I am completely disgusted with my K1C, one year old, bought new in February 2025. Often the extruder simply refuses to feed filament. This is an on-going problem. Once, the extruder stripped teeth from one of its plastic gears, so I replaced those with metal gears. Today, it refused to feed filament, even though it worked fine yesterday. Now I have to disassemble it and figure out what the problem is.
The filament moves freely from the spool and through the long Teflon tube to the extruder.
What the heck is going on? I don’t ask much from my printers, and my models are simple; this one is a holder for 1”x3” self-stick labels. It’s just a 1”x3” flat rectangle 0.05” thick, with four hooks on the rear; photo attached. It prints face-down on a smooth metal build plate (with glue) to get a smooth front face for the label.
I disassembled and cleaned the extruder mechanism. The piece of filament stuck in it had been ground away by the extruder wheels, indicating that something was preventing the filament from moving. I discovered the problem was that the filament tangled as it left the spool. This is not the first time I’ve had the same problem with this particular brand of filament, and not others. I will scrap this spool and buy a different brand that I’ve used before, and which has never given me this problem.
If you have a CFS with your K1C, be advised that cardboard spools (even those from Creality) cause problems with the CFS function. There are models for printing rims that you place on the cardboard spools that help some but I found the best solution is to stay away from cardboard spools if you have CFS. Another fix that works is to buy 1.5” steel ball bearings (about $15 for a set of 5 of them on amazon) and put one of them in the hole inside the spool. This adds enough weight to the cardboard spool that the CFS always turns the spool, but if you get filament tangled on the spool it will pull the spool out its nest and up against the top cover. With regard to the feed problems, the previous comment is absolutely the fix for almost all feed problems like you describe. When it happens with CFS, open the lid, grab the filament your trying to feed and see if you can pull a little bit of the spool. I almost always found the spool got jammed in its nest and wouldn’t turn OR the filament got tangled and wouldn’t feed. Both are easy to fix.
I also found that slowing your print down can nearly always fix most prints. On my printer, I set up two new printer settings that I title S50 K1C 0.4 nozzle and another I title S75 K1C 0.4 nozzle. All you have to do is create a copy of the printer setting you have been using then add the g-code at the end of the start string “M220 S(percent of normal speed you want)” . I usually use 50 if I have a layer shift failure, and 75 if I am having other quality problems. Below is a screen shot of what the g-code change is that I’m talking about. By the way, this seems to just reduce top speeds and it doesn’t increase print time all that much.
I hope this helps you some. I rarely get feed issues anymore, although I do sometimes get problems with the filament breaking or getting stuck in the buffer but they’re relatively infrequent and easy to fix and I haven’t been able to find a fool proof fix for that yet but I’m working on it.
My K1C doesn’t have CFS, just one spool on the OEM spool holder. Long ago I designed “hub bushings” that I glue to every spool of filament. The thin profile produces less friction than a full-width hole. Photo attached. I use “amazing Goop” to attach them so I can remove them for reuse when the spool is empty.
Needless to say, each pair of bushings is unique to a specific spool. Vendors can’t seem to standardize on hub sizes. 8^(
Bottom line: My K1C is working fine since I removed the stuck filament and cleaned the extruder wheels. I now believe the filament from a particular vendor became tangled on the spool, preventing it from feedling.
I agree: my K1C prints at marginal quality, and my K1 Max has even worse quality and has been unreliable. I keep going back to my old Prusa MK3. I’m also going to be in the market soon for another high-speed printer. I don’t know what I’m going to get, but I definitely know what I’m not going to buy.
