Hemera MK3s Upgrade - Parts and Firmware  

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dimitri.l3
(@dimitri-l3)
Eminent Member

Hello dear Community

I'm working on the 'ideal' hemera upgrade kit, which i would like to present to you. So far it's on Thingiverse, Prusaprinters will follow:

https://www.thingiverse.com/thing:4095229

hemera adapter v1.2

My goal ist to make a mod that does not sacrifice printing space, which will be called V2. I will move the Z-Axis by a bit so the carriage will not crash past X220, unlike in most custom Hemera mounts.

Unfortunately I don't have much time to test all the parts. I'm already at V1.2 but I'm still running V1 on the printer that I have access to.

I'd be happy to hear your feedback if you try my mod. Here you can see it running with V1:

hemera mk3s v1

Happy printing!

 

This topic was modified 7 months ago by dimitri.l3
Posted : 16/01/2020 6:29 pm
stev-10
(@stev-10)
Eminent Member

Been looking at a solution myself that wont loose any axis movement or the filament sensor.  I cant test as I'm still waiting for my kit to arrive and the delay has been increased it appears 🙁 Once it does, and I can prove it works, I'll upload the links.

Posted : 18/01/2020 12:06 am
dimitri.l3
(@dimitri-l3)
Eminent Member

@stev-10

I did it! V2 can should be able to use the full print area. 
You can print the parts meanwhile and have them ready as soon as your Hemera arrives 😉

I think modding back the filament sensor is not that big of a deal with some time and CAD skills. I might look into that next.

 

UPDATE V2: Full Print Area
 In order to allow the extruder to reach the right end of the print bed, i had to move the right Z axis by 14 mm. The result has not yet been tested. I'll post an update as soon as I put the mod on my printer.
If you want to give it a try: https://www.thingiverse.com/thing:4095229

full print space

This post was modified 7 months ago by dimitri.l3
Posted : 18/01/2020 7:16 pm
stev-10 liked
pingu
(@pingu)
Estimable Member

can you implement the filament sensor in the mmu2s version? this will fit for no mmu users aswell, but non mmu version not for mmu users.

the sensors need to be triggered right at the moment, the filament is insife the bondtech gears, because the mmu motors then shuts off imideadly, and the extruder start working.

thank you for your work and enthusiasm

 

Posted : 18/01/2020 10:22 pm
stev-10
(@stev-10)
Eminent Member

@dimitri-l3

Great - just downloaded and I'll have a look tomorrow. Need some more PETG too.

Posted : 18/01/2020 11:10 pm
stev-10
(@stev-10)
Eminent Member
Posted by: @pingu

can you implement the filament sensor in the mmu2s version? this will fit for no mmu users aswell, but non mmu version not for mmu users.

the sensors need to be triggered right at the moment, the filament is insife the bondtech gears, because the mmu motors then shuts off imideadly, and the extruder start working.

thank you for your work and enthusiasm

 

Hi Pingu - on the non mmu version the sensor looks like it triggers before the filament gets to the extruder gears? 

Posted : 18/01/2020 11:18 pm
dimitri.l3
(@dimitri-l3)
Eminent Member

@stev-10

I did a rather stupid mistake on the Z Top part. I forgot to extrude a contour for the screws. I updated the files on thingiverse and here on prusaprinters. If you already printed it, you should reprint that part.
I'm happy to hear about your feedback! 🙂

Posted : 19/01/2020 3:16 pm
stev-10
(@stev-10)
Eminent Member

Hi Dimitri - No Orange until tomorrow so I've only printed the adapter plate so far in black 🙂 Looking at it I've a small amount of curling on the corners so need to do some tweaks and reprint. I forgot to clean the bed, so that's the first thing...

Posted : 19/01/2020 4:15 pm
pingu
(@pingu)
Estimable Member

Yes dimitri, thats right. The non-mmu version triggers the filament about 3 cm abobe the bondtec gears. For the mmu2s it needs to be trigferes right at the moment its inside the bondtec gear pushed

Can anybody of the hemera owners put a full mk3s extruder wirh all the plastics, fana and stuff and measure the weight? And do the same for the hemera full usable build, with some kind of filament sensor?

