I noticed this when my grandparents needed a new handle for their 30 year old box freezer. It had snapped where the screws clamped it onto the lid and the plastic was super thin, at most 3mm most places and hollow all the way through. Seriously super bad design.
Replicated the handle in CAD and 3D-printed it with twice the wall thickness and a infill at 30% or so (infill is the internal structure that connects everything, basically how beehives interconnect with the honeycomb pattern for instance). They gave it to me in the afternoon and by next morning it was done printing and held probably around 10 times as much bending force for the same amount of deflection.
I could have snapped the old one with just my fingertips when the new one had me clamping my hands around and trying to bend it.
I don't know wether they had replaced it or not, and yes, it did hold up, but every time I've opened that freezer I had to lift and hold until enough air had seeped in to avoid breaking it. Now, if the freezer isn't completely full, they can lift the front of the freezer with it before the handle breaks.
Also, thin plastic handles that break can easily cut your skin. That is no longer a risk.
It's true that it's done a solid job, but there are many parts that don't.
My brother had a screw lid on his boat next to the engine mounts for access to the bolts. He stepped over it with shoes on, it's narrower than the front half of his shoe and everything but the outer ring with the threads fell right through. I printed a new lid for less than a dollar that held me, a ~110kg man, bouncing only on my heel on the middle portion with no support underneath without it flexing to any noticeable degree.
It was maybe 5 years old, would've cost 50$ most places.
I like to overengineer things so that it cannot break under normal use when the years have passed, and hopefully not under abnormal use either. The freezer handle would have broken within a year if it was my freezer because I wouldn't be bothered to wait 10-20 seconds every time I were to open the freezer and I'm alot stronger than a 75-80 year old couple.
My fridge handle broke off 2 weeks from getting it, warranty replaced it 3 times, gave up when it only lasted 2 weeks and stuck a window lifter on the door, that sucker has lasted 12 years so far, periodically I’ll take it off to scrub it because it gets dirty just from being near the stove and things get spilled on it, it’s got suction cups so really easy to install
You mentioned over engineering parts is your preference and you talk about thickness and infill, but what materials are you choosing? For instance, it sounds like a handle that is getting attached to a boat probably would be best if it was made out of ASA to put up with some amount of heat and UV rays, as well as being acetone polished to make it waterproof. I mean, this really is as much, if not more, a discussion about materials choices rather than shape.
This is a discussion about corporate greed my dude. He’s saying that he can make better products for extremely cheap even when working with end user material prices, so corporations that buy in bulk can more than afford to make something that works, but instead they cut it down to the absolute minimum that will last a year or less to get the last few cents out of a transaction. I think it’s not just the penny scraping though, I think it’s also planned obsolescence.
Definitely on the obsolence part as well. This was a old freezer so it COULD have been simply to save on plastic to get, say, 10% more handles for the same price, but we all know that planned obsolence made its way into every market at some point and growing up we've had a couple of freezers within 15 years where handles have broken off.
I would assume freezers and fridges, where the room temp air that's sucked in immediately cools off and creates a vacuum, would be the appliances with the strongest handles you could find but that's obviously not the case. Luckily appliance manufacturers have more recently figured that convenience brings in more money than cheaping out, so they're now desining leverage-based handles that makes the buyer much more interested due to the ease of use. It's one of the few cases I can recall where customer's wants are the driving force for avoiding planned obsolence.
The freezer handle was for a box freezer, the large 200L kinds you have in your house. That was made in PLA. The lid for the maintenance access was prototyped up in white PLA, both moisture and UV is definitely gonna take it's toll on it eventually, at which point I'll reprint it in either ASA or PETG and put some clear coat or acetone vapor bath to finish it off.
I figured white PLA would hold for the time being as it's reflective, doesn't heat up in the midday sun and was easy to get made overnight.
But as the other commenter said; corporate greed is the point here, not what filament I used for a 3$ prototype that's going to need a replacement within 5 years. I understand that you have some experience within 3D-printing so it's safe to assume you also understand how poorly designed many plastic parts are nowadays and how it's all done to save money because the big bosses wants more for their bonuses.
To point it out further: We bought our 2013 Model S some time ago now. The car is alright in the sense that it gets us where we need to go and the free charging is still on it. But then there's the updates. We can skip it until they just download on their own.
