Changes to newer machines? Hot steppers and PLA printing

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pleppik
Posts: 336
Joined: Sun Dec 11, 2011 2:14 pm

Changes to newer machines? Hot steppers and PLA printing

Post by pleppik » Mon Feb 11, 2013 4:50 pm

I bought my Up about 14 months ago (December 2012), and have had no end of trouble trying to print PLA. The problem is the feeder stepper motor gets extremely hot--I estimate 70-90C--and the PLA softens in the feed gear and jams. The stepper actually gets too hot to touch. I know some people with similar vintage printers have had success by actively pumping air around the feed gear to keep that area cool.

Here's the thing, though. A couple weeks ago I met someone who owns an almost brand-new printer (I can't remember if it was an Afinia or an Up), and he told me he prints with PLA all the time and has no problems.

I know there have been some under the hood hardware changes since I bought my printer. Does anyone know if one of the changes fixes the problem with the hot stepper? Or can anyone confirm that newer printers don't have the hot stepper problem?

Waycool
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Joined: Wed Feb 13, 2013 6:28 am

Re: Changes to newer machines? Hot steppers and PLA printing

Post by Waycool » Wed Feb 13, 2013 6:38 am

FYI, i got my UP Plus about a month back and it still can't print PLA.... I too suspect the motor is getting too hot and softening the PLA. I've even tried it with some expensive PLA from Faberdashery... still no go....

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: Changes to newer machines? Hot steppers and PLA printing

Post by roller » Wed Feb 13, 2013 6:57 am

I was told by the local distributor that the newer printers have steppers that don't run as hot. That said the stepper in mine still hits 70C on a long print and would deform the PLA and I had the same experience with the Mini I had for a short time. I am sure if I printed in aircon I could get away with printing PLA especially with a fan blowing on the unit but in my naturally cooled environment it gets too hot and does occasionally curl and jam the PLA.

Firstly, before we get into complaining to Up ... I have been building reprap printers for nearly two years and this is a common problem in all direct drive extruders with PLA. Secondly, their is different grades of PLA, some softens as low as 40 and some makes it well past 70C. Obviously the latter has much higher print quality and greater resistance to jamming. You cannot judge which you have by the final melt point unfortunately.

I suspect all that has been done is teh current is wound back a little on the extruder. I am not sure if there is a way to mod this ourselves (trimpot on the mainboard??) I intend to load up my stepper with heatsinks and just use a desk fan to cool both the print and extruder as I would do this normally anyway to help print quality.

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wilsonj
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Location: Australia

Re: Changes to newer machines? Hot steppers and PLA printing

Post by wilsonj » Wed Feb 13, 2013 9:58 pm

Waycool wrote:FYI, i got my UP Plus about a month back and it still can't print PLA.... I too suspect the motor is getting too hot and softening the PLA. I've even tried it with some expensive PLA from Faberdashery... still no go....
Interesting, as I also tried Faberdashery's filament and found it worked very well. One thing I did notice was I had to lower the platform slightly as the filament came out thicker than other materials, and the first layer wouldn't print.
Regards
Jamie
3DPrinterGear.com.au

mr6k
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Joined: Tue Feb 14, 2012 11:47 am

Re: Changes to newer machines? Hot steppers and PLA printing

Post by mr6k » Wed Feb 13, 2013 11:49 pm

My two pennies worth.

I also tried Faberdashery PLA, on several occasions with my UP plus in PLA mode, Had no end of problems with PLA softening around extruder gear. Gave up, I am now a ABS only man, especially as it is now available in a great range of colours. Although I am also trying some Taulman 618 nylon at present.

cheers

Peter

D3rax
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Location: Netherlands

Re: Changes to newer machines? Hot steppers and PLA printing

Post by D3rax » Thu Feb 14, 2013 6:28 pm

I received a new Up Plus this week. I noticed that mine up Has an improved extruder mounting bracket. Or at least I think it is. The bracket is not made from thin sheetmetal but from stainless steel that is 3 mm thick. I wanted to apply this upgrade http://www.thingiverse.com/thing:16710 from Drew. But I guess thats not needed anymore?

I also noticed that mine up hs a watenty seal so I have to wait a year anyways to replace the bracket....

So it looks like they did made some improvements. Soon as Im going to print PLA I will report my results and settings.
Up! Plus

roller
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Location: Brisbane, Australia

Re: Changes to newer machines? Hot steppers and PLA printing

Post by roller » Fri Feb 15, 2013 3:24 am

With respect to Fabadashery and all PLA in fact, some colouring in the PLA significantly affects the melting points and flow.

Waycool
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Joined: Wed Feb 13, 2013 6:28 am

Re: Changes to newer machines? Hot steppers and PLA printing

Post by Waycool » Fri Feb 15, 2013 3:22 pm

I, too, have the beefier extruder bracket....

I've tried "Crystal Clear" and "Glacial Blue" plus a few meters of sample PLA in other colours that Faberdashery always add to your order (for free!) but those don't feed too...

roller
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Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: Changes to newer machines? Hot steppers and PLA printing

Post by roller » Sat Feb 16, 2013 1:13 am

It is always a bit painful to print PLA with direct drive style extruders like the Up! uses - even ones I have (on repraps) that run much cooler than the recent model Up! still jam due to melted PLA from time to time. Cooling mods are often necessary though a deskfan and maybe a heatsink or two on the extruder stepper is often sufficient.

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