I cant imagine that its lighter than stock mk3s. So much metal on it.

What are your benefits of the hemera d

You hope for? At the moment i hope for easyer noozle swap. At the mk3s desihn with the round v6 i get every few times problems that i rotate the heatsink in this procedure and have then to take apart the extruder to fix it. With the mounting of the hemera this would not happen.

 

 

Posted : 20/01/2020 6:51 am
dimitri.l3
(@dimitri-l3)
Eminent Member

https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-hardware-firmware-and-software-help/prusa-i3-mk3s-is-not-able-to-print-flex-material/  

https://www.thingiverse.com/thing:4076234

@pingu

ali_g on thingiverse came up with a filament sensort that triggers when the extruder gears are pushed apart by the filament. I don't think there is another way to sense the filament at the extruder gears itself. Is it possible to make it push 2cm more before the MMU motor is disabled?

I got the upgrade mainly for printing flex material, since i never got it to work reliably on the stock extruder. I did a full thread about it (link in the top, i don't know why my phone does that) as there are many many other threads about failing to print flex with the MK3.

 

 

Posted : 20/01/2020 7:51 am
stev-10
(@stev-10)
Eminent Member
Posted by: @pingu

The non-mmu version triggers the filament about 3 cm abobe the bondtec gears. For the mmu2s it needs to be trigferes right at the moment its inside the bondtec gear pushed

Can anybody of the hemera owners put a full mk3s extruder wirh all the plastics, fana and stuff and measure the weight? And do the same for the hemera full usable build, with some kind of filament sensor?

I cant imagine that its lighter than stock mk3s. So much metal on it.

What are your benefits of the hemera d

You hope for? At the moment i hope for easyer noozle swap. At the mk3s desihn with the round v6 i get every few times problems that i rotate the heatsink in this procedure and have then to take apart the extruder to fix it. With the mounting of the hemera this would not happen.

 

 

The distance between the center of the bondtech gears and the sensor enable point on the non mmu MK3S is 15mm. On the mmu2 version the extruder body is identical? It's easy in firmware or software to tell the mmu to feed a defined extra amount of filament when filament sensor triggers and start the extruder running so it grabs the filament etc. so I don't believe the distance is a show stopper.

The Hemera itself weighs 388g including V6 hotside, 327g without hotside. Dimiri's adapter plate weighs 28g. Still haven't got my kit yet so can't help with original one.  

It has several advantages, especially if you plan to run flex filament. The chances of a misfeed are very low as the filament in and out path is so close to the extruder. It's capable of extruding 600 cubic mm/min approx and pushing force of 10Kg.

However - it has a couple of disadvantages. The tolerances are so so tight 1.75 +- 0.05mm that poor quality or damp filament may jam. It's also difficult to remove a jam in situ. Easier to remove extruder fan, heater and temp sensor, cut filament and remove extruder assembly from stepper completely then clear it. A bit of forward thinking required with heater and sensor wires, make sure there is enough slack to pull them out of the heat block and coat them with heat transfer grease before assembly (stops them seizing in the heat block).

 

 

 

Posted : 20/01/2020 8:24 am
pingu
(@pingu)
Estimable Member

i nearly destroyed my v6 hotend at mk3s this weakend to solve a massive clog. i was very suprised how messed up everything there gotten. in this procedere to open the baked screws i deformed the heatsink. and heatblock. i managed to straighten the heatsink, but something is still wrong. i guess the hetbreak is deformed and has a slight smaler iner diameter now.

so i need a new heatbreak, heatblock, and new spare thermistor and heater cartrige...

so i am thinking about to upgrade to hemera, but would like to hear about benefits. for now, i see a better mounting solution with easier noozle swap, but problems with firmware, mmu2, and the price

Posted : 20/01/2020 8:54 am
pingu
(@pingu)
Estimable Member

no its essential that the filament senor ist triggered as soon as the filament is inside the bondtech gears. it happens quite often that the filament dont gets loaded correctly. with a workaround that the mmu will push 15mm more filament its not ensured that the filament is loaded, wich woul lead into printing air till next filament change.

