CAD program for fins ...

Hey out there, I wanna get the hang of a CAD program so as to be able to have fins milled on CNC. Anyone got their head around a program, can I get a copy… Oh, and if it runs on Mac, cool!!!

ahh there was a day when it was shameful to be called an unspeakable Cad…ambrose…how language evolves

We use MasterCam 9.11 to design and program our fin CAD programs. I believe a seat runs about $18,000.00 right now. But, if you check with your local community college, they may have classes that will get you started and allow a limited version for very little cost. Then you’ve got to get your hands on a CNC router or mill. My brother is checking out the APS3000 right now for shaping boards with. I’ve read their site literature and they really don’t specify tolerance. But, I can tell you we’re working with models that have .00005"+/- tolerance. The APS may be fine for what you want. But, they’re quoting some pretty significant dollars for their CNC Router and a CNC Mill is typically starting around $80,000.00. So, exactly how many fins were you planning on making?

Tomadaum, I 've done an APS3000 board, it was good, the machine does exactly what you tell it to and I finished the shape in 15 mins. Check www.speedneedle.com.au - shortboard No. 12

Anyway, I’m interested in the CAD design of fins because I’ve come across a readymade building material which is the same thickness as FCS slots, lightweight and impossibly stiff… I would handfoil more prototypes but one set took hours as its aluminium.

How many fins? When I design the new box/plugs I visualise, and the foils, well, as many as I find demand for, with an engineering shop who I spoke to. They have the CNC machines and propose that its possible if I give them files. So…while I appreciate that guys with professional engineering setups pay serious money for these programs, as a shaper with ideas, I hope someone will offer up a pirate…

Thanks for your response.

Josh

I have messed around a little with CAD designing fins but havn’t had much luck. I can draw most of it, but the tip of it is hard to get to blend out smoothly.

Anyway I imagine most machined fins are scanned in hand shapes. Probably wouldn’t cost too much to get them scanned.

We originally scanned all our fin masters. But, I’ve got a sweet stereo lithography model sitting on my desk right now of an 80/20 fin foil I generated utilizing NACA formulas for the foil cross sections. We’ll be cutting cavities as soon as we finish machining the inserts.

Hey guys I appreciate the response. all of it gives me clues on the way to producing these fuckers. There must be programs to do it! All the existing plastic molded fins such as FCS must have a milled prototype which the mold is made from. Maybe, maybe fins such as FCS begin as a handfoil from which molds are made, but then those tabs have to be machined…and what of On a Mission, now surely that base isn’t handmade?

Making glass FCS fins isn’t that tough.

Quote:
Maybe, maybe fins such as FCS begin as a handfoil from which molds are made, but then those tabs have to be machined...and what of On a Mission, now surely that base isn't handmade?

I seriously doubt they start with a handfoil. It’s like Tom said above, they use a program like MasterCam to design the mold for injection molding. They might start with a 3D design program like Rhino, but they eventually will have to use a milling program to generate the toolpaths. The plastic fins are injection molded and the molds have to be made out of steel. Theoretically, they could be made out of anything, even wood, but they wouldn’t last very long.

On the other hand, there is no reason why you couldn’t machine fiberglass sheet into fins using a CNC mill. But you will still need to use a program that generate the toolpaths. MasterCam is probably the most widely used in the machining world, but there are others. I use VectorCam, which is quite a bit cheaper than MasterCam. It think it will be nearly impossible to “acquire” a copy of one of these programs, because most of them are dongle protected.

Hi Speedneedle,

                    Your idea's are O.K. but you don't need to go hightech to make F.C.S. I to use to think along the same lines 

but came up with a system were we produce between 30/40 sets per day and have a range of six templates MR-X,G3,G5,TC

K-FINS,YU. And a TC with an 80/20 foil these are great for channel boards in smaller waves plus keel,mal and paddle board

templates all core filled and lite i.e. mal 7.5 only 150 grams.

