17 Jan
2018
17 Jan
'18
7:52 p.m.
OK - I shaved down the other side of the resistor, but the end cap of the
resistor is starting to show through and it doesn't quite fit in the barrel
yet. I'll leave it up to Jake to take off the final layers if he dares -
I'm worried we might be getting some shorts against the heater barrel
though...
The alternative approach would be to buy a spare heater block (still
available from Lulzbot for $15), and ream out the heater opening until the
resistor fits. Not sure that's any easier to get a good fit though. Let me
know if you like that idea, and I'll order the heater block.
Patrik
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On Wed, Jan 17, 2018 at 6:25 PM, Patrik D'haeseleer <patrikd(a)gmail.com>
wrote:
Sorry for trying to be helpful, but I don't think
you could expect me to
magically know those details. It just seemed better to use the Lulzbot
resistor that you listed in your first email.
Patrik
PS: the resistor recommended by Lulzbot is available on Digi-Key for $1.50
<https://www.digikey.com/product-detail/en/vishay-sfernice/RWM06224R70JA15E1/RWMB-4.7CT-ND/1587939?utm_adgroup=Resistors&gclid=CjwKCAiAhfzSBRBTEiwAN-ysWEwePIQ6Rl2PioHblQy56f0W38XUWEMqlF8XKOAmPfNA1bfxALw10BoCBPwQAvD_BwE>
- might not help if it's the wrong resistance tho.
On Wed, Jan 17, 2018 at 3:48 PM, Jake <jake(a)spaz.org> wrote:
Patrik if we don't glue it in, it won't
make thermal contact with the
aluminum
block and will burn out. Thermal paste gets squeezed out when the
resistor
heats up and expands and then you end up with a gap and the resistor
burns out.
We already went down the road with the Lulzbot resistor that is out of
stock,
permanently. It's also the wrong resistance, and the software patch to
compensate for that fact doesn't work. I carefully chose this resistor
value
(8 ohms) and the thermally conductive epoxy that I want to use to glue it
in.
if you want to take over this project go ahead, but sowing doubt and
uncertainty will just leave us with no 3D printer for another three years.
-jake
On Wed, 17 Jan 2018, Patrik D'haeseleer wrote:
On Wed, Jan 17, 2018 at 4:04 AM, Jake <jake(a)spaz.org> wrote:
If someone gets the resistor shaved to fit in
there, i'll bring in the
special two-part thermal bonding epoxy and glue it in, and then i'll
hook up
the wires and we'll have a 3D printer again.
Don't glue it in place with epoxy, or you'll have to drill it out when it
burns out again. It should be a tight enough fit to hold in place by
itself,
no? I would expect regular thermal paste to conducts heat better than the
epoxy anyway...
Patrik
PS: the replacement resistor that Lulzbot sells is only $3.50, and I
would
expect that one to fit the hole like a glove. They seem to be out of
stock
right now though...