Extrusion head stops and makes a clicking sound

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dakenskys
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Extrusion head stops and makes a clicking sound

Post by dakenskys » Sat Mar 01, 2014 10:29 pm

Hi All -

I was printing a part and soon after the raft was started the head stopped extruding plastic and kept making a clicking sound.

I though it was dirty, so I removed the nozzle and the tube assembly and cleaned them very well, but the problem still exists.
It started to print the raft, but when it started to do the cross ribs, it stopped extruding plastic, although the machine kept
moving, but no plastic.

This is an original UP! and never had problems before except for an occasional cleaning. I'm using pp3dp blue filament.

Oh, and another thing...I tried just extruding in maintenance mode, and same problem, just a clicking noise. I look at the end
of the stepper motor, and it appears to be hung up as it just stutters while making the clicking.

Any suggestions?

Ken

roller
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Re: Extrusion head stops and makes a clicking sound

Post by roller » Sat Mar 01, 2014 11:09 pm

Nozzle is clogged by the sound of it. Search the forums for various cleaning methods if someone doesn't follow with advice below. I am not much of an expert in cleaning because I am so careful to keep my filament clean and fervently avoid running non pp3dp filaments too hot.

mb20music
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Re: Extrusion head stops and makes a clicking sound

Post by mb20music » Sun Mar 02, 2014 12:25 am

dakenskys wrote: I though it was dirty, so I removed the nozzle and the tube assembly and cleaned them very well, but the problem still exists.
How did you clean them? After cleaning, hold the nozzle up to a light and if you can't see thru it then you have a clog.


For the rare occasion when my nozzle gets clogged, I use a plumber's torch (propane). I remove the nozzle and hold it with a pair of pliers while holding the torch on it until the plastic evaporates, usually take just a few minutes.

Some people use Acetone but it takes several hours to melt the plastic causing the blockage.

It is also helpful to have an extra nozzle (or more) so you can just do a quick swap and deal with the blockage later.

dakenskys
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Re: Extrusion head stops and makes a clicking sound

Post by dakenskys » Sun Mar 02, 2014 12:47 am

I did the acetone and propane torch method. I always keep a spare nozzle in acetone anyway.
I even pushed the back end of a drill bit (.073") through the tube several times to make sure it
is nice and clean.
I just removed the whole nozzle assembly again and rain the extrude function just to check the stepper,
and it seems to work just fine. Now I'll concentrate again on another cleaning of the nozzle and tube.

Ken

dakenskys
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Re: Extrusion head stops and makes a clicking sound

Post by dakenskys » Sun Mar 02, 2014 1:50 am

Ok, so I cleaned the nozzle and tube once again, but I changed to a different reel of filament,
and it looks like it's working again.

On a whim, I measured my pp3dp blue filament, and it varied from 1.67mm to as much as 1.83mm and I'm
wondering if this had something to do with the material not extruding properly.

What tolerance should I be looking for and does it really make that much of a difference?

So far, my Up! is making parts right now, so I'm greatly relieved, but if it is the filament, then how do I
make sure that the plastic that I order is the right spec?

Thanks for everyone's help.

Ken

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DrewPetitclerc
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Re: Extrusion head stops and makes a clicking sound

Post by DrewPetitclerc » Mon Mar 03, 2014 4:30 am

dakenskys wrote:Ok, so I cleaned the nozzle and tube once again, but I changed to a different reel of filament,
and it looks like it's working again.

On a whim, I measured my pp3dp blue filament, and it varied from 1.67mm to as much as 1.83mm and I'm
wondering if this had something to do with the material not extruding properly.

What tolerance should I be looking for and does it really make that much of a difference?

So far, my Up! is making parts right now, so I'm greatly relieved, but if it is the filament, then how do I
make sure that the plastic that I order is the right spec?

Thanks for everyone's help.

Ken
Cleaning was not the issue, all manufacturers of the plastic wire we all use will have issues with diameter tolerance on occasion, sometimes it is due to their extrusion dies age and sometimes it is an interruption in the feed reel take-up or extrusion speed/temp that can allow the diameter to swell and shrink along the line, the design of our extruder barrel is a close fit tube, no taper that does not tolerate larger diameters and so when the plastic diameter enlarges it becomes stuck at the upper portion of the tube which is cooled by the heat sink stopping feed and causing the clicking that is the plastic snapping away from the stepper gear, since the plastic cannot get to the lower heated/melt point in the tube you will have a feed fail.
If you can catch the printer soon enough and use the "Pause" in the maintenance menu you can do a "Withdraw" and then snip out the larger diameter section and reinsert the plastic and "Resume" printing.
The "official" "PP3DP" plastic is better held on tolerance (still not 100%) and some resellers like "Makerbot" have pretty good quality control too but all can on occasion have a "Bad Batch" but remember all manufacturers can have issues and all the resellers have to trust them to make the plastic to spec so if you run into a spool that has issues contact the reseller and I've found they will try to keep their reputations by helping to correct it.
Another manufacturing problem can occur if the plastic wire is spooled too soon while still in a "soft" state, this can cause "out of round" shape and will also cause the feed stopping problem.
These issues are pretty rare as I've collected and used more than 70 spools of plastics from a wide range of resellers and only a small handful have been a problem and only a couple have been bad all the way through.
I realize that if you only buy a couple of spools and they are bad your experience is more aggravating so I hope you get it resolved.
Drew Petitclerc
Petitclerc Designs
Owner/Senior Principal Designer, prototype, tooling and test equipment design and 3D printing
http://flash-graphics.deviantart.com/
http://www.thingiverse.com/DrewPetitclerc

dakenskys
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Re: Extrusion head stops and makes a clicking sound

