MK3S+ 3.12-BETA firmware: new thermal mannequin safety and blob detection!

Our 3D printers have been generally known as extremely dependable machines for a very long time. We did our greatest to pack the MK3S+ stuffed with vital security options that may prevent a number of complications. There’s power loss restoration, crash detection and an entire lot of thermal security routines – Mintemp/Maxtemp, Thermal runaway, fan monitoring and preheat checks simply to call just a few. They’re designed to rapidly acknowledge potential points along with your machine and cease operation to forestall injury.

For the previous a number of months, we’ve been exhausting at work to deliver all these thermal-related security options to an entire new degree. The latest 3.12-BETA firmware (just for the MK3/S/+) is the primary public launch of the brand new Thermal mannequin safety. It is a nice alternative to provide you a extremely deep dive into your complete system that retains your 3D printer protected.

It additionally provides higher operation in case of false alarms – as an illustration, beforehand, a sudden draft of chilly air might cease your print with a MINTEMP error with none probability to get well. The brand new safety system all the time means that you can examine the printer and try to complete the print (nonetheless, elevated consumer consideration is strongly really useful).

We mentioned the brand new firmware in our Prusa Stay podcast:

Detection of thermal anomalies

With the brand new Thermal mannequin safety, we’re aiming to detect sudden heating points of any type and cease heating rapidly (in 10-12 seconds) to keep away from potential injury to your 3D printer. This encompasses cabling points, an incorrectly working heater block, thermistor faults and exterior elements too (draft, blobs forming on the extruder, and so forth.).

That is all based mostly on an inside simulation of the hotend, which means that the firmware always checks whether or not the thermistor readings are following a selected sample within the thermal mannequin. In case something appears off, the printer reacts inside seconds and shows a THERMAL ANOMALY warning which works away in case the readings return to anticipated numbers inside 5 seconds. In case the anomaly stays, the printer turns off the heating and prompts a warning sound to inform the consumer. In different phrases, this can be a welcome addition to already present thermal safety techniques which have been within the printer from the beginning.

Please needless to say the printer is aware of solely that one thing is fallacious, i.e., when the system shouldn’t be performing as anticipated. It’s as much as the consumer to examine the printer and examine for points.

Works on all MK3/S/+ 3D printers

So, the firmware can evaluate the values from the inner thermal mannequin with actual values and when a battle between these values is detected, the printer is stopped and an error is displayed.

Now, a few of you would possibly ask: what if my MK3S+ is situated inside an enclosure or is modded/personalized? This absolutely impacts the thermal mannequin, proper? The reply is straightforward: thermal mannequin safety shouldn’t be common. It’s based mostly on common default numbers from our manufacturing, however it’s custom-tuned for every particular person printer after the firmware is put in. So even in case you have an older printer, the routine can nonetheless acknowledge potential points instantly as a result of it doesn’t take your present machine’s values because the default (=good) state.

A newly applied automated routine must fine-tune the values of your machine to finish the configuration. It takes about quarter-hour and the printer is totally checked by working heat-up and cooldown cycles. Then, your printer profile is saved into the EEPROM reminiscence and is able to use. And sure, that is nice information for anybody who already modified the MK3/S/+ by putting in third-party parts: the thermal safety mannequin will work in your machine, too, though there could also be some exceptions – particularly since this can be a beta launch. Understand that when you usually change parts in your machine (heater blocks, hotends, followers, silicone socks), the Thermal Anomaly error might seem extra usually as a result of changing these components will change the thermal traits of your printer and you might have to recalibrate the numbers.

Below the hood

Evidently, the beta firmware releases are all the time meant for superior customers. To check the brand new capabilities, you will have to attach your printer to your PC by way of a USB cable and use Pronterface to provoke the calibration sequence by sending the proper G-Codes. Proper now, the process may be began by sending a brand new M310 A F0 instruction. After calibration, M310 S1 is used to allow the mannequin checking and the brand new calibration settings may be saved utilizing M500. For full directions, please see the changelog. Full integration into the LCD Menu will are available later releases. You may check the performance of the calibrated mannequin by setting the nozzle temperature to 210 °C after which placing a moist q-tip straight onto the nozzle – inside 10 seconds, a warning message ought to seem on the show.

One factor to bear in mind: we’re utilizing the temperature sensor on the Einsy board as a proxy – so when you place the electronics outdoors an enclosure and preserve the printer inside, the thermal mannequin might not work as anticipated. For these situations, a particular M310 T G-Code has been applied, permitting you to regulate the temperature distinction. Earlier than you begin the thermal calibration course of, although, it’s endorsed to carry out the PID calibration to make sure every little thing is working properly.

And right here’s a little bit of fascinating trivia. After we ran inside assessments and measurements in the course of the improvement of the brand new firmware, we seen some curious issues. Within the footage beneath, you’ll be able to see the distinction between a normal nozzle and heater block (higher image) and a heater block with a silicone sock (decrease image). Examine the best facet of the graph – you’ll be able to see that PID regulation is smoother on the machine with a silicone sock. We’re not saying it is best to instantly set up a silicone sock on the hotend as a result of every little thing works completely properly even with out it. That is simply to point out what our measurements revealed.

Now, when you understand how the proper thermal traits ought to look on an MK3S+, you’ll be able to check out one other studying – and you’ll clearly see that one thing is fallacious right here. See the image beneath:

See the janky studying on the left? The ability is nearly always at 100%, but the nozzle struggles to achieve a gradual 230 °C. At one level, the temperature all of the sudden shoots to over 250 °C with the PID instantly killing energy. The sudden bounce from 210 to 250 levels Celsius is suspicious as a result of it’s hardly potential that a normal heater block might warmth up by 40 levels so rapidly – therefore the problem lies more than likely within the thermistor. This habits is precisely what the brand new thermal mannequin safety is designed to catch.

Theoretically, when you had an EINSY board that may be very particularly broken (like intermittent electrical contact points as a consequence of thermal and mechanical stress, together with very delicate points similar to cracked solder pads or cracked ferrite beads) and it will nonetheless behave in a seemingly regular approach, not triggering any Mintemp/Maxtemp errors, the brand new thermal safety would nonetheless catch it – although it’s one in one million probability.

By the way in which, this complete code takes up 5 kB within the RAM and we needed to transfer stuff round fairly a bit to suit it within the very restricted house!

Diminished hazard of blobs

The brand new firmware can do one other helpful factor: as a result of it always displays the warmth block and compares the values with the inner thermal mannequin, it could actually rapidly detect anomalies in cooling as properly. So, when your print detaches from the heatbed and begins melting across the nozzle, it could actually set off the THERMAL ANOMALY error, too. If the scenario persists for a number of seconds, heating is disabled and the print is stopped. This manner, the firmware can cease the printer earlier than a big blob kinds across the nozzle. And that is no principle – we witnessed this actual scenario because it occurred on our print farm.

After all, it doesn’t imply that blobs might be fully eradicated to any extent further. What we’re saying is that we will rapidly detect blobs shortly after they start to develop – which is often early sufficient to spare you a number of work with eradicating the plastic monstrosity wrapped across the extruder.

Beta is out now

We have now simply launched the three.12-BETA model of the brand new firmware after intensive inside testing (see the changelog) and we’d be actually completely happy when you resolve to attempt the beta and share your expertise with us.

As regular, we don’t advocate putting in the beta model in a manufacturing setting, as some small bugs should still be current. Nonetheless, the thermal mannequin safety is performing properly in our testing setting and we’ll be able to launch the ultimate model quickly. So keep tuned for extra updates!


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