First layer quality?

I am generally happy with the overall quality of my prints but the first layer on large flat areas tends to be lumpy.



The picture above shows a typical example, this is the underside that is in contact with the bed. Are there any special Slic3r settings for the first layer to improve this?

Regards,

Les

EDIT: The X axis runs top to bottom and that piece is about 80mm x 110mm.

Edited 1 time(s). Last edit at 05/08/2014 03:00AM by Pointy.

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it seems that you have some problem in the layer height...

if your bed surface is leveled correctly and don't present bubbles of air, I think that this kind of defect was caused by the dangling of the noozle that could vary in the X axis position due to the PTE tube and wiring tension.

it's better if you can write the axis direction on the picture

Zonzo

Edited 2 time(s). Last edit at 05/07/2014 09:19AM by Zonzo.

Does it occur at more or less the same place on every print? It looks to me like a couple of irregularities on the bed - perhaps air bubbles, creases or overlaps in the Kapton tape? Setting the Z zero point a tiny bit higher (0.05mm) might improve it, but also consider using the wet method of applying tape without any bubbles or overlaps, or using one of the other bed preparation methods that do not use tape.

A less likely possibility is a bit of water contamination caused by not storing the filament in a sealed bag with silica gel - there will be similar defects in different places on other layers if that is the cause.

Dave
(#106)

Also, could be bed contamination. Give the bed a good clean, particularly to remove any oil (eg fingerprints), usually best with Acetone. See: [reprappro.com]

Ian
RepRapPro tech support

Quote
Zonzo
it's better if you can write the axis direction on the picture

The X axis is top to bottom in the pciture

Quote
dmould
Does it occur at more or less the same place on every print? It looks to me like a couple of irregularities on the bed - perhaps air bubbles, creases or overlaps in the Kapton tape? Setting the Z zero point a tiny bit higher (0.05mm) might improve it, but also consider using the wet method of applying tape without any bubbles or overlaps, or using one of the other bed preparation methods that do not use tape.

A less likely possibility is a bit of water contamination caused by not storing the filament in a sealed bag with silica gel - there will be similar defects in different places on other layers if that is the cause.

Dave
(#106)

It's only really noticeable on large flat areas, not sue if it's the same place each time though.

I do use the wet method, and the Kapton is the 200mm wide stuff so no gaps.

The filament is a new roll, and it was well sealed with silica gel.

Regards,

Les

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Hi Pointy,

You are not alone!

I have the same 'finish' with my printer, and am still trying to find what helps.
Since I print a lot of large flat areas, there is enough opportunity for testing...

When it prints, I see the plastic 'float' above the glass at some locations:

- When the head moves in one direction, it creates a sort of floating bubble.
- When the head moves in the other direction, it presses these bubbles flat.
- Sometimes the bubbles are damaged and they appear as plastic wounds.

This seems to indicate that it does not want to stick because of dirt / grease...
But I have *really tried* to clean the glass thoroughly with denatured alcohol!

I use kitchen paper when I clean the bed, could this introduce dust particles?
Can anyone advise some other kind of cleaning cloth that I might try instead?

Some other details about my situation:

- The first layer is perfectly flat.
- The patterns are always different.
- It happens when I print on kapton tape.
- It happens when I print directly on glass.
- It happens with the bed at 65 and 75 Celsius.
- It happens when I rub good with 70% alcohol.
- It happens when I rub good with 96% alcohol.
- It happens when I use vinegar before printing.
- It happens when I print at a normal speed.
- It happens when I print very, very slowly.
- I use PLA from RepRapWorld.com

Some things I could try:

- Rub with some other cloth.
- Clean the bed with acetone.
- Support the PTE tube / wires.
- Using a different PLA brand.
- Printing ABS (don't want to...)
- Add silica gel to my storage.
- Play with the nozzle airflow.

