Projectors and 3D Printing

[Diana Hotka]

Hi all, I’m relatively new to film but eager to do more! Currently I’m doing research exploring if 3D printing can be used to help fix portable 16mm projectors and wanted to ask you all what your thoughts are (are there any specific parts that would benefit this?), also are any particular brands of projectors that have a common issue associated with them that could be fixable with 3D printing.

I have seen that Van Eck Video Services does this but wanted to hear from you all.

Any information you share is helpful. Thank you!

[Marcel Birgelen]

Like with everything else, it really depends on the parts you want to print and with what technology... Many critical projector parts must be able to survive in relatively harsh conditions. Tension stress, constant heat cycles, UV light exposure and potential exposure to lubricants comes to mind. All stuff to factor in when choosing your replacement materials.

Replacing something originally made from metal with 3D printed plastics is usually not a good idea. A good altenrative for 3D printing might be CNC milling, as it produces genuine metal parts with considerable strength and durability.

[Randy Stankey]

A good altenrative for 3D printing might be CNC milling, as it produces genuine metal parts with considerable strength and durability.

You can also print parts with 3-D printing in the normal way then use that as a pattern to cast the part out of metal.

They sell a liquid ceramic dip that hardens in an oven like glass. Then you pack the result in refractory cement and bake it in a kiln. The plastic will melt and burn away, leaving a perfect mold for the part to be cast from.

Once the part is cast in metal, break the mold cool the part then finish by hand or machine, as the case may be.

[Mark Gulbrandsen]

Well, parts can also be 3D printed in metal. NASA is working with Rocketdyne to 3D print parts for the RS25, Artemis, engines. Spacex is doing the same. Sections of the rocket stages them selves have already been 3D printed and flown.

Thinking about this makes 16mm projector parts seem pretty insignificent. Plus, there are so many 16mm machines out there, that it's likely cheaper to acquire a replacement projector. Especially with Bell & Howells that have a cracked gear that can take a full day to replace. Those B&H's were pretty hard on film too. The shop labor cost to replace a cracked gear easily exceeds the cost of a good used replacement projector...

There are too few 35 and 70mm projectors left in service for 3D printing to become any more than a boutique service. There are already machine shops that can make one up or more parts.

https://youtube.com/shorts/r0hAO4EEP...dTRsc1lfVROPff

[Mark Gulbrandsen]

Interesting site...

https://van-eck.net/en/

[Diana Hotka]

Like with everything else, it really depends on the parts you want to print and with what technology... Many critical projector parts must be able to survive in relatively harsh conditions. Tension stress, constant heat cycles, UV light exposure and potential exposure to lubricants comes to mind. All stuff to factor in when choosing your replacement materials.

Replacing something originally made from metal with 3D printed plastics is usually not a good idea. A good altenrative for 3D printing might be CNC milling, as it produces genuine metal parts with considerable strength and durability.

I didn't think about the UV light exposure and the exposure to lubricants as factors to consider in choosing the materials for replacement parts. I will also look further into CNC milling. Thank you for your feedback!

[Diana Hotka]

You can also print parts with 3-D printing in the normal way then use that as a pattern to cast the part out of metal.

They sell a liquid ceramic dip that hardens in an oven like glass. Then you pack the result in refractory cement and bake it in a kiln. The plastic will melt and burn away, leaving a perfect mold for the part to be cast from.

Once the part is cast in metal, break the mold cool the part then finish by hand or machine, as the case may be.

This is a really fascinating way of processing! Thank you for the suggestion.

[Diana Hotka]

Well, parts can also be 3D printed in metal. NASA is working with Rocketdyne to 3D print parts for the RS25, Artemis, engines. Spacex is doing the same. Sections of the rocket stages them selves have already been 3D printed and flown.

Thinking about this makes 16mm projector parts seem pretty insignificent. Plus, there are so many 16mm machines out there, that it's likely cheaper to acquire a replacement projector. Especially with Bell & Howells that have a cracked gear that can take a full day to replace. Those B&H's were pretty hard on film too. The shop labor cost to replace a cracked gear easily exceeds the cost of a good used replacement projector...

There are too few 35 and 70mm projectors left in service for 3D printing to become any more than a boutique service. There are already machine shops that can make one up or more parts.

https://youtube.com/shorts/r0hAO4EEP...dTRsc1lfVROPff

Wow I didn't realize NASA and SpaceX were 3D printing at that level. You make a good point about the cost and time that is needed to be invested into making the replacement part. Additionally knowing about the Bell & Howells is helpful, I wouldn't want to repair a projector only for it to damage a film especially archival film. Thank you for your feedback and sharing the link and video of NASA, really cool stuff.

