Replicator 2 Max Temperature / Polycarbonate?

[Thomas Deal]

I asked MakerBot Support this, but they basically refused to actually answer the question, telling me that it wasn't supported, and that I should post here and see what other users said.

I'm curious what the max temperature of the Rep2 (not 2X) extruder/hot-end is. I saw Ultimachine's listing for Polycarbonate filament, and wanted to try it, but it mentions that many printers can't handle the temperature required. But I recently had the extruder assemble of my Rep2 off and apart to replace the thermocouple (I had pinched the wires accidentally while installing the spring-loaded drive block, MB support was spectacular that time!), and it looked to me like the parts that matter are all solid metal, which makes me think it should be able to handle it.

Can the Rep2 handle Polycarbonate? Has anyone done it? What's the highest temperature anyone's run a Rep2 at without (too much) trouble? What problems would I be likely to have if I tried?

[Damian Gto]

If I remember right the rep2 can handle up to 280 degree in the firmware. The hardware is little more complex.

You do have some plastic on the carriage that might not handle that temperature, so you need to protect them with aluminium tape or other stuff that will remove the radiated heat that comes from the hot end or you need to change the carriage to aluminium. 

[Dan Newman]

> Can the Rep2 handle Polycarbonate? Has anyone done it? What's the highest
> temperature anyone's run a Rep2 at without (too much) trouble? What
> problems would I be likely to have if I tried?

MBI limits the max temp to 280 C. Sailfish, which follows MBI's lead, does
the same. When MBI was considering allowing a max of 290 C, Sailfish did
the same but as soon as MBI settled on 280 C as the upper limit, Sailfish
did likewise.

So, your issue will be whether or not 280 C is sufficient. Some RepRap
folks report needing 300 - 305C, but they typically have externally
mounted temp sensors. The Rep 2 and Rep 2X have internally mounted temp
sensors. As such, when a Rep 2 is reading 240 C, an externally mounted
sensor may only read 210 C +/-. Consequently, setting a Rep 2 to 280 C
may be more than sufficient for Polycarb.

And, I've seen my Rep 2 maintain 290 C.

Dan

[Thomas Deal]

On Friday, July 19, 2013 10:29:33 AM UTC-4, dnewman wrote:

MBI limits the max temp to 280 C.  Sailfish, which follows MBI's lead, does
the same.  When MBI was considering allowing a max of 290 C, Sailfish did
the same but as soon as MBI settled on 280 C as the upper limit, Sailfish
did likewise.

I assume that if I decided that the hardware seemed like it could take it (or modded the hardware to take the heat), then I could just patch a different limit into a custom sailfish build. Software is more my area than hardware anyway :)
 

So, your issue will be whether or not 280 C is sufficient.  Some RepRap
folks report needing 300 - 305C, but they typically have externally
mounted temp sensors.  The Rep 2 and Rep 2X have internally mounted temp
sensors.  As such, when a Rep 2 is reading 240 C, an externally mounted
sensor may only read 210 C +/-.  Consequently, setting a Rep 2 to 280 C
may be more than sufficient for Polycarb.

And, I've seen my Rep 2 maintain 290 C.

Dan

Thanks, this is very encouraging, I'm going to order some and see how well it does!

On Friday, July 19, 2013 9:37:14 AM UTC-4, Damian Gto wrote:

If I remember right the rep2 can handle up to 280 degree in the firmware. The hardware is little more complex.

You do have some plastic on the carriage that might not handle that temperature, so you need to protect them with aluminium tape or other stuff that will remove the radiated heat that comes from the hot end or you need to change the carriage to aluminium.

Thanks! As far as I see, the plastic carriage plate only touches the hot-end assemble at either end of a big Al block that's got a heatsink/fan screwed on along the long side of it, so I'm not sure how much more heat I could pull out of there reasonably, but the block has always been cool to the touch (cooler than the stepper that's directly behind it!) when printing PLA, so I don't expect it to jump up dramatically from there.
 

 

[Jetguy]

Thanks! As far as I see, the plastic carriage plate only touches the hot-end assemble at either end of a big Al block that's got a heatsink/fan screwed on along the long side of it, so I'm not sure how much more heat I could pull out of there reasonably, but the block has always been cool to the touch (cooler than the stepper that's directly behind it!) when printing PLA, so I don't expect it to jump up dramatically from there.

