3D printing

[MartyS (Gromit)]

That's not something I would have thought of, do the motors on your printer have plugs on them for the wires?  I've only used motors that have wires coming out of them so the only way to have a bad connection at the motor would be a broken wire.

Those wire chains are cool, I've always just used the wrap around sheaths.  A bunch of years ago I bought a spool of 3mm PLA filament by mistake and didn't notice until I went to use it months later so I couldn't return it (I also didn't notice the size until I opened the sealed bag).  But it's great as a strain relief and wire bundle support, I used it on my big home built printer.  Just a a length of it in with the wire bundle and wrap it all up and the bundle is now stiffer and moves in a nice arc similar to what a chain does.

This week I got spools of ASA and polycarbonate (PC).  ASA is great for stuff you want to put in the sun.  PC is super strong and heat resistant.

Printing with the hot end at 270°C and the bed at 115°C are some serious temperatures.  So far the ASA has been printing just as nicely as PETG, but the PC has been more of a challenge.  I want to print the air nozzle for my Prusa out of PC so I should never have to replace it, I'm on my 2nd attempt now, first one I turned off the cooling fan as recommended, but after watching some videos on PC I am now running it slowly and faster during bridging.  Parts without the fan on are the strongest, but you get better prints with it on a little.  The cooling air duct doesn't need to be strong, but it does need an accurate shape.  It's about half way done now and already I see less stringing.  The air nozzles I've been printing with PETG start to sag after about 20 hours of printing, shouldn't have that problem with PC.

The ASA has a weak hot plastic smell, the PC has much more smell, I wouldn't have tried them if I didn't have the printer in the basement.

[MartyS (Gromit)]

I got my Raspberry Pi 4 set up with Octoprint (Octopi).

So far I like it, gives nice feedback of the printer during a print, I just wish the camera stream was a larger image.

Not sure I would spend the money on a pi just for this, it's not that much better feedback than the old smartphone webcam I was using before.  If I had a printer with a crappy interface maybe it would be more useful, but the Prusa has a good interface.

Also it doesn't support 2 printers at the same time, so I'll have to reconfigure it if I want to use it with my other printer.  It will be way more useful with that printer because that one doesn't have an LCD screen on it.  But I haven't used that printer once since getting my Prusa almost a year ago.

The Pi 4 with a printed camera mount stuck on it:


Here it is printing:

[MartyS (Gromit)]

Many years ago I got a palm sized screwdriver that held 4 bits in the handle, it was cheap and fell apart in less than a year, but I always like the size and shape of it.  Since I just got into printing with polycarbonate I now could print something strong enough to replicate it.

Used some tiny steel screws and 2 magnets scavenged out of tiny motors to hold the top on.

[Darth Geek]

Marty, I was just wondering how you store your filament rolls? I have been using two of these shelves:

https://www.amazon.com/gp/product/B0009AG2WQ/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1



The size is perfect, it fits even 1 Kg spools well. But it's quite rickety. And I'd like to get something even taller.

[stansimpson]

Marty, I was just wondering how you store your filament rolls? I have been using two of these shelves:

https://www.amazon.com/gp/product/B0009AG2WQ/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1



The size is perfect, it fits even 1 Kg spools well. But it's quite rickety. And I'd like to get something even taller.

I have these exact things to store my dvds. Rickety is a good way to describe it. I never feared they would fall over though. For the price, you probably can't do better. They come with wall mounts to make them less unstable too.

[MartyS (Gromit)]

Just realized when I tried to reply to this a few days ago it was the start of the forum issues and it never got posted.

I have my printers on a workbench in the basement, the workbench has a shelf under it and I just stack the spools of filament there.  Looks funky with stacks of big ziplock bags with filament and desiccant in them but it's the basement so I don't care.

[Darth Geek]

Woohoo! I finished making ALL 28 of the different McQ Heads for the different Quiptracks so far:

[Darth Geek]

The biggest problem I am having right now is "zits". I have gold decorative buttons on a Dalek figure I am making for my friend and they keep coming out like shit.
I still need to use the kit I got to convert my Ender 5 to a Direct Drive Extruder. Will that help with this issue?

[MartyS (Gromit)]

That depends on the type of "zit". 

