Missing temperature offset correction

Markus64
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Location: Germany

Missing temperature offset correction

Postby Markus64 » Wed Nov 04, 2020 9:25 pm

Since I also print highly abrasive filaments with my Pro2, I use hardened steel nozzles. This has the advantage of not having to change a nozzle for a long time and is therefore very practical.

For some time now, however, I have noticed that I have to set the temperatures much higher to get sensible print results. This is easy to understand physically, as the coefficient of thermal conductivity of steel is much lower than that of brass or copper.
Now there is the problem of not being able to calibrate the temperatures so that - as an example - 200 ° C via software or set directly on the printer actually corresponds to 200 ° C at the hotend. This in turn means that I have to use try and error to determine the correct values ​​for each filament profile. At the same time, create a list to note how many degrees Celsius I have to set more to get the desired result.

I work professionally with the printer and can't afford such gimmicks!

What is missing is a possibility to enter a temperature offset into the printer so that the temperatures correspond exactly to the target and the actual. I'm not talking about small temperature fluctuations, but about differences of up to 30 ° C.

As I said, it's not a hardware fault! It is a mistake by the developers not to have considered this damn important point!

An "open" firmware based on Marlin is prepared for such a situation and can be adapted or calibrated by each user.
The Pro2 is unfortunately a "closed" system and my hands are literally tied to adapt my system to my needs.
I also ask every Pro2 user, should they work with hardened steel nozzles like me, to check their printer.
The actual temperature can be measured reliably via a drilled steel nozzle into which a thermistor is pushed.

I therefore urge Raise3D to add this temperature calibration option to the firmware as quickly as possible.

Markus64
Posts: 279
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Missing temperature offset correction

Postby Markus64 » Thu Nov 05, 2020 11:03 pm

Update:

I will do an extensive series of test measurements on both extruders as soon as I can.
For this purpose, a high-precision thermistor is placed inside the nozzle where the melting process takes place. The target values ​​and the actual values ​​are then recorded.

Measurements are made with an original brass nozzle and a hardened steel nozzle.
I will publish the measurement protocols here in this thread.
I set the measured value tolerances for a device in this price range at plus minus 3 ° C for the original nozzle.

If the Pro2 were "suitable for industrial use" as described in the advertising, a calibration routine and storage of min. two correction curves per extruder be possible. Once for brass nozzles, once for steel nozzles. This is the only way that it makes sense, and this is the only way to distinguish an industrial printer from toys.

But I can tell you in advance that the series of measurements will cause surprises.
Stay healthy!

Paul123
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Joined: Fri Sep 11, 2020 12:22 pm

Re: Missing temperature offset correction

Postby Paul123 » Fri Nov 06, 2020 1:15 am

I am looking forward reading your test experiences because i have the same feeling about different behavior of different nozzle materials. But being honest summing up all reactions of Raise3d, their reaction in this case will be similar: ZERO.
We are both in the lucky situation of water cooled printing, but out of the box Pro2 will have an even more sever problem with such a kind of temp correction, because the corrected temperature on the hotend will even be higher. I only found one report of HTLTP (high temp long time print) with the Pro2 in the www, but even there it was stated that there may be issues with closed hood - and the "genius" suggestion in that case was "lower your nozzle temperature" :-)))

Markus64
Posts: 279
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Missing temperature offset correction

Postby Markus64 » Fri Nov 06, 2020 3:17 pm

@Paul,
the series of measurements will be expanded:
I will also measure the respective hot end temperature and compare it with the value displayed by the printer.

In the meantime, I have secured hard copies of the advertising and printer description from the two German distributors.
Not a single word is it mentioned that the Pro2 is a closed firmware and that the buyer has no way of calibrating the system to his own needs.
Configuration includes, for example, the ability to carry out calibration measures, as required here. Temperature calibration is a fundamentally important function in 3D printing.

It is also a fact that distributors and resellers willingly sell other nozzles, including hardened steel nozzles. There is no mention of a syllable that the printer does not provide a calibration routine for printing temperatures.

According to German law, however, this information must be available, otherwise it is misleading. In addition, there is the selling price, which does not allow any potential buyer to even come close to buying an island system.

If Raise - as you fear - actually does not offer a solution to this blatant problem, I will ensure that this information must be explicitly stated in future advertising for this printer in Germany. The price should then fall into the basement.

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Vicky@Raise3D
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Re: Missing temperature offset correction

Postby Vicky@Raise3D » Tue Nov 10, 2020 6:35 pm

You'd prefer to have the value preset in motion board firmware or you'd like to have a preset configuration then manually input the offet on touchscreen when editing temperature?

