Designing and 3D printing feeders & accessories

[texsuze]

Love your 3D port feeder--very anatomically considerate for those combs and wattles. I'm a 20th century non-geek still-use-a-flip phone driving a 17 y.o. truck kinda person but am very impressed with what you are doing.

Without knowing anything about 3D printing except that it is mystery magic, I've always wondered about creating (?printing) prosthetics for special-needs critters that might benefit from such aids, and that could be designed for specific critters, sizes, ages and life styles, i.e. prosthetic leg for a chick then another leg when it becomes an adult, or, piece of missing shell for an injured turtle. Perhaps it is already being done but imagine the possibilities.

 

[DonyaQuick]

Ok I'm quite pleased with this design too: thru-HWC panel to hold a power cord for my heated water bases in winter. There are 4 pieces in this design: a big square plate with screw hole, another square back plate to protect from pointy HWC bits, and a screw insert in two halves. The way this works is: (1) feed the power cord through the big hole shown in the first pic, (2) put the two halves of the screw insert around the power cord, and (3) screw the insert into the holder. When no power cord is needed, the gap left is no bigger than the regular 1/2in HWC squares. The tolerance is such that the halves cannot come apart or get out of alignment once screwed in.

As far as security/chewability, my previous solutions to this have been either plastic outlets or wood and never got chewed, so another type of plastic is no different for me really. I always put my cords through up high enough that they are not likely to get rodent attention.

However, I will absolutely need to reprint these in PETG at some point for better UV resistance. This version is PLA and is in a place that receives more direct sun than is a good idea for PLA long-term. I have a reel of PETG ordered and on the way...

 

[DonyaQuick]

Better diagram of what I was trying to describe in my last post:

One thing I might improve about this design is increasing the outer flange size on the plate pieces from 3" to 4" or perhaps making it hex-shaped. The reason for either of those changes would be to get the bolt holes further away from the core and therefore make it less critical to keep those 4 uncut corners of HWC where the bolts are meant to grab.

Also that little diamond hole in the screw piece is for a ziptie "lock" to ensure that it can't come unscrewed due to critters, curious chickens, or just freeze/thaw activity. As for why it's a diamond hole instead of a round or oval one, that's because of the orientation in which that part has to be printed; in this case, a diamond hole stands a much better chance of not collapsing or getting blocked with stringing during print.

 

[DonyaQuick]

Ah yes very good...my printer decided to make a modern art installation for me today after a fine performance of flinging fillament around at high speed in roughly a 3ft radius. I think I will call this one "Wet Filament #2."

 

[DonyaQuick]

Well I thought I had ordered PETG. Apparently what I actually ordered was a fine reel of PITB - Pain In The Behind! What is this snaggly garbage? Those blobs are not at seams. There is warpage in bizarre ways that isn't simply peeling up from the build plate. The edges are falling off. The settings are for PETG...but the only thing it prints well is that silly chicken model. Functional things look like a mess so far. I have two more enclosures that are going to need those thru-HWC inserts this winter...they might be getting PLA instead.

 

[DonyaQuick]

I don't think PETG is for me, not right now anyway. I have a large stack of failed prints with it so far, many abandoned after I see the first few layers are messed up. I've tried many different settings with the same results.

Things I have learned:

• The only positive point: PETG is fine for VOCs (with an open window anyway, which is the only way I tested). Bad stuff is basically undetectable unless I shove my meter right up by the hot nozzle, and even then the values are very, very low.
• It is much harder to clean up PETG prints to make edges smooth. More globs, more sharps, and the material doesn't cut as smoothly.
• When cleaning up prints, one of those curved, sphere-tipped deburring tools is actually NOT really all that much safer than a regular hobby knife. You can still drive one right into your thumb by accident in a fraction of a second because the model slipped.
• I believe my PETG reel actually started taking on too much moisture to behave well literally right after that first chicken figurine print I said worked fine. Within <48h I am seeing visible bubbles in extruded filament. So, I just do not have the environment for this material with a printer sitting on the floor in a room that has an open window looking out upon a temperate swamp forest. By contrast, PLA lasts me a solid week before that happens and I can largely fix it by sticking it in a bag with some dessicant.
• PLA seemingly has better outdoor resilience than it's often given credit for. There are many "PLA outside for X years" videos and the primary complaint is loss of color. There is some increased brittleness, but often shown with objects that have been dropped, which is a very rough test even for fresh PLA. PET and its variants do also gets more brittle when left outside in the sun year after year, although perhaps slower. The main complaint people make about PLA is "it will melt" - which it will NOT even in very hot natural weather outdoors. How can it melt? If you put it in a hot car in the sun where you could cook an egg on your dashboard. Melting point for PLA is way over 100C. Nobody's chicken coops should reach those temperatures...so it's really a moot point for PLA used as I've done so far.
• My Kobra 2 print bed has started to have corner warping issues at the higher temperatures required for PETG. I'm talking about the BED ITSELF warping, not things printed on it (although those warp too with PETG!). So far I haven't been able to find anything about this specific problem, which is really frustrating. Everything I've found is about print warpage, not warpage of the actual bed. The forces from the bed-to-ambient temperature differential (which will want to curl things that are heated from below and cooled from above) overcomes the magnetic pull holding the bed down, and so the bed curls up in places. For the moment, I've fixed the lifting corner with a long twist tie holding the edge down outside the range that the nozzle reaches. I guess I will have to contact the manufacturer about that situation.

