Lol

Clearly that’s progress 🙂

Thanks for the offer! But actually I didn’t model that part for me but for others who need a model of a finished lens. I already have real lenses myself.

The thing is, I shared the design of my glasses for others who might want to print themselves the same glasses too, and there seems to be enough interest that some folks printed them and went to their opticians with it, only to be turned away because the frames are unusual - or they didn’t want to risk having lenses made using the lens template only to find out that the lenses are unusable in the final frames - and they didn’t want to risk filing a notch in the lenses either, which is something that’s not usually done to fit lenses to frames.

And I can understand the opticians too: if they agree to order lenses and they don’t fit the frame, the loss is on them and they don’t need the aggravation.

I wanted to provide a model of a lens that those folks could print out of PLA to convince the opticians that it’s not sketchy or far-fetched. If this parts needs a resin machine - which, I agree with you, it absolutely looks like it does if you really want a quality part - then it sort of defeats the point of self-sufficiency of my little project.

Well, I toyed with the printer’s temperature settings until I found a combination of nozzle temperature and bed temperature that finally made it spew out parts without making a disaster.

It seems to flow best at 260C, but then when it lands on the bed, it immediately shrinks as it cools and the part curls up and comes unstuck. I had to lower the temperature to 245C and raise the bed temperature to the maximum this printer does - 110C - for the part to stick enough to complete.

The nozzle clearly isn’t hot enough because some layers on the final parts look like they’re about to delaminate. But any hotter than that and the material curls up. And it doesn’t matter what bed plate I use: that stuff doesn’t seem to stick to anything properly.

I printed spectacles with that mystery filament. You can see how floppy it is here:

https://toobnix.org/w/qJJ1htb9eqmiHx7gSpq2RT

It looks like TPU alright, but the temperatures involved aren’t really typical of TPU. Also, acetone does nothing to it whatsoever.

The material also doesn’t like to be filed or sanded, and the best results for a nice finish without bits of material sticking out all over the place is to “polish” it by running a very sharp x-acto blade across the surface until all the junk is gone and the surface is shiny.

Weird filament. Kind of useless…

There should be no need to pile on. Any one of those things would have been disqualifying in times past. Clinton almost got impeached over a blowjob. But Trump and all the things he said and done over the past 9 years is somehow okay. The mind boggles.

A post in all caps isn’t doing the work you think it’s doing.

I had no illusion in 2016. In fact, I had no illusion back in 2002 when I left the US and gave up my citizenship after Dubya was elected and signed the USA Patriot Act into law after 9/11. America is hosed and has been officially on the path to idiocracy and fascism since then.

It’s just that a 3rd round of millions of Trump votes should confirm it without the shadow of a doubt to even the most wide-eyed believers in American exceptionalism. America today is the 1933 Germany of our time.

Even if Trump had lost, one fact remains: tens of millions of Americans voted for this guy three times in a row.

The first time, it’s conceivable that Americans made a mistake.

The second time, they knew Trump as actual President.

The third time, they knew Trump as a convicted felon, insurrectionist and overtly wannabe dictator, and they voted for him even harder.

At this point, MAGA isn’t a freak event, it’s the norm. Even if the dems had won, they’d have won the presidency of a MAGA country, and quite frankly, what’s the point… You can’t cure someone who wants to be sick.

If you’re bothered by social media votes, you need to go outside more.

Social media isn’t real. It’s a poor simulacrum of human interaction. Find real human beings to interact with and whatever they think of you, tell you, or how they treat you in your face matters.

But whatever people become and how they behave once they hide behind a screen and cast simplistic one-bit click-clicks to express complex human feelings and opinions doesn’t.

What did George Washington ever do to deserve the insult?

It will be when the Trump voters discover that they will pay for the tariffs and not China.

I hate Elon Musk as much as the next guy - and all the more now that he has this massive conflict of interest working in his favor and at the American public’s expense.

But I will say this for the sake of exercizing critical thinking: everybody is happy to say AI hallucinates when what it says doesn’t suit their narrative, and call AI intelligent when it does.

MAGA ≠ republicans

Rule #1: don’t read an article entitled “How Do I Protect My Privacy If I’m Seeking an Abortion?” on the internet with your own computer or cellphone. Borrow someone else’s - preferably a man’s so you don’t end up potentially compromising another woman later - or go to the public library.

