A Cautionary Tale

I have to do something now that I wish I didn’t have to, but I feel it’s necessary. Recently, I bought 4 rolls of Sunlu brand filament from Amazon: 3 rolls of regular PLA and 1 roll of wood PLA. I bought the red to do the 2 Nintendo Switch game pack holders I posted about on Saturday. I also wanted to print a new photo infinity backdrop holder I found on Thingiverse and decided to use the silver filament I ordered.

Things did not go well.

First, I found I had to use a much higher nozzle temperature compared to the other PLA filaments I’ve used. That in itself is not a terrible thing, but it is something I noted. In fairness, the package does say to use temps between 200C and 230C. I found 218C worked relatively well for laying down filament.

Second, I had real problems with shrinkage, leading to deformation of the models and causing them pop loose from the print bed. I have used 4 or 5 brands of PLA to date and have not experienced this issue with any of them. I took photos to illustrate this issue:

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This image needs a little explanation. The print with the tweezers was printed first. Note how a number of the lines of filament did not adhere well, as shown by the tweezers underneath 1 of the lines. Also notice that I had to put a brim around the print. This was because, during a previous attempt to print all parts of this model, many of the ends lifted off the print bed. In all cases the glass print bed plate was coated with Magigoo.

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I fixed the layer adhesion issue by slowing the print speed down to 40mm/sec overall, with a first layer speed of 15mm/sec and inner/outer wall speed of 25mm/sec. However, even this didn’t fix all the layer adhesion issues:

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​​​ I managed to fix this with a little superglue, but it should not have happened in the first place IMHO.

Slowing down did not help with the lack of bed adhesion and shrinkage (I believe is causing the poor bed adhesion). The model without tweezers was printed after the one with tweezers. In Cura I simply multiplied the existing model, rotated it around to fit more tightly to the existing, then deleted the first model from the layout. The printing itself went not too badly overall, although the Sunlu prints seem to be more brittle than other PLAs I’ve used. The real issue is the shrinkage, as shown by the closest end of the left-hand model, where it lifted from the bed and moved to the left.

Looking at the model lifted from the bed got me thinking about something I’d noticed when printing the Nintendo Switch trays: that is, I had noticed that 1 corner of at least 1 of the trays had curled up a little bit from the bed. I didn’t really think much about it at the time, but the backdrop model made me wonder. I now suspect the trays didn’t lift up more only because they had such a huge percentage of their mass directly in contact with the print bed. IOW, the huge contact area overrode the effects of shrinkage.

(continued in next post)

I decided to test my hypotheses. The only way I could think of doing that would be to print some parts of the photo backdrop holder using a filament that has worked for me in the past; one that did not exhibit the issues I had with the Sunlu.

Besides 2 end pieces, the photo backdrop holder has a center piece, a 2-piece stabilizing bar, and a clamp to join the stabilizing bar pieces. I printed all 4 pieces. None of them had any issues.

This item was printed using some leftover Hello3D white PLA filament. It exhibited none of the issues I had with the Sunlu. Please ignore the knocked off top corner in the right-hand photo. That was my fault. But I do think it has pretty nice layering, showing no sign of brittleness or lack of layer adhesion, and no distortion/shrinkage on the bottom.

This photo shows the 2 stabilizing bar pieces and the clamp, all still on the print bed. There are no signs of shrinkage; everything is well adhered to the magigoo coated glass.

A closeup of 1 corner of the stabilizing bar pieces. I see good adhesion and no shrinkage.

My conclusion is that the Sunlu PLA filament is not as good as other PLAs I have used. I will be attempting to return all 4 rolls (2 opened, 2 still sealed) to Amazon as defective and not as advertised.

I recently tried a roll of Sunlu Blue Silk PLA+. I noticed it did not flow as readily as the other PLAs I tried and I’m convinced it had a moisture problem as periodically I heard popping noises and noticed small voids in the plastic lines. After drying out the roll, I was able to get it dialed in and make some nice parts. Bed adhesion was not an issue in my case. I think I started at 65C and then dropped it to 60C after the first layer, with a 220C nozzle temperature.

I don’t think I’ll be buying Sunlu filament, which is a shame as I liked the color.


P.S. – In one of the Facebook groups I follow, someone representing Sunlu was apparently offering $68 off of the Sunlu S8 printer for 4-star reviews on Amazon.?

Isn’t offering money for good reviews a violation of Amazon policy?

Interesting about the popping and voids. All in all, it sounds as though Sunlu is perhaps not the most reputable company, and their products aren’t the highest quality. I think returning the filament is my best course of action. Thank goodness I bought it from Amazon, so returning should not be an issue.

