Steam Train Whistle

Summary: My first print with custom settings. Use the pause function to correct minor errors during a print.

Since before I got my 3D printer, I have wanted to print this steam train whistle from Thingiverse. I thought it would be cool to print something functional, even if its only function is making noise!

first try

My first attempt didn't turn out so well because the filament feeder was skipping.

second try

I tried again after "fixing" the problem only to have the feeder start skipping again and ruin another print. I was feeling cocky after a successful print so I had upped the printer speed to 80 mm/s. That's still a conservative speed for the UM2 but maybe that was the reason for the skipping?  Rather than repeat the print at 50 mm/s, I ended up disassembling the filament feeder and performing an Atomic Clean on the print head. While feeding the filament back into the bowden tube I noticed that unless the curve of the filament matched the curve of the tube, the filament would bind firmly in the tube. The deep pits in the filament from the feeder probably didn't help either. So I cut off any filament that had been through the feeder already, made sure the filament was uncoiling cleanly and following the curve of the bowden tube, and fed it back into the filament feeder.

stray filament

Bingo, that did the trick. The PLA seemed to be flowing smoothly so I set up the whistle print again, this time at 50 mm/s. About a third of the way through the print I noticed a piece of PLA had been pulled out of place and was sticking up in the middle of the whistle chamber. I was worried that this might affect the sound of the whistle so I paused the print. To pause a print, just go to tune < pause printing with the navigation button on the printer. A pause also moves the print head out of the way. With the print paused I was able to cut off the piece of stray filament. Hit "unpause" and the print picks up where it left off with no visible sign of the interruption.

third time's a charm

About an hour later the print finished. I didn't hear or see the feeder skip once during the entire print. The whistle looks great and sounds just as good. And it is loud. The kids should love it...my wife will hate it.

I used the full settings and made some adjustments as recommended by the whistle designer. The final print settings were as follows.

220°C
0.25 mm layer height
0.75 mm bottom/top layer
25% infill
0.8 shell
0.3 mm initial layer
50 mm/s print speed
all other settings were default