How strong is WSF?

Discussion in 'Technologies and Hardware' started by mgrynberg, Jan 8, 2011.

  1. mgrynberg
    mgrynberg New Member
    Hi All,

    I'm new here and I'm working on a pretty ambitious project - a 6x17 panoramic camera.
    I'm planning to use WSF as material but I'm slightly worried about its rigidity.
    I need the camera to be rigid.
    I'm currently making wall between 3mm and 8mm depending on their placement, and I use reinforcements here and there.
    One major concern of mine is the lens cone for the camera.
    That's what connects the body to the lens - the most expensive part of the camera.
    What wall thickness should I use to make sure it won't budge?

    Maybe to simplify, lets say I have a hollow cube, or a cylinder. What wall thickness would be appropriate to make it really rigid in WSF?

    Thanks a bunch!


  2. jasolo
    jasolo New Member
    I should be more worried about the opacity of the material: 2mm of White SF can be enough rigid but let pass some light. I don't know the result with Black SF or wider walls.
  3. dizingof
    dizingof New Member
    3mm wall will be very rigid and tough.
    You can see here an example i printed:
    Charging Dock for iPhone 3G/4G

  4. mgrynberg
    mgrynberg New Member
    Thanks for the replies guys...

    jasolo: 100% correct, the plan is to use BSF but I asked the properties for WFS to get the most answers possible... I assumed BSF has the exact same properties since it's the same material just died. Is that not the case?

    dizingof: so that wavy upright is 3mm and 100% rigid?

  5. dizingof
    dizingof New Member
    yes this specific wavy upright is 3mm thick and very rigid.

    However.. since WSF is porous which gives it it's flexing properties i've learned the "hard way" that large prints could flex and bend if weight is applied.

    such as this design: ch.html?gid=sg28396

    or this: ch___2.html?gid=sg28396

    I finally ended up with this functional design and in Alumide: .html?gid=sg28396

    so it really depends on your design functionality.

    so far Alumide turned out to be the best rigid material for me.
    (haven't tested gray robust - don't like the FDM printing looks)

    Hope this helps

  6. mgrynberg
    mgrynberg New Member
    That's some awesome designs you got there...
    I think your problem of side arms bending under the weight of the iphone is most likely cause by torque because the attachment point of the iphone is off center of gravity unlike in the alumide model... Did you try models 1 and 2 in alumide?
    Anyhow, I doubt it would apply to me since I'm modeling fairly bulky symmetrical pieces...
    Plus I don't have much choice because of the size of the parts... Anything other than WSF shoots the price through the roof...

  7. dizingof
    dizingof New Member
    Well if you're going for the 3mm wall thickness might as well print it cheaply in sandstone for testing purposes then if all OK order it in WSF.

  8. mgrynberg
    mgrynberg New Member
    Because of the size, sandstone is $30 more than WSF, and about the same as BSF...
    part 1 is 25x7x5.5cm with ~20% density and part 2 is 19x7x9cm with ~15% density so I get the volume discount in wsf...

    So I'm gonna have to take a leap of faith and hope the my design will hold up...
  9. dizingof
    dizingof New Member
    Good luck :cool:
  10. TimberWolf
    TimberWolf New Member
    I am not sure what your 6x17 camera looks like, but I am a photographer myself.

    If you want a really sharp image, you need to ensure that your film/sensor plane (assuming film here, a 6x17 sensor would cost you a few cars) is really parallel and rigid to your lens.

    Personally, I doubt that even a 3mm-thick layer of WSF will be rigid or smooth enough to achieve that goal. You may want to consider a 3mm thick layer with ribbing to vastly increase the second moment of inertia in the directions that you want to resist bending with a relatively low increase in volume (and hence cost).

    Also, in addition to that, I do not believe that tolerances are tight enough to ensure a parallel film plane to your lens. I believe it will be prudent to include in your design 4 screws at the corners to enable you to tweak the position of the film plane. WSF is rather "soft" compared to metals and so may strip if you apply too much load or adjust the screws too rapidly. I recommend using a threaded insert (such as Helicoil) to protect the screw threads in the WSF. That way, you will have reliable adjustment capability.

    Finally, as WSF is rather powdery and rough, you may face problems with scratching and deposition on the film. A solution for this is to spray a few light coats of clear acrylic paint onto the film plane. Wait for each coat to dry before applying the next. Use sandpaper and lightly sand until the surface becomes matte-shiny.

    I know this seems like a lot of work, and to be honest it is. However, the results are very fulfilling and I wish you the best in your project. Let us know how it goes!

  11. mgrynberg
    mgrynberg New Member
    You hit the nail right on the head TimberWolf!

    I'm basically making my own this:
    Same principle, without the shift capability...

    My main worry is the lens cone that connects the lens to the camera body...
    But given the feedback it should be good enough... the walls taper from 8mm to 3.5mm (which I will make 4) with 3 reinforcing ribs in the length.

    For the problem of strictly parallel film and focal planes, I'm building in the capacity to 'shim' at the joint between the lens cone and the body, without creating light leaks by introducing a lip on the body side.

    The screws issue will also be covered by EZ LOK inserts, same principle as Helicoil...

    Now the part that I still haven't figured out is the material surface...
    I hear Black SF is even rougher than WSF which is good and bad in my case... Good because it's porosity will basically ensure no light bounces around inside the camera, but bad because it will scratch film emulsion. Major issue there...
    So I need to figure out a way to coat the parts in contact with the film emulsion without messing up my dimentions... I already built in rollers to ease the film advancing, but the film plane needs to be very smooth especially since I will incorporate a pressure plate to make sure the film doesn't buckle...

    Anyhow it is definitely a lot of work, and I'm not expecting to be done for a few months.

    I also need to figure out which lens to use, and how exactly to mount it (I have an idea but need to explore more).
    And also I can't finalize the cone unless I have the optics figured out...

    Oh well, it'll keep me busy for a while :)

    Thanks for your feedback!

  12. TimberWolf
    TimberWolf New Member
    Keep in mind though, that the lens mount is usually one of the most rigid parts of the camera. I've seen cameras having to be scrapped because an impact deformed the mount by a fraction of a mm. You might need to take into account the deflection caused by adding a lens (or even different lenses) if you want to be truly accurate.

    As for the roughness, maybe some parts don't have to be RP'ed? You could use a nice plastic sheet for that?