CR6-SE fails to heat hotend to set point

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TL;DR - Please help me rebuild my CR-6 SE so that I can move on


Here's a link to the latest issue that I had to make proof of in a video: CR6-SE failed

Basically, it's failing to reach/maintain temperature (set point of 240 °C, fails to heat above 230 °C), issues start to happen at temps as low as 210 °C. Creality support is evasive/dodgy. First, they want to see a video proof for the problem reported, and after a while and emails from me asking, suggested something obvious (set temp to 200 °C).

And without any video, they don't respond. Just like last time when I ran into the defective/burned power switch and failed bed leveling.

If you have some spare time, please quickly check the video and provide some feedback.

I already fixed the burned power switch and auto-leveling (Creality ignored me, so I got the parts from Amazon).

This is the last issue that I need to do a "mercy" fix, so that I can either repurpose it or, just give it away (but I still have to make it working again and safe!). I already placed an order for an i3 MK3S+, should've bought this in the first place to help me study 3D modeling, not working my degree towards fixing Creality printer failures :)

Thanks in advance.

My troubleshooting steps so far after a screw fell off during print:

  • Disassembled the hotend: found heater block loose, screws were bent and somewhat stripped
  • Heater resistor has a bad crimp
  • Thermistor is reading temp, but I don't know if it's accurate (don't have a multimeter+thermocouple)

Ordered a hotend from AliExpress, hopefully, that's it

bigpow

Posted 2021-01-30T00:04:44.543

Reputation: 37

Just to doublecheck, as there is no sound in the video. You don't have a nozzle fan turned on during heating? Please check my suggestion about PID tuning. – octopus8 – 2021-01-31T00:35:26.593

Yes, I disabled audio in OBS. – bigpow – 2021-01-31T23:10:31.667

I advice to buy digital electronic multimeter, even very basic. Learn how to use it, because mistakes may be dangerous: for electronics or for you (in case of high voltage, etc.). For me it is the very basic tool. And thermocouple ... not needed for standard calibration and troubleshooting, I think it is nice addition which may help from time to time. – octopus8 – 2021-02-01T03:08:54.540

Thanks. I have 2 Fluke meters at home. I just don't have one that can do temp. I'm a retired HW Eng. that's bored at home and jobless and trying to learn the latest 3D modeling & etc. :) – bigpow – 2021-02-01T18:01:51.830

Answers

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Perform PID calibration procedure for hotend using G-code 'M303' with nozzle fans turned off completely.

You may use detailed guidelines from AK Eric's blog, RepRap wiki or 3DMaker Engineering.

If this will improve or clearly change the situation, but you still observe some issues during or after tuning, review other posts for troubleshooting. For example: large initial overshoot, no oscillations, struggle to fit into functional range or narrowed down hardware issues of incorrect heating cartridges.

When succeeded, you should repeat the procedure with fans enabled at the regular speed you use during printing.

PID calibration can be performed from Marlin's LCD menu (Configuration > Advanced Settings > Temperature > PID Autotune E1). It will allow to select target temperature, but not number of tuning cycles. It is only accessible when PID_AUTOTUNE_MENU is enabled in firmware settings (Configuration.h):

//#define PID_EDIT_MENU         // Add PID editing to the "Advanced Settings" menu. (~700 bytes of PROGMEM)
#define PID_AUTOTUNE_MENU     // Add PID auto-tuning to the "Advanced Settings" menu. (~250 bytes of PROGMEM)

octopus8

Posted 2021-01-30T00:04:44.543

Reputation: 722

Thank you! This is really helpful. I will follow the guidelines; I always want to know how to calibrate the PID, especially now that I'm gonna be replacing the hotend assembly. Knowing how this thing works, it's probably not gonna be a swap-and-run operation. Since my heater block is stripped (the screws are harder than the block), I might just play around with it until the parts arrived. – bigpow – 2021-01-31T23:04:54.513

BTW: Will I need something like this for cal? https://amz.run/4Geu

– bigpow – 2021-01-31T23:23:18.097

No, for PID calibration, you do not need any extra tools. This is just running few G-code commands with serial terminal. Quicker for hotend than for bed (same process, but just takes longer). It will take you about 30 min for first time, including reading, so you will quickly confirm that this was just calibration. I hope to hear from you soon. – octopus8 – 2021-02-01T02:57:53.290

I added info about LCD menu to the answer. If PID calibration will help you to overcome an issue, please accept this answer. – octopus8 – 2021-02-01T07:51:48.363

I don't think PID calibration would help out in this case. There is a ton of issues with this printer type. – 0scar – 2021-02-01T08:23:43.030

@0scar It doesn't hurt, plus I get to learn something new. Agreed that there's a ton of issues with this printer type. But I also think, the biggest issue is with this company (Creality). – bigpow – 2021-02-01T18:36:21.830

@bigpow True, PID tuning is something that does not hurt, can be a challenge sometimes. I think the offset is too big to be fixed by a different D(ifferentiator). I suspect that there is a problem with the power connector. – 0scar – 2021-02-01T19:05:26.983

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I replaced the hotend with parts bought from AliExpress.

My printer is now able to reach/maintain temperature and complete prints successfully (no more heating failure).

BTW: It's harder to buy replacement parts for CR-6 (as compared to other Creality printers). There were only 2 type of replacement hotend parts for sale on AliExpress at the time I was shopping:

  • 40 USD for a full assembly (with carriage)
  • 28 USD for a nozzle kit.

There's an Amazon seller and a Canadian 3D printer store that sells individual parts, e.g.: heater block, but the prices are relatively expensive.

I bought a full assembly, but a nozzle kit would have worked as well.

Also, it looks like they're fixing their production process; my new hotend assembly was built better, even with what appear to be the same parts.

Not pretty, but at least it's printing - Hopefully this is it.

test print

bigpow

Posted 2021-01-30T00:04:44.543

Reputation: 37

Ok, so you have replaced the "thermistor"? And it helped, great. Btw. did you calibrate the PID after modification? ;) I am not kidding, could help to keep temperature in check. There are striiiiiiiings, lower the hotend temp. But cooling seems good looking at the rear pipe. – octopus8 – 2021-02-07T00:15:18.863