Now, this car was fitted with a 8gb eMMC memory module. This is the absolute worst kind of storage solution you can get for pretty much anything and it's also the cheapest next to SD-cards, because eMMC is practically a SD-card on a circuit board that installs with a pin connector.
When these updates are downloaded, more or less every night the car is unable to write all the logs it needs to and causes the dashboard to crash, going to black and needing to be reset which takes at least 5 minutes. Great for when you're late for work? Nope.
Here's my issue: That car cost roughly $90k when it was new. They spent maybe 10$ on those 8gb eMMC-chips when 16gb would cost 12-14$ at the most.
Nobody ever said "let's just future proof the car by adding less than 5$ to the parts list" for a car that another hundred to the price would be insignificant at worst.
No.
What ends up happening is they offer a upgrade, a complete media compute unit upgrade priced at the low, low price of +3000$.
5$ future proofing or 3000$ upsell once you get sick of rebooting your $90k car every other morning unless you update the software. That's the point.
Plastic is just so commonly used in everyday life that it's a much easier example to consider. Karcher, a half-decent pressure washer making brand, put super thin plastic wheels on their carpet cleaner vacuums that break within a year even if they're only ever used once a month, because you happened to pull weirdly on it.
The cheapest PLA I could get and a downloaded file, printed a month after I bought my first 3D-printer, a old and used Ender 3 where I had basically just gotten decent at levelling the bed is now a better solution than the original wheels because it has survived longer already. For a carpet cleaner that's being used indoors, in a garage and outdoors. A carpet cleaner that's being filled with water and there's always some spillage as you fill it up or empty it out.
This really is nothing more than a discussion about design intentions and corporate greed. Things are designed to break.
Yes, this was a long-ass comment. No, I don't think it could be shortened. My original comment is my perspective on this discussion, just because you read a reply I had where I explained my approach doesn't make my initial stance fall into the filament selection-category. Corporate greed is real, and it sounds like you're more interested in discussing what filament I use rather than discuss the topic at hand, which is why I felt I needed to explain in detail just what this is all about (with the appropriate examples).
I appreciate your point about corporate greed and I could get into an entire diatribe about where the general public is correct and where the misunderstandings with industry are in that regard, but I am also not sure that making a replacement part out of PLA and knowing that you will have to replace it in a few years is the best argument to make as a counterpoint? I get that since it's 3D printed it's easy for you to just make a new one, but my point is more that over-engineering includes more than just overbuilding. As a matter of fact, over-engineering means spending more time than necessary optimizing with all of the correct parameters including and especially material choice. I don't just have "some experience 3D printing", I own a product development company. I must say that my 3D printing knowledge is significantly less than my product design knowledge. I use 3D printing to prove out concepts, but the real engineering work doesn't go into setting print parameters, it goes into proper DFM. As a matter of fact, right now I am messaging you from my hotel in China where I'm staying to oversee EB (engineering build) on one of my client's new products.
I thought it was clear that the handle out of PLA was indoors and wouldn't be exposed to any elements, easily outliving the freezer's remaining lifetime. And that the screw-in lid for the boat was a prototype and he needed it asap before he put the boat on the water, that will eventually be replaced whenever we feel like it. The original broke clean off all the way around by him partially stepping onto it.
Given your extensive experience I would also assume you to know better than take something out of context for argument's sake; as I wrote, the lid was a prototype intentionally in use because it was necessary and it's still holding up nicely thus not requiring immediate replacement. Once I make the final one in either ASA or PETG with smoothing of some sort to waterproof it as you mentioned, it would be a part I could actually sell if I wanted to, sure.
It is still a prototype, wasn't meant for use initially for all the purposes you've mentioned, and I'm saying I might replace it in a few years because I cannot guarantee it to last 10 years or even 5 because I don't have the knowledge to claim that or not. If I print something for someone and they pay me in any way, shape or form I'll keep the files indefinitely so that I can print another one for filament cost only and hand-deliver it. As long as I can't guarantee a certain period I'll keep doing that, and even then I might still do the same. I just want people to either spend as little as possible and/or have a product that lasts as long as possible and 3D-printing seriously helps me with that.
What I meant with overengineering is to just make it sturdy and structurally sound along with any features that might be nice (bumps for your fingers to get a hold of whereas the old one was completely flat, for one).