So, what now? I popped for a cheap, single-reel filament dryer that can rehabilitate wet failament and also supposedly dry the reel while the print is going (although it seems a bit sticky letting the reel roll...so not sure about that feature). If that piece of kit magically solves my PETG issues and easily gives me a good print of that thru-HWC panel, then super - but I'm not holding my breath. More likely I will just be sticking to PLA and possibly its variations (like PLA+) and running my own long-term tests on their outdoor resilience.

 

[DonyaQuick]

Here's a good comparison here for what I'm getting with PLA vs PETG - which was run through the drying box and extruded bubble-free afterwords, so there's no wet filament excuse for its problems anymore. Aside from that one chicken figurine test print I mentioned (which is a fundamentally a lot easier print than the screw model), this PETG piece is about the best quality I have been able to get, and it's pretty bad.

Left is PLA. Right is PETG. Same model.

PLA model (left) was usable right off the plate. No cleanup.

The PETG model (right) is actually unusable for its intended purpose without very invasive and frankly risky cleanup given my unfortunate experience with the deburring tool on PETG. There are a lot of defects:

• Lots of blobs and irregular edges.
• Slow warping and drooping of overhangs long after the print head has left the area
• The top sagged in/down after the print had finished

For a screw shape where there are specific tolerances, those are deal-breakers to utility.

One of the root issues with these defects is the cooling fan. Turning the cooling fan on reduces the blobbing and irregularity. For me at least, it also causes serious layer adhesion issues at completely random points in the print job. The fan really has to be off on the lower layers for them to adhere properly - but then they blob! Tried it hotter, tried it colder, tried the fan at different percentages...nope. Pretty much all the suggestions I find for PETG issues online solve one probem and then make a new, totally different issue. Some people suggest adding custom gcode commands into the exported slicer file to fix this by choosing when to turn the fan on/off at tricky points. That's a step of fiddly stuff beyond what I'm willing to do to get a working model when it works with no customization in PLA.

Permit me a small rant related to this...

There are two kinds of people in the 3D printing world: those that want to use the printer as a tool where the goal is the thing it prints, and those for which the printer and fussing with it is the goal in itself regardless of what it actually prints. I mean no disrespect to people in the second category (I have even been one in other domains), but they often spend a lot of time fiddling/tweaking their machines while not producing useful items. Meanwhile, the printer-focused folks also dominate what you find if you go looking for guides and tutorials. So there is a lot of media espousing the use of different amazing materials and printing methods to produce...that stupid boat that everyone does. I have started paying closer attention to the boats people show for that - a lot of them actually have certain defects in PETG that might seem minor on the boat (and so the print is deemed a success) but are exactly what I'm seeing on my screw insert that makes it unusable. If your benchy boat's little smoke stack and windows aren't absolute perfection, you won't be able to print this thru-HWC design properly.

I am in the first category of people: my printer is primarily a tool to me. That's the crowd I wanted to design these chicken feeder-related things for as well. Perhaps I'm being too big of a grump about this, but I'm starting to wonder how many people are actually able to really, properly and realiably make useful items with non-PLA on entry level printers. I have 4 "ok" PETG prints, 1 good, 2 kinda ok, and 1 that at least didn't fall apart but isn't useful. Meanwhile I have over 20 mangled print failures from trying to get those 4 that worked to some degree. This tells me it must be a whole 'nother level of bad working with something like TPU (the stretchy filament) after seeing how bad mere PETG is to work with. Maybe I bought the wrong printer to work with PETG. Maybe I need to upgrade some part of the printer like the nozzle or hotbed. Maybe my ambient environment is too humid or unstable and the printer needs to be in a protected box. Maybe I even bought the wrong PETG (although I'm doubtul of that one because all the problems I'm seeing have been seen by many, many other people on the web). I guess I really I have no idea what needs to change to make PETG work with my device for the items I want to make. At any rate, the rest of that PETG reel is going to get sealed back up and go live in a dark corner of a closet for the forseeable future. If I feel like my printing is going too smoothly at some point down the line I can give it another go lol.

Back to PLA for now and back to designing...