[sudo-discuss] 3D Printer - needs new heating element
Steve Berl
steveberl at gmail.com
Wed Nov 13 15:19:57 PST 2013
Hol, were you able to find some tape? If not I can order some from Amazon
and get it with free 2-day shipping.
Any idea what width?
http://www.amazon.com/s/ref=nb_sb_ss_i_0_6?url=search-alias%3Daps&field-keywords=kapton%20tape&sprefix=kapton%2Caps%2C394&rh=i%3Aaps%2Ck%3Akapton%20tape
On Tue, Nov 12, 2013 at 2:35 PM, Hol Gaskill <hol at gaskill.com> wrote:
> the new heating resistors came in - to anyone who's interested in
> replacing the heating element, i'll be doing it before next week's meeting
> unless someone is itching to handle it themselves before then. It does
> require kapton tape from what i've read - anyone have a few inches of that
> stuff lying around?
>
>
> Nov 2, 2013 09:58:15 AM, steveberl at gmail.com wrote:
> Is the tape wrapped around the hot end anything special?
> >Steve
> >
> >On Saturday, November 2, 2013, Hol Gaskill wrote:
> >
> >
> al lashers is great! they don't stay open late enough for me to go there
> after work though, so i usually get this kind of stuff online.
> >
>
> >
> it is 12vdc so the LED warning is easily done. for AC you could still
> just use one LED at just under 50% duty cycle and it'll block the reverse
> current.
> >
> i don't know about all that empirical stuff - say you want 3V at the LED
> at 30mA, that's a 9V drop over the series resistor and R=V/I=9V/.03A = 300
> ohm resistor. could also just slap a chunk of 12V led strip down and call
> it a day - definitely bright!
> >
>
>
> >
> i would be curious to know if the problem resulted from simply being left
> on or what. the fan was not running iirc so that could have had alot to do
> with it, will have to check that as part of the repair - for now i'm just
> going to get these
> http://www.amazon.com/Resistor-Heating-Element-Printer-RepRap/dp/B00C44TBPA
> >
>
>
> >
> jake i'd be interested in learning more about how to tune the PID
> settings. no idea about the temperature sensing status since it stayed at
> room temperature, didn't think to use body heat or anything to test it but
> that'll be an easy enough check. i did not check the thermistor (or is it
> a thermocouple?) for continuity.
> >
>
>
> >
> cheers,
> >
> hol
> >
>
> >
>
> >
> Nov 1, 2013 05:45:36 PM, g2g-public01 at att.net wrote:
> >
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> Yo's-
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> And/or you can take the existing fried resistor to Al Lasher's
> >
> Electronics on University Ave in Berkeley and they'll find a
> >
> replacement, either exact-same or very close (the tolerances on
> >
> resistors used as heaters are pretty wide). If it's a 3 to 5 watt
> >
> resistor it shouldn't cost more than a couple bucks.
> >
> >
> >
>
> >
> >
> >
> Al Lasher's is an oldschool electronics shop that everyone in SR
> >
> ought to know about: their stock of raw component parts is
> >
> fantastic, and the folks who work there have been around forever
> >
> & know their stuff. You'll probably find stuff there that
> >
> suggests new projects to do.
> >
> >
> >
>
> >
> >
> >
> Chances are if you bring in the heat sink with the resistor glued
> >
> on, they'll also be able to tell you what kind of glue is needed,
> >
> and they probably have it in stock along with the resistor.
> >
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> Re. putting an LED on the heating element:
> >
> >
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>
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> Good idea and will need a dropping resistor ahead of the LED,
> >
> otherwise the LED will probably fry the first time it's turned on.
> >
> If the voltage used to run the heater resistor is AC, then wire two
> >
> LEDs together, one in reverse polarity with respect to the other,
> >
> and they'll both light up.
> >
> >
> >
>
> >
> >
> >
> To estimate the value for the dropping resistor, measure the voltage
> >
> input to the heater resistor and the current it draws (after you
> >
> replace it with one that works), and compare with the specs for the
> >
> LEDs you're using. If the dropping resistor or the LEDs get warm
> >
> when in use (aside from ambient heat from the heater resistor), or
> >
> the LEDs are excessively bright, substitute a higher value dropping
> >
> resistor.
