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erazz

Adventures in plates (3D Printed)

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I want to try and ride my softboot board with plates.

However, dropping $$$ on a power plate or gecko system is just not in the cards right now.  What is? 3D printing!

 

Fire up the CAD, sketch up a snowboard, drop in some plates (3 degree cant, 27/9 front/back, 25mm rise)

5a7a4f6909fff_TotalAssy.JPG.a60cd145dec1bb08dc99c3b246bff49f.JPG

 

5a7a4f7f616ed_BackPlate.JPG.f35e05b113884c22dfedc3df800aa46b.JPG

 

Slice it up

5a7a4f867d457_CuraCapture.JPG.14a2c924a9f516b693bee3fbf28e2d6f.JPG

 

Print in ABS

Printing.jpeg.74b906aea5876523fffd2868552e01e4.jpeg

 

And 16 hours later we have this:

Printed.jpeg.5caa47fda34911ec9f77989040686780.jpeg

 

Which is totally unworkable! For some reason I placed the screw holes 50mm apart. Wonder why I can't mount it...

So right now I got the new version printing. More to come!

 

 

And I'm also working on an adjustable version. Once it's ready I'll post the files.

Adjustable.JPG.bb41eba3ba05f3143734115380f13d1b.JPG

 

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These came out really sweet!

Both plates together weigh ~200 grams are dead straight and super tough. They position the binding exactly as I wanted. Now I just need to ride them.

If I can get a certain softboot rider to get over his disdain of no camber boards we might get a second opinion :)

 

2018-02-07_18-06-59_550.jpeg

2018-02-07_18-20-36_162.jpeg

2018-02-07_18-21-00_284.jpeg

2018-02-07_18-21-08_816.jpeg

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I'd love to compare notes between your soft boot risers and my lift/cant shims for F2 bindings, particularly in terms of how they hold up with time and use. (http://forums.bomberonline.com/topic/45886-3d-printing-binding-parts/ if anyone is interested)

I've been printing mine in ABS, but am going to try PETG next, to see how they compare in terms of strength and durability.

What kind of layer height and infill density are you using? For ABS, I've been using .1575mm layer height, and an 80% cubic infill, with vertical and horizontal shell thickness such that the walls of my shims end up solid (so, for 5mm walls, I'm using 6 shell layers, which result in solid 5mm walls). I've been wanting to try a .1mm layer height, to see if/how that affects the strength, but haven't yet devoted that print time to trying that out, nor to trying relative strength testing. (I have run over the shims repeatedly with a minivan, just as a gross level strength/durability test! :-)  I've also been contemplating trying to bake the shims, to improve layer adhesion, but haven't gone there yet.

Great work on these risers! Please share slicer details, if you're willing to do so, so that we can hopefully leverage each others results.

Edited by jim_s

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Absolutely, your thread got me thinking about printed plates so I have to thank you for that!  Honestly I was contemplating saving up for power plates. Here are the print details.

 

Slicer: Cura
Layer height: 0.2mm (0.4mm nozzle)
Infill: 20% triangles - I wanted good strength top to bottom
Material: ABS - For cold weather performance (see this link for good cold weather plastics). Once I run out of red I'll use Black as it is much more UV resistant. PETG should also be a good choice. Stay away from ASA as it gets really brittle.
Temps: 250/95 (nozzle/bed) with an enclosure. This combination yields excellent layer adhesion.
Wall/floor/ceiling thickness: 0.8mm

Print time was ~24 hours for both plates together

 

The plates came out super super strong. The rule of thumb for stress on general plastics is 3kg/mm^2. Taking into account infill density and wall thickness this should be able to support up to 3 metric tons before collapsing :eek:.  I weigh a lot but not that much. You'd be surprised at how strong these materials are in compression. I would only be worried if you set these up in tension perpendicular to the layers.

 

 

I would love to see what we can come up with next!

