Well decided to give a dryer a try. After some looking, went with the Sovol SH02.
Works great. Does exactly what their website claims. Heats fast, air circulation is excellent. Setting for each type of filament is preprogrammed, but any parameter can be modified.
Unit will heat up to 70 Deg C, holds two 1kg spools, and has bins in the bottom for desiccant if you can’t get to pulling out the spools right away.
Fan is a bit noisy (whines). Don’t know if they are all like that, or if I got a noisy one. Just sent them a message about this.
Have some reusable spools printed in PLA. Was able to dry them at 50 Deg C without any warping.
Got it on sale from Amazon for $64. Is no longer on sale, but keep an eye open around Christmas.
Have you tried printing directly from it, especially TPU?
I want to try TPU printing, but given how hygroscopic the material is and how people describe issues with printing it it seems printing from filament dryer is the best option.
Not yet. Busy printing parts for work. Hope to try TPU next week and will give the dryer a try. That will depend on whether I finish with the work stuff. Lately, as soon as I finish one work print projret, something comes up and I need to print another one.
Understood. The COMGROW has the same ‘list price’ as the SOVOL, so I am pretty sure they are the same. But if your comment is directed to both SOVOL and COMGROW being lower cost, you are absolutely right. I doubt if either one has UL certification, which gives me a bit of pause. tI does claim to have a thermal protection circuit on the heating element and a stopped fan alarm (both SOVOL and COMGROW - another reason to think they are identical), so they are at least a little bit concerned about safety, but I have dealt with Chinese companies professionally (30+ years as an electronics engineer) so I know some are more responsible than others.
I did buy the COMGROW SH02 dryer. Nice UI actually, although its suggested temperature and time does not match Bambu recommendations for their filaments. Two things I noticed is that the actual temperature runs about 5C lower than the temperature reported on its display, but the humidity reported on the display tracks a hygrometer in the unit pretty well.
I am not quite sure why, but it doesn’t seem to dry things as well as my Crealty dryer. When I dry a spool there, my hygrometer goes down to 10% (its lowest reading) and when I take it out and put it into a vacuum-sealed bag with a hygrometer, it runs about 15%. With the COMGROW, the humidity reading on both the display and my hygrometer in the unit both were bottomed out about 20-25% and that is about what I got when I put the dried roll in a bag with a hygrometer. Not sure why there is a difference, but it just doesn’t seem to work as well.
I have both of these, the Comgrow & Sovol. Both from Amazon, same price. They look almost the same, the Sovol’s screen is slightly larger & its grey over the comgrow’s unit is black. Otherwise they seem to be the same unit, down to they both throw out H1 errors atleast once a week. I agree them seem to underheat, i typically just crank it up 5 degrees. I went with these 2 units over say the big Sunlu, just so i can cook 2 types at once.
Just to make things clear, the hygrometer never shows the filament humidity but the air humidity. So whatever your hygrometer in the vacuum bag shows, its not the humidity of the filament but the left air inside (and thus ofc differs according to your actual room humidity). If you want to compare the two dryers, take a humid roll of filament, cut two equal long pieces and weight them on a fine scale. Put them in each dryer and when they are finished weight it again. The weight difference shows how much water your filament lost.
You are right that the hygrometer does not show filament humidity, but once a sealed container reaches equilibrium, there is a monotonic function relating the air humidity to the moisture content of the filament. In other words, a lower air humidity is representative of a lower filament moisture. This curve is not linear, and since I am not trying to get an absolute moisture content, I don’t really care what the actual function is, but it allows me to get a rough comparison of the effectiveness of drying, and once I have enough data, I can use the equilibrium air humidity to tell whether the filament is dry enough to get good prints.
A few days ago, I dried a new spool of PETG-HF at 65C (really about 62-63C according to my own temperature monitor in the dryer) for about 14 hours. I took the spool out and weighed it periodically during the drying time. It lost 4g of moisture total during that drying time, losing 2g during the first 2.5hr, another gram in the next 2.5 hr, and another gram during the next 3.5 hr. It did not go down any further for the final 6 hrs. My scale only has a 1g resolution, so it was probably still losing moisture, just very slowly. I put it in a sealed vacuum bag and it currently reads 19% RH in the bag. I have several other bags of PETG-HF that I dried and put into bags with a hygrometer, and they all started under 20% RH and are now 25-29% RH after several weeks in the bag. I believe that the additional moisture is coming from the inner parts of the spool which probably don’t dry as effectively in a few hours in the dryer, but some could be infiltrating through the bags, I suppose, because I am not using aluminized bags, just plastic vacuum bags, and water molocules are smaller than most other gases in the air (e.g., N2, O2, CO2).
My first batch of PETG HF black printed perfectly after 6 hours of drying at 65 with the SH02, I wonder if it needed drying at all.
My second batch - dried 8 hours, printed and found little pimples on the print, dried another 8, same issue, dried another 8 hours - looked ok in the beginning but same issue near the end of the roll.
Drying the inside of the roll is quite an issue!
I can tell somewhat how dry the roll is by looking at the humidity climb when I have the dryer closed, newly opened rolls will have the RH climb faster. Almost totally dry ones will settle at like 10%. But that doesn’t say much for the inside of the roll.
It seems like I need to dry 24h, and then dry between prints. For longer prints, have 2 spools and keep alternating them between the AMS and dryer…
Always check the weight of the filament before and after drying process. That will always give you a better indication as to how effective the drying process was. Standard dryboxes (the most common ones, no matter where one buys them from) don’t evacuate the excess humidity from the box (missing proper ventilation to remove excess humidity to outside), so what their hygrometers indicate lead users to false conclusions.
Check the weight of the filament before and after drying and you’ll be surprised by the results.
Eibos Easdry is one model that does have proper ventilation. I verify dryness by monitoring weight. When the Easdry indicates 10% for a half hour or more the filament is truly dry.
It would be helpful to know which other dryers actually expel the moist air instead of just recirculating wet air.
They are indeed the same, just with different labels for the SH02 filament dryer. I bought it from their website, and I find the prices on the website are always cheaper than Amazon, including the printer
