I have good news and bad news.
First the good news: As soon as you mentioned “sizzle” I immediately know what the problem is. There is but one explanation for sizzling filaments.
Now the bad news: You need to dry the filament and that can be … tricky.
Sizzling means you need to dry the filament. It has absorbed moisture out of the air. It sizzles and pops because moisture is absorbed into the filament. Water boils and converts to gas at 100°C … and you print at much hotter temps. So when the filament moves into the hot-end, the moisture immediately “boils” … and that’s the sizzling and popping sound that you hear (the boiled water converted to gas popping out of the filament as it is extruded.)
Storing your filament in sealed bags or containers with desiccant packs will reduce how much moisture it can absorb… but desiccant packs can’t “dry” filament that has already absorbed moisture. You have to dry it using a filament drying or oven.
This gets tricky.
Unfortunately I was not able to find drying settings for Armadillo. A LOT of filaments can be dried at 65°C … for various lengths – anywhere from 4 hours to 12 hours. If the filament is dried too hot then it can melt together on the spool and be ruined. But often you can dry it at a cooler temp … but for many many more hours to compensate.
You can try to contact NinjaTek for recommendations. I’ve used NinaFlex and Cheetah … just never Armadillo. Most TPU can safely be dried at 55°C. While I love the “quality” of the filaments … as a vendor, NinjaTek is not good about providing care instructions. The “better” filament vendors include information on how to properly dry the moisture out of their filaments.
When you don’t have proper drying instructions … you can sort of hedge your bets by using a lower temperature (just to be safe) but keeping it in the oven for many more hours (e.g. more like 12 hours rather than 4-6 hours).
To make things more tricky … it’s hard to control the temperature in a convention oven. Conventional ovens can have temps swing by as much as 20° as it cycles on and off. This means the filament can be much hotter than it can handle.
I destroyed several spools of expensive filament trying to dry them in my kitchen oven. Consider yourself warned.
I bought a couple of filament dryers and was disappointed because while the heater at the base of the dryer warmed up, the chamber isn’t insulated. When I put a thermometer in the chamber … it was nowhere even remotely close to the temps needed to dry it (and it was at the max setting possible). I wasn’t happy with either of these dryers designed to dry 3D printing filaments.
Then (this is going to sound like a sales pitch) I watched (of all things) America’s Test Kitchen talking about the quality of toaster ovens. They confirmed that ovens have massive temperature swings that can ruin food. But mentioned their “winning” oven made by Breville … which has a PID sensor that keeps the temp within 1°C of the temperature you set.
I immediately bought one … one of the smartest things I’ve ever done. The oven has dried countless rolls of filament and print quality is MUCH better. I was NOT disappointed. I should further caution… the model I bought has a “dehydrate” mode … this allows the oven to operate at lower minimum temps than most toaster ovens. CHECK the MINIMUM temp of any oven you consider buying.
I basically never print with a new spool that hasn’t been through that oven.