It has a long piece of 1mm piano wire running through that acts as a spindle. It’s a standard hinge design called a continuous hinge. I suppose I could have 3D-printed the spindle but it would have made the hinge huge and not very nice-looking.

That’s kind of my problem: my correction is not simple. I can get near or far lenses with my correction for relatively cheap - like $100 a pair. But progressives are eye-wateringly expensive.

As for my frames, they’re both free and priceless to me because I make them myself. And just because they’re not off the shelf, they’re more rewarding to wear.

So having some understanding and control of that part of the process could have helped.

The only things you can rely on with regard to how the lenses are edged is:

• The bevel will be “bevelly” - meaning it’ll be a bevel of some kind, between 90 and 120 degrees, but no flatter than that. In other words, you can rely on having something to grip the lens with and that’s enough.

• The bevel follows the curvature of the frame. If you frame is flat, the bevel will be placed all around the edge of the lens flat too.

• As much as your correction will allow, the bevel will be placed as far forward as possible so the lens looks like it’s tangent with the front of the frame all around, and all the thickness will be hidden at the back of the frame. So if your frame is, say, 2mm in width, the root of the bevel will be placed 1mm from the front of the edge.

The other thing you can rely on is that the bevel will be slightly oversized so they can be snapped into the frame, and the amount of oversize will be a bit higher for plastic frames which are more flexible. And that’s where the danger lies: if your frames are designed to hold the frame without pressure like mine, you have to tell the optician so they pass the information to the lens cutter. Otherwise you will received lenses that are slightly too big.

But don’t sweat it too much: the great thing with 3D printing is, even if the lenses you received aren’t the right size, you can always print another frame with slightly revised dimensions.

And if you really don’t want to print another frame, don’t forget that you pay beaucoup bucks for those damn bits of plastic, so you can always copiously warn the optician that your frames are not made of the kinds of plastics plastic frames are usually made of, and then the onus will be on the lens maker to make the lenses right for your frames (remember that they will be sent your frames, so they’ll know rightaway if the lenses fit).

If the lenses aren’t right, it’s their problem and you can reject the lenses and tell them to try again. If you warn the optician in no uncertain terms that your frames are PLA, they or the lens maker can’t claim they didn’t know.

Just design the frames you want with the shape you want, with a 120-degree bevel, and ask your optician if it’s workable for the lens maker. They might tell you they’ll ask them - and you can leave them a test print too if they want to sent it to the lens maker too. There isn’t much more to this really.

I’ll definitely add cable temples to the list of things to try and see what works well.

Be aware that cable temples are a lot more finicky to adjust than regular curved temples. If they’re too short, even a little, they’ll dig into the skin behind your ears and you’ll hate them. Likewise, if the hook is too narrow, the tip will hurt you under your ear.

That’s a big reason why cable temples went out of favor in the 1920’s: they’re great when they’re well adjusted, but they quickly become nasty and uncomfortable when they aren’t - unlike maladjusted curved temples which can simply ride up the ear a little without too much drama.

With regular metal wire, you can bend the temples this and that way to make them fit. Not so much with PLA. You can shape it with heat but if you do it more than once, it becomes rough and unpleasant to wear - if the PLA doesn’t delaminate completely. So take the time to design the right length and shape directly in your model. It’s a bit long and tedious but once you know the right dimensions, you’ll love how natural they feel.

Also, don’t make the wire too thin or it will dig into your skin as well. And too thick will make the wire inflexible and difficult to put on. The wire profile that works best for me is this (for PLA):

They’re prescription glasses. They’re my regular glasses I wear every day. I made the frames but I can’t print optical lenses, sadly. I wish I could because they cost a fortune and they’re a real rip-off…

Halting the print to insert the magnets would be problematic: I print on the company’s printer and it’s a 5-hour print, so I start it before going home in the evening to avoid annoying everybody during work hours.

We’re allowed to use the printer for personal prints. But the rule is, if someone arrives at the office and needs to print something for work, whatever private stuff is in the printer is removed to make way for work things. And of course, if the printer is running - or paused waiting for someone to attend to it - the print is cancelled.

