Hullo and help!

Hi All,
New, happy and excited M90 owner 'ere.
Just wonder if I can ask y'all for your best guesses on my teething issues.

My android test print came out pretty well despite, I think, having the Z0 too close to the bed, I printed it from the SD card as per the instructions. I think I was lucky to get away with it since the next print the extruder bolt chewed the filament (presumably because the nozzle was so close to the bed the filament had nowhere to go)
I redid the FW to move the Z0 up a bit and printed Chris' Dial gauge bracket, this printed out ok, with a few V minor artifacts.

I designed my first part (MTB helmet/light mount) and the darn thing came unstuck from the bed after about an hour and a half! (arrgh!)
I did a bit searching and found some suggestions to keep it stuck to the bed.

If I use heated bed and blue tape the part stays stuck to the build platform ok but I get weird lifted sections on the straight transitions inside the firstlayer, see the gear, phone case and the back of the helmet mount.

I'm guessing my issue could have something to do with one or more of the following: Bed temp, nozzle temp, Z0 height, partially blocked extruder, 1st layer height, head speed (ie deposition across the model) and presumably lots more I have not though of!

The issue does not seem to affect the outline, only the infills, as far as I can see.
I've tried changing the bed and extruder temps and bed Z0 height, I've also tried with the fan on first layer and off and the results seem very similar on both the glass and onto tape, though the edges peel more on glass (gonna try vinegar to clean instead of acetone)

I'm resigned to trying each of the things above in turn to find a solution but if any of you "old hands" look at the photos and think, "yeah, that'll be X for sure", I'd be grateful to know your thoughts.

As you can probably tell I'm a complete noob to this.
Cheers
David

The clamp base looks like Z was too high. The top of the clamp shows it was sliced with two outlines but there is only room for one, hence the gaps.

The prints on blue tape look like it sticks in some places but gets dragged around on others. I haven't printed on blue tape many years and don't recommend it. You could try degreasing it with acetone.

Don't use the fan on the first layer, it will prevent it sticking.

I think vinegar will solve your sticking problems.

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[www.hydraraptor.blogspot.com]

Thanks for that Chris,
I'll give the vinegar a try.
I have been using acetone but it leaves a very slight haze which I'm guessing is particles from the paper towels I've been using mixed with PLA from the base.
I have normally been running fan off first layer, then fan on, 190c first layer, 185c subsequently, 60c bed first layer, then 55c.
On further inspection it seems that the lift/warping on the first layer seems worse the longer the line is, shorter lines broken by islands, seem quite a bit less affected, if thats relevant?

I MIGHT have had a bit of an ephiphany, re-reading the manual, The Z0 should theoretically be touching the bed, the first droid I printed was done with this setting calculated as per the manual, The first layer was almost imperceptable.I'm wondering now if that's actually normal? Being a noob I didn't realise that that layer might have taken 3 rounds to complete and made the assumption that it had done 3 layers, presumably, wrong. :-(
I therefore thought the nozzle was too close to the bed when the next print, the extruder chewed the filament.

I'll try re-zero'ing the bed and cleaning with vinegar and report back.

Thank again for the assistance.
D

The Z Height setting procedure should place the nozzle 0.2mm above the bed to allow for hot-end expansion. Measuring the thickness of the skirt from a print will allow you to adjust to Z height further for the amount of expansion you actually get.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Hi Neil,
Thank you for that, I'd factored in the .2 expansion but again on re-reading the manual I think I might have missed something else (pattern emerging here:-)
I think I might have slic3r configured to do .4mm layers. I'll set it to .3mm and try that too.
Thanks again to all for the help (and tolerance so far!)
D

Just measured the bed and have a model helicopter mainshaft that is 4.97mm dia according to my caliper. If I set the z height so rolling the shaft under the tip just snags it and do M114 the result is 4.8 which unless my bleary head is mistaken is just about right?

Do I take it that I'd print the skirt and compare it to the layer height set in Sli3er?

Cheers
D

Yes, if you print something larger and measure the skirt you can check if you bed is level and your z height is correct. If the skirt is consistently the same dimension then your bed is level and if the height of the skirt is the same as your slicer height then you know your z height has been calibrated correctly.