> >
> >
> >
>
> >
> >
> >
> If I was doing this, I'd just go empirical and use a large variable
> >
> resistor in series with the LEDs, and turn it down slowly while in
> >
> operation, until the LEDs light up to a sufficient degree (not dim
> >
> but not too bright), then measure the value of the setting on the
> >
> variable resistor and find a fixed resistor of similar or slightly
> >
> higher value.
> >
> >
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>
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> >
> Useful tools for these types of purposes:
> >
> >
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>
> >
> >
> >
> A resistance decade box, and a capacitance decade box. These let
> >
> you do empirical tests by switching-in progressively different
> >
> values of resistors and capacitors into circuits until you get the
> >
> desired result. Lasher's probably has at least a resistance decade
> >
> box in stock. The reason these are called "decade boxes" is because
> >
> the traditional version has selectors with ten positions each, and
> >
> the values of each selector increase by factors of 10 relative to
> >
> the next lower selector on the box.
> >
> >
> >
>
> >
> >
> >
> The exception to the use of decade boxes is where a component
> >
> handles a large power level, such as a heater resistor, or an
> >
> electrolytic capacitor in a power supply. I'm guessing that your
> >
> heater resistor handles from 3 - 5 watts, but it may be more. The
> >
> resistors in decade boxes are typically rated at 1/4 watt to 1/2
> >
> watt and are designed for testing signal/control/audio circuits
> >
> rather than circuits that carry higher power levels.
> >
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>
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> -G
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> =====
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> On 13-11-01-Fri 5:20 PM, Jake wrote:
> >
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>
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> >I retract my assertion that you hadn't put any text in
> >
> your email.
> >
>
> >
> >
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>
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> >
> >
> as for the printer, it seems clear that you and steve are right
> >
> that the resistor is burned out. I wonder what caused this - i
> >
> haven't heard of it happening a lot bu on Nov 01, 2013, Jake
> wrote:
> >
>
> >
> >
> >
> Hol,
> >
>
> >
> >
> >
>
> >
> >
> >
> you forgot to put any text in your post at all! please be
> >
> clear of how
> >
>
> >
> >
> >
> you came to this conclusion.
> >
>
> >
> >
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>
> >
> >
> >
> The heating element is a resistor glued into a block of
> >
> metal on the end
> >
>
> >
> >
> >
> of the extruder. It has two wires which go to a connector
> >
> a couple inches
> >
>
> >
> >
> >
> from it, and they go back to the machine.
> >
>
> >
> >
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>
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> To test the heating element, one can unplug this connector
> >
> and use a
> >
>
> >
> >
> >
> multimeter to measure its resistance. It should be
> >
> something like 8 ohms,
> >
>
> >
> >
> >
> i don't know the exact value but 100 is too much and
> >
> indicates it's bad.
> >
>
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> it was replaced a little while ago by a technician from
> >
> the corporation
> >
>
> >
> >
> >
> that made it.
> >
>
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>
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> If the machine is acting up about heating, we need to know
> >
> whether the
> >
>
> >
> >
> >
> problem is with the heating or the temperature sensing. If
> >
> the
> >
>
> >
> >
> >
> temperature sensor is reporting ambient temperature, it's
> >
> probably
> >
>
> >
> >
> >
> working.
> >
>
> >
> >
> >
>
> >
> >
> >
> if the temp sensor is working but the heating element
> >
> isn't making it heat
> >
>
> >
> >
> >
> up, it could be the heating element (see test above) or it
> >
> could be the
> >
>
> >
> >
> >
> connector near it, or the wires from there back to the
> >
> main board, or
> >
>
> >
> >
> >
> where those wires connect to the brain.
> >
>
> >
> >
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>
> >
> >
> >
> can you give more information about what you tried and
> >
> what you observed?
> >
>
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> -jake
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> _______________________________________________
> >
> sudo-discuss mailing list
> >
> sudo-discuss at lists.sudoroom.org
> >
> http://lists.sudoroom.org/listinfo/sudo-discuss
> >
>
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>
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>
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>
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> _______________________________________________
> >
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> >
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> >
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> >
>
> >
> >--
> >-steve
> >
>
--
-steve
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