tomnagel

The bug is that Cura 2.4 beta leaves exactly 1 layer of air between PVA and PLA (where PLA needs to be printed on top of PVA). You can see this in the layerview when you look very well. This is such a shame, because the bottom of your PLA will not look optimal. Cura 2.3 did not have this bug, but the advanced temperature behaviour of 2.4 is very attractive because in most cases you don't need the prime tower anymore. This saves time and material. So keep a look on the soon to be released 2.4 version of Cura!

Is Active Leveling turned on? The z-distance between the 2 nozzles needs to be calibrated really carefully. Active leveling (especially since firmware 3.5) does that more accurate than most people can do manually. I agree with Erin, go for Cura 2.4 without the primetowers in most printing profiles. (keep an eye on the release of Cura 2.4 next week, and update your beta version. There is a bug in the beta2 version which harms the PLA/PVA interface) And most importantly: stick with the defaults. You should have good results with these. Only after you have good results with the default profiles you should start optimising settings. You mention for example that you have increased flow to 150%. The side effect may be (a little bit of) grinding in the feeder, leaving bite marks in your filament. A series of such bite marks will drastically increase friction in the bowden tube, causing underextrusion further on.

Try the default profiles in Cura. They work really well with PLA/PVA. A lot of time was invested in creating optimal printing profiles. In most cases, you should get good results. Cura 2.3 uses prime towers. In almost all printing profiles, the prime towers are no longer needed in Cura 2.4, because of some temperature tricks at the beginning and end of every layer. This suppresses oozing so well the prime towers are no longer needed in most cases. Wait a few days with downloading Cura 2.4. It is currently in beta, and the beta 2 version contains a bug which harms the PLA/PVA interface.

I would advise to use a more recent version of Cura. The printing profiles keep improving.

Why not use PLA for this? See http://3dtopo.com/lostPLA/ or http://www.instructables.com/id/From-3d-printed-part-to-metal-the-lost-plaabs-me/ for examples. PLA is very easy to print with, and will get you optimal results in terms of print quality and user friendlyness.

Thanks for your picture. I'm afraid there is no way to adjust this automatically. I'm not aware of any offsets in Active leveling. The Active Leveling system measures pretty accurate, with standard deviation of up to 30mu, mostly less. This means that there is a 95% chance that the distance between the nozzle and your bed during the first layer is 0.27mm +/- 0.060mm. This holds for the 3 probing positions. Outside these positions, there's other tolerances like unflatness of the build plate, bent shafts, etc. These tolerances are exactly why the first layer is usually thicker than the rest of the print: this gives some robustness against these tolerances. We did a lot of testing by printing 3mm high hollow cylinders on the probing points, and measuring those with a caliper. That is how we came to the standard deviation of 30mu (so it includes our caliper measurement error). Would you be able to indicate how much you adjust the height?

What makes you think the nozzle is too close to the bed?

You mention that extrusion is a function of extrusion speed. While that is true, it is more accurate to say that the transported amount of filament is dependent on the force that the feeder has to overcome when pushing the filament forward. The force is dependent on a lot of things, such as speed, hot end temperature, nozzle size, material etcetera. The counterforce at the exit side of the feeder causes sort of micro slip. You can actually see that the teeth marks in the filament get a different distance. The working point where you calibrate is up to you. I think it should depend on what you want to do with your printer. If you plan on pushing the limits on printing with high flows, maybe you should calibrate at a high flow.

This error has to do with the NFC feature. I suppose you get this error during loading a material. When the printer expects you to load a material, it starts detecting NFC tags. When it sees more than 1 new material, it asks you to offer only 1 new material. This is because the reader cannot distinguish materials loaded into feeder 1 and feeder 2. So what may have happened, is that the other material is not registered (anymore?) in the administration of the printer. So be sure to remove that other material from the spoolholder (place it >15cm away). Finish the procedure that you were in. And afterwards, you may want to unload/load the other material so it gets properly registered. @valcrow: the distance between the 2 spools is irrelevant to the reader.

The root cause of this is bad bed-adhesion. All default settings in Cura are geared towards Ultimaker materials. With UM PLA you should not have these problems. Depending on the part that you print, you may want to enable the brim to increase the surface touching the build plate. A second option is to apply some glue to your plate before printing. You may choose to use other filaments. These may require other slicer settings for good adhesion (esp. temperatures of nozzle and buildplate, possibly first layer speed).

Did you find any information on the minimum wall thickness to reach UL94-V0? i cannot find that in the formfutura info on the website.

In Cura 2.4 (currently in Beta), I just sliced an object of 210mm. 215 should be possible also, but I have not tried it myself. I did not use a special profile for this, Cura recognises that only one extruder is used.

