Is K2 usable with CFS for anyone?

dgatwood42 · May 17, 2025, 6:33am

I just got a K2 with CFS, or rather, I just got, returned, and replaced a K2 with CFS, and I’m still having nightmarish problems.

Though this is a new printer, I’m not exactly new at 3D printing, having used a Snapmaker for half a decade. I’ve never seen a 3D printer be as completely useless as this one is. Out of dozens of attempts, I’ve only had two attempts make it more than a quarter inch off the print bed before failing to swap filaments. And it is currently unable to even make it through the Self-Check process without throwing an error more often than not.

The only question in my mind is whether I’m missing something that is easily fixable, or whether this printer is simply fundamentally designed wrong in a matter that can never be fixed.

I’m using Creality PETG (non-Hyper) and breakaway PLA.

After a brief period of working correctly, just enough to get a third of the way through a single model, the filament switching began failing more and more often, until loading the filament fails approximately 100% of the time.

Most of the failures are either:

Bogus clogged tube errors
Bogus clogged extruder errors
Not extruding errors

Sometimes, it fails claiming (falsely) that the tube is clogged.

I’ve already tried:

Swapping the filament sensor
Swapping out the cutter
Bypassing the buffer
Adding a plate to extend the cutter spike
Lowering infill / wall overlap to 15
Verifying a clear path through the cold part of the extruder and verifying it can move filament by hand
Downgrading to 1.1.2.6 — no difference
Downgrading to 1.1.1.7 — would not install
Print temperatures as low as 140 and as high as 180
Switching from Creality PETG to Overture PETG — no difference other than worse adhesion for the brief moments of successful output; still issued a clog error

There is no evidence of clogging in the hot end. When filament moves at all, the extruder works normally. It just isn’t pushing the filament out reliably or extracting it reliably. It almost acts like the output hole in the plastic block above the hot extruder block is slightly too small. For every PETG filament, including Creality’s filament.

Current firmware. Calibration does nothing.

I’ve had it for only two days, and I have gotten a whopping sixty-three errors as of an hour ago, and that’s before I started trying firmware downgrades and alternative filaments. The errors are listed below:

AC0521

AC0104

AC)119

CM2784

F00528

CM2784

FR2865

FR2849

FR2836

FR2865

FR2836

FB2844

FR2836

FR2849

FO2837

FR2849

FO2845

FR2836

FR2865

FR2836

FR2849

CX2585

CX2586

CX2585

FR2849

FO2845

FB2847

FR2845

FR2836

FO0528

FR2849

FR2836

FO0528

CM2784

FR2865

FR2836

FS2843

FS2840

FO2845

FR2851

FR2836

Is this a typical user experience? Because this is by orders of magnitude the worst experience I’ve ever had with any 3D printer. Should I just write off the entire platform, ship it back, and buy something else? Because I’m at that point after just two days of absolute failure to print anything.

The best part is that this is my second Creality K2 Plus. The first one got here less than a week ago and went right back to Amazon because the Z axis was making an awful buzzing noise and the print head was crashing into the front of the front and back of the enclosure repeatedly while printing. Completely out of control. And the layers kept not adhering, etc., probably because the Z axis was hosed. No way was I going to deal with a lemon like that, so it immediately went back.

I think it was switching filaments correctly, but its failures were so catastrophic that it didn’t even make it to the few hours of printing when this second one started failing, so that isn’t necessarily an indication of anything.

Barring that last version downgrade turning out to be a miracle, this ons is probably going to go back, too.

Before I ship a second Creality K2 back to Amazon and walk away from the brand forever, is there anything else I can try to make this thing actually extrude more than 5% of he time?

Thanks,
David

dgatwood42 · May 17, 2025, 10:48am

I think I might have found the problem, unless my success is a fluke. I read a post talking about the temperature somebody else was using to print with Overture PETG, and was shocked by it being a whopping 285 degrees, which is 35 degrees over the maximum recommended by Overture.

The post also noted that the automatic temperature adjustments based on flow do not work correctly, and result in the temperature being too low.

Cranking the print temperature up to 285 degrees appears to have solved the clog. It has been printing for over two hours with multiple filament changes, and it hasn’t jammed up and ground a thin spot in the filament even once in all that time.

So apparently, either:

There’s a bug where the filament swap does not run nearly hot enough relative to the print temperature, or
The nozzle temperature is off by about forty degrees.

Amazingly, I’m pretty sure it is the second one. My Snapmaker prints the exact same PETG reliably at 245 degrees. At 245 degrees in the K2, the filament comes out as cold strings that don’t fuse correctly, so I had already experimentally pushed the temperature all the way up to 260 degrees — ten degrees above the manufacturer-specified maximum — just to get a usable print.

So apparently, the nozzle temperature is off by at least 15 and no more than 40 degrees. That’s terrifying, particularly given that one of the filaments giving me fits was a genuine Creality filament, and you’d expect that they at least tested their own stuff.

My first thought was a bad nozzle temperature sensor, but on two printers in exactly the same way? It almost has to be either too low a voltage going to the temperature sensor (hardware design flaw) or a software bug. Maybe I should try powering the thing off a Jackery instead of my probably-below-normal household line voltage and see if the issue goes away, but I wouldn’t think anybody in their right minds would use an unregulated power supply for something like that, so I’m not holding my breath.

Anyway, problem at least partially solved in that the printer is able to print something. I still haven’t found the root cause, quite, but at least I’m within spitting distance of it.

dgatwood42 · May 17, 2025, 4:25pm

Well, it almost worked. Except that the amount of time it took to switch filaments and print some of those areas of breakaway material was sufficient for the top layer to cool down, resulting in inadequate adhesion, so the model came apart between layers while pulling it off the bed, and with a little tugging, ended up in five parts.

This, coupled with the almost complete lack of strings, tells me that the nozzle temperature is actually MORE THAN 40 degrees higher than it actually is.

I’ve ordered an IR thermometer. It will arrive later today. Will follow up.

dgatwood42 · May 18, 2025, 6:58am

It’s hard to get a good reading from an IR thermometer. On my Snapmaker, with the temperature set to 240°C, the highest reading I managed to get was 203°C.

But on the K2, at 240°C, the highest temperature reading I could get was 173°C, a whopping 30°C lower.

So at this point, I’d call that an absolute confirmation that the temperature sensor in the hot end is likely defective, and I need a new hot end.

How I managed to get two 3D printers in a row with that defect is beyond me, though. If you want to know what lottery numbers not to pick, I’m your guy.

I’ve emailed Creality and asked them to send parts.