High printing temperatures?

[simon-nouws 0]

Hi everybody,

I'm using an Ultimaker 2 for half a month now, but have some questions regarding the print temperature.

When I'm printing PLA, the blue one from Ultimaker or a green one from an other supplier, I have to set my extruder temperature to 250 degrees to be able to print with 80mm/s.

I do not know if this is normal for an Ultimaker 2 or it happens because my thermocouple or thermistor is not working well.

When I reduce the temperature of my hot end to 230 or something like that the UM2 extruder will skip steps and show under extrusion.

Can someone tell me of the temperature I am using is normal with 80mm/s?

Thanks!

 

[ian 32]

Hi Simon. to be honest with normal PLA that you get with your ultimaker, you should have zero problem with printing PLA at 80 with a temp of 190 to 200... 250 is a little high in my opinion..

you could get yourself a small syringe needle and clean out the nozzle when it is hot...maybe there is some gunk up there ? and that is messing up with your flow...

also it would be well worth checking out carefully on the back of your hotend.. that the temp sensor is really nice and tight.

if that thing is loose. then your ultimaker will get of course inaccurate readings.

Also maybe check the cable connections from the heat sensor to the board under your ultimaker.. that all connections are nice and tight and nothing is loose..

then let us know what happens ok !

Ian :-)

 

[illuminarti 18]

It also depends what layer thickness you are printing. The limiting factor is not really the linear speed, but the volume of plastic per second. This depends on the linear speed, layer thickness, and the width of the bead that you are printing with (which usually, but not always, the nozzle width). If you use the 'spiralize' function in Cura to print a vase, that will also affect the bead width.

What layer thickness are you printing with?

 

[braddock 1]

this is pretty much the issue I'm having. It's been a chicken and egg thing not knowing if the feeder grinding was causing under extrusion, or the nozzle causing the grinding.

My nozzle is totally clear, in addition to cleaning it with wire, I've also pulled the hotend apart a number of times now... I had the same issue with both orange, and blue PLA from ultimaker. It's really trying my patience and affecting my overall experience with the ultimaker and 3D printing in general. I never know with any confidence if a print is going to fail or succeed.

Where is the temp sensor? what does it look like? I also have to print at about 250.

Would humid weather play any role in this?

 

[braddock 1]

I've just been testing using a small cube. 100mm/s 0.06 layer height.

I started printing at 260, obviously, it oozes out and prints like honey... but too hot once the layers add up.

Drop to 190, immediate under extrusion.

Up to 230, better, but still under extruding.

Up to 240 again, after a few minuted, under extruding, feeder wheel clicking

Increase to 250, still under extruding.

I've fiddled with the feeder tension, right now, it's just clicking no matter where I put it.

I'm in Sydney Australia, it's hot in my room, humidity is 85% maybe this is affecting it, it's by far the worst day / night I've had printing since owning my UM2... right now I feel like throwing it out the window.

 

[simon-nouws 0]

Thanks for the quick response Ian and Illuminarti!

The layer height was between 100 and 200micron during my tests, most of the time 120 micron. Cleaning my nozzle did not make any difference, and it my thermocouple/thermistor (still do not know what's used in the Ultimaker).

Spiralizing is set off in the settings. Next thing I will check are the connectors at the controller board.

Does anyone know why the guys at ultimaker chose for such a small hot end? It seems there is space for a hottend twice as large?

 

[illuminarti 18]

Well, ultimately there will be two hot ends, when the dual-extrusion capability gets added. :-)

Technically, it's a PT100 Resistance Thermometer on a UM2- which is, in a general sense, a thermistor - it's resistance varies with temperature - although technically it's different (according to Wikipedia at least).

The smaller hot end was a conscious decision to limit the volume of molten plastic, in order to reduce oozing e.g., during non-printing moves.

I'm not sure what the effect of humidity might be; it certainly might cause the filament to swell slightly, and bind in the cooler parts of the head; it might also reduce the effectiveness of the cooling overall, again causing thermal issues for the head.

 

[braddock 1]

There's gotta be another variable to explain the decline in my prints these past few days. Ambient heat and humidity are significantly higher than they were when I first received my UM2 and was getting great prints out of the box

[illuminarti 18]

Could you try blowing a table fan over your printer, just to see if greater airflow/cooling helps things get any better?

 

[braddock 1]

It's cooler today, and I've also set up a portable aircon unit in the room. I'll let it run for an hour or so, and try again.

 

 

Could you try blowing a table fan over your printer, just to see if greater airflow/cooling helps things get any better?

 

[simon-nouws 0]

Solved the problem yesterday, I had some serious clogging issue it seems. When I did set the hot end to 260 degrees centigrade, and took off the bowden tube I could not feed the filament through by hand.

Eventually I did got it right by using a needle(as Ian proposed) on the downside and manually feeding filament from above, now I'm printing at 220degrees 70 or 80mm/s with layer thickness 0.12mm without a problem!

Thank you guys!