Looks to me as overextrusion. So either increase the distance (like Neotko suggested), or just lower extrusion to 100%. Overextrusion will not immediately lead to this effect, there will first be a buildup of tension in the bowden tube. That may explain why at first you see no issue.

Nylon from Ultimaker prints *very good* with the Cura printing profiles. It has none of the ABS problems described here. And nylon is one of the materials compatible with PVA, which means removing the support is a matter of putting it in a bucket of water. Nylon is tough, but not stiff. It is kind of flexible. So if your part is holding a wheel or something, it might not be stiff enough.

I think this error is not caused by your hotter build chamber. Is your cartridge inserted properly (did it click?). Do you see anything out of the ordinary on the wiring of this cartridge? Have you tried the same print without the hood and the door? that would rule out the influence of the higher temperature. You may also try to print a dual color print with 2 AA cores (so leave out the BB core). if your problem disappears, try the BB core again. If it then reappears, your BB core is very suspicious, and I think you need to contact your reseller.

A few suggestions: - contact your reseller. He's your primary source for help. - Maybe you can press a piece of filament with a molten tip in the core, to fuse it against the piece of PVA in the core. Make sure the core is in the printer, and heated to 220 degrees or so, and bowden tube disconnected. You might be able to pull it loose. - Last resort: heat it up to 250 degrees, and press really hard with some other piece of filament (use pliers so your don't get injured when the filement breaks). Make sure the printhead is in one of the corners, so not to bend your axes.

But the missing ring cannot explain this waiting behavior. Is there or is there not a rubber flap on the bottom of the print head? It is (should be) located in the bracket of the front fan, the bracket that you open when you want to remove a print core. I received your log, thank you. We'll have a look at it.

I'm interested in the log files. If you want, please dump the logs to USB drive (system->maintenance->diagnosis) and send them to t.nagel@ultimaker.com

How long does it sit there? Indefinitely, unless you pause/unpause? What is going on: When one nozzle is printing, the other nozzle is lowered in temperature. This is to prevent the unused material from degrading. Before the printing nozzle is ready with its layer, the other nozzle is heated. This is so timed that at the switching time, the right temperature is reached. All this is done in Cura, so in the gcode. But this is timed, based on a simple model. Printing temperature might be reached a little too late or too early. So it is normal that after switching, the nozzle needs some time to reach the printing temperature, should be less than 30 seconds. If it sits there longer, something is not right. If you would like to diagnose yourself you can see what is happening with setpoints and actual temperatures on /temperature.html If you don't, contact your reseller. One specific question: do you see a white silicon rubber flap on the bottom of your print head, and does it seem to be well installed? Without this rubber flap, the nozzle is not always able to reach the right temperature.

Let me be more precise then: we've had our share of clogged print cores in the past 2 years of development. There is not a single core that we needed to take apart for cleaning purposes. I dare to say: the print core is the most reliable solution in the market today. We've solved the wear of the teflon part completely. It has been extremely well tested. The first users already report hitting 2000 printing hours with a single core. If you have problems with your print cores, we'd like to help you. Your problems can be solved. Do you use Cura? Are you using the default printing profiles? Are you using Ultimaker materials?

Did you lower the speed of the infill? Or did you increase the speed of the outer shell? I'm interested in why you find the quality of the infill important. I see it mostly as a support structure for the top layers. (Strength mainly comes from the number of shells). And in that sense, I don't really care how the infill looks like, as long as it forms the support structure that I need. So then, the choice to print it as fast as possible sounds like a good choice to me. Also, the choice to dump ooze into the infill structure sounds smart to me as well, if that (together with some other measures) removes the need for a wipe tower. But again, I would really like your opinion on this, Neotko and gr5.

No. Don't remove the nozzle from a print core, as you have a very high chance on destroying the fragile heat break. Removing a nozzle is never necessary. If it is clogged, the instructions on the website are always enough to unclog it. I'm sure we can help you get your printer going. Your reseller is trained to help you, and also here on the forum there's a lot of help available. If you describe your problem, I will surely try to help you.

I think you forgot to include the pictures.

Ouch, it is disappointing to see this. A few tips: * always use the default Cura profiles * use the latest Cura version. Cura 2.4 beta has even more advanced temperature behaviour, which enables skipping the prime tower (shorter printing times) * Watch ambient humidity. RH should be below 55% (RH=relative humidity). Do you know what the humidity near your printer is? * use Ultimaker materials . What PVA are you using? I understand from your post that the inside of your nozzle was clean when you tried the cold pull? So if your nozzle was clean, how did you solve the grinding?

The default print profiles in Cura are made such that 99% of the models print fine. Also the infill should print fine. What is wrong with your infill? maybe you can illustrate with some pictures? Are you using Ultimaker filament?