I bought some Bambu Lab PETG-HF and when I print with it, there are these tiny bumps randomly scattered across the surface that do not show up when using Bambu Lab PLA.
I would describe these little bumps as like if you get a little tiny snag in some of these high-tech fabrics like you can get from Under Armor for example.
I can print the exact same 3d model but using Bambu PLA which narrows it down to being a filament problem or a difference in how Bambu Studio is configured to slice PETG vs PLA as far as temperatures because I have not had any need to deviate from what is pre-programmed.
Truth is that even with what I would call the nit’s in the PETG flat surface, I would not reject the print. On it’s best day my Ender-3 Pro would not generate a print as good as what the P1S is generating, nit’s and all
Hi,
Can you share an image?
Did you dry your filament? To achieve a high-quality surface and print at high speed with PETG.HF, moisture, even if it is minimal, will matter.
Also, did you calibrate the filament? At least flow rate and pressure advance can make a difference in aiming for high quality.
Drying as in putting it in a dryer or letting it sit on build plate at a moderate temperature I did not. I thought of the heating and it may come to me buying a spool heater box, but that is the most recent Bambu filament I’ve bought and is only a week out of the vacuum sealed bag Bambu shipped it in. I do not have a picture as my brother now has the part His comment was “That is not a problem so leave it.”
You may be demanding too much, but printing PETG at high speed and keeping it high quality requires being demanding with pre-steps. Drying is critical, and PETG-HF is bound better to water than PLA.
BL also state it:
PETG HF must be dried before use
It would be best if you dried it using either specialised equipment or an alternative one (e.g., I use a food dehydrator). Never assume a filament is dried, even if it is vacuum sealed. It needs to be cooled down during manufacturing, and you can imagine how it is done.
I’m curious just how dry is dry.
I don’t discount it as I’m sure they’ve done some testing but what does Bambu Lab consider dry.
I have been mulling over how to keep the AMS warm by using air from the enclosure to purge through the AMS.
I have never laid eyes on any of the filament dryers so that is an open question as to if they are circulating and constantly purging hot air to carry away the moisture. I did still have a plate
PETG-HF is recommended to be dried before use.
LOOOL
What is your procedure for drying a full spool and keeping it dry?
I’d love to have a scale to weigh the filament before and after, but I haven’t gotten to buying one yet.
I never, ever, assume a spool is completly dry. I am more lax with PLA and usually use it and adjust accordingly.
With PETG-HF I will put it in the dryer over night. At least 8 hours but I’ve gone as long as 15 cause I gotta go to work.
PETG-HF is stored in bags or in my dryer, if not in the AMS with good desicant. Use and either store in AMS if I’m going to use again soon, or bag, or keep in the dryer. I have an S4 so I can store 4 spools in it. Tend to keep ABS, TPU, and PETG in it.
I’m going to see how much is involved in making a dryer box myself. Seems pretty basic. Does your dryer use warm air at all or just rely on Dessicant.
How is air circulated?
It’s a lot of text with a number of side conversations, but there’s a lot of information in there too.
https://forum.bambulab.com/t/filament-drying-preliminary-results
Short answers are that regular filament dryers are flawed because of how negatively ambient relative humidity affects drying. Think the difference between the dry heat desert and a steamy jungle. Sweat evaporates so fast in the desert you can get chilled. Manufacturer’s tell you how to dry filament using industrial drying ovens. Not the same thing.
What I’ve been working on is turning ambient air into dry air and pumping that into a filament dryer. Filament dries consistently faster and it’s easy to dry to low humidity in a filament dryer.
Filaments like PETG HF need to be dried and this does it. I’ve just dried one spool of PETG HF but it printed great. It actually printed pretty good out of the shipping box, but printed better after drying.
Here’s what I do with PETG HF
I then store them in sterilite sealed containers with desiccant. I don’t use the desiccant bags, I’ve dried those and none get the humidity down very low. All my storage boxes with bulk desiccant remain at 10%, according to the cheap hygrometer. A bit more expensive hygrometer puts them at 16%.
I dry the PETG HF, Basic and any PETG/ABS. I’ve not yet bothered to dry PLA.
Here’s my concern and is very dependent on your personal usage.
As a hobby, it doesn’t really matter but if you are heating the PETG-HF for days on end to keep it dry for a 3 hour print once a month, that can be an expensive print
If the quality stays the same as picture I posted, I’d probably not heat it.
Can I ask where you found those clips for your containers? I have the same ones and the blue ones from the factory brake within a week of opening and closing them.
After I dry filament, the spools go into poly cereal boxes with a packet of silica gel desiccant and a hygrometer. All of my open spools are in those cereal boxes and all hygrometers are showing 10% RH (the minimum they can display).
The cereal boxes are just a few dollars per and same for the hygrometers. If you have good storage and don’t leave the spools sitting out, including keeping the RH low in an AMS, you shouldn’t need to keep re-drying filament.
On drying PETG HF for days on end, that’s a fault of common filament dryers that can be sidestepped by drying filament with dry air. Use dry air in a filament dryer and you can dry spools in hours instead of days.
I’ve printed them in PLA, no issues so far.
Yup, definitely moisture blowouts.