cyan

If I remember correctly, one of the holes is slightly smaller than the other. When I printed it (v2 I think), an M3 screw fit perfectly, so that it could just slide through the one and bite into the other. The smaller hole is meant to be toward the body of the machine, so the screw can just be pushed through from the front, through the bushes that hold the bearing, and then be screwed into the smaller diameter hole on the back. I had to cut the screw down to length (I could only find longer ones at my local hardware store). Mine was completely solid when assembled, not loose or floating at all. I suspect that generally only people using printers that are giving some sort of trouble bother with printing an alternative feeder, so print quality issues might be to blame for some of the problems people have had (broken latches, etc). I'm still using the first |Robert|'s feeder I printed, and I honestly cannot imagine it physically breaking. Perhaps we need a bootstrap feeder design that is optimized to be as easy to print and as tolerant of underextrusion as possible, sacrificing beauty, openness, quick filament change, etc. Then when the machine is printing better parts, the final feeder can be printed. I can't immediately think of how that could be achieved with those trade-offs, but there are many designers on this thread smarter than me

I managed to print the cylinder up to about 14mm3/sec (test cylinder at 200% speed) without problems using ultimaker blue and without touching flow rate (which isn't valid for that test). 230% flow rate seems crazy. You sure you're not feeding it 1.75mm filament? (A joke, but the math almost works out)

Couldn't the hex shaped hole be rotated 30 degrees, leaving thicker walls at that point?

Yeah, mine is still going strong. Looking at the layers near the failure point it looks like they weren't cooling properly, might have weakened it enough to fail at that point. I added an additional fan at that point in the print to avoid that problem.

Looks like the extrusion is ok at 10 but the layers aren't cooling enough before the next one is laid down. For the tests I did above 10mm3/s I used an extra fan which helped with that. Realistically though I doubt it would happen on a real print, except maybe a vase. Over the weekend I printed a spacer bracket for my bike that keeps eating number plates, at an flow rate of 7.5mm3/s in Colorfabb XT and it came out beautifully, with the fans at 30% for all but the last layers that required more cooling, so the higher flow rates are proving useful when printing parts with .25 mm layers. Before all the mods I was limited to about 4-5mm3/s.

Juha Lehtinen: what material did you use to print the cylinders? From the photos it looks like Colorfabb XT, which needs higher temperatures than 230. My spools are labelled 250 - 260, although I've found that's too hot. At about 253 it starts to degrade and go milky white, and the extrusion is very uneven, and it creates spiderweb-thin strings everywhere. At 220 - 230 it starts to under extrude severely. I'm currently using 248, which prints beautifully, with good layer adhesion and clarity, but it's tough to keep the hotend in the narrow band of acceptable temperatures, it tends to swing wildly for me, overshooting and dipping 20 or so degrees below the target and taking a long time to ramp up with changes in speed and fan levels. Once I've got some more experience with the material I plan to start a thread to collect useful info about it (I found much less on-line than for PLA), but for now if anyone has suggestions I'm all ears. One more off-topic note: In trying to glue it to metal I found that epoxy and hot glue don't bond very well to it, but cyanoacrylate (superglue) does - I bent the tin can and stripped the outer wall of the bit of scrap I glued to it, although it did discolour a bit.

AxelEriksson: have you tried printing it the right way up?

I based it on post #5 where he saw it top out at 34%: 0.6 * 0.57 = 0.34 or 87/255

I'd like to go to a convention like this, but South Africa is a very long way from anywhere something like this is likely to take place. But if people are interested in visiting Cape Town I'll organize a mini-conference here

I've found that the firmware scales the values set by Cura (in the gcode) by the setting in the material properties, so if the setting Material->Settings->Customize->Fan Speed is 57%, it will produce the behaviour you saw.

It should be a .gcode file, which is what the printer reads, so you should just be able to put it on the SD card and it will work.

Maybe give the latest bleeding edge cura a try - I had similar sounding issues with the start of a print that are much better since building the SteamEngine branch of cura and curaengine from git yesterday.

Sorry, I messed up the link. Edited the post to fix it

I printed https://www.youmagine.com/designs/fanduct-another-idea (the v23 from a few days ago) in XT. It was my first print in XT so I had some issues with stringing, although not with overhangs, it prints those fantastically It's a few grams lighter than the stock metal bracket which is nice, and I'd probably print it with less infill or single walls next time to save even more weight (I used 0.8 walls, 0.6 top/bottom, 20% infill). Can't say yet whether it helps the right side cooling (which is why I printed it), since I haven't swapped back to PLA yet, and it seems like XT actually likes less cooling, so I run between 0 and 75% fan at the moment. One thing to watch out for if you use this fan duct is that even printed in XT it can start melting from radiant heat from the nozzle when printing XT at 255C and no fan. I haven't put the heat shield on yet so I'm sure that will help, and using even 25% fan seems to stop it happening. Previously what I was doing to fix the cooling issues for small parts that never really cool properly on the right side is to put a big fan in front of the printer aimed at the head which worked nicely. On a slightly more on-topic note, I printed the cylinder in XT at 250C with |Robert|'s feeder and low-friction spool holder, and Geeks filament guide. No filament feeder-feeder yet, I want to print that once I've swapped back to white PLA. It printed perfectly all the way to 10mm3/s. Edit: fixed URL

Did you ever try isolating which part fixed the issue, or if they both contributed to it, and how the working replacements differed from the problematic ones? That would be really valuable information to have.