Nozzle Temperature

[Izzy]

Ok so what's the temperature?
I wasn't happy with the printing temperature for a PLA so I decided to measure the temperature of the heater head at different points, these being,
A, at the rear of the block between the heater and the sensor.
B, at the front centre of the block.
C, right hand side of the block on the centre line of the Nozzle.
D, left hand side of the block on the centre line of the Nozzle.
E, on the boss below the nozzle block above the nozzle.
F, on the tapered tip of the nozzle.
S, on the head of the heating block screw.
T, on the very tip of the nozzle, the nozzle hole.

So the temperatures set on the display were 200'C and 230'C, and the readings
...200. 230
A, 201. 230
B, 175. 191
C, 175. 191
D, 176. 191
E, 180. 207
F, 155. 185
S, 200. 229
T, 155. 185

As you can see a wide range of temperatures for both so what was the actual printing temperature

[Amedee]

With which device do you measure the temperature?

I would like to 'calibrate' my printers as I am sure my UMO is colder that my UMO+, but I just have an inexpensive probe which is not accurate enough at these temperatures.

I have seen a couples of device -- including very nice FLIR -- but nothing really affordable...

(Apologies to hijack your post)

[Neotko]

I did 'calibrate' by using some filament on the nozzle. I know that at 100 it starts to be sticky and drags residue (that's how I clean the nozzle outside fast In between color changes). So on one machine I can do it at 87, other at 98-102 and other at 115C.

Since I do the atomics at 75-85-90 I assume that the temp in the middle it's my calibration point. I have a thermal camera for iphone but since the metal it's reflective it's quite imprecise for that. I wonder also about what's a good tool (cheap hopefully) to calibrate the temps.

[Izzy]

I used an AideTex VC99+ multimeter with a temperature sensor.
It's looking like a 45' drop from the selected temperature to the taper on the nozzle.
I will try an atomic pull and then inserting the sensor down inside to the tip and see what I get.
I was testing some rigid.ink PLA, but needed higher temperatures than for Faberdashery to get it to print.

[Izzy]

So temperature set to 200,
Outside nozzle temp is 182, inside nozzle, sensor down from the top 209

[Amedee]

I used an AideTex VC99+ multimeter with a temperature sensor.

My meter does that as well...
... If only I could remember what I did with the sensor

[Dim3nsioneer]

I mean no offense, but are you sure you measure the temperature in exactly the same way at all spots? Especially thermal contact is the crucial point. Is your sensor a specific surface temperature sensor or just a general temperature sensor? On what is the temperature sensor based? NTC? PT100? Thermocouple?

[Anders Olsson]

Measuring temperatures is all about getting good enough thermal contact between the sensor and the measured object.
The difficulty when measuring at the heater block and nozzle is that the sensor wire acts like a heat sink, drawing heat from the sensor tip and thereby giving false readings.
I have done some measurements of the internal temperature of the nozzle (without plastic) here:

[LePaul]

That's very informative. I wonder if there is a better way to get an accurate temperature from the machine itself? Or just adjust knowing the +/- of what is being read?

I mean, perhaps there's a difference between sensors too?

[Izzy]

Ok so here is a photo of my multimeter with the temperature sensor.
As you can see it has a small round tip, each temperature measurement was taken a least 3 times to average the reading and the sensor was held in place for 15 seconds for the reading to stabilise. The very tip was used to take the readings and was applied to the surface which was free of any plastic. As well as the 200 and 230 I also took a set of readings at 150 which fell within the same pattern.
It's the best I could do with the equipment I had, I hope,

[Dim3nsioneer]

You equipments seem to be ok but as Anders pointed out a bit, there are a lot of effects to be considered and whenever possible to be excluded.

On the long-term equilibrium state heat conductance through the sensor certainly plays a role. However, the biggest influence I see with measuring at different spots is the ambient temperature. I fear the thermal contact between sensor and measurement spot might be insufficient. I would recommend to repeat the measurements with some copper grease or heat conducting paste on the temp sensor in order to ensure proper thermal contact. If the contact is insufficient, ambient temperature has a large influence and reduces the reading.

[Iltacitoduca]

You equipments seem to be ok but as Anders pointed out a bit, there are a lot of effects to be considered and whenever possible to be excluded.

On the long-term equilibrium state heat conductance through the sensor certainly plays a role. However, the biggest influence I see with measuring at different spots is the ambient temperature. I fear the thermal contact between sensor and measurement spot might be insufficient. I would recommend to repeat the measurements with some copper grease or heat conducting paste on the temp sensor in order to ensure proper thermal contact. If the contact is insufficient, ambient temperature has a large influence and reduces the reading.

Yeah! totally agreed!

Furthermore the sensor is not adequate for the task to perform. It may also be small, but the contact surface is critical to detect the correct temperature! Moreover, precisely because of the size and shape, keep it in contact, in a good thermal contact, it is almost impossible

try a PT100 sensor like this one
http://it.rs-online.com/web/p/termoresi ... o/8937115/
and use thermal paste and a PTFE or fiber-glass piece to keep it in contact with the hot surface (despite the instruments is not adequate, you'll have a more precise readout...)