 

Um, yeah, about that. So there is a reason Carl started selling aluminum carriages for those guys like myself who wanted to try nylon because there were pictures and threads of other folks who said "it doesn't get too hot",.

 

Take it with a grain of salt. If I'm wrong, no big deal and it works fine. If I'm right and other have had problems at less than 260C, and MakerBot basically said they do not support it and won't fix it if you melt the carriage.

 

In other words, sure, I'd love to tell you it just works. I personally spent the money and purchased an aluminum carriage from Carl because it's not worth the chance to me.

 

It's your money and your machine, but again, MakerBot told you they don't support it either in "stock" form.

[Thomas Deal]

On Friday, July 19, 2013 12:07:15 PM UTC-4, Jetguy wrote:

Um, yeah, about that. So there is a reason Carl started selling aluminum carriages for those guys like myself who wanted to try nylon because there were pictures and threads of other folks who said "it doesn't get too hot",.

 

Take it with a grain of salt. If I'm wrong, no big deal and it works fine. If I'm right and other have had problems at less than 260C, and MakerBot basically said they do not support it and won't fix it if you melt the carriage.

 

In other words, sure, I'd love to tell you it just works. I personally spent the money and purchased an aluminum carriage from Carl because it's not worth the chance to me.

 

It's your money and your machine, but again, MakerBot told you they don't support it either in "stock" form.

Wow, that's good to know! I had pretty much assumed/expected that if I break something I'm on my own to fix it, so this warning is pretty much exactly what I was hoping to find out by asking! Maybe I'll hold off on buying the PC filament until I get the carriage upgrade done...

[Bonekollector]

+1 on Carl's aluminum carriage replacement - I just (finally) installed mine last weekend & part of the reason is so I can experiment with nylon + other materials.

[Damian Gto]

The problem with that advice is that not many people have measure the temperature and I can easy say its not that hot that people thinks, due the fact I have measure it. The only problem I did see is there is some heat coming from the hot end and go up to the carriage and the stuff that sits on it, but in the same time its very very easy to remove this heat with aluminium tape. So no the aluminium carriage is not anything you MUST have, but in the same time its a good safety thing to have so you do not need to worry about that.

[Dan Newman]

On 19 Jul 2013 , at 8:18 AM, Thomas Deal wrote:

> On Friday, July 19, 2013 10:29:33 AM UTC-4, dnewman wrote:
>>
>> MBI limits the max temp to 280 C. Sailfish, which follows MBI's lead,
>> does
>> the same. When MBI was considering allowing a max of 290 C, Sailfish did
>> the same but as soon as MBI settled on 280 C as the upper limit, Sailfish
>> did likewise.
>>
>
> I assume that if I decided that the hardware seemed like it could take it
> (or modded the hardware to take the heat), then I could just patch a
> different limit into a custom sailfish build. Software is more my area than
> hardware anyway :)

Correct.

% find . \( -name \*.c\* -o -name \*.h\* \) | xargs -n1 grep -l 280

You'll actually get too many hits (ATmega1280), but the obvious one
will jump out: Heater.hh which has

#define MAX_VALID_TEMP 280

Dan

[Dan Newman]

Heat radiation is NOT linear but rather follows the fourth power of the
temperature. What Bjorn may have seen at 240C in no way reflects behavior
at 290 C. A 10% increase in absolute temp (K) is nothing to sneeze at when
powers of 4 are involved. So, aluminum heat shielding which works around
240 C may well be far more inadequate than expected when doing a 2 hour
print at 290 C. (Also, Bjorn's findings with his experiments with aluminum
tape are inconclusive: the differences he saw were approximately the same
as his measurement errors and possibly smaller than his measurement errors.
Mind you, he claimed his temp measurements to be +/- 1C which was a big tip
off in the first place.)

Dan

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[Thomas Deal]

On Friday, July 19, 2013 12:56:26 PM UTC-4, Damian Gto wrote:

The problem with that advice is that not many people have measure the temperature and I can easy say its not that hot that people thinks, due the fact I have measure it. The only problem I did see is there is some heat coming from the hot end and go up to the carriage and the stuff that sits on it, but in the same time its very very easy to remove this heat with aluminium tape. So no the aluminium carriage is not anything you MUST have, but in the same time its a good safety thing to have so you do not need to worry about that.

