Revo (Voron) Issues

[MichaelOToole]

A couple of print failed with hotend temperature errors (something like hotend temp out of range) or Heater extruder not heating at expected rate...
One additional fail due to hotend temp over max when it wasn't.

Here is an image of the temps for the failed print:


As you can see the temps vary quite a bit, normally it's a straight line with little deviation...

I redid the pid tuning just in case... it had changed a little from previous values...

Basically, a few minutes into a print, temperature appears to fluctuate by 10° or more within a second or two (which is not actually possible).
At some point temps must drop below whatever the lower limit is set to so print job halts.
It looks like the heater or more likely (almost certainly), the sensor/thermistor is close to failing, so I ordered a replacement.

Could not find the HeaterCore sold separately so bought the Revo Hotend Starterkit...
I assume this is the HeaterCore contains both the heater and thermistor as it has 4 wires?

The Starterkit kit includes:

• 1 x 0.4mm Revo Nozzle Brass
• 1 x 0.6mm Revo Nozzle Brass
• 1 x 40W Revo HeaterCore with spring 24V

Question, is the HeaterCore the same as that sold with LDO kit (40W seems low)?

If the issue is either the Revo heater or thermistor, that's not saying much for E3D's Revo longevity...
I have much less expensive heater/thermistor combinations working for more than 5 years with far more prints completed.
I need to search for alternatives, but I like Revo

 

[5twenty]

All I know...is that I had 2 separate Revo hotends that did similar. They'd print for a bit, then clog up. Turns out it was a widespread thermistor issue. One that was said to be fixed. I wouldn't know as that was E3D's last chance...and now I have zero Revos, zero Titan Aeros, zero V6s, nothing marked E3D. Been printing fine ever since I took them out...

Not saying this is your issue, but it was a LOT of the problems when they were first released.

I'd say, by empirical evidence...it's the thermistor.

 

[MichaelOToole]

As I've ordered a replacement HeaterCore, and a new Revo Voron, I will hold off switching immediately.
I did email them to express my concern and pointing out that my three other printers still have the same hotends from purchase and have printed far more hours.
I also noted that the combined cost of their hotends was less than a single Revo. Basically, I was just venting but suggested they should reduce the cost of replacing faulty Revo's...

I bought a Red Lizard K1 and a Creality Spider Ceramic to try out on my CR10 but never got around to it... perhaps I can try them on my 2.4

 

[5twenty]

I've had zero problems with my Red Lizard K1...except the pro version - it also had the ceramic heatercore, the thermistor went bad on it too...seems like a trend with ceramic heatercores, or All In Ones?

I hope you get it figured out and don't have to change it, or pay to fix it. I wasn't prepared to shell out more money to E3D in order to fix the part that was faulty that they hadn't admitted to as of that time, which means I was on the hook for fixing it...so I agree wholeheartedly - they shouldn't pass on their costs to repair faulty engineering to the customer who may not be?

But I'll stop shaking my fist at the clouds. Good luck.

 

[MichaelOToole]

I've had zero problems with my Red Lizard K1...except the pro version - it also had the ceramic heatercore, the thermistor went bad on it too...seems like a trend with ceramic heatercores

I expected as much, I read quite a few posts on various sites mentioning ceramic heater problems, almost all of which were newly developed.
There is always issues to overcome with new tech, lets hope they fix the problems as ceramic heaters have many benefits...

shaking my fist at the clouds

An expression use by many cultures, I love it, perfectly expresses my thoughts

 

[claudermilk]

That looks like a failed heater core. I ran into that in my first Revo from the first batch shipped. They replaced the heater core and it's been solid ever since.

 

[5twenty]

Was it the heater core itself...or a thermistor or heater element issue? I guess it's moot, and why I don't like the style any longer, as if one is bad you have to replace all 3!

 

[MichaelOToole]

Mine is from Dec 2023...

Printing a test Benchy, looking for fluctuations in temp which occur every now and again.
It temps drop below some minimum, print fails but so far it's still printing...
I'm capturing the screen for the graph to post (in case it fails).

The thing is, since the seven fails in a row, it has printed two print successfully but the temp are still fluctuating... see below.

Note drop at ~04:41, below 200 but it didn't stop...



Spoke too soon, it crashed with the usual error...

Heater extruder not heating at expected rate
See the 'verify_heater' section in docs/Config_Reference.md
for the parameters that control this check.

At the end about 05:59 temps drop below 200 but this is less than first drop in image 1, where it didn't crash but now at this point it did?

I will know as soon as replacement arrives but it looking very likely to be the heater core (thermister/heater) as expected...

 

[claudermilk]

Yes, that's what my graphs looked like when the heater core or thermistor failed.

 

[5twenty]

Mine too!

 

[MichaelOToole]

To support my logic: In another life I worked in Manufacturing, Test Engineering, R&D, and Product Maintenance (Electronics 35+ years).

I have examined all connections and found no issues (cursory, that is, I did not probe during motion but did twist, flex and tug all connections while metering them)...
The type of issue one would not associate with processor boards, problems don't suddenly fix themselves...

Faulty heater and thermistors electrodes can disconnect during heat cycle, and reconnect during cool down cycles.
The fabrication methods and materials used may exhibit disconnect/connect period from a few milliseconds to seconds (or even minutes).

What's strange is, the fluctuations on the graphs look real, that is, they are in accordance with what one might expect if the temperatures did actually occur.
What the hell caused them if not the thermistor (or heater)?

With this reasoning I suspect the the thermistor but will know for sure when the replacement I ordered arrives...
I need some before and after graphics

 

[5twenty]

I haven't looked a at a Revo in a while, but the K1 Pro's thermistor and heater are spliced toward the ceramic block. If the Revo is similar, I'd check there as well. Weird splice thing on the K1, like a brass c-clip type thingy.

 

[MichaelOToole]

Guys, check this out (CNC Kitchen) worth viewing (around ~19:20), might be the exact same issue... do you agree?

 

[MichaelOToole]

I was convinced it was the heatercore in my case, I may have been mistaken (almost certainly). With more than 40 years of fault finding I still get it wrong.

While swapping out the heater core with the new one, I decided to test the cables again but this time tugging them slightly more aggressively. While doing this, I noticed one cable was longer that the other, which was strange, I cut them to the exact same length.

It was obvious... the cable must have become lose or broken away from the connector.
With a slightly more aggressive tug the cable came free (was in fact being held in place by the heatshrink).

The crimp has indeed failed but as the heatshrink held the body of the cable in place, the connection became intermittent, explaining the graph and looking exactly like a dodgy thermistor.

At least I got the thermistor part right and the graph does reflect that of a thermistor breakdowns...

I know this is only one successful test after re-crimping but the fact that the graph of the temperature was perfectly flat for the entire print, leads me to believe it was the cable on this occasion. I could be wrong, I often am...

All I need now is for it to fail again and turn me into a moron...