Absolute Max Temp for PCB heatbeds?

Has anyone ever experimented with the max temp it's feasible to get a PCB Heatbed up to?

My wife has a vinyl cutter she uses to (amongst other things) make tshirt prints. It's very small scale so to date she's been applying with an iron. The problem is the inconsistent pressure/temperature application sometimes causes issues.

Being a bit of a geek the garage is filled with half finished printers, and I figured this is an easy solution to bodge together a more uniform heatpress type setup with some spare steppers and an extrusion frame. I could order a mains heater, but I wondered what the viability of using one of the MK2a type ones I have up to about 160c is? Has anyone tried it, am I going to get issues with delaminating etc?

... PCB starts degassing, when heated above 100degC, so not safe to overheat more!

Better use a thicker sheet of aluminium and high power resistors as heaters - this can be used for more than 500 degC when using clamping or brazing instead of soldering the wires ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Pcb can withstand heat up to 170 degrees depending on the Tg rating and tor shorter duration a little higher even. I heated my mk2b up to 140 degrees with no issues. I've made a heater plate based on mk3 bed, an aluminium plate with copper tracks and standard conformative coating. I've tested it at up to 180 degrees by powering it at 12V terminals with 24V. It began off gassing a bit so made it to go no higher than 170 degrees. Just try it out and test it at 10 degrees increments. If the surface starts feeling rubbery, you've reached Tglase point.

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

... "withstanding" is another game than emitting problematic gases over long times

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

The heater plate was used all day long for many days, in a room with parakeets which are known to be rather sensitive to poisonous gasses and are still alive and tweeting

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

any method used should have redundancy for thermal control failure,
for example have a thermal fuse, enable software shut down if temp goes out of control,
and always have a fire extinguisher handy. even with every precaution, something will eventually fail.

I'm not a big fan of pushing pcb board to its temp limits, thermal creep, glue delamination of copper from heat cooling cycles. if higher than 100Deg C
i think industrial heated bed with aluminum heat spreader, possibly using heater coils. also the way the bed is mounted requires design considerations
as well to reduce wear and tear and warpage. common designs i have seen have bottoms spring loaded free floating beds with a top holder or sets of fingers that keeps bed level no
matter how much bed expands. below the top the bed can expand freely. enough pressure is applied to keep heated bed from wiggling.

The "PCB heatbed" that I have is an aluminium core PCB, it's not made of fibreglass like most PCBs are. It might be worth checking what yours is made of, aluminium core PCBs are designed for heat spreading, under LED chips, might be good to a higher temperature.

Idris

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{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

... here some infos for "aluminium core PCB's", which my company is distributing as "Polytherm":

[gie-tec.de]

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Thanks all, and apologies for the lack of followup. Based on the suggestions (and the fact that i couldn't figure a way to mount it) I'm going with silicon heaters on the back of some 6mm aluminium plate. It's complete overkill, but it should work pretty well and gives me an excuse for some more packages arriving