How long to heat a tip?
April 29, 2011 01:00AM
Hello All.

How long does it take to heat up a hot tip? Ive had it on for about 45 minutes and the temp is only at 150C according to my IR Thermometer. My repsnapper is not reading the current temp I dunno why...

How long does it take for yours to heat up?

Thanks all.


[omemon.wordpress.com]
Re: How long to heat a tip?
April 29, 2011 01:44AM
Well, my NiChrome wire hot end gets to operating temperature (200degC) in about a minute. And my brass block hot end is a little slower and takes about 4 or 5 minutes to get to full operation temperatre (again 200degC).

So something doesn't sound right with your setup somewhere.

What kind of hot-end do you have?
Re: How long to heat a tip?
April 29, 2011 02:09AM
Do you have a fan blowing on it? If so, you need to insulate around the heater block. A couple of times around with Kapton should do it.
Re: How long to heat a tip?
April 29, 2011 03:24AM
You can't take accurate readings of shiny metal using an IR thermometer.
You need to use a thermocouple to get accurate hot end temperature readings.
What resistance does your thermistor have?


Bob Morrison
W├Ârth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
Re: How long to heat a tip?
April 29, 2011 04:27AM
It takes about 150 seconds for my resistor in aluminium block heater to get to 250C.

I agree with Bob that IR thermometers are useless for measuring extruder temps. Not only is the emissivity of metal parts too low, they are also too small for to fill the aperture.

I use a thermocouple on the inside of the barrel. It's hard to get an accurate reading with a thermocouple on the outside. It needs to make good contact and be insulated. Simply pressing it against the barrel or heater gives a low reading in my experience.


[www.hydraraptor.blogspot.com]
Re: How long to heat a tip?
April 29, 2011 08:33AM
to answer the question on how fast my nozzle tip heats up:

it takes about 300seconds for my rap man, and about 180seconds for my other printers.

If you have pla, you can touch the feedstock end to the tip, if it melts then you know you are above 160deg c.

as per nopheads post here [forums.reprap.org]

ABS softens at 90C, melts at 105C, can be extruded at ~180C but needs to be ~240C to bond strongly to itself.

HDPE melts at 130C, extrudes at similar temps to ABS.

PLA softens ~50C, melts at ~ 160C, extrudes and bonds well at 180C-190C.


But all aside, it seems like you should be addressing the issue with the temp not reading correctly in firmware. I would offer to suggest you get help on that. there are several experts around this forum that can help in troubleshooting firmware issues.

IMHO. thx.
Re: How long to heat a tip?
April 29, 2011 09:24AM
Thanks all for your advice.

I do have a thermocouple touching the tip and insulated under silicone cement which techzonecom.com provided: [www.reprap.org]

They state that its a :
Quote

(1) Type K thermocouple wire; This is insulated in a fiberglass braid, it has two wires in there, one wrapped in Yellow the other wrapped in red.

I tried to print after taht 45 minutes and what happened was that the extruder kept pushing the filament and I guess it wasn't melting, (or maybe the extruder is set too fast?), and that caused the tip to scratch against the print bed.

No damages, just some ripped tape... I followed all directions on the techzone assembly page so im sure I have contact to the tip. I'll double check the tip manager board to make sure I have contact when I get home.

Any more advices?


[omemon.wordpress.com]
Sorry, only registered users may post in this forum.

Click here to login