eldrick

I spent another day fooling around with it, and I've given up on the MK8 hobbed wheel. It seems like every time it skips (not infrequently) the filament (Ultimachine White PLA) clogs the grooves, and it starts underextruding. It's also not that easy to clean out even with Robert's feeder, compared to the TrinityLabs version that I had at one time.

Try printing one of the fan ducts by Venkel: https://www.youmagine.com/users/venkel These improve cooling to the point where you will often turn the fan speed down, and also kill a lot of fan noise from the metal shroud.

I had some decent results using transparent ABS and then vapor-bathing it in acetone. It came out mostly clear, almost like glass, with some cloudy parts where the plastic was thickest.

I Want this!

I had the same problem with this part - one method is to print it on a room-temperature printbed (not heated). (I'm assuming PLA) Pieces this small never have a chance for the plastic to cool quickly and freeze in place during the print even if you have the fan on high immediately after starting the print. It takes several seconds for the plastic to get solid, and having a heated printbed right under the overhangs makes the problem worse. So try using gluestick for adhesion, and printing without heating the printbed.

Update - I've been working upward from e-steps=340 with the MK8 - currently at 354.

Interesting report. In my year-long experience with a TrinityLabs hobbed wheel, it did occasionally clog as a result of some other issue, but when it didn't unclog on its own, it was quite easy to clean out (assuming easy access). I've just started using a MK8 hobbed wheel on my UM2, and so far it seems to get a better grip on the filament with fewer skips than the original knurled wheel. Having smaller effective diameter, it should give a bit better extrusion resolution - I'm still calibrating, but using e-steps around 340 for now.

Just for the record, glue stick usually only needs to be reapplied every dozen or two dozen prints.

anon4321: If any of those reasons apply to the prospective purchaser, then why not just ask the questions directly? "Why are you selling" implies a lack of trust on the part of the buyer if he asks that particular question to try to pry for more information than was freely offered, and invites an evasion or a lie if the seller is not trustworthy. Either way it's irrelevant information, when what is actually of interest is the condition of the goods offered.

Why do some people always ask "Why are you selling it"? I've never understood why one would ask that. Perhaps "I'm selling it because I have cancer and need to pay the medical bills before they repossess my wife," would make you buy it, or maybe you are expecting to hear a sudden fit of total honesty, like "I'm selling it because it is a POS that arrived broken in the box, and besides, I'm too stupid to make it work"? Why is it of any interest why someone is selling something, and why would you intrude into someone's private life by asking? It also seems, on reflection, that persons who ask this are never the eventual buyer. That's another reason why I never honor bother to answer that pointless question with a response.

Here's another solution - bowden clips in different heights: https://www.youmagine.com/designs/ultimaker-2-bowden-clips%C2%A0/

It could stand to be a mm or two longer, but I think I've spotted the problem - I don't have a washer on the screwhead end of the spring as is shown in the images on Youmagine. A washer or two there would probably do the trick for me. I'll give that a try.

Were there any changes in the dimensions of the yoke?

Speaking of Robert's feeder plus a Mk. 8 gear, I had no luck with that combination. I was unable to tighten the yoke enough to get reliable extrusion.

That's a really good idea - I'm in. You could also use it for switching colors in mid-print.

Kisslicer and Slic3r do this by printing the infill every N layers as an option.

Z-hop is exactly what you need when printing PLA with overhangs that tend to curl upward. It allows you to keep printing without knocking over the piece and ruining it. I use .08 as a value.

Your log scale makes sense, but not at 150% ratio. A .5mm nozzle has about 55% larger area than a .4mm, and it is the area of the nozzle that controls the amount that can be extruded. I'd suggest .33, .4, .5, .62, .75mm would be a good set.

Removable/replaceable tip would be excellent. My interest would be interchangeable .4mm and .5mm.

Use ABS, not PLA.

If "the zscar" you refer to is the vertical line of layer start points that Cura creates because it does not bother to try to randomize or hide start points, you should try Kisslicer - it gives you Much better control over start points than any other slicer. It places start points at corners, and also allows you to restrict random start points within a range of specified angles around the periphery.

My experience - YMMV. Most PLA won't print well below 220-225C - some PLA needs as high as 230-232C. 60C is OK for the Buildplate temp, but most small parts will print well with the buildplate at room temperature. (The default used to be 70C, which was too high.) Fan at 100% is often too high, and varies by print - larger prints require less fan. ABS should print well at 235-245C - depends on brand. 260C is almost always too high. Build plate temp of 100C works better. Generally ABS needs no fan at all, but 10-40% may be needed if overhangs curl up. I don't know why they default to 107% flow for ABS. As you can see, these are complex issues, and are not readily addressed by a single set of defaults, which is why I choose to ignore the defaults completely and manually set temps/fan/flow for each print.

However, it "just takes a few seconds" every bloody time you start and restart a print, which is infuriating after the first few hundred times. Perhaps you or Ultimaker would provide a simple guide to changing the default material settings? Or, just maybe, Daid and Ultimaker could actually update the firmware with settings that work well and don't create support issues? The material settings are an issue that would take seconds for UM to correct in any Cura update, and would save a lot of posts from unhappy customers - it's hard to understand why UM hasn't addressed it after many months.

That doesn't work - you cannot add more pigment or "dye" to get a better color, because it becomes too much pigment and alters the plastic characteristics, and you cannot get rid of or hide whatever combination of pigment is already in the recycled plastic. Adding red pigment to a green material does not make it red, it makes it mud-colored. Pigment colors are additive, not subtractive. Try melting some wax crayons together and tell us what you get.

I find that the easiest way to reorient a part if you need to before using Slic3r is to open it with (free) netfabb Basic, where you can scale and rotate it without losing any precision. The program also alerts you to problems with the .stl file, and can repair many issues before printing. Every slicer has a different combination of features, and none of them can do everything I'd like. Cura isn't superior to any of the others, but at least it does fan-speed control properly.