Since dirt and grease seem to be obvious culprits,
I have ordered a bottle of acetone, let's hope it helps

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RS-Online Ormerod #263, Kossel mini with Minitronics, Prusa i3 MK2

Thanks for the reply 3D-ES, I have been using IPA to clean the bed and like you, I use kitchen paper. I don't think that is the cause but I probably have some lint free cloths around to I will give one a try. I would have thought if it were problems with the axis or PLA it would continue through the layers, but usually over something like a 2mm high print, it will flatten itself out and the top surface will be pretty good. I thought maybe it was something to do with some Slic3r settings for the first layer.

Regards,

Les

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Quote
3D-ES

Some things I could try:

- Rub with some other cloth.
- Clean the bed with acetone.
- Support the PTE tube / wires.
- Using a different PLA brand.
- Printing ABS (don't want to...)
- Add silica gel to my storage.
- Play with the nozzle airflow.

Ad this to your list (works for me when all other things fail)

Sand Capton tape lightly with sandpaper P350-P400, clean out the dust with acetone, if not use dust free paper towel, blow across table with oil free air hose

Erik

I had similar issues as well, where prints got blisters without any hint as to why. Once I mounted the aluminium Xrib (thanks Davek0974!), and changed to 5mm thick glass, they were gone. As I did both changes in one go I can't tell which one made these blisters go, but I can for sure recommend the aluminium Xrib, it's one of the best upgrades to my Ormerod. Together with firmware and sensor upgrades my printer reached a fire-and-forget point in printing, where before I had to stay around for the first layer to finish.
Looking at the picture supplied, it looks like your nozzle is to high at the bottom left side, and to low at the top right/center of the print, as filament seems to build up in the nozzle and come out in small blobs

Quote
onno
I had similar issues as well, where prints got blisters without any hint as to why. Once I mounted the aluminium Xrib (thanks Davek0974!), and changed to 5mm thick glass, they were gone. As I did both changes in one go I can't tell which one made these blisters go, but I can for sure recommend the aluminium Xrib, it's one of the best upgrades to my Ormerod. Together with firmware and sensor upgrades my printer reached a fire-and-forget point in printing, where before I had to stay around for the first layer to finish.
Looking at the picture supplied, it looks like your nozzle is to high at the bottom left side, and to low at the top right/center of the print, as filament seems to build up in the nozzle and come out in small blobs

Thanks for the reply Onno.

I have just finished fitting my aluminium xrib/xplate but I haven't done any large prints yet as I seem to have a bit more variance across the X axis since fitting it. I have just checked and it seems the vertical profile is not at 90 degrees to the bed.. It will be interesting to see if it makes a difference once I square it all up.

I am wondering if it is the filament, although it is quite new it is left out in the cool workshop 24/7. Strange that it doesn't seem to affect other parts of the print though. Here's another picture of a print that was done the day before the one above. It's much better, it was printed on the same glass/kapton with the same settings.



I will have to do some more experimenting.

Regards,

Les

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Quote
Pointy
.. it seems the vertical profile is not at 90 degrees to the bed.. It will be interesting to see if it makes a difference once I square it all up...

Is your aluminum extrusions, Y and Z at 90 degrees to each other? - if so the vertical part of the X-axis should be 90 degrees to the bed - if you do not have any fault in the printed parts, esp. the bearing clamps that is

Erik

I squared everything up today, and it made no difference. So I did some searching and I found another thread that shows the problem here.

I printed the test piece and measured it at an average of 0.56mm, this means the extrusion multiplier should be 0.89, which seems quite low to me. I also measured some other parts that I had printed and the wall thickness was consistently size.(2mm was 2.24mm)

Anyway I did a quick test with 0.89 and it made no difference.

I think I might start with some clean Slic3r settings, unless anyone would care to upload theirs? If that doesn't work I might try some other filament tomorrow.

Regards,

Les

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Hi Pointy

attached my settings as of now, notice the extrusion multiplier is set at 0.791, works beautifully for me, all measurements right on target, but you may need to change that
also notice Print settings, Advanced, First Layer, 160%

Good luck!

