foehnsturm

@Ultiarjan, Great summary! So good to have well-organized and conscientious people like you and neotko working on this project. It looks like you perfectly realized the tool changer idea on the UM2. What remains to be addressed is oozing. While we already benefit from the fact that oozing nozzles cant't do anything harmful to the print, the required amount of priming to fight underextrusion more or less successfully is high. If the standard hotend behaves similar, what I assume, I perfectly understand why UM ditched dual extrusion ... With a retraction of 20mm no additional filament should melt during idle times. The already liquified one just drains. So far I see no way to prevent this reliably. One could live with that if the following priming process would safeguard consistent extrusion immediately thereafter. But this seems to be difficult.

You both are correct, with bulky printheads there isn't much benefit from a software z height adjustment. But given the small footprint of a Merlin, E3D hotend etc. and a crossflow fan or fans attached to the holder it's interesting. With parking positions outside the printbed even 10 oder 15mm height difference wouldn't be problem. So you could use a PTFA hotend like Merlin which is best for PLA and a full-metal type for higher temp materials within the same print even if they are not the same length at all.

neotko, ultiarjan Just had a simple idea: Don't make the same mistake as I did. Don't care about z alignment of extruders! Just measure the offset. We are not moving both extruders over the print at the same time. So we can easily add a z correction movement when a extruder is selected and deselected. Would be even easier if G10 wasn't misused for retraction, but there should be a workaround using other gcode commands.

Forum:sort by latest takes 30 to 40 seconds now to display ... This thing becomes unusable.

So far I tried ooze shield, priming tower, extra retraction and prime on change, lowering temp, ... To make it short: Ooze shield / priming tower help to dial in extruder flow before printing the actual part and to deposit eventual filament blobs somewhere else. Some filaments are quite easy to control (e.g. faberdasherey white) some ooze like hell (e.g. Recreus filaflex). If one extruder pauses for more than a few layers, none of the above mentioned methods will really solve the underextrusion issue due to dripping. But the benefit of this approach is having the idling extruders parked in a separate place and perform a special movement pattern to get there. One could take advantage of that. The most successful attempt so far for prints with long idling times: I extrude quite a large amount before picking up the extruder (depends on filament, up to 10 mm with filaflex / remember I'm using direct drive!) and use a small spring steel blade (attached to the holder) to wipe off the excessive filament when the printhead moves out of the holder. AFAIK this is like some working dual solutions handle it as well: move somewhere outside the printing area, do excessive priming, clean the nozzle, return.

Congrats! Great to see the machanism handling the stock hotend assembly as well. There is one idea I'd like to discuss. To me it looks like there's an easy way to use different nozzle sizes and slicing settings (infill etc. NOT layer height) per extruder. Just run the slicer two times on the entire part with different settings and replace [extruder2] sections in file1 by [extruder2] sections in file2. With the same layer height and the printer running in relative E mode everthing should be fine. Am I missing something?

Wild guess: A few times, I had an extremely slow moving Y axis after picking up the printhead when Cura's minimum layer time came into effect. When slicing Cura has no idea that there will be such a long distance to move after picking up the head. However, after completing this initial move the print continued as expected. You might check the F value in the first G0/1 command after the change sequence.

I'm using Merlin hotends which are screwed into an aluminum mounting piece. So I can rotate the hotend a little to adjust height. However that sounds better than it actually is because the nozzle tip is not perfectly in line with the rotation axis. So adjusting height has to be follwed by adjusting x/y offset.

Just printed a bracelet with Faberdashery and Recreus Filaflex. I suppose I won't do that again. Filaflex is almost impossible to handle with dual. When idle the hotend more or less empties by itself.

Just because so many did that before including M*bot. All with mixed results. I had some expectations towards Fuel3D, but it looks like I was too optimistic. I simply don't see how UM could reinvent this.

But please no scanner!

Oh I expected that ;-) Ietzad müassad ma hoid schaugn ob jemand wos wissad der boarisch redt.

