RAF Camera customization

MacM545 wrote:

Are you able to print in metal?

In theory, yes; in practice, no. Metal printing isn't really a thing in the same sense plastic is. Basically, plastic parts often come of the bed ready to use, whereas metal parts need a LOT of postprocessing: burn-out of binder, sintering bake, bandsaw removal from build plate, CNC mill clean-up of build plate and part where it touched build plate, etc. Metal parts also change dimensions a lot during postprocessing, and you have to allow for that in your design.

I have printed with steel filament, but it's nasty stuff. Very abrasive on the nozzle. The material is about 30% nano steel particles, 70% plastic binder... which gives you some idea how much this stuff will have to shrink if you burn-out the binder after printing. Things are a tad better for laser sintering 3D printers, but there's still something like 30% binder in the metal powder. There's some hope for minimal postprocessing with welding-based metal printing, but that's not really an established tech yet.

I was looking for someone who might be able to make me a M39 to M52 macro coupler. I'm not entirely sure about plastic being strong enough. The weight of the lens going onto the end of the main lens is 260 grams. Thank you for any information!

I wouldn't be worried about 260g (nor even 500g). Well-designed and correctly printed plastics are surprisingly strong. For example, this bracelet can actually hold >30 pounds without having the tiny clasp fail. That said, 3D-printed adapters are more subject to wear and especially abuse. For example, leave a 3D-printed PLA adapter on your car's rear deck at 140F for a day and the odds are the adapter will have "wilted" a bit, deforming slightly and maybe even partly delaminating. After all, PLA is a thermoplastic monomer -- not a thermoset -- so it can be remelted multiple times, and is extrude-able goo by around 190C (around 370F).

The bad news for you is I don't make adapters as a business. You'll have to do it yourself or find somebody else. I make adapters mostly for my own needs and kindly post many designs as a public service. Every so often I consider making adapters as a side business... but I'm too well payed and too dedicated to my real job as a professor to make a side business worthwhile.

jogar wrote:

Do you know shapeways? https://www.shapeways.com

We used them extensively during my PhD, I needed fairly complex geometries to do some experiments with radioactive liquids, one of my colleagues needed some parts for a miniature PET scanner. In both cases they delivered very good results. That was in 2014 though.

I know that they have many materials now, including some steel alloys and aluminum.

They are a good alternative once a design has been tested & tuned.

They also tend to make things 100% fill, which is ok, but truth is by something like 40% you already have max strength. On the other hand, they charge by weight, so.... They are NOT cheap.

MacM545 wrote

Are you able to print in metal? I was looking for someone who might be able to make me a M39 to M52 macro coupler. I'm not entirely sure about plastic being strong enough. The weight of the lens going onto the end of the main lens is 260 grams. Thank you for any information!

As your in the states I would imagine a firm like SK Grimes would fix you up no problems .

Other engineering firms would also turn one down for you . Just make sure you state the correct pitch of the threads etc before ordering .

In the UK we have SRB Gritturn ( SRB Photographic supplies now iirr ) who turn these things down and make any other adapter you could want .

jogar wrote:

What I see is that we do different things, so that might explain the difference in our approaches.

In general, I don't print screws, since those are easy to buy. What I print are parts that are attached with screws.... The inner m23 was printed 0.1mm bigger, and then "improved" with a smaller tap that had 0.5mm thread pitch. That took some time, but the thread is very, very smooth, so one can focus the lens without difficulty. ...

I think your approach is more common -- and perfectly reasonable.

However, I've never been a fan of tiny, fine-pitch, threads as structural fastening of plastic parts. I don't always print screws, but if I stick to things around M6 or 1/4-20, or larger, then I always have the option of either purchasing metal screws or 3D-printing plastic ones, and there will be enough "bite" for me to trust them a bit more even if the plastic isn't the most rigid stuff.... For the larger threads, I just haven't seen my tap and die set do much good.

Btw, both parts are made with openscad, that I know you also use.

I think quite a few of us folks needing parts to have precise dimensions favor OpenSCAD because it provides a fairly clean open source way to express parametric 3D models with various numeric parameters. There's a python-based library a bit like it under Blender, but it's more awkward to use. There's also the OpenSCAD-like ImplicitCAD , which isn't quite compatible with OpenSCAD, but it displays way faster and handles curves as a fundamental type rather than approximating them with line segments (although it will approximate them when rendering to an STL).

