3D printer uses

[hollo]

Two related thoughts about making the change gears. 1. Unless you are planning to make deep cuts on low thread pitches the plastic gear will probably do just fine. The possible failure would be the keyway to lock two gears together for compound gears. Make a metal bushing for the part with the keyway and that probably goes away. 2. How much would it cost you to make a gear to try out? PLA is fairly strong and quite cheap. Why not give it a try.

I finally got round to trying number 2 here. I couldn't find an existing set of files for Harrison M250 change gears, but found some code for doing Modulo 1.5 gears and measured the central keyway bit. It seems to work quite nicely - here is the 22, 100, and 45 tooth set installed as a first go. It runs well and I haven't broken them on a few light passes!

[epicfail48]

Welcome to 3d printing! Be prepared for a lot of moments like that...

[loose nut]

OK now I tried it with .2 nozzle in ultra quality and it worked, there be rifling??? I thought i had done this before but............................................

[epicfail48]

OK I downloaded and tried the Prusa Slicer and guess what the STL file shows up with all the rifling there. So does that mean that Cura just doesn't show it in the model or can't show it in the model because it can't process it. Neither will necessarily be able to print the rifling, I'll have to wait until my printer shows up and I figure out how to use it correctly. In a lot of ways the Prusa program seems a lot easier to use and there is a couple of things that it can do that Cura can't but Cura has 80% of the slicer market so that is where everyone will migrate too for support.

Boy that Josef Prussa has some ego, has to have his name on everything.

In fairness to Josef, Prusa Slicer is a forked version of the Slic3r software, made specifically for Prusa printers

As to the model, im guessing that your second guess is correct, Cura doesnt render it in the model because it cant print it anyways. That said, couldnt reproduce something similar in my copy of Cura. Could be that my test model didnt have small enough details, but i dunno

[loose nut]

Switch to PrusaSlicer

OK I downloaded and tried the Prusa Slicer and guess what the STL file shows up with all the rifling there. So does that mean that Cura just doesn't show it in the model or can't show it in the model because it can't process it. Neither will necessarily be able to print the rifling, I'll have to wait until my printer shows up and I figure out how to use it correctly. In a lot of ways the Prusa program seems a lot easier to use and there is a couple of things that it can do that Cura can't but Cura has 80% of the slicer market so that is where everyone will migrate too for support.

Boy that Josef Prussa has some ego, has to have his name on everything.

[loose nut]

OK I went back into the CAD program and made some adjustments in the STL export settings and the polygonal problem is gone, the lack of rifling on the full length barrel is still missing but is on the short section of the same model.

[loose nut]

Prusa... Prusa ...we don't need no stinkin' Prusa

Well maybe???

I don't understand why the rifling Is there on the short section but not the full length version, it is the same model

[elf]

Switch to PrusaSlicer

[epicfail48]

I've been playing around with Cura and it is doing something weird. I exported the barrel model of my model as an STL file and then opened it in cura. Everything looks good but the rifling ins't there. I also made an STl of the same barrel but only a 1 1/2" long section. In cura this model has the rifling but the outside is a course polygon about 10 or 12 sides instead of being round????? Any ideas, they are the same model except for the length.

Certain features might be too small for the printer to actually print, so the slicer omits them. Usually you see that happen with things like walls that are thinner than the nozzle size, but it crops up other times as well. Im guessing that the rifling in your model is just getting caught as an unprintable feature. If memory serves theres a setting in cura called "print thin walls", you might try ticking that box and seeing what happens.

About the polygonal outside, could be one of 2 things. Could be Cura displaying a low-poly render during the placement stage to ease up processing needs, could also be that when the STL file was exported by whatever software you used, it wasnt done at a high enough resolution. Fusion 360 i know will let you choose how much refinement an exported STL file has, set it too low and you get that polygonal look

[loose nut]

I've been playing around with Cura and it is doing something weird. I exported the barrel model of my model as an STL file and then opened it in cura. Everything looks good but the rifling ins't there. I also made an STl of the same barrel but only a 1 1/2" long section. In cura this model has the rifling but the outside is a course polygon about 10 or 12 sides instead of being round????? Any ideas, they are the same model except for the length.

[Mike Amick]

Sometimes the hot end isn't totally primed so it takes a while (5-10 secs) for the filament to actually come out so the skirt just gets the printer printing properly
before it starts on the important part. You're right, it has little to do with helping your object to stick.

Also if your lucky enough your printer will support baby steps which allow you to adjust the head up or down in .1mm steps while it is printing the skirt.
So it lets you fine tune the distance from the bed .. to get the best first layer.

[loose nut]

I know what the brim and rafts are for but what is the skirt for???

Doesn't seem to have any purpose.

[thin-woodsman]

changing too many things at once can take you down the rabbit hole.

boy does it ever

With an new model/filament combo, you really have to watch the first couple of layers as they print, to make sure bed adhesion is suitable and the filament is doing anything stupid. It's very tempting at those early stages to abort, tweak a setting, and start over without making a note of what you've gone.

I've taken go keeping my Cura projects in a git repo so that I can save them when I have a definite improvement, and roll back to that improvement when I have lost that breadcrumb trail back to a working print.

[Stu]

The Ender3 default settings for Cura are pretty good and work well for most prints. The only ones I mess with are skirt, brim and raft for adhesion and Infill percentage and wall line count for strength. I've found changing too many things at once can take you down the rabbit hole.

[loose nut]

Well I spent 30 years doing "manual additive manufacturing" AKA: welding so I get your point. I have been doing CAD for many years so that isn't a problem and I downloaded Cura and have been playing with it so I can at least get some familiarization with it's operation but that isn't the same as actually printing stuff.I've also been watching everything I can on YouTube including Teaching Tech. CHEP on YT is also really good especially about Cura.Still not the same as doing it. I'm taking a positive outlook with this, I've already ordered spares, tools and some upgrade parts that have been recommended on many videos.even though my printer won't show up for several weeks, Covid shipping mess.