illuminarti

It is normal to get the extruder click backs on the first layer, if your bed leveling is incorrect. The head can be too close to the bed so it is hard for plastic to escape. After the first layer, it shouldn't happen with the settings you quoted. What version is your firmware? (See maintenance -> advanced -> version) on the printer. Retraction should also work ok at those speeds. You might tweak the settings a bit in the materials settings - try 5.5mm retraction length.

I think this is the link anon was going for: http://www.extrudable.me/2013/04/02/the-myth-of-z-speed/

As a practical matter, it's very hard to predict or control where Cura will put the z-scar, and it tends to move around in odd ways too. When I was working on the second generation extrusion test models, I actually just gave up and switched to another slicer. I think that Kisslicer and/or Slic3r give you some control over the start point, but I haven't used those in a while. I've actually ended up using the commercial package, Simplify3D, which lets you specify the orientation of the z-scar, or chose to have it randomized, or simply wherever makes the toolpath quickest (as Cura does).

I don't think that, for practical purposes, it's possible for the long belt pulleys to end up too tight against the sides of the printer on a Ultimaker². The pulleys that directly touch the bearing have slight standoffs on that side, and the rest are in separated by small diameter plastic spacers. So all that any of them ever touch is the rotating part of the bearing anyway. It is definitely possible for the motor pulleys to be incorrectly assembled such that the outside of the pulley rubs on the side panel, introducing friction, and causing these sort of skipped step problems. The other thing that is worth checking is that the pulleys are all on the right way round, since if they are not, that can lead to twisting and wear on the belts. All the pulleys have two ends - a thick end (with the screw) and a thin end (just an end plate to keep the belt lined up). In all cases but two, the fat end should be towards the nearest wall. The exceptions are the two short belt top pulleys. For the y-axis (back left) it's a single piece with two sets of teeth, and two thin ends. For the x-axis (back right), the short belt pulley has the thin end towards the back wall.

There is no start gcode on a Ultimaker². I mean, you can add it manually to the finished gcode, but there's nothing that gets included automatically by Cura. And I think the intent is that you should be able to adjust the bed from the machine end, without adjusting the gcode you already have. The current bed leveling wizard in the printer allows you to adjust the back height in 0.05mm increments if I remember correctly. Arguably, that's a bit too coarse - certainly for fine tuning, I'd go with perhaps half of that height.

While the bushings used are nominally 'self-lubricating', the reality is that all the sliding parts benefit from the added lubrication. The smooth axes are the four, smooth 8mm diameter rods that the sliding blocks run on. The cross rods are the two smaller rods that run through the head. All of them benefit from the addition of a little light oil. Turn the power off, and put the head in the middle position, and put a drop of oil either side of the sliding block on one axis. Slide the head back and forth to spread it out. Repeat for each axis in turn. Then also repeat for the rods going through the head. Finally it won't hurt to add a drop of oil on the two smooth vertical rods, and move the bed up and down a bit to spread that out.

Can you explain a bit more what you mean? Not being able to see the model file definitely sounds like a bug. Probably related to video drivers if I had to guess. Are you able to see the bed itself? What 'back plot' command are you referring to? The layers view is showing what the gcode will do when it is printed.

It depends on the size of the smallest layers. So long as the head doesn't have to slow down below about 10-20mm/s to meet minimum layer time, then printing one at once is still very useful.

It sounds normalish to me - all I hear is the head moving. It does sound like the axes might be rattling a bit, but its hard to tell. If you grab the four axis rods one at a time, and try to shake them side to side, do they move and rattle?

Yay! Can't wait to hear how it goes... keep it up! :-)

It should work very well. I use SpaceClaim, the full version of DSM, and it prints great. DSM has some modeling and feature limitations compared to SpaceClaim, but pretty much all the features you need are there. The STL files that both produce are well formed, and print well (subject to the limitations of FFF printing technology).

It will print them one at a time, by default, so long as none of them is taller than the gantry clearance height in the machine settings. If any are, then they print layer for layer at the same time, so that the cross rods don't knock over the print. You can force it to print all at once, even when it could do them one at a time, by picking that option from the tools menu. The advantage of printing one at a time is that the head doesn't have to move as far, and retract between objects, so you get a faster print and better surface. You also are at less risk of everything being ruined, if there is a failure midway; any parts already finished do not need to be reprinted.