IRobertI's greasemonkey script with some additions if someone wants to use it. // ==UserScript==// @name UMCompactor// @namespace Ultimaker// @include https://ultimaker.com/en/community*// @version 1// @grant none// ==/UserScript==// Message preview$('.communityblock-description').hide();// Top "Ultimaker community" title$('.minihero-content--community>h2').hide();// Shrink down some of the white space in the top$('div.minihero-content--community').css("padding-top", "0px");// Smaller font size for thread titles$('.communityblock-title').css("font-size", "100%");// Reduce padding between thread title and "Started by" etc$('.communityblock--topic').css("padding", "10px 0px 10px 0px");$('.communityblock-topicinfo').css("padding-top", "0px");// Move search bar higher$('.sectionsearch').css("margin-top", "0px");// Make search input shorter$('input[type=search]').css("max-width", "300px");// Shrink down top background$('.section.pagesection').css("height", "60px");$('.contenthero--image').css("min-height", "60px");//$('.r-mobile-hidden').css("display", "none");$('.communityblock-topicinfoentry a').css("display", "none");$('.communityblock-page').css("display", "initial");$('.communityblock-topicinfoentry a:first-of-type').css("display", "initial");$('.communityblock-topiclabel:contains("Replied by:")').text("Last reply by:");$('.communityblock-user').css("font-weight", "normal");$('.communityblock-pagination').css("font-weight", "normal");$('.communityblock-topiclabel').css("font-weight", "normal");

我说UM应该考虑限制信息泄露的一种营销手段像苹果一样。

Just use Japanese or Chinese, no one will notice ;-)

Well UM says they keep an eye on my toolchanger approach and the work of the other guys there, just in case something they are working on fails. So there is R&D related to this area but no idea if this is meant by the "pretty awesome".

Ok peace now. Just hoping that other people at UM had a conversation as serious as yours because the way this thing was launched was "totally inappropriate and wrong on quite a few levels as well. And I could totally see how most companies would take no effort to fire anyone over something like that."

Regarding printing quality I'd say the E axis falls behind X/Y/Z and needs something "innovative". There is more than one competitor with better control of extrusion, retraction etc. So, no bowden anymore? New firmware with sailfish-like compensation of extruder lag or independent axes and velocity-based extrusion?

I don't expect something revolutionary from UM ;-) But I'm hoping for something innovative ... So what component needs improvement most?

Someone will get rid of costly, bulky and heavy steppers sometime (what 2D printer uses steppers?). If they fullfil their promises TIKO will be one of the first to do that (3 millions a Kickstater is not that bad).

Bug: Posts of new members waiting for approval already show up in the forum's latest by sorting and in the members profile. Not critical but confusing when you click on that topics and there is no new post there to be seen.

But what could be "awesome" but somehow closely related to the current product? AFAIK UM hired Erik Zalm some time ago. So new firmware based on new electronics like smoothieboard?

To relax from talking about bugs and a at least partly misdirected new forum design: According to several insiders, there is something "pretty awesome" coming on which UM has been working for a long time. But what? There is no doubt that UM needs some innovation drive in the near future. Despite its economic success (which I assume), UM keeps more or less selling the same printer for several years now. Much prettier and more silent with the UM2, smaller and taller with the Go and Extended but basically the same. Right now, they won't tell anything as far as I know. Be it because of the competition or the epic fail with the dual extrusion announcement. So let's speculate (or find an information leak ;-)

Well Sander mentioned something similar. I know there is hard competition and a lot of copycats in the market. Therefore I understand the "we won't tell a single word about it" attitude. However, the lack of any information where things are heading and when is unsatisfying for the more experienced people here. Hey, UM is (still ;-) not Apple. The community which is supposed to be hurt might be the community this gamificated thing was designed for but not the community which used to provide the valuable content here. So you have my full support as a speaker of the old-fashioned plain talking.

That's just a draft sketch to check how parts could be arranged. The main difference is that the stepper shaft and the filament path could arranged on the same side of the main shaft with the gear and drive wheel. The orange thing shouldn't be orange ;-) it's the counterpart to the idler arm which is missing. To be honest, I just used the bearings lying in the box here. With 3mm ID and 10mm OD you can use the same bearing for the pressure wheel.