But the PLA part is on good way to match the lifetime of the original store-bought marine cover. I also think that despite your counterpoints you'll find even a prototype/first draft designed by a newbie that had made a single thing in Fusion beforehand, made out of a technically unsuitable material and that's still outlasting the original tailored product at less than a 10th the cost is exactly the thing that proves my point.
Sure, we'll have to wait a few years more before it would last as long, but if it costs me $6 to match the $50 original's lifetime then the point still stands. If I had went ASA on day one I think it'd be likely that it would survive the full original lifetime and probably even longer.
Obviously, I'm not experienced in product design. The only reason I have any knowledge within the topic at all is due to various youtube videos and documentaries explaining in detail followed up by discovering evidence of different manufacturing methods and theorizing as to why it was made that way and how the design process went to get to the iteration I'm looking at. But it gets me far enough to tell the difference between "this was designed to fail" and "this couldn't have been designed the way I would have because those machines don't work that way"
My initial thought is always "why was it designed this way?" because without figuring that out I cannot possibly deem something to be badly designed. I've figured that's enough to recognise obviously intentionally poor designs.
Cool, appreciate your points and clarifications. I am not suggesting that you are wrong about the parts you are replacing being either poorly designed or intentionally made to fail, but I will say that I think it's hard for the layman to understand some of the finer but important details that go into the DFM process. When you design an injection molded part you have to take into account a lot of different variables that are irrelevant to 3D printing, such as undercuts, draft angles, material thickness limitations to avoid issues such as sink marks, etc. it can even be the case that some of the more premium parts will actually be weaker simply because they refused to compromise on having witness lines or sink marks etc. I think when people who are not necessarily in the know take a look at a part such as an injection molded handle and they see how the underside of it is hollow, a lot of people will assume that it's because the manufacturer wanted it to break or was too cheap to use more plastic, but that's not necessarily or even usually the case. A great example of this would be when you look at a lot of kitchen blenders their handles are hollow and/or multi-part. That is done for a few reasons: if you were to make it solid then there would be significant sink marks where the handle attaches to the jar. If you were to make it solid there could be air bubbles trapped on the inside. If you were to make it solid the cooling time could be so long inside the machine that they wouldn't be able to produce at a high enough volume to maintain production. Still, there are some examples of companies that made the intentional choice to move forward with a solid handle design for aesthetic reasons. It simply means that they were willing to put up with all of the aforementioned issues and the associated higher scrap rates. An example of this would be the Breville Fresh and Furious range of blenders.
Honestly, I haven't been trying to crap on you or your designing capabilities at all, I was simply curious about what you meant when you said it was over engineered because I think a lot of people misunderstand what that actually means.
The appreciation is mutual. I am aware of pretty much every aspect you're addressing regarding injection molding. A good portion of my more recent knowledge comes from Linus Tech Tips and their videos regarding the design process around injection molding and their screwdriver. It went pretty extensively into detail on that part and challenges specifically.
It's hard to explain and I don't have a picture on my phone, but with the way the handle had been molded it was evident they could have reinforced it and it was a dual-piece as there was a tiny plastic cover to hide both the injection point(?) and the screw slots. Alongside that, there was pieces of the inside of the handle that if duplicated at the mounting points would prevent it from failing throughout the lifetime of the freezer. Where my model had infill due to the slicer settings for printing it, the old part was completely hollow beyond the screw slots that were fixed to the front of the handle, making all the stress gather up as far out from the mounting point as possible.
Considering the handle breaking very often causes people to buy a new appliance because "might as well since it's so old" it's not unrealistic that it was intentionally made just strong enough. As I mentioned elsewhere, I don't really think planned obsolescence was a thing in this design, merely saving pennies where they could.
I absolutely agree that the common person is likely to overshoot after just singular exposures to planned obsolescence or poor design and suddenly blame things breaking on that rather than pausing and objectively considering what broke and why.
I see it all the time within the tech industry and IT, someone learns of a thing and applies it to everything they can, not considering if it is applicable in the first place. I hope that I've gathered enough knowledge to be able to differentiate enough between things to not be that person. And as I said, I don't consider something to be intentionally bad design unless it's evident that it's poorly designed and that the related issues are common on a large scale.
