IEMAI Carbon Fiber PC Filament 1.75mm, High-Temp & Impact Resistant Reinforced Polycarbonate (PC-CF) 3D Printer Filament, High Strength & Rigidity, Black 1kg Spool

I was searching Amazon for a Carbon-Fiber PETG filament and this product popped up because of an Amazon flash sale (about 1/3 off). It was already a good price but with an additional third off I decided to buy 3 rolls. Opening the package I was pleased to see the filament was wound onto the spool as neatly as pictured. I loaded into the printer for a test print, it came out OK, but obviously needed to be dried. After an overnight in my filament dryer I tried again. Much better. Like other black CF filament it printed with a nice steel-gray sheen. I used the suggested temperatures for bed and nozzle. IEMAI recommends a .6mm nozzle but I had no trouble printing with a 0.4mm diamond head nozzle. I went back to Amazon and ordered 2 more rolls before the flash sale ended.

I've been buying the same brand of CF-PLA for a few years now. They were out of stock, and this (IEMAI Carbon Fiber PLA) was both cheaper and in stock. (EDIT: Eight spools deep. I'm not going back.)For context; I print exclusively functional parts, not figurines etc.Print quality is outstanding, dimensional accuracy seems very consistent. Very low to no stringing. It handles vase mode prints very well; 8mm dia x 30mm length test pins printed very quickly (~80mm/sec actual) with no flaws. It bridges extremely well with high airflow -- honestly I've never seen better bridges from my printer.Info on my setup;- Extruder is a custom dual-drivegear 3:1 non-bowden extruder, hardened steel nozzle, 0.5mm bore, 0.3mm retract at 40mm/sec, heated to 223c- Bed is glass, coated with a light mist of hairspray diluted to a thin layer with a coat of water from a spray bottle, heated to 57c- Layer heights are usually 0.2mm or 0.25mm, outliers at 0.15mm and 0.3mm- Print speed began around 60mm/sec~90mm/sec with ~1500mm/sec^2 acceleration, but recent improvements and tunings has it closer to 90~120mm/sec @ 3500mm/sec^2 with 0.2mm to 0.3mm layer height, with negligible notable change in quality.It carves well if required, it drills well (unless you get it hot, obviously - it softens at a lowish temperature compared to hotter filaments, due to the PLA blend) and as stated it retains flawless dimensional accuracy. Ironed top surfaces look fantastic, and parts have a very satisfyingly solid sound when impacted. Side surfaces are smooth but grippy, a bit rougher than my normal brand of CF-PLA.I'll update this bit as I order more rolls, but thusfar:I've ordered eight rolls to date. I made no adjustments between rolls, and prints remained flawless with the exception of;- The first print or two (~100g) from the first roll had occasional blockages which self-cleared within the same layer; I'm willing to attribute that to possible contamination on my end.- The first few meters of the fifth roll, which needed a 5% feed reduction for 'perfect' surface finish.- One nozzle jam, less than one meter of filament from the end of the sixth roll. Would've killed the print, but it was on the final, small area on the very top layer. Cleared with cold pull at 150c.- Roll seven (Batch No 20221017ZD) had (to date) four clog issues which caused failed prints. Two abrupt, complete blockages fixed by hot-pull with no cycling after print cancel. Two partial blockages, one fixed via hot-pull, other fixed via cold-pull. I'd be more upset if these weren't non-final prototyping parts.- Most pics are before resonance tuning, so their surface finish isn't flawless. I also had some frame stability issues causing irregular layer height, which have been solved.- The ironing finish is astonishing. I've added three shots of 1mm thick, 115mm long vanes from an airflow project, with an ironed top surface. Ironing was 0.125mm, 20% flow rate, 30mm/sec. Lines are (BARELY) visible at this setting and using a 0.5mm nozzle; for perfection I would suggest 0.1@25mm or so. I'm not aiming for visible perfection with this project, so this is not an example of attempting such.- Also, three additional pics of the underside of the same vanes - I literally forgot to enable supports for the underside of a dead flat, unsupported, 2mm deep, 115mm wide overhang. It's tiny so it's impossible to get better pics, but it printed, perfectly. 500mm/sec bridging acceleration, 60mm/sec bridge speed, 0.98 bridge flow rate. I've honestly never seen anything like it.- I printed the auto-rewind filament holder, including the clutch and springs, from CF-PLA. I'm shocked to say, it has good spring-like qualities due to the TPU additive in the base blend, and the CF-on-CF clutch seems to be surviving very well so far. My extruder gearset is also printed from CF-PLA, and doesn't wear like I had expected -- this one gearset has lasted at least 12kg of printing so far.Sum total; seven rolls (~7.5kg by filament tracker) printed on one hardened steel nozzle (so far). Five failed prints from the same roll. No filament-derived bed adhesion issues. No layer adhesion issues. No significant diameter variances or other visible/brittleness problems with the filament. Roll seven aka Batch 20221017ZD has given me the most problems. If my experience were based on this roll alone, it would be three stars. Thankfully, I do know better. This is still 'my brand'.

This filament is awesome. Honestly, it prints better than regular PETG. Yes, PETG alone is slightly flexible, but the introduction of carbon fiber changes all of that. Prints are stiff and strong, but there is a tradeoff in that prints are more likely to shatter if dropped or hit. This filament is so stiff that caution should be used when processing prints, so that you aren't cut or stabbed by your print. If you heat up your nozzle and pull off the ooze that forms, you pretty much have a needle, once it cools.This filament likes lots of cooling. The more air hitting the part, the less "foamy" the resulting print looks. It took me a bit to realize that it was the cooling that was causing my prints to look the way they did at first, and not an issue with my print temperature. Parts printed with this filament have a matte finish that helps hide print layer lines. The CF completely removes the shine of normal PETG.Order a spool and try it out...you won't regret it. This brand is also the cheapest I've seen on Amazon...great value for what you get.

I've printed a fair amount of PC filament in my experience, and for the most part the majority of the brands can be printed with a nice quality finish with very similar settings. But this stuff behaves a bit different in that it needs 100% cooling if and when you have your slicer set for the printer to slow down on outer walls. It prints fine at faster speeds and low cooling, but if you don't cool it off when it slows down, it'll look like trash. But when it does cool properly, the CF leaves a really nice MATTE finish.Also, unlike other PC I have printed, this smells like ABS when it's printing. So make sure you are well ventilated while using it. My printer is in my office and while sitting at my desk with the printer running, I started getting a mild headache, and when I walked past the printer I could smell the polystyrene smell of ABS coming from it.I don't think I would buy it again for that reason, but otherwise it prints great once you get the settings tweaked.

I blow through this filament like there's no tomorrow for lenses. I've compared it to another more expensive brand and found the print quality to be as good if not better. At least it seems more consistent. Do be sure to dry it for optical clarity, as with all transparent PETG filaments. I think people skip that step and have mixed results. I've had these on a vehicle for lenses for over a year now with no warping or fading. Really a good filament.