Wear and tear on PLA and PETG
This is one of those things I'm not going to learn from experience for a good while because it'll take a lot of use of printed objects to see the results.
I'm working on a locking connector that holds parts together. Here's a few snapshots of the test parts. When I finish what I'm making, two of these parts will be attached to larger items:
The plate on the left will connect to a pipe and the part on the lower right will connect to a wall plate. The "key" in the upper right will go through the slots and turn and hold the parts together. The other part, with the read "205" on it is the lock plate. It slides into the part on the lower right so when the key is turned, it can snap into place, so it doesn't easily come undone. Please note these are test parts, printed as part of the design process, so there are a lot of changes I'll make for the final versions.
And in this snapshot, you can see the "locking plate" as been slid into the holder. The key has been put in and turned and is held between two of the locking bumps. You can also see a different kind of bump on the top right of the notch for the key. That's to make sure the key is turned in the right direction.
This test print has been done in PLA. One part of the system attaches upside down to the soffit on my barn, so it'll be outside and I'm going to print that in PETG, since my understanding is PLA can break down and PETG won't, so PETG will last a lot longer outside, with exposure to sunlight and elements. (If I'm wrong, please let me know - and let me know if I should use something besides PETG for the parts that will be outdoors.)
My concern is wear and tear. While I won't be locking and unlocking the outside parts more than every 6 months or so (just for a quick clean-out), I'll be using this same design inside, where I'll be taking things apart periodically to move what's attached to them for cleaning and maintenance. So this little key will be turned back and forth much more often on the inside parts than the outside parts. One reason I've made this lock plate, with the bumps, as a separate piece is because I do not know how PLA or PETG deal with wear and tear. Will the bumps wear down as part of the key slides over them multiple times over a long period of usage? My thinking, with the test, was to be ready to deal with that, just in case. That way, if those bumps, or the bars on the key, wear down, I can easily replace those parts. But if that's not necessary, cleaning up the design will be easy.
What can I expect on small parts like this, over time with PLA and PETG? Will those bumps and the key wear down rapidly with use or hardly at all? Will I find a need to replace the parts that rub against each other frequently, every now and then, or almost never?
RE: Wear and tear on PLA and PETG
Clever design, nicely done.
I think the only way to know for certain is to print and test the parts (yeah, I know, stating the obvious here…).
I would try printing the locking plate with the bumps in PLA and the key in PETG. In my experience, PLA is pretty durable but potentially brittle where PETG is more ductile and should flex a bit while traversing the bumps.
I’ve also had good success with PETG outside in the elements so you might find printing all parts in PETG to be a safer option.
Good luck and let us know how you get on.
Cheers
Both PLA and PETG are degraded by ultraviolet light, PLA goes a little faster...
The secret to preservation is paint. A couple of coats of opaque paint will extend the life of both considerably.
Cheerio,
RE: Wear and tear on PLA and PETG
Clever design, nicely done.
Thank you! I'm still learning how to think in terms of printing. It took me over a week to work this design out since most of my ideas seemed great until I sketched them on white boards or started making them in Blender and realizing that I had designs that needed supports in places where I didn't want supports. (Because they'd create major work in cleaning up where they were or something similar.)
I would try printing the locking plate with the bumps in PLA and the key in PETG. In my experience, PLA is pretty durable but potentially brittle where PETG is more ductile and should flex a bit while traversing the bumps.
I've read something like that a few places, so it seems to be a regular characteristic of the materials. But when it comes to applying that to this particular kind of design, I'm not sure just what it means. I would think it means that the horizontal bar on the key would flex more when going over the bumps with PETG. As for PLA being brittle, I'm wondering if that means the bumps (or the bar on the key) are likely to be worn down as bits break off over time, which would amount to it wearing down. By the way, that's an older key design. I went to this and it "snaps" in place much better:
Oh, on the lock plate, notice that as the key is turned, it goes over a series of bumps. That's quite intentional, so if the key is super-stiff, just turn it until it locks after a smaller bump With this key, it feels like a stronger "lock" in place, but it could also wear down bumps or wear notches in the key faster. Since the wall plate and the connectors that lock to the wall plate take 8-15 hours to print, depending on configuration, it took me a while to work out a design where the parts that might wear down were small things I could print in an hour or less for replacement.
I’ve also had good success with PETG outside in the elements so you might find printing all parts in PETG to be a safer option.
At this point, how long have you seen PETG parts lasting outdoors?
Good luck and let us know how you get on.
Thank you! No problem - when I have the parts together, I can post pictures of what they look like. This is all part of a ventilation system for my workshop in my barn. I have 2 printers (and I'm sure I'll end up with more) and a CNC with a laser on it. I can't use the laser because the smoke detector is right above it. I need a vent system and vent hoods. One over the CNC for smoke, and one over the printers because I hear some filaments really stink and because my less dependable printer, a Creality Ender 3 Pro, makes a lot of noise all the time (there's apparently not a good way to slow down the printhead fan, even when it's just sitting there!). So I need vent hoods (which will be wood frame and plexiglass) and vent pipes that go to my printed wall plates and connectors. I know me - if I make it really easy to detach the wall connectors, I'm much more likely to take them off and move the tables for cleaning than if I have to deal with something like a hose clamp. There's a decent sized crawlspace behind the wall and there'll be 4" vent conduit there, with a fan, and I also am printing a vent, since 4" vents go out walls, and this has to go out the soffit instead.
