Heated Chamber for MK4S  

RE: Heated Chamber for MK4S

At 65 °C inside the enclosure you will almost certainly get problems with the printer's electronics overheating. When printing ASA or PCCF the temperature in my enclosure reached up to about 45 °C and this caused overheating errors with the printer crashing. I solved this by installing a fan on the electronics box but if you want to reach even higher temperatures you should consider moving the electronics box out of the enclosure altogether.

RE: Heated Chamber for MK4S

I am (off and on) working on an insulated enclosure design based on the Lack V1, with active ventilation, which will pull cool air through the electronics box, to keep the electronics cool, without cooling the enclosure below the set point. Still very much a work in progress, but the new GPIO G-code is making it much easier.

RE: Heated Chamber for MK4S

Thank you both. 

The electronic was one of my concerns but I was not expecting issues already at 45°C. Do you know which components are causing the errors?
If it's Loveboard on the nextruder, moving it out of the enclosure already sounds like a nightmare. 

I would be curious to see photos of your setups for inspiration .

RE: Heated Chamber for MK4S

The components on the xBuddy board that will get (too) hot are the stepper drivers and the mosfet for the heated bed. Those have thermal pads on the back side of the board touching the back wall of the case. I guess nobody at Prusa was expecting that those pads can work in both directions and will contribute to the stepper drivers getting too hot when the heated bed is at or over 100 °C for ASA and PCCF. 🙂
I glued some Raspberry Pi cooler fins on to the stepper drivers and the mosfet chip.

RE: Heated Chamber for MK4S

Hello,
I designed my Enclosure to be a simple enclosure to print PLA and PETG. If I would to convert my PRUSA Ikea Lack for MK4S (that now is basically only a fume extractor) to a heated chamber it would required some big changes in design:

1. All the Plexiglas parts would be almost sealed to the box (now it has a 4 mm gap)
2. All the part would be reprinter in hi-temp resistant material like PC instead of PETG.
3. The power supply would be installed outside, under the lack.
4. The Buddy box would be removed and relocated under the the lack base.
5. All the cabling of the stepping motor to the Buddy Mainboard would be rebuild from scratch to allow a much longer distance.
6. All the cabling of the Nextruder to the Buddy Mainboard would be rebuild from scratch to allow a much longer distance.
7. Two special designed air channel would be put under and enclosing the Z and Y stepper motors to with forced ventilation that goes on the motor but not enter into the box.
8. The X motor would required another special mini cube enclosing the motor with a flexible tube that push cold air and pull the hot away.
9. And last but not least, verify if the Loveboard is still able to work at such high temp (over 60° C I presume) or require another customisation.

Of course such complex system would require a Chamber Heather to be installed and connected to the GPIO Hacker board so that the chamber temperature could be controlled through GCODE.

A huge work. For this reason I purchased also a CORE One Kit in case I need to print some materials like PC and ABS.

Regards

RE: Heated Chamber for MK4S

If you're talking PC or ABS temperatures, most of your points are just wrong. The only one that is fully accurate is moving the power supply outside the enclosure, and the standard cables are long enough for that. The gaps, in my Lack enclosure, I filled with weatherstrip foam. Significantly less than 4mm gaps, though. I know this, because I am currently making a production run of ASA printed parts, on a Mk4S, in a lack enclosure, and I'm holding the chamber temperature at 43C, and it's working fine.

RE: Heated Chamber for MK4S

I agree that regarding the chamber temperature I may be wrong, since I never printer special materials that requires high hot chamber temperature.

I was not thinking to ABS or PC, but rather to special (and sometime expansive) materials. I read lots of comment of people that use the new generation of printers that claims to print special materials with real hot chamber like Polypropilene that requires 65°-80° hot chamber, or Polycarbonate 60°-90°, so yes I was thinking to those ranges when I wrote the comment even if probably the MK4S can't reach even the nozzle and bed temperature required to print such materials. 😉 

Regards

RE: Heated Chamber for MK4S

You were thinking about far more exotic materials than what is being discussed in this thread. Particularly ASA and PA-CF. Both of those are far easier to print than what you're talking about, so your assessment of the needs to print those materials is utterly unhelpful.

RE: Heated Chamber for MK4S

Polypropilene doesn't needs a high chamber temperature. The main problem with this filament is getting a good adherence to the bed. I print it with the enclosure doors open and a bed temp. of 40C. PC,PA and ASA will benefit from highish temperatures in the enclosure, but 45C seems good enough most of the time. Only really huge models maybe would need 50C or more to keep warping under control. If the filament has carbon fibers, then warping isn't usually a problem.

RE: Heated Chamber for MK4S

I taped over all the holes and gaps with painter tape, including the doors and enclosure bottom holes. I had a bunch of 10mm cork underlayment and I just put 1 or 2 layers on all interior surfaces, using the painter tape as needed. Then I just stacked pieces in the enclosure everywhere there's extra space, just to make the free volume smaller.
I'm able to get the enclose to 42 degrees while printing abs by using the bed to preheat (set to 115) for 15-20 minutes. I print the abs with the bed at 110.
I'm pretty sure I could probably get the temp a little higher with a more careful effort, because the whole thing is rather haphazard.

RE: Heated Chamber for MK4S

Posted by: @fil4ment

Loveboard is mostly just a passthrough, with no significant processing on the board.

Yet there are several semiconductor devices on the love board. Here is the schematic. I don't know what the EEPROM is for, but there is a chip for the load cell, a voltage regulator to create 3.3V, an RS-422 transceiver for the I2C signal over the wire loom, and a couple discrete mosfets. I wouldn't expect any of them to have much internal heating, but they are all probably commercial rated parts that will probably stop working (or work unreliably) over 70°C. Shouldn't be a problem for chamber temperatures up to 60-65°C (with a safety margin).

OK, I was wrong for the one part I checked (I was double checking the term "transceiver" since I haven't spoken in EE for a while)... The transceiver (if it really is a MAX490eesa as indicated on the schematic) is rated up to +85°C. Funny thing though, Mouser has that specific Maxim part number marked as obsolete... Makes me wonder what chip is actually on the love board, but not curious enough to tear down my Nextruder to find out.

RE: Heated Chamber for MK4S

Quick update on my project

I managed to build a heated chamber using a 220V car heater, which wasn’t too difficult to set up. I can now maintain a chamber temperature of around 45 °C.
1) The heater itself can go higher, but I’ve run into two problems:
2) The main xBuddy board crashes above this temperature.

I overlooked the impact on the printer materials (MK4 upgraded to MK4S).cf photo.
I’ve noticed some deformation in PETG parts under stress inside the chamber, particularly on the Z Bottom and Top, and to a lesser extent on the X axis. Fortunately, I was able to reprint everything using PETG I had on hand.

Since I cannot source Prusament PC-CF at the moment, I’ve ordered a roll of Extrudr DuraPro PC/PBT CF to test. At the same time, I’ll relocate the electronics outside the chamber.

I’d love to see a future Prusa product that can compete directly with the Bambulab H2D, though I doubt it will happen anytime soon.