Erik

Thanks Erik.

So my 0.89 extrusion multiplier isn't low after all. I had also tried higher first layer heights, but then found that it didn't stick to the bed. Anyway I will try it as it is on my 40x40x2mm test piece and post the results. What's puzzling my is the 2nd thin wall test was almost spot on, and the quality looks pretty good on both pieces. Surely if something was amiss it would show during the rest of a print and not just the first layer! The mystery continues.



Regards,

Les

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I am still not sure what's going on but things are getting better. I tried Erik's settings and they made no difference, but somewhere along the line it has improved. The attached picture show my latest print on the right, with another that I did just yesterday. Same filament, same settings.



Since yesterday I have had the hotend apart to fit a new X carriage, fan mount and Z homing micro switch. The Z homing seems much better with the switch so maybe that was the problem, but I have yet to do a bigger print to verify if it's completely fixed.

Regards,

Les

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Hi.

Just a thought:
-Have you tried to increase the bed temperature? It has helped me before. I also turn on the bed manually to let it have some time to get evenly hot. 5 minutes or so works for me.
The heat sensor measures the temperature below the glass, so the top surface of the glass will have a lower temperature at the the time the sensor reaches your programmed level and the printer starts.

I did some tests on this. After the bed thermistor temperature has stabilised, it takes another 2 minutes for the top of the glass to reach a stable temperature, which is about 10C lower (when the bed temperature is set to 65C).

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I've been suffering the same problem, only in the last couple of weeks, I've made no changes to the machine other than filament swaps.
I did find that wrapping a couple of elastic bands around the Bowden tube made quite an improvement, not perfect, but better than it was.
Additionally what I was finding is that I had blobs appearing in the perimeters, usually around the same places. The elastic band trick seems to have cured this but I'm still finding bumps in the first layer infill (not as bad as before though).

I've had this same issue, and same inconsistency..

The an adjustable lamp near my printer turned out to be the main cause of the problem.

having the lamp directed at the printer results in a different Z height to when its faced away slightly. Not much but enough to bodge the first layer.

Saying that, it does seem to still occur at one point of the printer still, this could be poorly layed kapton tape though...

The last few prints have been really good.

I think it was probably a number of things combined.

• Z height not being spot on, this is obviously really important. (I am now using Kim's micro switch idea)
• Extruding too much filament. (I did the thin wall test and calibrated. to 0.87)
• Possibly my fan duct was cooling the nozzle as it had burnt a hole in it, see photo. (I have reprinted, tweaked the hotend and put some kapton tape on the middle part)

Regards,

Les

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Hi,

Same problem here too, I can't hand over the printed parts to my customer because of this problem. I have nearly 1kg of wasted prints in my bin. ( thinking of building a filament extruder to extrude my own filaments one day, to save material cost )
I still can't find the main reason yet. I'm going to tighten up everything and see how it goes.

Edited 1 time(s). Last edit at 05/13/2014 10:02PM by tru168.

Hi guys, I was running the 59 firmware, and noticed something similar....
Blistering of the Brim mainly, which was strainge because I always have the bed set to 57' now as it seems to work for me....
Tonight I tried running the new web controller... I'd set the nozzle temp to 195' tried printing....nope, it was messing about....
Restarted it all again after cleaning the glass incase it was that, and sat and watched the first layer....
The nozzle temp was going up as high as 240' (it should have been 195'), and was hanging around at 220-235'
It did eventualy settle, but by that time the print was dead.....
I tried about 10 times to get the print to go, but each time it got wrecked due to the temp..
I've gone back to 57y firmware for the time being....
Keep a close look on the temps of the first layer and see if it's wandering....
With just the heaters on it was ok. But running the homez or any gcode was not working....

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Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

As stated above I think my main reason for this were Z height inaccuracies and too much filament being extruded. The last 2 days my prints have been really good. I haven't done any really big flat pieces yet but a 40mm x 40mm test piece was spot on.

Regards,

Les

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