[Leo Enticknap]

A consumer liquid resin or filament 3-D printer could likely be used to make parts that don't have to withstand a huge amount of pressure, heat, and in the case of liquid resin printed parts, UV. I've used mine to make a few 9.5mm film cores for a friend (though that raises the question as to whether 3-D printed plastics could potentially produce offgases that would not be friendly to film in archival storage).

If someone could come up with a design for a 3-D printed worm gear drive for a Hell & Bowell, it would be interesting to see how long that would last.

[Ryan Gallagher]

I think there is a lot more choice of materials with the resin variety of printers. I'm sure some of them are oil resistant, not sure about UV resistant... but as that is what you typically cure resin prints with, certainly not going to harm them immediately.

And yeah, using 3d prints as a "lost wax" for casting is definitely a thing. But really depends on the parts you are after and in what quantity! Fun for a hobby, but maybe not economical.

[Randy Stankey]

The turbine blades inside a jet engine are made by investment casting.

[Diana Hotka]

A consumer liquid resin or filament 3-D printer could likely be used to make parts that don't have to withstand a huge amount of pressure, heat, and in the case of liquid resin printed parts, UV. I've used mine to make a few 9.5mm film cores for a friend (though that raises the question as to whether 3-D printed plastics could potentially produce offgases that would not be friendly to film in archival storage).

If someone could come up with a design for a 3-D printed worm gear drive for a Hell & Bowell, it would be interesting to see how long that would last.

That's really cool that you 3D printed a film core, I'm not sure how 3D printed plastic offgas either, that would be interesting to know. I believe PLA filament is biodegradable and I did find that you can buy polyethylene filament which is one of the archival plastic materials so I'd assume that would be safe for film, https://xtellardirect.com/braskem-pe-filaments.html

I did print with resin one to make a functional prototype and dropped it by accident (aka an accidental stress test) and it shattered, later I learned that resin prints in consumer grade filament is typically used to make pretty objects, not necessarily for function and durability.

On the Van Eck Video Services, they have Bell & Howell worm drives that look 3D printed to me but I could be wrong. https://van-eck.net/en/product-categ...rts-en/page/3/ (in case you need one) I'd definitely be curious how long a personal printed one would last, I'll keep that in mind.

Thank yo for your input!

[Diana Hotka]

I think there is a lot more choice of materials with the resin variety of printers. I'm sure some of them are oil resistant, not sure about UV resistant... but as that is what you typically cure resin prints with, certainly not going to harm them immediately.

And yeah, using 3d prints as a "lost wax" for casting is definitely a thing. But really depends on the parts you are after and in what quantity! Fun for a hobby, but maybe not economical.

You make a good point about the economical aspect. Thank you. Definitely will look into "lost wax" casting

[Diana Hotka]

The turbine blades inside a jet engine are made by investment casting.

Thank you for your input, I'll check that out for sure!

[Marcel Birgelen]

If someone could come up with a design for a 3-D printed worm gear drive for a Hell & Bowell, it would be interesting to see how long that would last.

I also have a resin 3D printer and although those prints are very detailed, even the harder ABS-style plastics aren't good for high mechanical loads. Most resins I've used are far too abrasive for extensive use. It's fine for some small prototypes, but nothing like a high-stresss worm gear.

As for UV-light resistance: The interesting thing is that this resin is usually cured using UV light. Many resin formulas start to become brittle after extended UV exposure, much like many plastics, especially the flexible ones. I guess the UV light causes the softeners in those plastics either to evaporate or to react in such way that they don't perform their work anymore.

That being said, I've seen some nylon SLS 3D prints that are very heavy duty and perform very well under high mechanical stresses. Those prints can also be ordered from 3D printing services. Those same services also often offer metal SLS prints, usually at far higher costs though. Keep in mind though that a CNC milled component will almost always outperform a 3D SLS printed component on strength and flexibility.

PS: I own a Lamy 2000 fountain pen dating back to the early 1970s, which apparently used one of the first metal sintering "3D prints" ever in an industrial production run. Many of those concepts have been around for a while, apparently.

As for metal casting in wax:
It's something I want to try someday. The problem here is obviously heating the metal and confidently working with it.