Straight Line Fail

[zobom]

Ok a little background...

I have a Rostock Max V2 1st edition 269mm arms, melanine carriage and such... Only mod i have was that sorry excuse of a power supply...

Now the problem...

I'm printing the attached file, its a small viewport for an APC, can't tell which is because of a contract related clause. When i started the print in the first layer i saw the error and stopped right there.

Just before saying it's a misalignment of towers, bed ondulation and such, it isn't. I've rotated the drawing in many directions as you can see by the image album and still persisted in the exactly same location. It sounds more like a slice error, but i've tried in many slicers and the problem still persist. Can someone print this first layer and see if it is just my printer or it is in everyone?


http://imgur.com/a/D10Tt

Day Periscope_revA-.stl

(290.12 KiB) Downloaded 217 times

[geneb]

When you view the layers in the slicer, do you see the same anomaly?

g.

[bvandiepenbos]

I do not understand what you see a a slicing error?
The wider spaced lines are auto generated support created by slicer, correct?

Did you run the model thru netfabb repair before slicing?
What orientation are you printing?

The attached file has been run thru netfabb repair, give that a shot.

[zobom]

When you view the layers in the slicer, do you see the same anomaly?

No, just in the print. In the slicer looks all good... But read below and i'll try to explain why i cogitated this...

I do not understand what you see a a slicing error?
The wider spaced lines are auto generated support created by slicer, correct?

Did you run the model thru netfabb repair before slicing?
What orientation are you printing?

The attached file has been run thru netfabb repair, give that a shot.

I'll try out the repaired file. But the thing is, the priting line in that specific area that i pointed out are tending to one direction. You can see by this photo below... Look how the inner lines how in the top they have a space between them and on the bottom they are blend together.

But the most curious thing is.... if i rotate the part (45/90/180º....) and print again in any other direction, it follows the part no matter what. That's whats killing me...

[img]http://i.imgur.com/OIX79jh.jpg[/img]

[Mac The Knife]

Backlash comes to mind. When's the last time you've checked your belt tension?

[zobom]

Since i've instaled the printer actually... I'll double check this, tks for the insight!

[nebbian]

Well, it's not your model.

I checked in meshmixer, and those parts are all exactly 3.00 mm.

I also started a print to see if that problem was apparent, and while I had some other issues relating to printing big parts (I don't usually print such large items), those lines were all parallel as far as I could see. Note that I didn't use support on this one, as the support would have made the print head go too close to the edge of my bed. The outer line you can see is the skirt.

So it's something in your slicer, mechanics or firmware. I'm not sure what it would be.

As a first step, I'd try slowing down the first layer printing speed and see if that helps. I use 18mm/s.

I'm using slic3r, marlin (RC-bugfix as of about a month ago), and a Kossel XL if that helps.

[Qdeathstar]

what about effector tilt?

[zobom]

Looks great your print! Yeah, i think it's a mechanical problem... as Qdeathstar said, looking at the effector plataform it tilts a small amount to the right while doing the movement, i believe it's the joint between the aluminium holder and the plastic arms... I didnt sand the excess plastic of the arms, it must be it...

Thanks for all the tips, i'll shall return with the answer!

[Holy1]

Check that the aluminum ujoints are not seized to the shaft.

[geneb]

If you're rotating the part on the bed and the oddity always happens in the same place on the model, it's not a mechanical issue.

g.

[zobom]

I've calibrated the bed using the Steven Rowland tutorial (https://www.youtube.com/watch?v=im5MDpTkzCM), and the problem still persist, only this time is way less diference than before... The good part is that the first layers now have better quality.

Gene, you have a good understanding on the delta printers... Can you give some pointers to what you would do next? I flashed another firmware with some tweaks in the measures of the carriage, effector and such, but it was no good as well...

The effector tilt was a 40mm layer fan mount that was scratching in the axle when the arm was in full horizontal position, sanded a little and it was gone... but the straight line problem still persists...

[geneb]

If the error is following the part no matter how you rotate it on the bed, the issue isn't mechanical.

Design a rectangle about the same size and about 3mm high. Try printing that and see what happens.

Also, is your printer using the old aluminum u-joints or the white, injection molded ones?

g.

[nebbian]

Have you tried slowing down the print speed?

I'd try it. If this makes the quality improve then you've definitely got a mechanical problem. If not, then the problem might be elsewhere.


The reason I think it might be mechanical is that the main difference between the inside and outside lines on your print is that sharp corner on the inside. If you've got some serious slop in your system then that sharp corner might cause the effector to overshoot. The rounded outer corner won't have nearly as sharp an acceleration, so won't cause the same overshoot.

[zobom]

I'm using the aluminium U-joints... Tried the retangle with the same dimensions, same result as the part.

Well, I've installed a Z-height caliper to check the bed for unusual geometry and such and the following thing is happening when i'm jogging around, i don't know if its related with this problem, but its definitely a "dahell?" moment...

I'm jogging to the edge of the bed and everything is in the 0,00mm so no warp in the bs glass, but when i go back in direction of the center of the bed the following thing happen...


[img]http://i.imgur.com/eDD1ZJT.jpg[/img]


Looks like i'ts retracting from the bed about 0,20mm and only returns to the "normal" 0,00mm near the center of the bed...

Have anyone saw this in other printers? It's normal?

[zobom]

Code: Select all

Have you tried slowing down the print speed?

It happen already in the first layer with 5mm/s movements... So probably its not tension in the effector from the movement or sharp corners...

[geneb]

If you've got the aluminum u-joints, check to make sure they're all spinning freely. I suspect one or more has become frozen on the shaft, or nearly so.

g.

[zobom]

There was some resistance in the movement, but nothing drastically. I've sanded the inside of the arms to get them very flat, put a little sewing machine oil in the joints and a small heat shrink in the U part of the U-joint to garantee that they are well fixed and wont accidentally stepout of the aluminium pin... It done wonders in the effector, its very tight now and dont shake in fast travel movements (150mm/s+), im in 300mm/s now and looks very stable...

But none of the problems above had any change... I dont know what to do anymore...