks. Summer break!!!)

[RocketMagnet]

Yahoo! Lowe's 1/8" brass rods - 2 for $3.
Brass+aluminum= much happier interface.

Good find!
You may also follow guanu's advice and buy the parts he listed. Long term the acetal u-joints are much better.
I agree that aluminum on brass is better than aluminum on steel but anytime you are working with dissimilar metals in contact with each other corrosion will occur.
See http://en.wikipedia.org/wiki/Galvanic_corrosion" onclick="window.open(this.href);return false;

There needs to be an electrolyte present so as long as it's dry it doesn't matter. Basically the interface between the metals needs to get wet and stay wet for long periods of time.
In very humid areas it may be an issue but generally it's not something I would ever consider on an indoors item that's not supposed to get wet.

On point with this issue I'd imagine infill orientation, type and %age would impact dimensional accuracy in specific directions due to shrinkage. Clearly you've got a mechanical issue but it's something I've messed around with when going for tight tolerances with ABS.