My Prusa i3v 10" Build === Photos, Comments & Questions

[printbus]

...Though I did like the idea of putting a fan on the side so i could see the extruder better.

Just to show you it can be done, I had temporarily installed the clough42 print cooler on the left side. The shroud mount was bolted onto a piece of hobby plywood shaped to follow the X-carriage, except it went higher. You can't see it in the picture, but there's a hole in the plywood below the shroud mount that was used with the existing screw location on the left side of the X-carriage.

I say this was temporary in that I only used it until I could get a blower system (not a fan) in place, also mounted to the side. I found the airflow lacking with a shrouded axial fan, since axial fans aren't designed to operate with the backpressure that a shroud creates.

[jtice]

Glue stick, hmm yea might try that, I dont like the idea of spraying hair spray around the printer anyway.

Nice side mount, I think I will do something like that for now.
Once I have some more parts printed and have the complete Clough42 shroud, auto level, etc. all ready to go I will just install all that at once.
But for now your solution would let me print PLA correctly for a while.

[dacb]

I say this was temporary in that I only used it until I could get a blower system (not a fan) in place, also mounted to the side. I found the airflow lacking with a shrouded axial fan, since axial fans aren't designed to operate with the backpressure that a shroud creates.

So true. I have a blower fan incoming for experimenting.

[jtice]

Twice now I have had the filament snap in the extruder.
I had the filament skip once (printing in air), so I tightened the extruder up some.

I am hearing a good bit of clicking/cracking noises, I cant tell if its the stepper motor, or the extruder itself.
I THINK its the extruder itself though.

Read up on it some, but seems very random and spread out with issues.
The prints are turning out pretty well at least, just hate the risk of failure during a print.

Printing ABS at 230c @ 50mm/sec
Sometimes turn the Prusa up to 103% to 112% but it does it at 100% also.
Any ideas?

[dacb]

Twice now I have had the filament snap in the extruder.
I had the filament skip once (printing in air), so I tightened the extruder up some.

It snapped below the bobbed bolt but before the metal collar for the hot end? What brand of filament are you using?

[jtice]

Far as I can tell, yes.
Once it snapped and curled the filament out the side of the extruder right below the bearings.
The second time it looks like it folded over right above the hole in the top of the plastic extruding housing, right below the bobbed bolt.

The first two days of printing did not do this.
Its still printing decent, but definately sound different. Just hear alot of little clicks and crackles, and at times, its a crack louder than the heat bed relay clicking.

I thought about raising the temp, seeing if it made it easier to extrude.
I pulled back the tensioner and pushed the filament in by hand with the head at 230c
It took some pressure, but wasnt all that hard to do.

Using Winbo ABS

[dacb]

I don't suppose you could youtube a video of the sounds? You sure the noise and the filament breaking are related?

When I've had it break inside the extruder it was because the filament was tangled on the spool and providing too much resistance.

How tight are your screws for the extruder idler block? Could it be that the hobbed bolt is digging too deep into the filament?

[jtice]

Sure, I will make a video tomorrow for you.

No, Im not sure of anything, isnt that obvious yet?
I read about the extruder motors clicking, but I dont think thats it, the gears dont stop turning or anything, motor is warm, but not hot.

Spool seems to be unrolling pretty freely. I dont think thats it, since its breaking below the feed bolt.

I will also get pics of some filament I pulled out of the extruder, that has marks in it from the hobbed bolt, so you can get an idea of how tight I have it.
I think I have it so the bolt is a mm or two from being flush with the hole on the opposite side of the extruder, if that makes sense.

Also,
Is there a good thread, blog, etc. for examples of print issues, and what their causes/solutions are?
Something maybe with photos of a print issue, then a description of what causes it?

[printbus]

On the print issues & causes, I've seen some starts at it but none that were complete. Here's the most complete one I am aware of - http://reprap.org/wiki/Print_Trouble...ictorial_Guide . I just wish they printed in something other than white since detail is hard to photograph on white prints.

On the snapping filament, how brittle is the filament? Does it break when you bend it by hand? I'm not sure whether this is a good/bad sign, but it would give an idea of what you're working with.

Assuming it's not caused by the filament above the hot end getting soft from temperature, one possibility is that repeated retraction is weakening spots in the filament. This would make the filament easier to fold over and explain why some prints go fine without issue. What are your slicer's retraction settings? I used to have frequent problems with the hobbed bolt cutting into the filament until I backed off on how often the slicer was performing a retraction. Increasing the minimum extrusion after a retraction was part of the "fix". Even with that, I turn retraction off on some prints where I know the printer will be moving to different parts of a layer, adding just dabs or short lengths of extrusion at each area. One roll of filament was especially bad with the hobbed bolt cutting into the filament, until I finally noticed there were small bumps in the filament that wouldn't pass into the hot end. They were small enough that I couldn't see them - I just happened to feel one when I fed the filament through my fingers to reload the extruder. Unrolling a length of the spool, I could then find many similar bumps. I spent many hours tracking that one down.

On the sound, I'm assuming you have no layer slippage in your prints that would happen if the X or Y belts skip a gear tooth. What is your retraction speed set to in the slicer? No one else has concurred with it, but I found reducing it from the MakerFarm default of 30mm/Sec to clough42's recommendation of 10 mm/sec eliminated a pretty hefty thwack sound from my extruder. If the sound happens often enough, try listening through a length of hose held to different areas of the extruder in an attempt to locate it. As I worked through my i3v to eliminate noise, I was left with sort of an annoying creak in the extruder. The hose trick narrowed it down to the area of the idler bearing. You could also try marking the large gear with a Sharpie pen when you hear it so you can see if the sound always occurs at the same spot in the large gear/hobbed bolt rotation.

Such fun.

[jtice]

Retraction Speed: 25mm/s
Distance: 3mm
Min Travel: 1.5mm
Min Extrusion Before Retraction: 0.02mm
Enable Combining: checked
Z Hop When Retracting: 0mm
Travel Speed: 150mm/s
Print Speed: 50mm/s
Winbo ABS Filament from eFilament
230c

Not noticed any belt slip. I had a few issues with the teeth on the small gear I printed, but my guess is that it was printing too fast,
and the teeth were still soft as it made it next pass and it was warping them out of shape a bit. I will include pics of that also.
But I dont think its what you said, a shift in an axis due to a belt slip. Since half the teeth look fine, it was mainly one side I think.

The Filament is not brittle at all, you can bend it a good ways before it tries to snap.
I will look over the printer tonight, make sure everything looks good, everything is tight.
Then I will upload a video of the noises, and photos of some hobbed bolt marks on my filament.

I will then try changing the restraction speed from 20 to 10mm/s as you suggest.