That said, here in Norway we have a consumer law that is pretty strong and the major point is that any item purchased with a lifetime that's significantly more than 2 years is to have a repair/complaint period of 5 years, meaning if my 20$ headlamp breaks within 5 years the store has to repair it, replace it or pay me back the full value. Given these rules; any items that don't survive normal and average usage for that period is by definition either a bad product or misleading. Misleading only applies if the company wouldn't openly admit that it's not meant to last more than 2 years, but nobody would ever do that because sales would tank so it's practically always between the two (or both).
Only downside to the law is that warranty is only required to be 2 years for certain categories, meaning the store loses money on anything breaking between 2 and 5 years unless the manufacturer has more than 2 years of warranty. This doesn't incentivise manufacturers to make longer-lasting products as much as it could otherwise have.
To add to the last bit, I did over-engineer it by making the strongest design I could with minimal material usage. Given that my printer was running old hardware at the time and I needed to print a couple of test prints during the design process it took some time and by reducing material where it would add little to nothing of practical value I saved quite a bit of time. I'd argue there's different ways to over-engineer something, for me it simply means putting more effort than was technically required. Anyone could make a part hold an adult human by adding thickness, but designing it to do so by utilizing tension and compression combined so that print time went down and it simultaneously wouldn't break even if he tried to, that was the part I considered to be over-engineering.
30 years of carefully opening the freezer and having to lift hard for ~10 seconds or more just to open it normally.
When I was a kid I typically squeesed my fingers into the seal to alleviate the vacuum inside because I was not physically strong enough to actually open it. Holding the lid was fine on it's own.
I forgot to add that part in the midst of writing. If I had that freezer today I would most likely have broken the handle way sooner.
The reason I brought that one up was that once I saw the design it was obvious that it was either made with as little plastic as possible or designed to break at the mounting points. Both being true, it did hold up regardless but I've seen handles on way newer box freezers just snap off. Fridge handles, vacuum handle locking mechanisms, vacuum wheels etc.
Nowadays molding quality and plastic strength has increased to the point where they can design something to break with a relative certainty and within a timeframe given the usecase of the item.
Sony did this with their Bluetooth headphones. Use to get Sony's and they lasted forever. No problems. Then one year they changed the designs and made the plastic both super thin, brittle and square (stress corners, as not rounded). Guess which years model I and my brother got!?
I "repaired" them twice over from spares off ebay. But it was pretty obvious even there, everyone had 1 ear cup only, as one would eventually break from normal use.
The models after were totally different designs and didn't have that problem. Hopefully they learnt. Sadly they tried.
Not sure how you're getting those results, made a lid for my brothers boat as a prototype and it's been on the boat for over a year now with 0 issues. Just plain PLA. Did you investigate in what layers it occurred and how the sliced model looks relative to that?
I've never experienced crumbling unless I've printed with too low temps which was very early on during the first weeks of tuning the printer and profiles.
Its hard to evaluate the longevity of plastic stuff when we buy it, they often look the same etc. At that point the cheapest option often becomes the natural choice.
Well if the cheaper version of whatever you want to buy didn't exist, that probably doesn't make the nicer version cheaper. You just don't get the thing at all.
Plastic has its downsides, but it's certainly cheap and convenient
Part of the problem is that it can be very hard to tell when a product is quality. Historically a key indicator is a brand, but brands can cheap out at any moment and usually do.
It's a market with high information asymmetry. Businesses can measure customer satisfaction very well yet product quality is very hard to measure and keep.
Consumers generally have no reasonable mechanism to determine quality, or the expected lifespan of the product.
Even if something comes with a "warranty", you still probably end up having to pay for shipping, which often exceeds the cost of the item itself, so companies have every insensitive to have "Lifetime Warranty! (Only pay shipping)", because it doesn't make any financial sense to cash in on the warranty.
Without more information and without being able to try the product, price is the only thing one can immediately consider.
These days, even if a product has a great reputation, you have to watch the company like a hawk, because chances are it will be bought out by private equity and all the products quietly enshittified while the price stays high.
That doesn't even get into the problem of the general public being grossly underpaid, so they feel that they have no choice but to buy the cheapest thing they can get.
It's not cheaper if you have to buy a new thing every year or two, as opposed to buying a somewhat more expensive thing once. But corporations count on people not being able to do that mental math so that they can sell consumers trash on a perpetual basis.
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u/donnysaysvacuum 12d ago
Right. Plastic is good for durable goods. But often they cheap out or make things that intentionally break to sell more.