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Comment by bambax | Hacker News Reader

> CNC machining is fantastic for prototypes [but] it is not for consumer devices. Figure out a way to cast your metal parts.

Why is that?

I'm trying to build a better quick release plate for DSLR cameras, compatible with Manfrotto tripods but that lets you do a couple of other things (like attach a hand strap to it directly).

I had prototypes made in China with CNC machining, and they are of a very good quality (superb, even, it seems to me).

For production, injection molding is of a reasonnable price but the result would not be the same quality (plastic is a poor choice for this).

Die casting is too expensive for the volume, given it's really a niche product.

So I was thinking of doing short runs with CNC: what' wrong with that option?

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There's nothing wrong with CNC for that type of product, and it is necessary as well. Many of the higher-end products in that market use nearly 100% CNC, whereas lower-end mix casting and CNC.

I'm not sure the quoted statement is fully correct, CNC and Casting are processes and each have advantages as well as capabilities the other cannot easily replicate. (Try casting threaded holes -- there are ways to add threading to a casting process, but it's not the same.)

I think the original quote intended to convey the following idea, instead of never CNC: if you have a high-volume product, while CNC machining can effectively handle shaping operations, casting will be less expensive for shaping in the long run, leaving CNC to more difficult to cast operations and final product fit.

In the camera market, there are tons of companies selling equipment in thousands and tens of thousands of units that are fully-CNC'ed and no casting. (See Kessler, Dynamic Perception, CamBLOCK, etc.)

The problem is people build a little widget that would happily fit in a box from Hammond, but they would rather have it customised at great expense and it eats into their profit. CNC is pretty time inefficient and expensive when you get to very large volumes.

The major advantage of CNC though is that if you mess up the first time, you haven't ruined an entire batch. You just send the new model to the company. With molding or die casting, fuckups can easily cost tens of thousands.

If your margin can absorb the cost of CNC - and for photography it's probably a marketing feature - go for it. Plenty of companies sell CNC machined housing simply because they can say it's CNC'd and people go "ooooh".

Oh okay, so it's just a volume thing?

Does it make sense to do metal casting for low volume (under 1k)? It would be economic nonsense anyway...?

I'm mostly familiar with plastic molds, but for durable/production ready molds, you're normally starting off at like 20k per mold. You can usually bring your part to manufacturers (both CNC and casting shops) and ask for some quotes.

Have you looked at Really Right Stuff and Kirk Enterprises, they are machining the parts you are making, basically a sick release plate. But they are now ubiquitous enough that I would hate to see yet another quick release style. Never been a fan of the large ManFrotto/Bogen style. Take a look at the two aforementioned, I think they take a cue from Arca/Swiss, and are some of the nicest designs in quick releases that I have seen.

Thanks for your comment but why would you "hate" to see another design?

We're not creating a whole new system, just an alternative. And as a start we will be Mamfrotto compatible only, since that's what we use. I could be wrong but Kirk doesn't do Manfrotto at all.

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