If your printer is newer than Mid-March, then the tension indicator should be one-third to halfway down. Relatively speaking, the clicking back is a good thing, because it means the filament isn't being chewed up. The 14.07 firmware update from software.ultimaker.com will probably make a big difference.

Since I end up leveling a lot of print beds these days, I've made a point of remembering that 'Right is NOT tight' (contrary to the normal mantra for regular screwdriving). In other words, turning the front of the thumbscrew towards the right INCREASES the gap between the head and the bed. When leveling, I also prefer to do it by looking along the glass and noting when the nozzle tip exactly touches its reflection. I level it to that point on the first go round, and then only bother even checking the second pass through if I had to make any significant adjustments on the first pass - otherwise I just click-click-click through those three. It's important to make sure the nozzle is totally clean before leveling, so you aren't leveling to a blob of plastic, rather than the real tip. Also when adjusting the screws, always adjust until you just get a touch, back off slightly and allow the bed to settle untouched, and then tighten to a touch again. Another critical factor in bed leveling is that the screws are all positively engaged, and the springs are under proper tension. Since the springs are quite short, and the bed tends to droop a couple of mm or so towards the front, there's actually quite a narrow range in which you can get everything lined up properly. Before you run the leveling wizard, the rear thumbscrew should be tightened until the wiring terminal block is about 1mm from touching the heavy base plate. From that datum, the gap at the front between the two plates when it's level should be about 12-13mm. In that arrangement, the screws are all well seated and the springs are providing useful tension.

Heat the nozzle up, then power the printer off before pulling the filament. That way you can be sure you aren't fighting the energized extruder motor.

Did you cut off the damaged part when you put it back in? You should be sure and upgrade to the latest firmware in Cura 14.07 - that fixes a bunch of things that make grinding more likely at the start of the print. Finally, you can adjust the tension on the feeder by turning the adjustment screw (accessed through the hole in the top of the extruder, above the white indicator mark). Turning the screw anticlockwise (as viewed from the top) will lower the indicator, as it increases the tension.

because it's just a single wall, the print depends on having plastic to rest each layer on. If the filament tangles briefly, or for some other reason, a layer doesn't lay down right, then the next layer has nothing to stick to, so it just gets pulled straight until something catches. And then for the next layer, there's nothing to stick to still, and it gets pulled until it sticks to what's left of the previous layer. So, you get a big hole, until the accumulated filament ends up back in roughly the right path again, and things start to stick. The print quality of this test is pretty much irrelevant... the only thing that really matters is whether it's still extruding filament consistently without clicking back the extruder by the time it gets to 10mm³/s. When you say thinned out... was it skipping steps and clicking, or just printing thinner and under extruding, without clicking? The latter suggests that the tension is still a little bit low, so the full driving force of the extruder isn't getting transferred to the filament.

The test is fine. Just something went wrong at the start. And it took a while to fix itself. It recovered perfectly, and printed great at the high speeds.

As I've noted elsewhere, I don't use the filament guide either. But if you want to, it's not too hard to get it to fit - just cut or file a slight chamfer on the back of the keyhole tab part.

I haven't tried it yet, but it appears that it allows you to insert material, without having to pretend to eject filament that isn't loaded, first.

Nothing to do with the firmware, no. Unless you aren't seeing full speed on the upper layers. And even then, probably not.

Yes, but you have a 5mm 'full speed height'. So it won't reach 100% until z=5. Above that height the fan should be full on. Below that height it will gradually increase from off, on the first layer, to full speed by whatever layer corresponds to 5mm high.

The fan speed increases gradually from off at the start to whatever speed you set in the Cura, by the height you specify. So check the settings in Cura's expert settings. The gradual increase is done by setting a new fan speed on each layer. Consequently, if you change it in the tune menu, it will get reset on the next layer start.

Great write up, and fantastic looking print, Valcrow. Thanks for taking the time to share that with us.

0.6 what? Do you mean 0.06mm layer height?