 

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Yes, the whole 3D printing thing opens up all kinds of new avenues, doesn't it?? Very glad to see another carving geek working on this stuff! :-)

Its interesting - I've seen 2 different convincing studies that claim 2 different theories on layer height and its relation to the strength of the printed product. One showed that lower layer height yielded a stronger print, and another showed that lower layer heights yielded a weaker print. As you note, both of our applications are under compression - there are literal bolts holding our pieces in compression, so the likelihood of them coming apart is very low, but still, given that its something I'm entrusting my physical well-being to, I feel compelled to make it as strong as I reasonably can. :-) 

ABS is documented to have a compressive yield strength of 65 MPa (http://www.matweb.com/reference/compressivestrength.aspx), which converts to 6.6 kg/mm^2 (https://www.convertunits.com/from/MPa/to/kilogram-force/square+millimetre). At 50x55 mm for each of my shims (there are 2 shims under each boot - one under the toe, and one under the heel, but I'll assume worst case of someone landing with all force on just their toe or heel), that should be a prodigious amount of force bearing capacity when printed at 100%. Hollows form underneath the shims when the height of a piece exceeds 5mm, but even assuming a dire case where the printed ABS is somehow only 1/4 of the established ABS compressive yield, with the wall bases providing 1200mm^2 area, at 1.65kg/mm^2 (ie, 25% of rated compressive yield strength) that should still support over 2 tons per shim.

My van test (4500lb van, 57% front axle weight distribution, 50x55mm shim under a single front tire) only loaded them to 1kg/mm^2 - I'm gonna need to find a bigger test van. :-)

I've variously read that anything over 50% infill is largely pointless (apparently there's approx a 10% increase in strength between 50% and 75% infill), but for my relatively small cant shims, it seemed silly not to just print them effectively solid. (at 80% there are still a few areas where walls meet with fillets, where some infill is still produced)

I've been printing mine at 265 deg extruder temp and 95 degree bed temp, also in an enclosure. Extrusion multiplier is 1.25. I joke that I like it hot, thick and sloppy...  ;-) It makes for good inter-layer adhesion, though!

Thanks for sharing - lets keep in touch. I'll let you know how the PETG goes, and I definitely want to find a way of imparting several times more kg/mm^2 to some finished prints, just to be sure they're living up to the expectation.

I look forward to seeing your designs, when you get them all squared away and released!!

Edited by jim_s

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10 minutes ago, erazz said:

I might skip work tomorrow and test these out.  Will let you know!

That sounds like the best idea I've heard all week, on multiple levels! :-)

We anxiously await your report!!

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Just due diligence.

You'll get them tight initially, and then when you start loading the board/binding combination, the stack height and slip between the layers may lead to loosening. The standard fasteners are loaded more or less in straight tension, and these may see combinations of tension, leverage, and rotation, all of which could wind them out of the inserts.

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Fair enough...

 I made the screw holes a tight fit to minimize the side loads. Should also help with them backing out. 

I’ll examine them today and see if anything came loose. Possibly loctite them in. 

Thanks for the heads up!

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Aaaaand the verdict is....

They work.

 

Well what did I expect? They felt solid and nothing came loose. My stance was a lot more comfortable and I had no problems moving the board around. I rode this board with softboots and hardboots before and this setup really reminded me of how the hardboots felt. Definitely had more authority.

I looked over the board and nothing was sticking out, broken, or loose so I'm calling this a success! I'm going to go back into CAD and make a version I can post on Thingiverse. If I get it right it will be customizable so anyone can get in and get the angles/cants they want. Democracy!!!!

 

One nice thing I noticed is that since there is essentially a hard plastic tube around each screw, there isn't any binding suck! The base is totally flat. You could really feel that in how the board ran on the flat.

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2 hours ago, erazz said:

! I'm going to go back into CAD and make a version I can post on Thingiverse. If I get it right it will be customizable so anyone can get in and get the angles/cants they want. Democracy!!!!

Let me know if you have any OpenSCAD problems - i've gotten fairly involved with it of late.

Congrats on a good day out on your plates!! :-)

Edited by jim_s

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5 hours ago, jim_s said:

Let me know if you have any OpenSCAD problems - i've gotten fairly involved with it of late.

Congrats on a good day out on your plates!! :-)

Thanks :)

I've been using Onshape for some time now for personal stuff. Really great fro stuff like this. It's completely free, parametric, and easy to share. They only stipulate that your designs are public unless you pay. I don't mind that one bit as it's really powerful. Probably can do 90% of what you can do with Solidworks. Maybe a bit less convenient. Oh, and did I mention it runs in your browser? No installation needed. Yeah, it's a game changer.

I'll get around to makind an OpenSCAD model but for now this will have to do :)

Anyway, here's the link to the CAD model of the plates. It's parametric so anyone with CAD familiarity should be able to modify it to their needs. If anyone is shy about that, let me know and I'll generate STL files for you based on the cant and angles you need.

https://cad.onshape.com/documents/c7776aa1f3f95b931cb7cf21/w/7c3a90a27e138083b406b429/e/11d76d5de9e966be0f554e2c

 

3 hours ago, Lurch said:

Nice work! Between you and Jim there should be some really useful info. Bravo to you both.

