Making WSF NOT flexible

Discussion in 'Design and Modeling' started by 72649_deleted, Jun 15, 2011.

  1. 72649_deleted
    72649_deleted Member
    Hello!

    I saw the torture test video of Black Strong and Flexible a while ago, but the video is now removed.

    Is there a minimum thickness of sorts that makes WSF more rigid?

    I like the price and apparent strength of the material, but I want it to be rigid and not flexible, yet use WSF. Is this possible, or do I have to use Grey Robust?
     
  2. TomZ
    TomZ Member
    It's quite possible to make it rigid. It depends mostly on the geometry of your design, not the thickness. You could make a model with 1mm walls still very rigid by giving it the appropriate shape but at the same time a flat piece of 2mm thickness can be bent quite easily.
    It's like how a flat piece of steel can be quite bendy, but when you form it in to a tube it becomes nearly impossible to bend.
     
  3. 72649_deleted
    72649_deleted Member
    Thanks for the quick reply!

    For the most part, the particular part I am designing is mainly circular in shape, extruded out for a bit of thickness and with flat protrusions to mount screws onto. The part will act as a clamp, and will be in two halves.

    Here's a screenshot of what I mean, to make more sense.

    Would this geometry make the part rigid? (the "flaps"/wings of the clamp can be flexible, but if so, not too much)
     

    Attached Files:

  4. TomZ
    TomZ Member
    That already looks like it would turn out quite rigid. The main point of concern is of course the groove, it looks a bit thin at that point.
     
  5. 28396_deleted
    28396_deleted Member
    My experience , spray it with acrylic or epoxy spray .
    The first coat will be absorbed fast as WSF is porous - wait 15 minutes and apply another coat from about 20cm from the model with short bursts - this way you dont make one area too wet then the rest

    hours later it will be rigid and also protected from dirt spots.
     
  6. 89303_deleted
    89303_deleted Member
    If I may borrow this thread :D...

    I am 3D-modelling a custom chassis for an arcade controller, as is customary among fighting game players, to suit every individual's preferences, hand positioning etc.

    If you are not familiar with how arcade controllers (or among players: fighting sticks) look like, please enter "fighting stick" or "arcade controller" into Google image search.

    My chassis is hollow, about 50cm long and 25cm wide and slanted back-to-front (8cm high on one end and 1cm on the other end). Therefore, the only material that I can choose is White strong and flexible.

    Now the question I'm asking is: How thick should I make the walls of the chassis in order for it not to flex? How thick should the upper wall of the chassis be in order for it not to flex under the force of moving the joystick? How can I make WSF more rigid?

    Mr. Robert Schouwenburg was very kind and helpful explaining some general characteristics of the WSF material, but he suggested that for more datailed advices, I'd be better off consulting you community gurus here.

    If I may quote him:

    White Strong & Flexible (WSF) is flexible as a coke bottle. That means it is
    quite flexible when you make thin walls (1.5mm or lower). When you go ticker
    it becomes less flexible. The total surface area also is important. The
    bigger surface area the bigger the flexibility. It is like with any plastic.
    The best option would be to make it at least 2mm thick and place
    strengthening beams every 4cm which makes the material rigid.

    Another option is to order it 2mm thick and afterwards dip it in superglue.
    Other community members have good experience with that method to make WSF
    rigid.


    By the way, I would really like to avoid having to incorporate "strengthening beams", so to speak, in the center of the chassis, so that it wouldn't flex as much in the middle? They would interfere with the wiring etc.

    Should you need some extra information, I can post the 3d file of the work in progress here in this thread.

    Thank you all very very much for your help.

    Sincerely,
    UFOKatarn
     
  7. dhammond
    dhammond Member
    You may be able to use strengthening beams without interfering with the wiring. You do not need them to be very high. You may be able to get away with something like a 3mm by 1.5mm section on the ribs and a 2mm general panel thickness so that you have 5mm overall thickness at the ribs with the ribs on a 1 inch grid. You would want more strengthing at the joystick mounts ans at any screw fixing points.

    I would recommend that you design some small test pieces first at 10cm by 5cm so that you can perform some trials before you commit to a full size piece. (I tend to chuck in test pieces in with normal orders thus avoiding the minimum order charge and the cost can be negligible).

    The ribs will make the part a lot cheaper than printing the whole part at a uniform thickness. The advantage of rapid prototype printing is that you do not need to worry about sink marks unlike injection molding.
     
  8. 89303_deleted
    89303_deleted Member
    Thanks for your suggestion DHammond :D!

    It's a really great idea :).

    Ribs I guess will definitely help with the overall rigidity, but wil not get into way of the wiring or swallow my entire budget :rolleyes:.

    What did you mean by:
    ?

    Do you mean that due to the shipping cost you add smaller items alongside a larger one you've been working on and know that it's done as is should.

    I don't intend to buy any other item for now, but I did want to order a material samples package. I can add those small pieces to that order I guess :).

    Regards,
    UFOKatarn
     
  9. dhammond
    dhammond Member
    Normally it will be a larger piece that I need to order and I will either add the small test piece onto the large piece on a short hidden sprue that I can then cut off or upload the small pieces as separate items and add them to the order.

    For example, I recently did some small test pieces to check how well snap fits would work in a number of materials to create a captive nut feature. That way I was able to confirm that the design of the part would be suitable for my application prior to incorporating the feature in a large part (I knew it would work fine as an injection moulded part but did not know how well it would work using rapid prototyping techniques. A few years ago I would never have considered using snap fits in rapid prototypes as the materials were too brittle).

    The test piece in WSF worked out at $2.40 each. The end part that used this feature was $30 each.
     
    TheAndrian likes this.
  10. 89303_deleted
    89303_deleted Member
    Thanks for the info again DHammond :).

    I'll make a few different material strenghtening setups and see which one is the most rigid.

    -------

    Does anyone perhaps know whether there is a price difference between ordering separate small pieces or making them "attached" to each other with tiny "connecting sticks"?

    .
     
    Last edited: Jul 2, 2011
  11. stannum
    stannum Well-Known Member
    Yes, you save 1.50 per extra item in WSF, minus material needed for the sticks, obviously. So pretty easy to save >1.40 per extra item. You can also put the parts in the same item, and hope they don't go missing. The rumors around say sprues will be needed anyway, so you can start now instead of trying to save those 10 cents.
     
  12. 89303_deleted
    89303_deleted Member
    Oh, ... I see Stannum :rolleyes:!

    I guess it's pointless then to make it one large object for just two or three items connected, at least in the beginning :laughing:.

    Thanks for the info :).