Post by dakenskys » Mon Mar 03, 2014 1:09 pm

Hi Drew,
Thanks for the explanation about the varying size of the filament.
So, if the tube above the nozzle is purely for holding the plastic before it gets to the nozzle to be melted, why not ream out the tube to be slightly oversize to handle all these differences?
It would seem to me that making the tube a few tenths of a mm larger may help this problem.

Ken

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DrewPetitclerc
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Re: Extrusion head stops and makes a clicking sound

Post by DrewPetitclerc » Mon Mar 03, 2014 4:58 pm

Hi Ken,
Doing that would most likely introduce other issues and cannot be undone.
Remember the tube has to be a close fit so that the cooler portion of the plastic can act as the "plunger" forcing the softer plastic out of the nozzle, any increase in the diameter of the tube could mean when the plastic diameter gets smaller there will be plastic flowing up the tube and then cooling and creating the same kind of blockage.
Sorry for all the shoot downs, my day job has me designing robotic and mechanical systems so I do a lot of trouble shooting and I have invested a lot of time in solving a lot of issues with this printer design.
Regards
Drew
Drew Petitclerc
Petitclerc Designs
Owner/Senior Principal Designer, prototype, tooling and test equipment design and 3D printing
http://flash-graphics.deviantart.com/
http://www.thingiverse.com/DrewPetitclerc

dakenskys
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Re: Extrusion head stops and makes a clicking sound

Post by dakenskys » Mon Mar 03, 2014 5:05 pm

Hi Drew,
I can understand that, as my day job is engineering for a toy company, and I'm involved in plastics and molding every day.

I was thinking of machining my own part to experiment with, and perhaps enlarging the tube only until the end before the
nozzle where the opening would taper to a close fit again. Maybe this way, at the area of melt, the tube would act as a gasket
to prevent backup of plastic.

Ken

dakenskys
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Re: Extrusion head stops and makes a clicking sound

Post by dakenskys » Mon Mar 03, 2014 5:16 pm

Actually, looking at my machine again, see the attached drawing...
I wouldn't be changing the outer diameter of the tube as that would still fit snug against the ID
of the nozzle.
I would just buy a small reamer to enlarge the ID of the Tube only.
Attachments
nozzle.jpg
nozzle.jpg (54.18 KiB) Viewed 14399 times

dakenskys
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Re: Extrusion head stops and makes a clicking sound

Post by dakenskys » Mon Mar 03, 2014 5:25 pm

Perhaps this is clearer to my previous post.

The only area that I would ream larger, would be about 95% of the upper part of the tube,
and the smaller, original ID would only remain where it is inside of the nozzle, and getting
the maximum heat for melt.
What do you think?
Attachments
nozzle2.jpg
nozzle2.jpg (68.1 KiB) Viewed 14399 times

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DrewPetitclerc
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Re: Extrusion head stops and makes a clicking sound

Post by DrewPetitclerc » Mon Mar 03, 2014 10:51 pm

Think about the plastic as it melts at the bottom but flows back up around the cooler plastic in the gap between the tube wall and filament until it reaches the cooler area of the tube, this will happen as it is the lower pressure path, then it cools and plugs up that area of the feeder tube, there will be a tube size that is too large and this will occur, but if you creep up on the diameters without going over the max it will tolerate you might make a small difference for larger sized plastics but it will fail spectacularly on smaller diameter plastic.
After all my research about printer extruder designs there is no one solution unless you restrict yourself to engineering for one material supplier and that is what the original design shoots for.
Drew Petitclerc
Petitclerc Designs
Owner/Senior Principal Designer, prototype, tooling and test equipment design and 3D printing
http://flash-graphics.deviantart.com/
http://www.thingiverse.com/DrewPetitclerc

pleppik
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Re: Extrusion head stops and makes a clicking sound

Post by pleppik » Tue Mar 04, 2014 4:36 am

dakenskys wrote:Hi Drew,
Thanks for the explanation about the varying size of the filament.
So, if the tube above the nozzle is purely for holding the plastic before it gets to the nozzle to be melted, why not ream out the tube to be slightly oversize to handle all these differences?
It would seem to me that making the tube a few tenths of a mm larger may help this problem.

Ken
Some of us have done this, just by using an electric drill and a 2mm bit.

Drew's warnings notwithstanding, it does work, doesn't cause too many issues, and can give you a little more tolerance for bad filament.

But Drew is right, it's best to not use bad filament in the first place. Once done, this can't be undone, and the potential exists to make an $80 slip of the fingers.

A couple years ago it was much harder to find 3rd party filament with reasonable quality control, which is why this was sometimes necessary in the past.

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