My main problem with OpenSCAD is that it is SLOW, especially with things like minkowski()... which other CAD systems tend not to have at all. Second problem is that it sometimes creates incorrect STL files, and open source software for fixing them isn't great.

neilt3 wrote:

MacM545 wrote

Are you able to print in metal? I was looking for someone who might be able to make me a M39 to M52 macro coupler. I'm not entirely sure about plastic being strong enough. The weight of the lens going onto the end of the main lens is 260 grams. Thank you for any information!

As your in the states I would imagine a firm like SK Grimes would fix you up no problems .

Other engineering firms would also turn one down for you . Just make sure you state the correct pitch of the threads etc before ordering .

In the UK we have SRB Gritturn ( SRB Photographic supplies now iirr ) who turn these things down and make any other adapter you could want .

Thanks. I've sent a quote to RAF camera. Seems much cheaper than the one you mentioned, even though it's from the UK.

ProfHankD wrote:

MacM545 wrote:

Are you able to print in metal?

In theory, yes; in practice, no. Metal printing isn't really a thing in the same sense plastic is. Basically, plastic parts often come of the bed ready to use, whereas metal parts need a LOT of postprocessing: burn-out of binder, sintering bake, bandsaw removal from build plate, CNC mill clean-up of build plate and part where it touched build plate, etc. Metal parts also change dimensions a lot during postprocessing, and you have to allow for that in your design.

I have printed with steel filament, but it's nasty stuff. Very abrasive on the nozzle. The material is about 30% nano steel particles, 70% plastic binder... which gives you some idea how much this stuff will have to shrink if you burn-out the binder after printing. Things are a tad better for laser sintering 3D printers, but there's still something like 30% binder in the metal powder. There's some hope for minimal postprocessing with welding-based metal printing, but that's not really an established tech yet.

I was looking for someone who might be able to make me a M39 to M52 macro coupler. I'm not entirely sure about plastic being strong enough. The weight of the lens going onto the end of the main lens is 260 grams. Thank you for any information!

I wouldn't be worried about 260g (nor even 500g). Well-designed and correctly printed plastics are surprisingly strong. For example, this bracelet can actually hold >30 pounds without having the tiny clasp fail. That said, 3D-printed adapters are more subject to wear and especially abuse. For example, leave a 3D-printed PLA adapter on your car's rear deck at 140F for a day and the odds are the adapter will have "wilted" a bit, deforming slightly and maybe even partly delaminating. After all, PLA is a thermoplastic monomer -- not a thermoset -- so it can be remelted multiple times, and is extrude-able goo by around 190C (around 370F).

The bad news for you is I don't make adapters as a business. You'll have to do it yourself or find somebody else. I make adapters mostly for my own needs and kindly post many designs as a public service. Every so often I consider making adapters as a side business... but I'm too well payed and too dedicated to my real job as a professor to make a side business worthwhile.

You can massively improve the temperature resistance of PLA by annealing it, but that comes with a little warping that would probably render a filter thread useless. Very handy for part cooling ducts for printers!

xlucine wrote:

You can massively improve the temperature resistance of PLA by annealing it, but that comes with a little warping that would probably render a filter thread useless. Very handy for part cooling ducts for printers!

Not that massive, and not literally annealing. So-called high-temp (aka "dishwasher safe") PLA basically gets completed parts baked once at around 100C for up to about 10 minutes -- not the repeated temperature cycling pattern of true annealing. Alternatively, the printed part can be heated by submersion in near-boiling water for a similar period.

This single post-processing heating cycle basically causes an internal crystalization-like process that increases resistance to deformation at temperatures up to a bit above 100C. However, it doesn't really make the parts that much more rigid, and they'll still deform under load when heated. I'd say HTPLA is about as heat resistant as ABS... and I do prefer it to ABS because it is more dimensionally stable (suffers less warping). There are higher-temperature extrudable plastics (e.g., Nylon), but they generally require a higher print temperature and are less environmentally friendly; many of them also have poorer light-blocking ability, which matters for camera parts.

Incidentally, some claim that non-HTPLA given the same heat treatment also might get a similar benefit, but I haven't really seen that. HTPLA incorporates some additive that enhances the crystalization.

Note that parts very often fail by delamination of layers when exposed to heat. Thus, the best durability trick I've seen is to print a little hot -- basically increasing bonding between layers. For example, filament that could print at 195C, I'll often print at 215C. This does make printing unsupported spans harder (they tend to sag more) and can also increase stringing. This issue is also why I haven't really seen better strength for things like carbon fiber reinforced PLA: the carbon fiber actually causes a poorer bond between layers, making delamination failure more common. Printing with non-planar layers can help a lot to prevent delamination by shearing, but is not well supported by most slicers; you also can get a little better shear resistance by using different layer thickness for walls and infill (e.g., 2X thicker infill layers).