mini 2 heater mod

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arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

mini 2 heater mod

Post by arhi » Thu Apr 25, 2019 7:56 pm

20W is just not enough to heat this bed properly so I did a small mod, made a small break board so now have flat cable (new) going from motherboard to my break, and original flat going from my break to the bed heater. the 2 lines (PT100 and head sensor) are going straight trough while heater lines are broken, the two from the motherboard go to SSR that breaks external 36V source and sends it to the bed. this way we have ~80W heating and it works like a charm :)

I also removed 0R resistor under the fooptint for the thermostat and soldered in TO202 135C thermostat to act as a safety switch
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arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

Re: mini 2 heater mod

Post by arhi » Fri Apr 26, 2019 4:56 pm

another img
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masrodjie
Posts: 11
Joined: Thu Mar 16, 2017 9:35 pm

Re: mini 2 heater mod

Post by masrodjie » Sat Apr 27, 2019 1:02 pm

Wow it's really nice. Can you post the wiring diagram?

bjorn
Posts: 172
Joined: Fri Aug 10, 2018 6:00 pm

Re: mini 2 heater mod

Post by bjorn » Sat Apr 27, 2019 3:16 pm

My concern with increasing the temperature is its held by ABS that may well deform, and it definitively will deform before the thermal cutoff.

Not sure if the parts are annealed or if that is worth trying, I'm gonna sacrifice some Z height to get a adjustable 3-point mounting going, which also decouples the heat from any plastic part.


I don't recall off the top of my head the exact rating, but I think 2A pr conductor can be a bit much. Might want to keep an eye on the temperature of that cable, especially at elevated ambient temperature.

arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

Re: mini 2 heater mod

Post by arhi » Sat Apr 27, 2019 6:17 pm

I am not changing the temperature!! the mini2 is controlling the temp, just like without mod, the only difference is that now it heats up faster, but the temp is still exactly the same as it used to be. Ignore the 135C TO202 that's just a mechanical fuse if something goes wrong (pt100 dies, cable snaps and shorts pt100, tt electronics die, tt firmware hiccups...) it will not allow the heater to go over 135C .. I could use 100C or 150C same thing, it's there to prevent fire nothing else, it is not controlling the temperature, as I said, mini2 has a pt100 and firmware is keeping the temp for TT ABS at 90C.. ABS holding it should not have issues with 90C

cable is rather cold :) checked that first :) that is 2.2A going trough 3+3 conductors in the cable, more then enough capacity there :)

bjorn
Posts: 172
Joined: Fri Aug 10, 2018 6:00 pm

Re: mini 2 heater mod

Post by bjorn » Sat Apr 27, 2019 6:36 pm

SWINM have experienced numerous internal plastic parts failing after increasing the ambient temp to help the bed reach 80C.

Just saying, it may not be a coincidence that is seems the Mini 2 has been designed to resist any temperature over 60C.

arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

Re: mini 2 heater mod

Post by arhi » Sat Apr 27, 2019 6:40 pm

the PCB kicad source + PDF (both normal and mirrored)

"connection schematic"
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arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

Re: mini 2 heater mod

Post by arhi » Sat Apr 27, 2019 6:42 pm

bjorn wrote:
Sat Apr 27, 2019 6:36 pm
SWINM have experienced numerous internal plastic parts failing after increasing the ambient temp to help the bed reach 80C.
we'll see .. easy to replace everything if need be :D ... anyhow, again, I'm not increasing anything but speed bed gets to 90C so ambient is actually cooler then without this mod :)
bjorn wrote:
Sat Apr 27, 2019 6:36 pm
Just saying, it may not be a coincidence that is seems the Mini 2 has been designed to resist any temperature over 60C.
that's weird as you can't print ABS at 60C and this is ABS machine, this extruder assembly and no proper part cooling fan and.... this is ABS only machine really :D ... and I doubt ABS would even stick to 60C bed..

bjorn
Posts: 172
Joined: Fri Aug 10, 2018 6:00 pm

Re: mini 2 heater mod

Post by bjorn » Sat Apr 27, 2019 8:05 pm

Internal "ambient" temp will be the same-ish.

