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is my PLA bad?

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Does this look like poor quality PLA or do I need to work on my settings?

I just got some new PLA (light green, light blue, pink).

This is the Green test. I think I am seeing random under extrusion, but I am very new to this.

Here's a tower (10mmx10mmx50mm) I changed the temp every ~10mm (see pic)

3.07mm diam - light green PLA

0.1mm height

0.8mm wall

0 infill

(speed was slow, the 5 second/layer setting made this go at about 16mm/sec)

temp test greenPLA 3mm

In the 225deg section i see what i think is under extrusion. (yes?) Nothing else changed on my end and i was not aware of different sounds or motion from the machine during this time. By the way I think 220 is a good temp for this PLA.

Next I printed a hollow box (20mmx20mmx10mm), I did not change anything during the print.

3.07mm diam - light green PLA

0.2mm height

0.4mm wall

0 infill


wall test greenPLA 3mm

SO here i am seeing more of what i think is under extrusion.

I think the spring screw on the feeder is snug, i think the filament freely turning on it's spool. What do more experience eyes see here?

I will test the other colors next


i did not have this happen with the Silver PLA(2.85mm) that came with the ultimaker.


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If your filament actually measures at 3.07mm diameter, then there's a good chance it's going to get stuck in the Bowden. Higher friction against the tube walls could well cause random under-extrusion patterns.

How does it feel just sliding a clean piece of filament through the Bowden by hand, compared to the 2.85mm PLA?


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Thanks! yes, the green 3.07mm does feel more fussy going through the Bowden than the Silver 2.87mm.

I just rechecked all the have:

The light Green gives readings like: 3.04mm, 3.09mm, 3.11mm, 3.06mm

The Pink: 2.99mm, 3.00mm, 3.01mm, 3.02mm, 2.96mm

the light blue: 3.01mm, 2.95mm, 2.97mm, 3.00mm, 2.99mm

the silver: 2.88mm, 2.89mm, 2.90mm, 2.86mm, 2.87mm

What should I do, is anything over 3.0mm a no no?

Stop using the green since it may clog or damage the machine? (or just be annoying by giving random results)

Do you think the others will be fine? They do not move as smoothly as the silver, but certainly move easier than the green.

PLA Source question: - I used amazon and did NOT order from one seller who had poor reviews for just this issue (too large), and ordered from a seller who DID have good reviews. Is there an official/unofficial rating system or any kind of QC rating for PLA manufacturers? Maybe I need to find a more reputable supplier, feels a little like the wild west out there.


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Anything above about 3.05 is going to cause problems. It's unlikely to do any permanent damage but it will cause poor or failed prints. High variability in the diameter is also going to cause uneven extrusion, since the input diameter is assumed to be constant, and is what determines the amount of plastic that gets extruded.

You're going to have to measure a bunch of both filaments to get a sense of how they will perform. Also, when measuring, at each point you should measure in two directions at right angles, since filament is rarely properly circular.

In general, you get what you pay for when it comes to filament. Personally, I wouldn't buy from Amazon since its hard to know what you're getting - there are plenty of specialist 3D printing sources online. A kilo of filament goes a pretty long way - the few dollars that you save by buying an off brand are fairly insignificant compared to the cost of the equipment, and the time involved in operating it properly. Invest in decent filament from good source. Companies like printbl and faberdashery are generally regarded as being among the best, but there are plenty of other specialist 3D companies that are pretty good.


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Either never use the green, or some day get a larger bowden tube and use the green filament then. Sorry, man. The other filaments are probably okay. Or maybe you can send the green back. Give them some feedback about the diameter.


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thanks for the great info and help!

I am contacting the seller to find out their return/refund policy. Also I understand how the large variation in this filament will be an ongoing issue (looking at standard dev of my measurements silver=0.016mm, others = +0.024mm). So I bet even if i did get a larger Bowden (great suggestion) i will probbably have more trouble with this stock than the silver stock.


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