Tested a small square in the centre of the bed, only 20mm square so too small really to see if the bed is level.
With the layer height set at .3mm I could measure it nearly anywhere and it was about .22mm
Just prior to printing the square I tested the extruder into air at 195c and got a consistent .65mm up and down the length and at 4 points around the diameter.

But what does it mean? (said like Spock)
:-)
D

If your layer height was 0.3mm and the skirt height was 0.22mm it means your z height isn't quite calibrated. So in your firmware you will need to raise the z height by 0.08mm. Your skirt should be 0.3mm.

To see if your bed is level print something big but stop the print after the skirt has been printed and measure the skirt to see if it's the same height throughout.

Cheers,

RyanMark,
Thank you for the suggestions, I'll give that a go and report...
Cheers
D

Hi all, just reporting in!

The bed adhesion was massively improved using vinegar instead of acetone, However I discovered something even better by accident.
I took the printer to work and forgot to take the vinegar with me, all I could find was a bottle of 50% ethanol and tried that instead. Even at 20c I was struggling to get the parts off the glass. I thought I was going to snap them. So good result there.

After experimenting with the ZO I can get some really nice glassy looking surfaces so that's all good too!

I only have one slight worry now and that is, it sounds like the extruder tip is slightly catching the surface of the parts during rapids. It does not seem to cause any problems but wonder if it's another trick I may have missed?

Cheers again all for your help!
D
:-)

What do you exactly mean by the word "Rapids"?

If you mean when it moves from part to part without printing, you can slow that down in skeinforge in the speed tab. You could also use the "lift" tab to lift the nozzle between moves but this usually isn't used unless the parts have only a small surface area contacting the bed and the nozzle has the potential to knock them off.

RyanMark,
Yes, I'm referring to when the head moves quickly between areas. I'm using Pronterface/Slic3r but imagine there is a similar setting in Slic3r somewhere?

Quote
RyanMark
You could also use the "lift" tab to lift the nozzle between moves but this usually isn't used unless the parts have only a small surface area contacting the bed and the nozzle has the potential to knock them off.

It seems this would suggest that it's normal for the head to graze the top of the part on the way over it? I wondered if the expansion of the filament after it hits the part causes it to grow slightly in height and allowing the extruder tip to graze it if traversing over it?

It does not seem to cause any problems I just thought that since the z axis ends are effectively just perched on the nuts, any striking of the part by the head could very slightly tap the ends upward away from the nuts.

Cheers
D
:-)

Check your Slic3r settings to ensure that the infill layer height is set the same as your perimeter layer height. If infill layer height is higher than perimeter layer height you will get this effect.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Hi Neil,
Thank you for the suggestion.
I've looked at Slic3r but can't see any settings referring directly to perimeter and layer "heights" ?
I presume I'm about to be shown something obvious

Cheers
D

No, you are right, that is a Skeinforge option.

Slic3r has Layer height and First layer height in the Layers and perimeters page of the Print Settings tab.

Also of interest are the Extrusion width values on the Advanced page of the Print Settings tab. I am always nervous of anything with an auto setting so I use real values for them.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Hi Neil,
I think you might be on to something, I measured the first couple of layers after an aborted print and found the perimeter to be .8mm average and the infill to be 1mm average. I make the assumption that since the perimeter is done first the layer height is too high, after looking closely it would appear that there are furrows in the part, all of which seem to span it from perimeter to perimeter.

I am new to this and the situation could be normal.
Cheers
D

I think Slic3r attempts to adjust these things when Auto settings are used.

I fix all the width values to 0.5mm so I can separate mechanical effects from software-induced ones under this sort of circumstance. Skeinforge is my preferred slicer and, if you get to grips with the multitude of settings, it can produce excellent results.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Hi Neil,
This is my first 3d printer and I just finished building it a few days ago. I'm looking to experiment with different software soon. Chris' excellent kit included info for Pronterface/slic3r enough to get things up and running so I'm trying not to jump about from program to program just yet. It's exciting that much software is available to "play" with but I'm still at the slightly bemused stage of the game
I'm looking forward to trying Skeinforge and Cura and possibly Repetier and I guess much of the perceived differences are those of terminology?

I'm going to explore the auto setting thing as a start and see what I can suss out.
Cheers
D