Thanks!

I'm really psyched about incorporating these two hobbies :biggthump

Edited by erazz

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Nice! When you said 'Thingiverse' and 'customize', I was thinking you meant the Thingiverse Customizer, which runs on OpenSCAD, which is often highly unintuitive to people, LoL. :-) I've only played w/ OnShape at a very high level before - I've learned a lot just in the last 15 minutes playing around with a copy of your model. I'll definitely fiddle with the copy more this weekend - it should be a great learning experience!

I'm not at all familiar with this type of snowboard accessory - I see that your model has a cant capability - is it common for this type of riser to also have a lift feature, or is it just cant? Also, what is the purpose of the twist between the top and bottom surface of the plate?

I pretty quickly discovered the ability to alter the thickness, the cant and the amount of twist. It might be helpful to folks to spell out the various parameters that can be changed, and point out where to find them, as I'd imagine not everyone is familiar with CAD tools. (I realize this is early in the process, just food for thought once you sort of officially release this.)

Great work on all of this - I'm impressed with the tool and your use of it, and I'm genuinely looking forward to learning more about the tool through this great example of its use! :-)

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Yeah, that was and still is the plan. However the deeper I delve into OpenSCAD the more it looks like I have to write a Python script to really get the geometry I want. :(

Some people like to have toe lift and this can be added with the definition of another plane. Since I don't use lifts I didn't bother.

 

Keep in mind that the thickness (23.5mm) is critical for the 40mm countersunk screws. 

The twist is there so the bottom is perpendicular with the board. When you mount your bindings at an angle this creates an asymmetry that might make the board twist while you bend it. The theory is that having the bindings mount perpendicular to the board eliminates that. In my very non scientific test yesterday it seems that the board reacted to this very well.

 

I come form a background of CAD. Have been using various tools for the past 15 years or so. I really like what Onshape is doing. They're basically building a first rate parametric modeler and giving it to everyone through a browser. I've been waiting for years for something like this to come along. To me, having the files also being hosted by them is awesome as well.

 

p.s. They have a phone app (iOS and Android I think). Check it out. If you have an iPad you can design on it.

Edited by erazz

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Ah, thanks for the explanation on the twist factor - makes sense, especially in the context of a softer board than we typically run hard plate bindings on.

One of the challenges of allowing lift and cant is that the screws end up being at an angle with respect to the binding body. Spherical washers are the only answer I can think of on that. (For small amounts of lift and cant, its probably not a big issue, but for larger values, it starts becoming a problem.) Its great that your plates support that, though (and in reality, I'd be especially in soft boots, people aren't running large lift or cant angles...)

I threw something quick & dirty together in OpenSCAD, just to see what it would entail. The basics of the plate with lift, cant and whet I'm calling 'twist' is straightforward. As with many things in OpenSCAD though, what might look to be complex is simple (the configurable block with lift, cant and twist), but what should b e simple is complicated (getting nice rounded edges - fillets and rounded edges in OpenSCAD are invariably a pain, and are often very slow to render due to the use of what's called the 'minkowski' operation.)  The following renders in seconds w/o rounded edges, but takes about 30 minutes to render with rounded edges, even at a relatively low polygon count - thus the scalloped ends. This is shown with 6 deg lift, 6 deg cant and 20 deg twist (my overall dimensions don't exactly match yours - I was just shooting for the same overall proportions in this test.) Good news is, its a very simple/short OpenSCAD script (no holes added yet, but that'd be the simplest part), and is completely controlled via a handful of parameters (which would work directly in the Thingiverse Customizer). Anyway, I like the your Onshape model, its beautiful, but if you are interested in going down the OpenSCAD path, the following is about 20 lines of script in OpenSCAD, and every aspect of it - length, width, height, lift, cant, twist, corner rounding radius, etc is just a matter of changing a value in a text field.

 

5a7f5f79569fd_ScreenShot2018-02-10at4_08_16PM.png.4073fc8767460fe6db132cffbf82d8a3.png5a7f5f7869208_ScreenShot2018-02-10at4_08_25PM.thumb.png.670769939c2e150b4fd4e1e6cdbde2ce.png

Edited by jim_s

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That looks great!

Can you post the code? (maybe as an attachment or in line if it's short?)

The lightening holes should be dead simple as they should not have any rounding on them.

