Few questions about the rostock

[ichiban]

Hi guys,

Been lurking here for awhile now and have been trying to trouble shoot the printer and get it to print reliably. I am still running into a few problems that I'd love some insight into.

Firmware: Repetier Max
Software: Repetier 0.90C
Extruder: Ezstruder
Hotend: Seemecnc hotend with heat cartridge
Bed: Onyx Bed with 24V supply

My biggest issue is probably temperature. I just can't seem to reliably tell what the temperature of the extruder is. I have a contact thermal couple that I stick into the nozzle hole (.5mm hole) to get a temp reading. In order to print reliably without the extruder slipping, I have to take my temperature up to close to 270C as read on the thermal couple. The host software was reading the temperature way low compared to the thermalcouple, so I recently changed the multiplier in the firmware to adjust the LCD/software reading to that of my thermal couple. I get brown spots on my prints from time to time so I know there is something going on with the temperature, but when I try to drop the temp to 230C, the ezstruder would slip and the print turns to crap. I can get semi decent prints with the temp at 275C anything less, i start to see slip in the ezstruder.

Here are a few pictures of my most recent print:

This one is done with kisslice, it has raft/support/and 25% infill.

[JohnStack]

It has been recommended to use the contact reader at the head and not the nozzle hole. Just unscrew it a bit and put it in there and gently screw back on the nozzle.

You appear to have some blobs - which might indicate too much feed and heat.

The ideal temp truly is 240 - but yep, you have to find it. My multiplier was a crazy value - like 4600 or something.

Also, slow your print down a bit - that might also be a cause.

[ichiban]

It has been recommended to use the contact reader at the head and not the nozzle hole. Just unscrew it a bit and put it in there and gently screw back on the nozzle.

You appear to have some blobs - which might indicate too much feed and heat.

The ideal temp truly is 240 - but yep, you have to find it. My multiplier was a crazy value - like 4600 or something.

Also, slow your print down a bit - that might also be a cause.

Thanks for the heads up. I've read about screwing the thermal couple between the brass and aluminum part as well, the brass part is so gunked up, it's hard to crank it open, is there a big difference between that and the nozzel hole? maybe i will give it a try. As for the feed, the print in the picture was done at 55mm/s, just haven't been able to bump it up higher than that without print quality going down.

[ichiban]

I am doing another print now with the support gap set at a lower .25mm. The biggest difference is turning on the air, it seems to have helped a little bit.

[ichiban]

still trying to figure out this temperature issue. Anyone have ideas why i'm running at 285 to print abs?

[Polygonhell]

still trying to figure out this temperature issue. Anyone have ideas why i'm running at 285 to print abs?

If you were really running 285, you'd likely have destroyed the interface between the PEEK and the aluminum on the hotend and the PTFE liner.
So I would suggest you get a thermocouple and get the actual temperature.
I assume that the thermistor reads reasonable values at room temperature?
It's possible you have something (bad connection) changing the resistance of the thermistor circuit, or the firmware setting is bad.

[Jimustanguitar]

I am doing another print now with the support gap set at a lower .25mm. The biggest difference is turning on the air, it seems to have helped a little bit.

Do you have a link for that air nozzle setup?