So I’d have to arrive really early in the morning to make sure I get there before the most early birds but there are no buses at the wee hours of the morning. Therefore realistically, my long prints need to complete unattended and be ready to be chucked out in the morning if I’m not first to arrive at the office.

But I’m not worried about the magnets coming out: the fit is tight and I use really strong epoxy. I’ve yet to see anything assembled with that stuff come undone.

Thanks!

I just made one initial print but I didn’t leave enough free play in the frame holder at the bottom of that case, so while it worked, it was kind of a pain to insert the frames into it. I widened the play from 0.4 to 1.5 mm and now there’s zero usablility issue.

Another unexpected problem I discovered with that first print is that I couldn’t tell the top shell from the bottom shell when the case was closed. I completely overlooked this and it turned out to be a massive PITA: 50% of the time, I would open the case upside down. Silly eh 🙂 It seems obvious in hindsight.

But I like the symmetry of it. So I added “engraved” text at the front edge to tell if the box is the right way up before opening, and put my name and a description of the particular correction in that case as a bonus.

The rest - stiffness, hinge, lid fit. magnet fit - came out okay the first time out. I’m getting really good at knowing the printer’s tolerances in advance and leaving enough play for things that shouldn’t assemble with an interference fit.

Sounds like OptiBoard

The name rings a bell. Admittedly, I started looking into that stuff well before social media was even a thing 🙂

I didn’t realize you worked with a lens maker directly and not through an optician

Sorry I thought you meant to choose frames and for fitting. For that, I do my own, obviously.

But yeah, to order the lenses, I do have to go through opticians. And yes, they did measure my pupillary distance (only once, I’m not a shape-shifter), they do issue the order for the lenses in the correct format and they double-check the lenses when they arrive. Some of them tried to make me pay an extortion fee of $50 or something for bringing my own frames, but considering they wouldn’t be doing any added-value work beyond ordering the lenses for me, I thought that was a bit rich so I went elsewhere.

I did order lenses direct from Hoya once, because I had a friend who worked there. But apparently they found out and my friend told me never again, or he’d be in trouble. So now I go through my local optician when my prescription changes - which isn’t that often: the lady who owns the store knows me well, she’s kind of amused to see my various eyewear contraptions and she knows she’s never going to extract a fortune out of me, but also she doesn’t have to spend any time on me either. So she passes her supplier’s costs onto me almost without any surcharge.

I’m surprised to read that superglue is sometimes used

It’s only for round lenses, either in light-fitting frames, for safety in case the screw backs out in metal frames, or in plastic frames because plastic is a bit more slippery. Round lenses typically shift when you clean them with a little too much gusto and it can happen surprisingly easily even in well-fitting frames.

Glue is not ideal but sometimes it’s needed. And obviously it’s never used with non-round lenses that are always naturally oriented properly.

Without the simulated weight, they’re fine. But with weight, they slip off if I look down.

Firstly, are you sure those test lenses you’re using are polycarbonate? If they’re glass, they’re a lot heavier. And of course they might be thicker than necessary for your prescription because they’re cheap: thin lenses are lighter but more spendy.

But essentially you’ve discovered why I always wear glasses with cable temples 🙂 Yes, they’re a bit more annoying to fit in a case, but they hold your frames put on your nose and you never have to worry about your glasses slipping ever again.

Although the 3D-printed glasses I designed fold the temples at an angle to position the wires more smartly, so they fit in regular cases. And I’ve just finished designing a very nice 3D-printed custom case for them too, which I will publish on my Github soon. But here’s a sneak preview:

Also, I’ve been wearing cable temples for so long that the nose bridge of all my glasses, which all land more or less at the same place on my nose all the time, ended up leaving a permanent indent in my skin. So the nose bridge always fall in it now. I could almost do away with the temples and the frames wouldn’t even move at this point.

I think there isn’t an inexpensive way to do that.

If you don’t intend to change the shape of your frames, the easiest is to design around old lenses you have lying around. If you screw them up, you weren’t doing anything with them anyway so it doesn’t matter. And presumably they used to be as nice lenses as you could afford when you wore them, so they should be close to the new ones you’ll order after you’ve finished your design.