If they are blobs of extra plastic randomly on the surface then better control of the extrusion might help avoid extra plastic coming out.  Also check if there is simply some extra plastic that has built up on the nozzle and randomly falls off.  A small brass brush used on the nozzle when hot before each print can help with that.  If they make a silicone sock for your hot end one of those can also help, I put one on last summer and it does a great job keeping the nozzle clean, it has greatly reduced the tiny bits of burnt plastic that sometimes show up on the surface of a print.

If there are tiny holes in the surface that sometimes make vertical lines that is an issue with the starting and stopping of the extrusion on each layer.  Sometimes slicer settings to randomize the start position of each layer can help, or some slicers have a setting to force all starts to happen in a location you don't see (sometimes called seam position).  Also changing when it does inner and outer layers can reduce those holes, you normally want outer perimeters put down after inner ones, and go slower on the outermost perimeter.

  Direct drive may help with that also, especially if there was a retraction before a new layer start so plastic might not be flowing fast enough before a layer starts, leading to a larger than normal hole at the start of each layer.

And the other cause of bumpy surfaces: if they are small objects or object with some small sections, there might not be enough cool down time between layers and things can look quite ugly.  A few ways to help with that are run the fan at 100% for the entire print, try dropping the hot end temperature a few degrees, and set a minimum layer time in the slicer.  If you set it to something like 30 seconds depending on the slicer it will either pause and wait for one layer to cool down if it's done in less than 30 seconds or it will just slow down so every small layer takes 30 seconds.

[Darth Geek]

Thanks for the suggestions Marty. I looked at it closer and it's actually indented into the plastic not sticking out of it. Turns out it is the Z-Seam. It's a contoured surface with no edges, so it was just putting them randomly and causing them. I specified the alignment and they are now a line. So now I know what it is. The problem is that these parts are decorative and you can see all around them, so I want to get rid of the z seam entirely.

[MartyS (Gromit)]

It can be difficult to get rid of those seams. 

One way is to use much thinner layers and do not line up the seams, print times go way up but with very thin layers one layer can melt into the previous one more and fill in those holes.

There is also vase mode, but you can only use that on single wall objects.

Turning off retraction can also help, if the filament is never pulled back it's less likely to leave a hole at the start of the next layer.  This can lead to more stringing but you can sand off strings easier than filling in holes.

If you have a lot of small objects it is a pain to print them one at a time, but the quality of the walls does improve quite a bit if the head can stay on one part during the print, especially if you turn off retraction.

[Darth Geek]

Well that sucks!
I started getting severe underextrusion issues today on a part. It was one that I had run before so I knew the gcode was okay, so it wasn't the speed or retraction. I was getting filament grinding on the extruder end so I figured I might have a nozzle clog or something. I found a video talking about that and they told me how to do a "cold pull" to get any debris out of the nozzle. I took the Bowden tube connector out of the Hot End, but the tube itself wouldn't come out of the fitting. I was able to do the cold pull all right and there was a little stuff in there, so that probably was the problem. But I could not get the tube out of either of the fittings. The hot end fitting would go up the tube but it would NOT go closer to the end. So because it moved up while I was taking it out I couldn't get the hot end fitting back in the hot end. And since the extruder fitting wouldn't come off either I couldn't just run it up and out the other end.
I was planning on going to a Direct Drive anyway, but this forced my hand. I had to cut the tube in half so I could get the hot end fitting off in the only direction it would go. And even with the tube cut I had to really yank with pliers to get the tube out of the extruder end fitting!
So I really hope this Direct Drive conversion works because my Bowden Tube is destroyed. All because I was trying to clean it.

[MartyS (Gromit)]

Those push-pull fittings can be a royal pain to deal with.  Sometimes they lock in place so tight it takes 3 hands to get the tube out.  A good one you can easily push in the plastic ring around the tubing and then pull the tubing out, a "medium" one you have to push the plastic ring in very hard and push the tubing in first then pull it out, and the crappy ones you mess with the plastic ring until it breaks and you are screwed...

[Darth Geek]

Now that I have a direct drive my biggest problem is "ghosting", and particularly the corners being bulged. Also with ghosting the layer to layer isn't as smooth as it was before. I've already lowered the wall speed from 40 mm/s to 25 mm/s, and I adjusted the acceleration and jerk settings.

[MartyS (Gromit)]

That's to be expected, direct drive has more mass so you can't move it as quickly as a bowden, belts stretch more and you get more vibration so you've got to slow things down when changing direction.