Yup, if they get caught.

I’m also trying a spool of eSun blue PLA+ and so far have had good results. With supply problems resulting in MH Build and Hatchbox being unavailable at times, I’ve been experimenting with different suppliers.


Comparing to other fillament manufacturers, eSUN, Treed, Devil and Prusament have the best PLA ( as far as i’ve test them ).

I completely swapped to Noyes Filament. Their PLA and ABS filaments are great and the best thing is their reseller is local, so I can go to their shop and look at all the colors and even pick up cheap rolls that where returned from customers. Color changing and glow in the dark filaments I also tried. Something I would never had done with the usual price tag. Here it is just 1 or 2 euros more.

Before the pandemic 1Kg PLA was at 11,50e now do to the shortage it is 16,50e, but still much cheaper than other stuff. I hope they will go back to at least 14e, but well 16 works for me, too.

I plan on trying their PETG and TPU soon. Before I used JanBex filaments, but they somewhat failed me with several spools and each roll was 22,00e so nearly twice as much.

For over a year now (since I learned there is a reseller out here) I use Noyes Stuff and it is simply great in any way.

Noyes hmmm, not a familiar name. A search on amazon.com comes up empty.


It seems more or less in german online stores only and since it is next to my home town and I could pick up filament by bike it is a nice bonus. :smiley:

This is the shop I go to in person: https://netco-shop.de/

Interesting. You know what I really find fascinating: the mixing of 2 or more languages. It’s funny how the mix is often comprehensible to people who only speak 1 or the other language. I’m certainly not a speaker of German, but I can pretty much figure out everything on that store’s website. For example, can I assume that “kabel” is “cable”? Also, they have “details” buttons to get more info. I assume “details” is not the correct German word, but I suspect it works for English and German speakers, much like their use of “bestseller”.

On that amazon.de site page: that is truly an impressive selection of colors.

I think there’s a possibility that the mixing of languages, over time, will lead to a hybrid, common language that virtually everyone on the planet will understand.

I’ve been using Sunlu filament (currently using there blue) and have had no problems. I did find out after several prints failed to stick to my ender 3 v2 stock bed that you do not clean the bed with alcohol seems to remove it’s ability to allow the filament to stick to the bed over time. Had to replace it with another bed. After i did that the problem went away and is sticking to the bed just fine.now.

Hey Larry. I have experienced something similar using rubbing alcohol. What you might want to try is cleaning the bed with the alcohol and then clean it with plain water. Be sure to dry it afterward. I used paper towel. That said, I pretty much use Magigoo right now.

I’m just finishing a roll of Sunlu white and have received another yesterday. I’m presently at 13 hours with 83% done of a lithophane for my lamps. My lithophanes usually take only 6 hours but I tried a smaller layer height and it seems to be coming out quite nicely. I did have one print of a button stick for a lamp that lifted up but no other problems that weren’t of my own doing. I do however have sporadic problems with my metallic filaments silver, gold and copper from from Esun. I like them but every once in a while they clog the capricorn tube I have stuck in my hot end. It doesn’t clog the nozzle just the tube. It is quite amazing actually, I have to undo the bowden tube from the hot end and yank the filament out of the capricorn tune, but the nozzle isn’t plugged. It doesn’t happen very often but it is annoying when it ruins a long print.

good to hear about Sunlu @roon4660. Maybe I’ll have another look before sending it back. I don’t like returning things. I wonder if I can cancel an Amazon return request?

I have never returned anything so I wouldn’t know.

Is it possible you set the retract to high? That way hot filament would get up to the tubing and could form a clog at the end. Since capricorn is smaller in diameter than usual bowden any molten plastic inside the tube will plug it, while with normal tubing there is more space for the plastic to move, even with a blob at the end.

I like that thinking @Geit. To me, there’s a great deal of logic to that argument.

Yes’ that makes sense to me too. I will have to check on my retraction settings . I will have to think about how to test them. I guess I can do the two posts test.

Extruding in two ways : Pushing ( bowden ) filament or pulling ( direct ) it. Pulling has less effort to extrude than pushing due to the tube length ( diameter, PTEFE quality ) up to hot end. While right before the hot end there is a small cheap tube ( explaining in one of my posts) 3mm outer diameter and 2mm inner, it possibly can cause clogging because of the high temperature of the hot end. I haven’t find a tube similar to Capricorn in 3mm outer diam to replace it and possibly to solve cloggings after lots of prints ( by saying lots, i mean that my printers prints 24/7 ). If someone could find that tube, please tell us.