And you're right, at 60C it prints only smaller area parts.

bjorn
Posts: 172
Joined: Fri Aug 10, 2018 6:00 pm

Re: mini 2 heater mod

Post by bjorn » Sat Apr 27, 2019 8:13 pm

btw did something similar, but used cheap ready made fpc adapters instead of custom pcb, maybe easier for others contemplating the same path.

https://www.aliexpress.com/item/OOTDTY- ... 33232.html

arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

Re: mini 2 heater mod

Post by arhi » Sun Apr 28, 2019 4:50 pm

those breakers are nice but I don't like to advise ppl that don't know how to make super simple pcb and solder super simple components (if it was 0.5mm pitch maybe but with 1mm pitch that is really not a problem for anyone that know how to use soldering iron) to mess up with power stuff and this is "power stuff only", there is need to connect mains, there's potential for blown parts and fire hazard .. those ready breakers would tempt those with zero knowledge to try to mod this thing and I don't think they should :)

bjorn
Posts: 172
Joined: Fri Aug 10, 2018 6:00 pm

Re: mini 2 heater mod

Post by bjorn » Wed May 01, 2019 12:43 pm

..I stumbled onto my calibration card today. Noticed it said operate under 60C.

They certainly meant that, I had my bed at 60 and left the card on for like 5 seconds; it didn't like that at all! So when you get the bed up to real temps, use something else to do the calibration :lol:

Owen Sparks aka Marksman
Posts: 610
Joined: Tue Mar 15, 2016 9:56 am

Re: mini 2 heater mod

Post by Owen Sparks aka Marksman » Wed May 01, 2019 2:26 pm

I'd like to make some out of "flash paper" but I think you have to light that rather than just heat it...

arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

Re: mini 2 heater mod

Post by arhi » Wed May 01, 2019 11:26 pm

don't have those calibration cards :D mini2 has that nozzle height detection thingy :D

bjorn
Posts: 172
Joined: Fri Aug 10, 2018 6:00 pm

Re: mini 2 heater mod

Post by bjorn » Thu May 02, 2019 12:01 am

I only have a Mini 2, it came with the calibration card.

Nozzle height detection only determines max z travel, still need to use the card to perform the 9 point "mesh" bed leveling, unless you got lucky and got a bed that is both flat and perpendicular to the z axis (I most certainly did not).

Owen Sparks aka Marksman
Posts: 610
Joined: Tue Mar 15, 2016 9:56 am

Re: mini 2 heater mod

Post by Owen Sparks aka Marksman » Thu May 02, 2019 8:41 am

Card is used to offset the auto nozzle height detector. (Unrelated to bed leveling.)

TT have had a few iterations of this sensor:-
(1) Fixed position detector (mine were quite a way out)
(2) Adjustable with a screw (customers too lazy to use it / didn't know it was even there)
(3) Software offset version with the card. I like that method best. Downside is PC not being with arms reach of the printer so press button, walk to machine, test, walk back, press button. It's tedious but good exercise. :lol:

Owen S.

bjorn
Posts: 172
Joined: Fri Aug 10, 2018 6:00 pm

Re: mini 2 heater mod

Post by bjorn » Thu May 02, 2019 9:11 am

Getting slightly OT here, Up Mini 2 manual only says to use the card for leveling.

http://up3d-dev.github.io/downloads/doc ... Manual.pdf
Page 43. No mention of it during nozzle height setting. Although quite amusing the "hypothetical" example has the bed overall 1mm out of tram, which isn't all that hypothetical after all..

arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

Re: mini 2 heater mod

Post by arhi » Sun May 05, 2019 5:45 pm

hm, this one is very flat and very perpendicular, I didn't do the 9point calibration at all :D

arhi
Posts: 256
Joined: Sun Mar 08, 2015 10:51 pm

Re: mini 2 heater mod

Post by arhi » Sun May 05, 2019 6:00 pm

btw, anyone knows the thickness of that card?

bjorn
Posts: 172
Joined: Fri Aug 10, 2018 6:00 pm

Re: mini 2 heater mod

Post by bjorn » Sun May 05, 2019 7:08 pm

0.35mm

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