Vertical lines striations in manifesto case

[gregh]

I have printed Day1, day4, test case and manifesto case. On the latter 2 where there are untextured aread, I get vertical striations.

The attachments perhaps exaggerate the issue and maybe I am being too picky. Unless you have light reflecting off these lines (as I do in the photos, as well as the fact that these were taken with a macro lens) they are far less noticeable.

I have seen other examples of this on other hubs photos, but I’d love to figure out how to eliminate it. I am acheiving good quality apart from this.

I posted to the Ultimaker forum too, and have already tried a couple of things to eliminate this without any luck so far.

http://umforum.ultimaker.com/index.php?/topic/7966-vertical-lines-striations-on-fairphone-case/

Some colurs show this issue up more than others.

Does anyone have any thoughts or suggestions?

Thansk,

Greg

[gregh]

Apparently my posts on the Ultimaker forum need to be moderated until I’ve posted enough to satisfy them that I’m not a psychopath or something. So in the meantime i’ll post what I tried so far here:

I reduced the temperature in 5 deg steps from 210 down to 175, and also reduced the speed from 30 mm/s down to 75% on the front panel for the very low temp prints.

I have also tried multiple materials.

None of the above made any difference.

Thanks,

Greg

[gregh]

Now also tried printing rotated at 90 deg from the original orientation. This has also made no difference.

[jbainesy]

Hey mate,

You’re printing this with the text facing forward / backward on the Y axis of a mendel-style “moving bed” machine, is this correct?

What I see there is vibration. Think about your machine not as an “X/Y axis machine” but as having a seperate X axis and a seperate Y axis:

The Y axis goes from moving at 30mm/s to instantly STOP (and the X axis begins moving) when it hits a corner. Because the Y axis weighs a fair bit and your model is ON the Y axis, it doesn’t physically stop when the motor stops spinning, it ‘wobbles’ for a little… The vertical lines you see are this “wobble”. The same effect is seen when the Y motor goes from stopped to instant motion. (you get the same wobble at the START of any direction change and it continues for a small length along the part)

Try these steps to help eliminate it:

1) Make sure your Y Belt is sufficiently tensioned

2) Check your acceleration settings in firmware (you can safely send an “M201 X250 Y250” command to the printer to set the acceleration to a low value (250mm/s^2) and if you find the vibrations go away, try again with M201 X300 Y300 and so on until you find a value that you are happy with. Too low will bring in other problems, around 750-1500 should work well for a mendel. X can usually be a bit higher, I run my mendel’s acceleration at up to 3000 on x) The difference you should notice is with lower acceleration values the printer will slow down in corners. These more “cushy” movements aren’t as jerky and reduce vibration.

NOTE that if your EEPROM is turned off, the above M Codes will be ignored and you will notice no difference.

[jbainesy]

Oh. you can add those M Codes to your G Code file (toward the top) OR if your host software allows sending of manual commands you can send it through the terminal of your host software (Repetier and Printrun at least allow it)

[Filemon]

I know @key23d and @James_2 to be experts on this matter

[key23d]

Hi Greg,

I didn’t experience this problem so I don’t know if there is anything else, apart from the changes you already tried, what could cause this. At the moment I don’t have time at all to “dive” into this but when I have any idea I will let you know.

Kind regards, Guy

[James_2]

@gregh you are in a trcky triangle of printspeed, temperature (getting the layers to bond) ringing and some filaments just looking worse than others.

I slice in S3D - I print slow and ‘cool’ (never below 200 - and then betwen 204 and 208 depending on the filament).

I am assuming a generally tight setup - i.e. i tightened all bolts, tightened the extruder, checked pulleys were tight, belos reasonably atensioned. lightly oiled my bearings - and then I always try tomake sure that the model is slightly off centre - i.e. to the frint and slightly to the side - not where every other model is placed.

I used the joris trick of the .6mm nozzle in s3d and a random z (spialise) and al this ‘improved’ the atefact to t alvel where i thought it was acceptable.

Some cases show this more than the others - and that one is one of the ‘worst’ but it is there in all of them (if you look hard enough

James

[gregh]

Thanks @james_2 and @jbainesy.

Firstly @jbainesy, this is an Ultimaker 2- I should perhaps have led with some basic background, but the points are taken about loose belts and possibly tweaking the acceleration.

Thanks @james_2, sounds like you have given me a lot to explore. A general tightening up might be in order.

I have moved the model around on the bed, I have also printed in 2 different orientations in the XY (facing the front and facing the side) I get identical results, on that evidence I am tempted to say that it may be more down to slicing and acceleration than loose belts, unless they are identically loose or worn in both directions, which is entirely possible of course.

On the flip side though, I have slowed it down considerably and seen little or no change which might lead one to think acceleration is not the issue.

I will use your text below to just do a general hardware healthcheck and if that doesn’t help I will experiment further with acceleration and slicing with S3D; I will feedback with any findings.

Thanks again!

Greg.

[gregh]

Thanks anyway for the reply Guy, and thanks Filemon for flagging this for me.

When I figure it out I will post the solution.

Cheers,

Greg

[gregh]

OK, I have tried lowering the extrusion rate which was suggested on the UM forum but that didn’t resolve the issue.

I also did a hardware health-check, belts and bolts all tightened up, still no change.

What did help a little is setting the model up at a 15 deg angle in the XY instead of being parallel with either the front or the side as I had before.

I am just letting the current print finish as it’s better than before, but I want to experiment more with alternative slicers.

[gregh]

Hi All,

thanks for the responses, for the record, here are the 2 results for comparison. The only difference being the angle of the model on the bed, and I also printed a few degrees cooler as I realised I was possibly printing at the upper end of the range and thought it might help with the stringing across the gaps.

I still want to try alternative James’ suggestion of alternative slicers and will report back when I do.

[gregh]

sorry , to clarify, I printed at 15 deg from the front plane rather that parallel to the front or side.

[jbainesy]

Another cause can be the belts “riding” over the pulley flanges…

Try running a simple box large enough to test the axes for 100mm length or so - watch EACH of the pulleys a few times back and forth. If the pulleys are not aligned from one end to the other the belt can ride up on the flange and with a toothed belt this means it will ride > slip > ride > slip every tooth creating lines similar to those you have there…

NOT likely to be the vibration I first suggested on an ultimaker 2, especially not at those slower speeds.

[vvdesign]

Lower the speed, 20-25.

Add a fan in front of your printer.

This may help you

[gregh]

Thanks jbainesy, that’s definitely something worth looking at. I glanced at it this morning and one of the belts is very close to -if not riding up against- the pulley flange. I was printing at the time so couldn’t do the test you suggested, but I will later on.

Cheers,

Greg

[jbainesy]

Good luck! Its easiest to spot when moving slowly, watch the belt just as it comes off/on the pulley, it should be pretty much dead-straight and not jumping up and down (even a little)… Look at the top and bottom of every x/y pulley and watch it in both directions… It usually only happens in 1 direction so you must watch both!

[Ian_White]

Hi, I know this is an old post but did you solve this? Or at least find out what was causing it? I have similar problem that I believe is down to the slicing - probably something I have done, just testing a few of my suspicions now.