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Hello,

I've been reading the epic fails, and as it turns out, the thermister can be off by +-10° C.

Get a zero contact thermometer, and calibrate the thermister to the temperature you read before, you fire it up for the first print. The Bowden Tube, can melt, and even prevent a print. Probably take about 20 minutes.

I'm fairly certain, that you should do as much in calibrating the print bed. It could explain some problems printing ABS.

James

Flavored Coffee wrote:Hello,

I've been reading the epic fails, and as it turns out, the thermister can be off by +-10° C.

Get a zero contact thermometer, and calibrate the thermister to the temperature you read before, you fire it up for the first print. The Bowden Tube, can melt, and even prevent a print. Probably take about 20 minutes.

I'm fairly certain, that you should do as much in calibrating the print bed. It could explain some problems printing ABS.

James

Thanks for your input. We have discussed many times on this forum about the importance of using a thermocouple and meter to measure the actual
temperature of the hotend verses what is reported by the printer. You are right, they can vary significantly. It can't hurt to remind everyone again.

Is this necessary for the Orion, or is it "calibrated" at the factory?

rportune wrote:Is this necessary for the Orion, or is it "calibrated" at the factory?

The Orion is calibrated at the factory but I doubt that they use a thermocouple to verify actual verses reported HotEnd temperature.
I always recommend that every user of a 3D printer have a thermocouple that will fit into the HotEnd and a meter that can read it.

^^ I ignored this guy's advice about temperature and thermocouples when I started. To my own detriment.

Then I paid attention and a whole slew of printing issues disappeared.

@Captain Starfish: ibid.

I want to do this and make sure I am getting accurate readings for my hot end.

Mayeb dumb questions but ,where on the hot end do you put the thermocouple? Is it a one time calibration or are you keeping it in all the time?

Similarly, where do you tell the software the calibration setting? If you set it for 190 and it reads 180, where do you say: "Hey Rostock, you're off by 10 degrees!"?

Mike B wrote:I want to do this and make sure I am getting accurate readings for my hot end.

Mayeb dumb questions but ,where on the hot end do you put the thermocouple? Is it a one time calibration or are you keeping it in all the time?

You take the filament out of the hotend and remove the bowden tube going to the hotend. Then you insert the thermocouple wire into the hotend down
to the nozzle and record the temperature. It should be the same as the reported temperature from the firmware. See the next couple of threads about
what to do if they are not close.

Brian wrote:Similarly, where do you tell the software the calibration setting? If you set it for 190 and it reads 180, where do you say: "Hey Rostock, you're off by 10 degrees!"?

You would need to change your thermistor table in the firmware which is one of my weak points. Search the forum for thermistor table, there should be some entries that tell you how to
edit the tables to report the proper temperature.

Mike B wrote:I want to do this and make sure I am getting accurate readings for my hot end.

Mayeb dumb questions but ,where on the hot end do you put the thermocouple? Is it a one time calibration or are you keeping it in all the time?

You can jam the thermocouple up the spout like eaglezsoar has suggested, I personally had problems with this because you get an air gap between probe and metal and if you push it up too far you're past the heat break and not getting anything like the nozzle temp.

Instead, I prefer to unwind the nozzle, put the thermocouple end between the back of the nozzle and the heat block, and gently tighten the nozzle again until it just holds the thermocouple in place.

[img]http://www.simonlockwood.net/linky/3dp/ ... cement.jpg[/img]

The black tube coming in from the left is the thermocouple insulation, you can see the wires coming out of that and just sneaking in behind the back of the nozzle nut. And yes, I like my hot end like my women - dirty and wrapped in plastic.

This way you are measuring actual, repeatable nozzle temperature.

As far as telling the software the setting is concerned - http://forum.seemecnc.com/viewtopic.php?f=36&t=5562

Captain Starfish wrote:

Mike B wrote:I want to do this and make sure I am getting accurate readings for my hot end.

Mayeb dumb questions but ,where on the hot end do you put the thermocouple? Is it a one time calibration or are you keeping it in all the time?

You can jam the thermocouple up the spout like eaglezsoar has suggested, I personally had problems with this because you get an air gap between probe and metal and if you push it up too far you're past the heat break and not getting anything like the nozzle temp.

Instead, I prefer to unwind the nozzle, put the thermocouple end between the back of the nozzle and the heat block, and gently tighten the nozzle again until it just holds the thermocouple in place.

The black tube coming in from the left is the thermocouple insulation, you can see the wires coming out of that and just sneaking in behind the back of the nozzle nut. And yes, I like my hot end like my women - dirty and wrapped in plastic.

This way you are measuring actual, repeatable nozzle temperature.

As far as telling the software the setting is concerned - http://forum.seemecnc.com/viewtopic.php?f=36&t=5562

I did not suggest that the thermocouple goes in from the bottom of the hotend but rather it goes into the top of the hotend and pushed into the hotend until it bottoms out on the nozzle.
Your method will also work as long as the nozzle has a small lip to grasp the thermocouple wire.
Thanks to the link to your sticky that describes how to setup the thermistor in firmware, I added that to my favorites so that I may advise other users on where it is.
Very valuable information you gave there Captain and you should win the Forum's most valuable Starfish award!
Thank you sir and Happy Printing!

Sorry mate, misread your post. A few times

Now I'm reading it as no need to do owt but pop the Bowden tube and run the thermocouple down through the PTC connector? That makes a lot more sense, and is easier!

Captain Starfish wrote:Sorry mate, misread your post. A few times

Now I'm reading it as no need to do owt but pop the Bowden tube and run the thermocouple down through the PTC connector? That makes a lot more sense, and is easier!

You Got It. That is exactly how I do it.

Getting the reading from the inside as eaglezsoar suggests is ideal, but the thermocouple I use won't fit through the PTFE liner. Since I actually check the temperature relatively frequently, I just hold the thermocouple at the interface between the brass and aluminum.

You don't need to be 100% accurate here! but you do want to be close.

Captain Starfish wrote:

Mike B wrote:I want to do this and make sure I am getting accurate readings for my hot end.

Mayeb dumb questions but ,where on the hot end do you put the thermocouple? Is it a one time calibration or are you keeping it in all the time?

You can jam the thermocouple up the spout like eaglezsoar has suggested, I personally had problems with this because you get an air gap between probe and metal and if you push it up too far you're past the heat break and not getting anything like the nozzle temp.

Instead, I prefer to unwind the nozzle, put the thermocouple end between the back of the nozzle and the heat block, and gently tighten the nozzle again until it just holds the thermocouple in place.

The black tube coming in from the left is the thermocouple insulation, you can see the wires coming out of that and just sneaking in behind the back of the nozzle nut. And yes, I like my hot end like my women - dirty and wrapped in plastic.

This way you are measuring actual, repeatable nozzle temperature.

As far as telling the software the setting is concerned - http://forum.seemecnc.com/viewtopic.php?f=36&t=5562

Thanks for the detailed instruction and for the laughs! I guess my hot end isn't as dirty as yours yet, but that will come from using it more often! I am certainly going to get the thermocouple and do as you guys suggest. Thanks!

EDIT: Removed duplicate photo of said dirty hot end