Posted : 20/01/2020 8:56 am
stev-10
(@stev-10)
Eminent Member
Posted by: @pingu

no its essential that the filament senor ist triggered as soon as the filament is inside the bondtech gears. it happens quite often that the filament dont gets loaded correctly. with a workaround that the mmu will push 15mm more filament its not ensured that the filament is loaded, wich woul lead into printing air till next filament change.

There is no way to put a sensor inside the Hemera. It would have to rely on firmware feeding the correct amount from the MMU to the filament sensor and then the correct amount from the filament sensor to the extruder rollers. There is nowhere for the filament to go inside the Hemera other than down the heat break (or get chewed to powder).  See pic attached. The feed is from left to right and the powered roller has been removed so the distances involved are visible. For scale the linear distance between the center of the crowns of the gear teeth is 2mm. 

It "might" be possible to have a sensor on the manual feed lever as its position changes dependent on whether filament is present or not.

If it's happening quite often, is it always in the same place? 

Posted : 20/01/2020 1:26 pm
pingu
(@pingu)
Estimable Member
Posted by: @stev-10
Posted by: @pingu

no its essential that the filament senor ist triggered as soon as the filament is inside the bondtech gears. it happens quite often that the filament dont gets loaded correctly. with a workaround that the mmu will push 15mm more filament its not ensured that the filament is loaded, wich woul lead into printing air till next filament change.

There is no way to put a sensor inside the Hemera. It would have to rely on firmware feeding the correct amount from the MMU to the filament sensor and then the correct amount from the filament sensor to the extruder rollers. There is nowhere for the filament to go inside the Hemera other than down the heat break (or get chewed to powder).  See pic attached. The feed is from left to right and the powered roller has been removed so the distances involved are visible. For scale the linear distance between the center of the crowns of the gear teeth is 2mm. 

It "might" be possible to have a sensor on the manual feed lever as its position changes dependent on whether filament is present or not.

If it's happening quite often, is it always in the same place? 

well, you have an spanner arm that moves. somekind this part needs to be remixed andneeds to triger the sensor. im not good enought in CAD to do this on my own. just take a look at the mk3s mmu idler door and how it triggers the sensor. so the same must hapen on the hemera to work reliably with the mmu2

Posted : 20/01/2020 4:51 pm
pingu
(@pingu)
Estimable Member

this is fr the bmg extruder. this is the way i think it could work. maybe some genius cad geek can adapt this to hemera!

https://www.thingiverse.com/thing:3681157

Posted : 20/01/2020 9:25 pm
stev-10
(@stev-10)
Eminent Member

@pingu

You mean CAD expert, rather than the derogatory cad geek 😉

 

Posted : 20/01/2020 10:39 pm
dimitri.l3
(@dimitri-l3)
Eminent Member
Posted by: @dimitri-l3

https://www.thingiverse.com/thing:4076234

@pingu

ali_g on thingiverse came up with a filament sensort that triggers when the extruder gears are pushed apart by the filament. I don't think there is another way to sense the filament at the extruder gears itself. Is it possible to make it push 2cm more before the MMU motor is disabled?

 

@pingu did you check this link that i posted before, as well as in my parts description?

It's basically exactly what you're talking about.

Posted : 21/01/2020 7:18 am
john.h68
(@john-h68)
Estimable Member
Posted by: @stev-10

@pingu

You mean CAD expert, rather than the derogatory cad geek 😉

 

 

At least it wasn’t CAD monkey

i3 Mk3 [aug 2018]...
Posted : 21/01/2020 7:42 am
pingu
(@pingu)
Estimable Member
Posted by: @john-h68
Posted by: @stev-10

@pingu

You mean CAD expert, rather than the derogatory cad geek 😉

 

 

At least it wasn’t CAD monkey

i asociate withj the word geek positive enthusastm and skills for one thing. i did not meant it harmfull or disrespecting. sorry if this reads so. english is a foreign language for me, sometimes i have trouble to write what i want to say.

Posted : 21/01/2020 8:29 am
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