Print gets rough after the first inch or so

[nancy 8]

Hi all. I'm trying to print a flute--small cylindrical structure. I would like to print it solid so the sound resonates better and air is less likely to escape in the walls. The first inch prints fine but then the rest of the print is very rough.

This problem goes away if I use the default 20% infill. I was wondering if you guys have any suggestions on what I can tweak. I'm printing at 100mm/sec, and 100% infill, 0.2mm layers. I'm using 3mm PLA, temperature is set at 220C. Retraction is enabled (40 mm/s; 4.5 mm).

The flute works even with the rough print, though it's out of tune. I would like a smoother print though.

 

[nick-foley 5]

Picture seems broken, but I'm assuming you're trying to print it vertically? It sounds like the part isn't cooling enough. Does the part seem to be coming loose from the bed at all during the print? That could also be a problem.

For a print where I care about the quality, I would print slower, in the 40-80mm/s range, lower my temperature, and reduce my layer thickness.

I would try 70mm/s, .1 or .15 layers, 200-210°-ish temp, depending on the PLA.

 

[nancy 8]

Thanks, I'll give those settings a try. I had a few prints where the part came loose, but I think that's because my z-stop is messed up. I have to watch the first layer very carefully and oftentimes adjust it.

 

[gr5 2,170]

You are printing at a speed that is possible for the UM but you are on the edge. 100mm/sec is pretty fast for the volume of plastic going through the nozzle - you have quite high pressures going on in the nozzle and your feeder is probably slipping a bit causing some underextrusion. I agree with nick that you should slow down a bit and see if that helps. Try 50mm/sec and be patient. Also if your part pops off the blue tape let us know as there are some reliable techniques to keep that from happening (isopropyl alcohol, brim).

Other things to mess with:

1) You can set the "shell thickness" to 10mm if you want and it will fill with lots and lots of passes.

2) Or you can set the bottom/top thickness to 200mm. That creates a different kind of infill than if you do 100% infill and many people prefer that type of infill.

 

[illuminarti 18]

Another cause of gradual decline in print quality is having the fan blowing on the tip of the nozzle... at first the fan is off, and the nozzle is hot. Later the fan kicks on, and gradually lowers the temperature of the nozzle tip, making it harder to extrude consistently,especially when printing fast.

Try printing it without the fan enabled, but with a minimum layer time of at least 7 seconds, and see if that makes a difference.

 

[gr5 2,170]

Also to get it to stick better:

1) Enable the brim feature. This will add more surface for your part to stick to. Do around 5 to 10 passes.

2) clean the blue tape with isopropyl alcohol. The blue tape as it comes off the roll has some wax to allow the tape to unroll at all (did you ever wonder how the sticky side doesn't stick to the other side of the tape when it is rolled up?). So you the alcohol removes that waxy stuff. And then the part sticks much better. You might need a larger piece (wider) of blue tape if the entire tape lifts off.

3) The first layer should be pressing the filament into the tape a little bit - the top of the first layer of filament should be squished like a pancake.

There are other tricks but those 3 should be enough. I've printed very skinny, very tall things with just these 3 tricks.

 

[nancy 8]

Ok, got it. Right now, I have it printing some spare parts for the dishwasher--just some legs to make the dishwasher stand evenly. I'll get back to the flute tomorrow and try these tips. The only thing is it's not gradually worse.. it's instantaneously worse. You might not be able to see clearly in the photo but one layer is perfectly fine, and then it gets rough. Once it gets rough, it stays the same quality. I'll give these suggestions a try.

 

[gr5 2,170]

Just slow it down the print by 50% and I bet that will fix much of the issues. Once underextrusion starts happening it can kind of get in a new mode for a while.

 

[nancy 8]

I turned off the fan, turned down the speed, added a brim. It worked! The print is much smoother. Thanks all.

Now I need to adjust the flute file to bring the pitch down a few keys--the small flute I have is very high pitched.

Here's a video of me playing the flute, for those who are curious: http://mixeelabs.tumblr.com/post/62172358622/fully-functional-flute-3d-printed-on-ultimaker%C2%A0

 

[nancy 8]

So turned the fan back on, but tuned down the speed to 50mm/sec. The print is better than ever! With the fan off, the key holes (overhangs) got very stringy.

Maybe I'll post another video of the new and improved flute, but no need to burden you guys with my bad flute playing for now. The new flute functions A LOT better though, I can get the lower notes just fine as well as the high notes.

I'm printing a penny whistle now, and I'll get to play with my friends new and shiny U2 next week (I'm printer-sitting.. that's a thing now right?), so I'll print a few flutes on the new machine too!

Thanks everybody for your help!

 

[gr5 2,170]

Love the video!

I would use an electronic tuner. Then mathematically figure out in % how much to change the frequency then move the hole that much closer or further from the other end of the flute.

In other words if the pitch for a note is 450Hz but you want 440Hz you need to lower the pitch by 450/440 or lengthen the distance to the hole by 450/440 or 2.3%.

Or you can do it by ear but that is harder. Each half tone is 5.95% (each step on the piano).

- George

 

[nancy 8]

So I tried again at 50 mm/sec, and the prints were great! And in tune! I should start working on the flute creator now. Hehe.

Next week I'm printer-sitting my friends new Ultimaker 2, will report back on how the flute prints on her machine. I'm thinking of setting up a livestream or something so people can see the new printer in action. I did it for the Ultimaker 1 and my friends found it amusing.

Any ideas and what else I should try on the Ultimaker 2?