tweak and reprint the frame a bit to match the lenses. That’s not really the end of the world, but I don’t count on any opticians to understand that

Oh believe me, they understand perfectly.

Here's the thing - and I'm not inventing this: my current optician is a friend and she told me this verbatim: an optician's bread and butter is selling you frames, and the services around fitting the lenses on the frame and fitting the frame on you. Opticians make almost no money on the lenses - which they have made abroad in developing countries usually.

I don't deny that there's a lot of measuring prior to ordering lenses, counselling the customer, and then a lot of fiddling with the temples and the nose pads after the glasses are completed to make sure the glasses are comfortable and yada-yada. The services provided by opticians are definitely useful, particularly for young wearers and for people who change frames often.

But really, if you're a lifelong glasses wearer, you're reasonably handy and you settle on one frame geometry, those measurements never change and you just don't need the services.

Me, the last time I needed an optician's services was over 20 years ago when I made my first frames out of nickel silver. Since then, I've only made copies of those exact frames because I really like them - including those 3D-printed ones I drew a few weeks ago: they're a bit different to account for the nature of the 3D-printing process, but the key measurements are the same.

So whenever I go to an optician to order new lenses - which you almost have to because you can't order the lenses direct, even if you have all the measurements needed by the lens maker, the convo always goes something like this:

• Hello, I need a pair of lenses with these dimension (or for these frames), with this prescription. My pupillary distance is x, the vertical angle is y, the bevel is z all around and the optical axis is marked here. I don't want you to mount the lenses on the frames and I don't want you to fit me. How much and when?
• Well okay, the lenses are $something. But since you don't buy frames from us, we'll have to charge you an extra $something.

I kid you not, it's extortion. They hate it when you can do their job yourself so they charge you for the privilege. And since you don't have access to their suppliers (they look out for each other) you have to go through them.

Resin is well within reach of the casual hobbyist now - we’re talking a couple hundred dollars to get an entry level machine, and a little extra coin for the materials/consumables. I have a (now old) Mars 3 that is ticking along beautifully

I am very tempted by a resin printer. However - and this is going to sound weird - I actually like the limitations of FDM.

And this is why: I'm a hacker at heart (in the old sense, not the nasty illegal stuff) and I like to push the envelope of what our Prusa Mk4 printer can do. I've printed stuff with that thing that I had no right to print by working the workarounds in the model, playing with layer sizes and controlling the path of the nozzle so it ends up printing features that are right at the limit of what it can do. Hell, even the hinges in those specs of mine are kind of pushing it.

And it's fun! It provides hours of good fun trying this or that and finally getting the little printer to print something right.

A resin printer would make very good prints without anything to do, if that makes sense 🙂

Also I want to work with different materials. I'm actually looking into getting a Prusa XL with several heads to combine TPU for flexible, hollow parts and PLA for the supports inside the parts. That's something a resin printer can't do: resin printers print... well, resin.

And finally, I'm always kind of designing parts with a view to making it available to anybody who has any old printer at home for them to print and enjoy. That approach entails designing for the lowest comon denominator (to a reasonable degree), something a resin printer is not.

So you see, while I would like a resin printer, I feel it's just not the right printer for me.

If you really want entry-level, the Geeetech Alkaid is regularly on sale for $99 and I've had one for a couple of years and it's fine. I'm not aware of anything it's missing versus more expensive entry-level SLA printers, but no one seems to be aware it exists. Nearly all the problems seem to be because it's full of Chitu hardware and runs Chitu firmware, but that's true of nearly everything cheapish.