tomnagel

PC is not easy to get right. It warps, and when bed adhesion is too good, it chips your glass plate. We advise to print it with a raft. Remove the raft at high temperature, otherwise it is hard to remove from your object. Also the advanced printing kit is advised which contains a front door, but you can improvise that yourself easily. Though PC is yet to be officially released for the UM3, the printing profiles are already in Cura. (it enables the raft by default) Have you also read this?

Have you tried printing your object without primetowers (with the latest version of Cura)? In most situations, that works really well (if you use the provided printing profiles, and use Ultimaker materials).

Because what you call "priming" is not seen as priming by Cura. The 2 "custom prime towers" are not prime towers, but just regular objects. There is no way to tell Cura in what order objects must be printed.

you cannot damage it. At full power, it reaches 107-115 degrees, depending on tolerances, insulation and ambient temperature.

I agree with gr5, bigger nozzles is what you need. Expect 0.8mm from UM within 2 months. With a 0.4mm nozzle, 0.3mm layers is really pushing the limits. Please note that the Cura default profiles are a coherent set of settings. If you change things like the layerheight, and printing speed, the profile is not optimal anymore. You may want to increase the printing temperature for example, to prevent underextrusion. An interesting option may be gradual infill, but that depends on what you use the infill for. Infill can have 2 goals: strength, and something to carry the roof of the print. If you care mostly about carrying the roof, gradual infill can really speed up your print. It uses a low % of infill in the bulk of the part, and only increases the infill-% in near the roof in a few steps. I notice in your picture that I can see the PVA through your part. Your part has no bottom there, is that supposed to be the case?

When you take out the PLA during hot-pull, is the tip melted? That is hugely important. If you have material stuck in your cold zone the hot and cold pulls will never work. If you have placed the print head in one of the front corners like described in step 1, you can put a large force on the PLA. (Use pliers, because when the PLA breaks you will cut your hand). Just press very hard. That may help to press out the clogged material. If there is still no flow, raise the temperature to 275degC. If that still does not work, there are 2 more options: 1) Use a needle (injection needle, or acupuncture needle) to puncture the clog (just take care not to damage the relatively soft brass) 2) use polycarbonate for the hot and cold pulls (use 270 and 135degC)

ABS is not the easiest material to start your 3D printing career with. Is PLA not an option for your application? (PLA is often undervalued. Its printing properties are great, and some mechanical properties come close to ABS (like stiffness). ABS is tougher though, PLA breaks more easily. And of course PLA cannot handle loads at elevated temperatures (stay below ~45-50degC)

This is strange behaviour. Though I don't recognise the problem, updating your firmware to the latest version is always a good idea. Did you do that? And which slicer did you use? Does this always happen? Also when the previous print was ended successfully?

Cura allows a positive Z-offset when the option "drop model to build plate" is turned off. I think zerspaner_gerd has given the right answer, though it is not easy. Ask for help if you can't get it done. Some day, this will be more user friendly!

I'm sorry to hear your nozzle is clogged. Maybe we can help you solve the problem here on the forum, and/or you can contact your reseller. Please don't disassemble the core yourself. At UM HQ we have never had a print core that could not be cleaned without disassembly. What do you mean with "During the Atomic method the temp PLA material comes out clean (no burn marks)"? You mean that you are able to extrude PLA when the nozzle is hot? That is good, at least it's not completely clogged then. But what exactly goes wrong during the cold pull? And what do you mean with that you used 2 different methods Atomic and cold? Cold pull and Atomic method are the same I think?

This is almost certainly caused by failed bed adhesion. Plastic is collected around the nozzle, and forms a shell. The printer keeps extruding, and (after a while) the only way the molten plastic can go is up. You will have to contact your reseller for this. If it's PLA, you might be able to fix it yourself, but the risk of ending up wit damaged hardware is large.

Did you follow the advice on the support pages to use a raft?

For every material there are printing instructions on the UM website, look here for the instructions for PC. These are valid for PC from UM, your mileage for other brands may vary. PC is tricky. For example, it is easy to pull the chips from your glass plate if you don't follow the instructions.

You can try Ultimaker CPE+. The benefit is that Cura has printing profiles for UM material built in, so you don't have to find optimal settings yourself. These profiles are improving with every release of Cura. Look up the specs here: https://ultimaker.com/en/products/materials/cpe

have you set "travel avoid distance" to zero as well? This is default set to 3mm.

That is annoying indeed. Your printcore might be wrongly programmed. Please contact your reseller.

yes, you are not the only one who didn't find this. Today, I saw a Cura 2.6 demo where the visibility of this option is improved.

load your part and use "per model settings" to select the extruder number that you want to print it with. If PVA is loaded in the right extruder (like default) then select extruder 2.

Labern is right, you don't need to change your spring. The newer firmware works with old and new spring.

There have been changes in the springs. The latest produced models have 3 equal springs. Earlier models have one spring that is significantly less stiff, and that is supposed to go on the backside of the printer. This has to do with the auto leveling feature. Since the firmware that was released late december/early january, the probing locations have changed. There is no longer a need for a weaker spring on the backside, so all springs were made equal.

It's a known problem, and I have not yet seen solutions. If you want to experiment a little, maybe you can try to put some (high temp resistant) oil on the outside of your nozzle.

Initial print and final print temperature are a new feature in Cura 2.4. It is designed for dual material printing. This is designed to prevent oozing. The nozzle that is not printing is warmed to 'initial printing temperature' just before it is due for printing. Immediately after the nozzle starts printing, the temperature is raised to the normal printing temperature. At the end of its turn, things go the other way around. In the standard Cura profiles the difference is 5 degrees. In practice, this trick enables you to turn off the prime tower, as oozing is minimized already.

I think you understand the formulas. Happy foodprinting! (Post some pictures if you like, I'm curious)

The FDM printers also have a round nozzle, but the extruded plastic is pushed onto the previous layer. The shape of the deposited line has a rectangular cross section. So the slicer calculates how much plastic is needed to print such lines, and puts this number in the gcode. You reason the other way around. You calculate with the cross section of your nozzle, and multiply this with the speed. If the slicer would use this calculation, the printer will still flatten the extruded amount of plastic to the chosen layerheight. With normal layerheights (which are normally lower than your nozzle diameter) this will lead to a printed line that is (much) wider than your nozzle, with ugly results.

Your calculations are both right. The slicer uses the first method because that approaches what is happening when printing. The nozzle prints a line with a more or less rectangular cross section (line width x layer height). The second method is only valid when you would calculate for printing in air.