I also need a "bullet" for pulling flexible 4" conduit (like the kind used on the back of a clothes drier) through about 16' where humans can't go.
I checked for parts I can use off-the-shelf, but for various reasons, I can't use those.
Both PLA and PETG are degraded by ultraviolet light, PLA goes a little faster...
Do you have any idea how quickly they degrade?
A couple of coats of opaque paint will extend the life of both considerably.
That I can do. Only one element of my vent system (the outside vent) goes outside, so I don't have to paint much. Most is in my workshop or in crawlspaces.
RE: Wear and tear on PLA and PETG
I've had several PETG parts outside for a long time (almost two years), exposed to cold, heat, weather. They've held up fine but I can see some serious degradation of color, which shouldn't be an issue for you. And I'm seeing that decolorization even with thick coats of polyurethane. Paint may be more protective, I don't know.
For things that involve bending or any flex, I much prefer PETG over PLA. Those bumps, they'll wear off quickly, regardless of the material. That doesn't mean they become non-functional. I have used something similar in a rotary style of nozzle indicator, (a dial with numbers to indicate nozzles sizes inside a part with a window that shows the chosen size, and nubs to "click" from one size to the next), and a year later, it's turns more easily but still does the job. I usually design the nubs a bit larger than they need to be, for a very tight fit, but it'll loosen up quickly.
Another material to consider is ASA, which is a bit hardier, I feel. I've been doing much more work in ASA lately, mostly holders for AirTags for dog collars and key fobs. Some have been through serious exposure to elements including underwater. I think they're more prone to scratching than PETG printed parts but otherwise have also held up well.
RE: Wear and tear on PLA and PETG
I have some parts printed in PETG that I use for my pool during the season, which is May to September in the north east US. They’ve held up well for 2 seasons with no apparent degradation.
Cheers
RE: Wear and tear on PLA and PETG
I've had several PETG parts outside for a long time (almost two years), exposed to cold, heat, weather. They've held up fine but I can see some serious degradation of color, which shouldn't be an issue for you. And I'm seeing that decolorization even with thick coats of polyurethane. Paint may be more protective, I don't know.
Thanks - tells me a lot I can use! I had found both PLA and PETG filaments that came close to matching the paint we were using, but with the paint issue in mind, I'll paint the parts that'll go outside. It's good to know they're standing up!
For things that involve bending or any flex, I much prefer PETG over PLA. Those bumps, they'll wear off quickly, regardless of the material. That doesn't mean they become non-functional.
Again, quite useful and it makes me happy that I planned to have the areas that might wear down on pieces that can be reprinted easily and won't take a lot of filament. That's one of those times where I went paranoid in thinking things through and I'm glad I did that.
I usually design the nubs a bit larger than they need to be, for a very tight fit, but it'll loosen up quickly.
If you look at my lock plate with the nubs on it, I used a series of nubs, starting from smaller to bigger. The smallest got in the way on my first few turns, but even after leaving my test parts by my computer, as a "fidget toy," so I've turned that thing over and over and over, the big ones are still hard to move the key over. Also, using the key in the photo in my reply, above, it doesn't allow as much flex in the key part. With PETG, I may find it works better with the room for bending and flex. Part of my concern for this project is that a lot of the parts go in my workshop, where I'll be using the CNC, a drill press, table saw, and other tools that cause vibrations. I doubt those would lead to things coming undone, I tend to be more cautious.
Another material to consider is ASA, which is a bit hardier, I feel.
How is that in terms of fading, or do your ASA parts get enough exposure to UV and sunlight to tell? And when you say they're more likely to scratch, is that to the point where it'd wear nubs down?
I have some parts printed in PETG that I use for my pool during the season, which is May to September in the north east US. They’ve held up well for 2 seasons with no apparent degradation.
Good to know! Thank you!
RE: Wear and tear on PLA and PETG
How is that in terms of fading, or do your ASA parts get enough exposure to UV and sunlight to tell? And when you say they're more likely to scratch, is that to the point where it'd wear nubs down?
ASA is supposed to be UV resistant but I don't have any long term use data myself. When I said scratches I meant surfaces scratches. It seems to be a softer material than PETG. But I honestly don't know how that translates into a tendency to wear nubs down or not.
RE: Wear and tear on PLA and PETG
One of my projects, which has been pushed off to this year, is an alarm sensor holder for the pool.
I plan to print the main part in ASA, as PLA and PETg have lower deforming temperatures and this will be in direct sunlight for part of the day.
IIRC, ASA has much better ultraviolet resistance than PLA/PETg/ABS. I have not ruled out a coat of paint in addition.
How is that in terms of fading, or do your ASA parts get enough exposure to UV and sunlight to tell? And when you say they're more likely to scratch, is that to the point where it'd wear nubs down?
ASA is supposed to be UV resistant but I don't have any long term use data myself. When I said scratches I meant surfaces scratches. It seems to be a softer material than PETG. But I honestly don't know how that translates into a tendency to wear nubs down or not.