Yeah, I haven't actually measured anything around  the hotend or barrier block while printing, apart from the thermocouple that's built in. A quick look over some of the past discussion showed that I was clearly way off in assuming that the conduction through the metal was going to be the biggest problem, and that radiated heat is actually far worse, if I've understood the discussion correctly. Does side fan on the Rep2 that blows on the side of the nozzle and the just-extruded portion of the print help, or is it directed too low to make any meaningful difference?

I probably would have searched for "MAX" or "TEMP" first, assuming a sane named constant, but would have reached the same place! In any case, I probably won't even try building a custom tweaked firmware until I've actually tried what I can do without doing that. But thanks ahead of time, should I end up going down that path :)

On Friday, July 19, 2013 1:47:01 PM UTC-4, dnewman wrote:

Heat radiation is NOT linear but rather follows the fourth power of the
temperature.  What Bjorn may have seen at 240C in no way reflects behavior
at 290 C.  A 10% increase in absolute temp (K) is nothing to sneeze at when
powers of 4 are involved.  So, aluminum heat shielding which works around
240 C may well be far more inadequate than expected when doing a 2 hour
print at 290 C.  (Also, Bjorn's findings with his experiments with aluminum
tape are inconclusive: the differences he saw were approximately the same
as his measurement errors and possibly smaller than his measurement errors.
Mind you, he claimed his temp measurements to be +/- 1C which was a big tip
off in the first place.)

Dan

So basically, there are no shortcuts when pushing the hotend temperature that far, and my choices are to try to heat-shield it, watch it very carefully, and expect it to fail (and soon), or to get the aluminum carriage plate and not have to worry about it?

[Jay]

+2
I just received my carriage from Carl (from France!!). I also have the arms from Bottleworks which are aluminum. This weekend, Murphy willing, i'll have both on there. I have my nylon 618 waiting too...

There were some older posts that really bring home what Jetguy and Dan are talking about....maybe someone can point you to them but they were pics a user took after running nylon for several hours and he had a noticeable droop to the plastic carriage. This was not a few minutes or a couple of hours, I think he had 12 or so hours on the printer in Nylon...YMMV!!!

Jay

[Damian Gto]

To use aluminium to shield from heat is very common in many areas, like cars and electronics.

The aluminium tape can stand way over the temperature you need.

The experiment I did was a success and it was verified with more measurement, even if you do not believe that. So there was NO errors in that readings.

What I did find is that there is a lot LOWER temperature in the part than people thinks. 

People thinks there is over 100 degree on the parts, but even when I used 250 degree to test it out and have done a lot to make sure the temperature was high I could not get any higher then 60 degree. Sure I know every degree you add will make stuff hotter, but it still a lot cooler then people thinks.

Also shielding with aluminium is a very common thing to do and you can easy reduce the heat coming from the hot end.

Why do you think company use aluminium tape( or other thin aluminium sheets) in so many areas if it do not work to remove heat radiation from heat source?

You also keep forgetting its not only the aluminum that reduce the heat, its also the glue that is used. Both is acting like a heat barrier, thats why its important to use good quality aluminium tape, the low quality will have the aluminium to thin and the glue can not stand the heat. The really good one can stand to about 500 degree celsius, but the low quality maybe not even stand 100 degree celsius.

[Dan Newman]

> Does side fan on the Rep2 that blows on the side
> of the nozzle and the just-extruded portion of the print help, or is it
> directed too low to make any meaningful difference?

No idea what the effect is. You can play around and turn the fan
off and on while printing. If it's off and the temps are stable
and you then turn it on, you will see the extruder temp initially
drop by 2, 3, or even 4 C before it's again restored by the PID
control. So, it would appear that there is at least an initial effect
to blowing away that blanket of hot air on the underside of the
extruder. But as to the long term effect, I don't care to
speculate.

Dan

[Dan Newman]

> Does side fan on the Rep2 that blows on the side
> of the nozzle and the just-extruded portion of the print help, or is it
> directed too low to make any meaningful difference?

And just to be clear, what that fan is intended for is to help with cooling
the PLA when quickly transitioning from one layer to the next. PLA has
a significantly higher heat capacity than ABS. So when a low surface
area layer is printed and you then are turning around quickly to print
the next layer atop it, you either need to wait some number of seconds
or have been pro-actively speeding up the cooling of the layer. Hence
that particular fan. That it might (or might not) keep the extruder carriage
a tad cooler is incidental. (I've certainly never heard anyone from MBI
claim it has a secondary function of helping cool the carriage a tad.)

Dan

[Carl]

Just saw this post... I have posted a video of my Rep 2 printing at 280 deg C here...