[Harp-L] 3D printing and carbon fiber as springs

[Tom Halchak <thalchak@xxxxxxxxxxxxxxx>]

The subject of 3D Printing came up just yesterday on MBH. As one who owns a comb making business I took the bait and did a little research. I found a local 3D Printing company and emailed them CAD plans for a Hohner MS-Series comb. 

A "Sales Engineer" named Chris got back to me very quickly and we had a pleasant conversation. Bottom line. To get a prototype made out of ABS plastic costs $100. That's not too bad. But bear in mind that I already have the CAD files, which would be an additional expense for most of you. If I got 100 combs made the cost would be $25 each, which is considerably higher than the cost of CNC milling. The cost of CNC Milling and 3D Printing are both a function of two things: material cost and machine time. One advantage of 3D Printing is that it takes no more time to print an intricate design than it does a simple flat comb (assuming they are the same size). So it is conceivable that 3D Printing a comb such as a Special 20 could be cheaper than milling it. But that's plastic.  A stainless steel prototype would cost $700. So to go through the expense of creating the CAD plans for a Special 20 and then have them 3D Printed for $25 each only to wind up with an ABS plastic comb that would essentially be the same (albeit a better version) of the stock comb is totally impractical. At this point I would consider a 3D Printed comb little more than a novelty item. 

Finally, with regard to carbon fibers being used as a spring, my other passion is golf. Graphite (carbon fiber) golf shafts have bee on the market for over 40 years. A golf shaft is most definitely a spring. Golf shaft manufacturers have become very skilled at producing shafts with the exact flex (stiffness),  kick point (where does it flex) and torque (resistance to twisting) that they want. I think harmonica reeds are doable. 

Tom Halchak 
www.BlueMoonHarmonicas.com

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