So you can do great things with out spending all your dollars

just think outside the square.

                                    Regards Rod.

www.bobcad.com is where you find what you need, you can even download a demo version. I personally prefer to design in Rhino and import into Bobcad as it has a CAM part. be prepared for a steep learning curve, follow your dream, ignore the obstacles and Bob’s your uncle.

Hey is that the Langenbach?! How are you Mis-Tah!!!

I reckon your tip on the CAD program is the hot news, thanx again!

I seriously doubt that they don’t start with a hand foil, for most fins at least. I am sure more and more fins will be completely cad designed. But for now I’m sure that Al merric(or whoever) sends FCS a fin and they duplicate it.

Basically here is how to do it. take a hand shaped fin that has proven to work. Digitize or 3D scan the fin into the computer. Take the scanned surfaces into a CAD program and draw the tabs or base on it. In the CAD program create a 3D model of the mold. Take the 3D model into a CAM program, like MasterCAM, toolpath it and machine it.

3D Scanning/Digitizing is cheap.

If you take a fin and use it to cast a mold, you are old school.

If anyone has CAD designed a fin I would love to here how they did it. I drew and machined one a few years ago but there was an area on the tip that had to be foiled a bit by hand still. Machined it out of G10, worked well but don’t know what happened to it.

Droptrow,

   The method you refered to is exactly how we cut all the first generation Red X fin cavities. The digitizer used CadKey to generate the surfaces from their point cloud data. Before that method alot of molders would hand shape EDM electrodes from carbon or copper and burn the fin cavities in. I'm currently using MasterCam to generate the entire fin geometry and the surfaces are coming out cleaner than any surface model we've had to date. In injection molding you're dealing with injection pressures of 20,000 psi and clamp pressures in the 110 ton range. With high filled materials we have to use steel molds. You can cast or Resin Transfer method mold fins from a urethane cast mold. But, I haven't done any hands on mold casting.

Let me clarify. He was asking if plastic fins could be made from a mold cast from a prototype and then just have the tabs machined. But I was explaining that injection molded fins require a machined steel mold.

Without a doubt, fins (or anything else) can be scanned to use the data to make a CNC machined mold.

Any Nurbs-based software, like Rhino, will make fin design effortless.

I have mastercam, how do you draw the fin in Mastercam? Basically how do you get the curved surfaces? Loft? I don’t do much drawing in Mastercam, I use Solidworks for drawing and Mastercam just for toolpathing.

E-mail me and we’ll talk about it. tom@daumtooling.com

about twenty years ago, an austrian named Bernhard Brandstaetter started a CAD fin business on Maui with a little 3 axis router as used in schools and universities (see google for Isel for example). with his Nacra based profiles he changed the sailboard world, at some time supplying his fins to over 90% of the world cup sailors. most importantly he introduced the sailboard world to the importance of the little thing sticking out of the board which started a revolution in rigg design and later in board design.

the system he used was very basic and not very fast but precise and many of his fins became the originals for the moulds. with this new technology the world speed record went up by about 10 knots in one hit and the impact on the sport was comparable to Simon Andersons thrusters. later the technology was improved by advanced moulding technology with different flexing resins at different parts of the fin and high tech materials and “constructive” layups in the mould. its a long way, will be good fun…

I am an engineering student at Maine Maritime Academy, and a surfer from San Diego. For a CAD class we were assigned a project either designing a hull or tooling. I chose the hull, and am sneaking a surfboard in. I can do basic hulls on KeyCreator (CADkey 21) and Pro lines using points and splines, but I’m not sure how to do surfboard hulls with concaves. We have a CAM setup here, thru a local yacht boatyard, so if I design it, I most likely can get it made, and fine tune it over the long winter. Is there someone out there with an old CADkey file, or maybe somewhere I can look to get this project going?

did you ever have any luck with this one speedy?

i have been trying to get my head around rhino lately for some fin prototypes… anyone have a fin file they can lend me to pull apart and see how its done?