Filament feeder wood gear spins backwards in short spurts..?

[benny 0]

I have my diy build UM working so far. Prints seem to start ok and the first few layers are good, but every single print so far fails after a few minutes because the feeder mechanism at the back stops feeding in but rather starts to briefly spin backwards and continues forwards a bit and repeats this foward/backward behavior. This stops new filament going up the bowden tube resulting in a failed print due to lack of pla.

I have marked on the filament in black ink just below the wood gear to visualy see the filament being pulled it. It starts the print ok but then this strange spinning backwards starts to occur for about quarter of a second then resumes forward..

Can anybody suggest what might be causing this.? The gripping bolt has a good solid grab on the filament as far as I can see but why would the UM suddenly turn the wood gear backwards even for a quarter of a second.?

Pulling me hair out with this... :???:

 

[illuminarti 18]

It's supposed to do this. This is called 'retraction'. When moving the print head between sections of the print, the printer sucks back a little filament to stop any oozing out during the move. When it gets to the next print section, it quickly moves the filament back, and then carries on printing.

In and of itself, this isn't what is causing your print problems. Perhaps you could tell us a bit about what you are trying to print, and the settings that you are using?

 

[benny 0]

Im trying just the robot and the 20mm test cube to setup my printer. My first print was the robot guy that started really well and got as high as 3/4 cm before this problem arose. All prints so far have had exactly the same result, as in extruder is no longer putting out new layer after a few mins.

Im using the UC mainly and preheat the pla to 220 wait for a string to come out then load the gcode from the sd card.

As for other the settings I havent touched anything exept flow which I dialed up to 110, but it had no effect.

Im pretty sure its something silly I have missed, but the printer seems to work ok. No problems there. Just this lack of extrusion after a few mins or so over each print..

 

[benny 0]

I also just noticed that I was sent the old Extruder drive kit and not the new V2..Does the new one improve the old one a lot..?

 

[gr5 2,167]

As illuminarti says - it is supposed to do this. You can disable this feature in cura (disable retraction) but it's very useful for ultimakers. Please post a picture of your print that shows what is going wrong if it isn't coming out how you hoped.

 

[illuminarti 18]

When you load the filament, and preheat, its ok to turn the big gear wheel by hand to get the filament loaded into the nozzle. I wouldn't use the Ulticontroller to advance the extruder, as that can push too much plastic too fast, and cause problems.

Are you sure that you have the filament loaded correctly? The lever on the extruder drive on the back of the printer should have it's bolt slid all the way to the bottom of the slot, and then be rotated a little past horizontal, to ensure a good grip on the filament.

 

[illuminarti 18]

So your extruder drive doesn't have a spring on the back of it - just a knurled knob?

 

I also just noticed that I was sent the old Extruder drive kit and not the new V2..Does the new one improve the old one a lot..?

 

[gr5 2,167]

Pictures please. Please send a picture of your extruder.

Also maybe you could send a picture of a failed print or a video of when the print stops working and show the extruder in part of the video?

I can't tell you how many times we give bad advice up until the moment we see a photograph.

Maybe you should disable retraction in Cura to eliminate that as part of the problem. Then show a photo of what is going wrong.

 

[gr5 2,167]

To post a picture, click "gallery" on the top left corner of this page. Upload your pictures to that, then create a new reply to this topic and click "my media" and choose the pictures in the gallery.

 

[benny 0]

Ok, here are some pics of the problem I am having. Everytime it is the same. The extruder stops after a few layers for some reason. What can you tell from the failed prints here. Is it called under extrusion. Still very new to this so please forgive the ignorance.. :-P

 

 

 

[illuminarti 18]

In all of the pictures you posted, the extruder drive isn't shut properly. (And it looks like it is the latest greatest version - v2, plus an injection moulded piece with the spring (rather than a printed/wooden piece)).

With the plastic lever pointing up, you need to squeeze the two black plastic arms tight against the wooden block, then push the lever all the way down, so that the M3 bolt is at the very bottom of the slot. Only then do you rotate it into the horizontal position.

As it is, the feeder is barely pressing on the filament, causing it to slip.

 

[gr5 2,167]

I was going to say the same thing as what Illuminarti said.

The feeder should be able to pull about 22 pounds force (with no load at the nozzle end). So you can test that whithout even powering up the ultimaker.

 

[benny 0]

Thanks illuminarti, got the feeder sorted out. It was a simple case of not pushing it firmly enough against the knurled bolt for grabbing the filament. retraction works fine now also. Here are a few first prints I have done. Still working on fine tuning the UM but so far I am very happy I can now create all my 3d work I have done over the last 20 years or so into real models.. Very exciting..

 

[benny 0]

What would you guys recommend for printing upgraded parts for my UM.

Which ones of the many available would really benefit me using my UM almost 24/7?

I have a ton of models I have produced over the years as a 3d artist, so I will be printing non stop pretty much, and dont want the stress of having a broken printer.

I am going to order a new hot end & bits an bobs, possibly an extra motor, and pulleys etc.. But what could I print that would make the UM do an even better job..?

Any thoughts.?

 

[illuminarti 18]

Yay! The prints look great - I'm sure you must be pleased to see some of your creations come to life.

Some of the upgrades I would suggest include simple things like a handle and feet, plus belt tensioners for both the short and long belts. You might also benefit from a shim to reduce the play in the Bowden tube coupler on top of the drive motor - that improves retraction by helping to keep the Bowden tube a constant length.

Here's a selection of things from Thingiverse that you might want to consider....

http://www.thingiverse.com/illuminarti/collections/ultimaker-upgrades

Most people also print new fan shrouds - there are a ton of designs available on Thingiverse, although I'm not sure anyone has really done a definitive study of what works and what doesn't - there's just a sense that the default origami one is clever-but-ugly-and-probably-not-as-good-as-it-could-be.

 

[benny 0]

These pics are of course not my work, just testing the printer and climbing the vertical learning curve that is 3d printing..I will post some pics of my models, and later when ready I will show some printed versions.. Just tried one of my characters I made for HL2 about 10 years ago but it dosent like the printer.. Lots of editing on most of my meshes me thinks...

Managed about 8 great downloaded prints today..

Stay Tuned..!