 

The bottom rounding is the most important as that prevents a sharp contact point with the board (and possible topsheet damage)

 

 

Anyway, that's the way I thought to make the parts. Design in an easy to use package and then, once I know what I want, import it to OpenSCAD.

Edited by erazz

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59 minutes ago, jim_s said:

One of the challenges of allowing lift and cant is that the screws end up being at an angle with respect to the binding body.

That's the advantage of using countersunk screws. They are surprisingly forgiving for a mismatched angle. The real problem is in length though. Once you have a lot of cant ant lift the difference between the 4 screws is big and then you need to be careful when you screw them in so you don't punch a hole through the bottom of your board.

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@erazz - here is a modified and commented version of what I first posted. The first approach applied the OpenSCAD minkowski() operation to a linear_extrusion() operation, which does rounding/smoothing, but takes absolutely frickin' forever. This modified version uses minkowski() in a more conservative way, and fakes a linear extrusion, which runs  in a different way, and renders instantaneously. It should be producing the same output as the fist approach, but I can't confirm, as the first approach (tried rendering it at a higher resolution) seems to be following Starman around the inner solar system, and hasn't been heard from again...

I documented the various params, so you should be able to twiddle with those to get your desired dimensions. Note that at present, this Q&D little test only supports left cant and heel lift (that having been said, you can flip it around, and what was left cant becomes right cant, and what was heel lift becomes toe lift. If someone wants left cant w/ toe lift, though, its not going to work. Its totally do-able, just not with this proof-of-concept model.)

Let me know if this is not behaving as advertised or needed - again, this was a quick & dirty attempt, so there'll definitely be something I've hosed up, LoL. :-)

 

len = 200;  //total length
wid = 100;  //base width (twist will result in wider overall dimensions)
edge_rad = 4;    //edge radius of top and bottom surfaces
ht = 10;        //minimum height (cant and/or lift will result in taller overall height) - NOTE: ht must be >= 2*edge_rad
twist = 10;     //degrees of twist
cant = 4;       //degrees of cant - this simple demo only supports positive (leftward) cant
lift = 6;       //degrees of lift - this simple demo only supports positive (heel) lift
steps = 100;     //smoothness factor - more steps = smoother sides

//this adjusts the total height, to take into account height added due to the edge radius - shouldn't be changed by user
adj_ht = ht - 2*edge_rad;

//call the plate module to initiate the render
plate();


//because OpenSCAD performs all rotations around the X, Y and Z axes, it is necessary to move the geometry to
// proper relative position wrt X, Y and Z. Cant and Lift will be rotated wrt X and Y axes, respectively, so
// for Cant and Lift rotations, the geometry should be aligned with X and Y axes
//for Tiwst rotation, because this needs to be around the center of the plate, the geometry must be centered
// on the Z axis, which requires moving the piece so it is centered at Z, rotating around Z, then moving it
// back to where it needs to be (it needs to be in a different position for Z rotation than for X and Y rotation...)
module plate() {
    translate([len/2, wid/2 + (len - wid)/2 * tan(twist), edge_rad])    //move finished plate to the positive quadrant
        for (s = [0:1:steps-1]) {
            translate([0, 0,  adj_ht/steps * s])
                rotate([0, 0, twist/steps * s])
                    translate([-len/2, -wid/2, 0])
                        rotate([cant/steps * s, -lift/steps * s, 0])
                            translate([len/2, wid/2, 0])
                                component_plate();
        }
}

//generate a plate of the desired length and width, with a thicness of 2*edge_rad (this how minkowski() works)
// minnkowski operation here is cheap/quick, as its applied to a very thin piece of geometry
//$fn value should be high on the end radii, for smooth side surfaces on the end
module component_plate() {
    minkowski() {
        hull() {
            //note the adjustment for edge_rad contribution to X and Y that will be added back by minkowski()
            translate([-len/2 + wid/2, 0, 0])
                cylinder(r=wid/2 - edge_rad, h=.001, $fn=120);
            translate([len/2 - wid/2, 0, 0])
                cylinder(r=wid/2 - edge_rad, h=.001, $fn=120);
        }
        sphere(r=edge_rad);
    }
}

 

 

 

Screen Shot 2018-02-10 at 9.08.58 PM.png

Edited by jim_s

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I think it's absolutely brilliant!

Way different than what I had in mind but it works excellent!

 

This works just as well for generating STLs for printing. More to play with. Thanks!!!

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