For example, if you are looking for +20C offset for 200C tempearture, there are two ways to achieve:
1. Preset the offset in firmware. It will still show 200C on touchscreen but actually it has added the extra 20C when heating.
2. Or inputting 220C on touchscreen and it shows 220C.

Markus64
Posts: 279
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Missing temperature offset correction

Postby Markus64 » Tue Nov 10, 2020 7:25 pm

Vicky@Raise3D wrote:You'd prefer to have the value preset in motion board firmware.


For example, if you are looking for +20C offset for 200C temperature.
1. Preset the offset in firmware. It will still show 200C on touchscreen but actually it has added the extra 20C when heating.


Thanks for the feedback Vicky!
That's exactly what we need.
Last edited by Markus64 on Tue Nov 10, 2020 8:43 pm, edited 2 times in total.

Paul123
Posts: 34
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Re: Missing temperature offset correction

Postby Paul123 » Tue Nov 10, 2020 8:15 pm

@ Vicky
Great that you show some willingness doing something in that case. If you really are going to provide this feature in a future firmware version, you will have to provide a method finding out the right amount of offset, too, because one has to be sure, that the corrected value is really the desired value.
@Markus64: what do you think - would be a small table with different nozzle types and its offset values a simple and reliable enough solution?
2. @Vicky: if the nozzle offset is e.g. +30 you will have to allow the firmware raising the hotend temperature. Surely by now, if the Pro2 then should be running at 330 deg. C, you will have to think about the LTHT (long time high temp) issues of the Pro2!

Markus64
Posts: 279
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Missing temperature offset correction

Postby Markus64 » Tue Nov 10, 2020 8:42 pm

Thank you for your input, Paul.

I have to make it clear that this offset calibration only makes sense if every user who wants to calibrate purchases or builds the appropriate hardware. The costs for this measuring device including measuring probes amount to about 50 bucks or even less. I will publish a construction manual for this.

As shown correctly in the post above, it makes sense to store the offset values ​​and then display the temperature as the printing temperature which is actually present in the nozzle.

Since the Pro2 has two extruders, calibration must also be feasible for both extruders - independently of one another.

Since users work with different nozzle materials, it makes sense to record at least two materials: brass and hardened steel. Three configuration options would be fantastic.

However, it will not be enough to simply add a value as an offset. Since the calibration / correction is not linear, a type of table must be used to record setpoint and actual values. From these different measuring points, the firmware then calculates a calibration curve with different offset values ​​which later result in the exact printing temperature.

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Vicky@Raise3D
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Re: Missing temperature offset correction

Postby Vicky@Raise3D » Wed Nov 11, 2020 6:21 pm

Thanks for your suggestions.
We will see how we can get the proper values for this for widely used nozzles in market.

Markus64
Posts: 279
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Missing temperature offset correction

Postby Markus64 » Wed Nov 11, 2020 6:49 pm

@Vicky,
Thank you for your feedback signal.

I strongly advise against entering fixed or predefined values ​​for different nozzles in the firmware.
My suggestion that every user can enter their specific measured values ​​has the advantage that the setpoint temperature and the actual temperature of the nozzles that are physically installed are determined.

The manufacturer of the nozzle does not matter. This functionality assumes that every user who wants to carry out this calibration also provides a suitable measuring device.

You also have to keep in mind that users outside of the USA rely on nozzle manufacturers who generate different measured values ​​than the offset values ​​you specify.

The version I recommend is the most professional calibration option..

Markus64
Posts: 279
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Missing temperature offset correction

Postby Markus64 » Sun Nov 22, 2020 2:39 pm

The measurement data are now available and prove that the Pro2 is only partially suitable for printing with steel nozzles. In order to arrive at the actual printing temperature, the determined offset values ​​must be added to the printing temperatures in the printer.

At 280 ° C, steel nozzles end because the firmware does not allow any entries > 325 ° C. This is not in any description of the printer and represents a gross defect. "Industrial grade" is just a marketing promise and has nothing to do with reality!

The manufacturer is hereby requested to remedy this defect. Either through the calibration option I requested, or by entering a printing temperature higher than 325 ° C.
IMG_20201120_223211.jpg

Steel.JPG

Brass.JPG

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Vicky@Raise3D
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Re: Missing temperature offset correction

Postby Vicky@Raise3D » Tue Nov 24, 2020 1:15 am

The motion board of Pro2 series won't be able to support any temperature higher than 330C.
You can find we put 300C as Max Nozzle temperature on Pro2 printer's product page. https://www.raise3d.com/products/pro2-3d-printer/

Markus64
Posts: 279
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Missing temperature offset correction

Postby Markus64 » Tue Nov 24, 2020 1:18 pm

Then you should add that these temperature specifications only apply to operation with brass nozzles and a maximum temperature of 280 ° C for steel nozzles!


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