Simple Metal erratic extruder readings

[kolakidd]

Hi,

I don't know if anyone else has had this issue, I am using Cura 15, with a Ubis 13S hot end. I started getting really erratic hot end readings in Cura, variances of up to 20 degrees during printing. I ran a PID loop and got these results, this is with no filament.

I was going to input the PID settings as per the instructions on another post on the forum, but the KP value looks really low, does this look right to anyone? And are there any other issues I should be checking for?

> M303 E0 S210 C8
< PID Autotune start
< bias: 137 d: 117 min: 194.12 max: 210.63
< bias: 133 d: 121 min: 192.10 max: 210.63
< bias: 112 d: 112 min: 206.25 max: 211.91
< Ku: 50.35 Tu: 12.45
< Clasic PID
< Kp: 30.21
< Ki: 4.85
< Kd: 47.03
< bias: 111 d: 111 min: 206.13 max: 211.88
< Ku: 49.23 Tu: 13.50
< Clasic PID
< Kp: 29.54
< Ki: 4.38
< Kd: 49.84
< bias: 137 d: 117 min: 188.28 max: 220.54
< Ku: 9.24 Tu: 13.37
< Clasic PID
< Kp: 5.54
< Ki: 0.83
< Kd: 9.26
< bias: 101 d: 101 min: 197.70 max: 224.29
< Ku: 9.67 Tu: 14.94
< Clasic PID
< Kp: 5.80
< Ki: 0.78
< Kd: 10.84
< bias: 137 d: 117 min: 189.14 max: 227.00
< Ku: 7.87 Tu: 16.12
< Clasic PID
< Kp: 4.72
< Ki: 0.59
< Kd: 9.52
< PID Autotune failed! Temperature too high

[RetireeJay]

Check your thermistor wiring; you probably have a fatigue failure where the wires get bent back and forth repeatedly at a point. You can do this by just setting the hot end temperature to, say, 150C, letting it warm up, and then exercising the wires by hand. If the reading gets erratic (particularly if the reading goes to lower temperatures) you have wires that need to be replaced or repaired.
Don't activate the new tuning parameters until you have good wires.

[kolakidd]

Thanks RetireeJay!

I will check that, however, I think I may have picked up the problem this morning. The fancy shroud I was using has melted close to the hot end housing. I'm printing a new shroud now. The past couple of days I have been doing 5-12 hours prints, which is why it probably happened.

Just out of interest, seeing as though you're probably the most active user on this forum, what slicer software are you currently using?

[RetireeJay]

When I was using the Printrbot, I was using the current version of Slic3r and the current version of Repetier.

The Printrbot has been mothballed since April, as I'm using my new Prusa MK3. In this case, I'm using the latest version of Prusa's modified Slic3r, called Slic3r PE, and I'm still using Repetier for the connection to the printer.

[novice]

CuraB.jpgCuraA.jpg

Four years ago I would have told you Repetier-Host 1.06 ? using Slic3r produced superior prints over Cura 15.04.6. Today I use Cura exclusively to produce clean prints that wow even my cynical mind. IMHO it turned out to be the operator and machine that required the changes. Perhaps these SM/Ubis 13s settings will help in some way.

[kolakidd]

@RetireeJay, that Prusa i3 Mk3 looks like the business, It's been high on my wish list since launch. I am an electronics hobbyist primarily, so the 3D printer facilitates parts and prototyping, I need it to be as low fuss as possible. I also happen to live in South Africa, which has an extremely weak currency, so cost-effectiveness is also a big part of the package!

@Novice, Many thanks for those settings! I will try them out right away.

[kolakidd]

@Novice, those settings are the bomb, I am getting really nice quality out of them. Thank you!