ahoeben

Sorry, I was mistaken in my previous reply. {machine_nozzle_size, x} should work just like that (with the extruder nr filled in) {filament_amount} is replaced by a list, so you cannot specify an extruder number. For the full list of replacement patterns, see http://files.fieldofview.com/cura/Replacement_Patterns.html

Holdup, I'm mixing up some things. I'll be right back.

I think you used {material_used,x} before. {used_material,x} never was something that Cura recognized. Similarly, you should use {machine_nozzle_size,x} not {used_nozzle_size,x}.

See the "revert" icon here:

See the "Machine Settings" dialog, available from the Printers page of the preferences.

Yes. Unless you set it back to "Ultimaker 2" in Machine Settings before exporting gcode. But then you have to set it back to "Marlin" to print succesfully with OctoPrint again. My advice: choose whether you want to print via SD or via OctoPrint. You could edit the start gcode to not do that prime.

If you don't see the "Set G-code flavor to 'Marlin'" option, then the gcode flavor is already set correctly.

I am not aware of any changes in info.plist files making ancient versions of Cura and Python work on modern Apple processors. I do know that all Windows and Mac OS versions of Cura come with their own "baked in" version of Python (2.7 for legacy Cura, 3.5-3-10 for newer Cura), so installing a version of Python on your system doesn't really change anything as far as Cura is concerned. Ultimaker only creates and maintains profiles for Ultimaker printers. All other printer definitions and profiles are created by other manufacturers (like Lulzbot) or community members. An effort to get Lulzbot printers included in Ultimaker Cura is underway here: https://github.com/Ultimaker/Cura/pull/10232

To produce gcode compatible with OctoPrint, the gcode flavor for your Ultimaker 2+ should be set to "Marlin". Cura 5.3 currently has a bug that stops the Machine Settings dialog from registering the change of gcode flavors. Are you using the OctoPrint Connection plugin from the Marketplace? It has an option to set the correct gcode flavor for you.

That would give you an incredibly fragile surface Even removing dust from the surface - let alone finger prints - will damage the mirror.

Er... both. The software is telling the hardware to do something the hardware can't do. What probably happens is that the both the bed heater and the extruder heater are turn on fully. The powersupply can not handle this "spike" of power draw, and the voltage dips as a result. The dip in voltage causes the controller to "brown out" and reset. So it is a hardware issue, caused by software.

You can burn your fingers on concrete while it is setting. Here is some concrete steaming, 15 hours after pouring: Polyurethane also has an exothermic reaction while curing. The pressure from it expanding in combination with the heat may cause deformation of the "mold" if it is not properly supported. Pour in small batches, not in one go. That way you keep the heat under control.

It can, but not in combination with OctoPrint.

It sounds like you are having bed adhesion problems. Perhaps cleaning the bed, and/or applying a fresh layer of gluestick will improve that. It is also possible that your glass plate is upside-down. There are two different sides to it.

You are going to have to ask Lulzbot, not Ultimaker. The 21.08 version is based on a version of Cura that Ultimaker stopped developing in 2016. Also Lulzbot have been making fairly major changes to the original Cura code since 2015, so it is hardly recognizable anymore. Finally that version just depends on too many 3rd party components that are no longer working on a modern Apple computer, such as Python 2.7 (as you already found out). If you want to keep using Lulzbot Cura 21.08, you are probably going to have to do so on an older computer.

Provided the meat is very tender, you can use a spoon to divide a steak into bite-size chunks. But a knife will always work better. You could write all kinds of hacks to get Cura to make toolpaths for subtractive CNC. But Cura is really made for 3d printing (and actually specifically for FDM 3d printing). There are other tool far more suitable for subtractive CNC.

The AA cores use "normal" brass (if there's such a thing). They will not wear much (if at all) if you only print PLA without abrasive additives. You should be fine, even after 5 years. You don't need a new printcore, unless your current one is giving you issues.

You can already print the "support interface" with a different extruder than the rest of the supports. See the "support extruder" and "support interface extruder" settings. I must admit I am not 100% sure if and how support interfaces apply to the new tree supports. Try it out and let us know!

The ArcWelder plugin actually works, but Cura just cannot display the G2/G3 curves that the plugin creates. Cura itself does not create G2/G3 commands, so the display of those commands was never implemented.

You are "abusing" the support blocker to easily create blocks and then change them using the "per model settings" tool, but you can load in any geometry to use instead of those blocks. I know that is not the same as painting, I know, but painting like that either depends a lot on the topology of the model, or it is actually quite complicated to implement. Also realise that painting on the surface does not "define" what happens inside the volume, and the inside is actually what you want to affect.

See the setting "Remove empty layers". Interestingly, this is the fourth or so post I see about this in a single week, and this has not changed since Cura 2. Why is "everybody" suddenly trying to do this?

The reasoning is that there are no empty layers when you print with supports. Granted, there are edge-cases, like when you turn on the supports but the model does not need supports. Technically they are two different things. One is how models behave on the buildplate in the Prepare tab. The other works on the generated toolpaths.

I think that is way to thin to print with FDM, and you will not get the material properties you are after by directly printing this. What you could do is use FDM printing to create prototype formers for vacuum forming (eg https://mayku.me/formbox)

Are you using multiple displays? If so, try disabling all but one. Cura currently has a problem running on some systems with multiple displays.

You could save projects with each printer selected, and open cura with one of those projects. You can save a project without a model on the buildplate.