Comment by hef19898 | Hacker News Reader

Comment by hef19898 | Hacker News Reader

>> CNC machining at scale CNC machining is fantastic for prototypes and pretty awesome for high margin parts like hip implants and turbine blades. It is not for consumer devices. Figure out a way to cast your metal parts.

Having a manufacturing back ground, I did extended workbench management early in my career, this is just wrong. Sure, at high volumes casting and injection moulding is unbeatable at per unit costs. At smaller volumes, not so much. Casting and moulding tools cost a fortune, and those upfront NRC are just prohibitive for small volumes. So smart CNC machining it is. Added benefit, there are tons of small CNC machining ships around that are really good at that.

Nothing to add on ejector pin marks, if you see those on the outside of your part, your part design and manufacturing / tool design sucks. No need to be a billionaire genius, just a decent plastics engineer.

But since the target audiamce of this article are start-ups, it kind of makes sense, doesn't it? Brcause how many start-up founders have a solid grasp of hardware manufacturing, design, tooling and manufacturing processes? Especially those that want "Apple" without understanding what that means deffinitely don't.

It stood out to me that the author of the post is the COO at a meditation service start-up, not a manufacturing one... Unless Ten Percent Happier is making physical products that I'm unaware of.

I think this guy was just musing about Apple's quality and has watched a lot of AvE and This Old Tony on YouTube and wanted to share his opinions with the world. They're not all entirely correct.

For anyone who wants to go on the whole manufacturing journey, don't miss the Linus Tech Tips video about why their screwdriver took 3 years to bring to market (https://www.youtube.com/watch?v=2K5Gqp1cEcM). And they based their design on a fully functional production-ready screwdriver, they did not start from scratch.

Going from idea to production is really, really hard. Even today, even with CNC and 3D printing and other prototyping tools. Even with all the money LTT has to spend on it (millions of dollars, as I understand it).

> It stood out to me that the author of the post is the COO at a meditation service start-up, not a manufacturing one... Unless Ten Percent Happier is making physical products that I'm unaware of.

The guy started bolt.io. A VC for hardware based startups and got $100 million funding. So I think he knows a thing or two about manufacturing.

He knows a thing or two about getting money to fund hardware start-ups. Which is something different.

The assumption that the people that get growth-hungry “investors” to splash the cash in a cheap-money environment is what makes this a cycle.

To give him the benefit of the doubt, he seems to be writing to people wanting to make small electronic gadgets. You can't sell something for $19.99 retail that requires a lot of hands-on time.

At a quick scan, Bolt.IO includes "Carbon Robotics - Building intelligent robots for agriculture-related applications", "Denizen - Personal prefab offices...", and "Spyce - An original restaurant concept featuring a robotic kitchen that cooks and serves delicious meals". I guarantee those robots, office furniture, and kitchens contain CNCed parts, if not hand-fitted parts.

On the other hand, he also wrote "What happened when Apple wanted to CNC machine a million MacBook bodies a year? They bought 10k CNC machines to do it." If a CNC machine can't make more than one piece every 3.5 days, you're either building aircraft or you're doing it wrong.

You need experience, and hands-on approach.

"3 years, and millions of dollars" — is very typical when you keep going from factory, to factory, leaving tooling investment every time they screw up.

Instead, you have to pick at least a sane, and understanding factory owner, and wait for them to improve.

>I think this guy was just musing about Apple's quality and has watched a lot of AvE and This Old Tony on YouTube and wanted to share his opinions with the world. They're not all entirely correct.

IDK what the author's qualifications are but the ones you list would make him at least as qualified as whoever's "simple but wrong" take on a problem is thrice guided on Reddit or at the top of HN at any particular minute.

The reality is that if you wanna write "popular" context you gotta cater to a low common denominator, maybe not the lowest but you will have to stare deep into the abyss of ignorance and hubris to find it. A nuanced take that will pass the muster of a subject matter grey beard is going to be too nuanced, too informed by 1st/2nd hand experience and physical reality to resonate with the hordes of casual readers it needs to resonate with in order to gain any traction. Regardless of the qualifications of the author the content MUST be dumbed down to the point of being useless to anyone with the problems discussed therein in order to resonate with the audience it needs to resonate with for it to gain enough traction for us to be talking about it here (and frankly it's a lot easier to write that kind of resonating content from within the abyss than looking in above it).

I'm not really in the mood to write a sufficiently internet-nitpicker-proof wall of text but this sort of content where people opine on things of which their depth of knowledge is only a hair deeper than that of the casual or create content from that perspective despite being smarter than that is highly, highly incentivized by how we have set up the platforms and information flows that control where/how entertainment content (like a blog article or a video) gets dolled out to people seeking to consume such content.

The partially blind leading the blind then?

The legally blind leading the blind in practice.

> Casting and moulding tools cost a fortune

It depends very heavily on the complexity and size of the part.

Earlier in my career I worked in Medical/BioTech product development for a consultancy working with startups. We found the most cost effective route (in the UK) was to have tooling manufactured in China, but then shipped to the UK. We worked with moulding companies who had in house experience building and modifying tools, so they could make alterations to the tools on site.

Tooling for small plastic "clam shell" type products would be in the £20k-£50k region by doing it that way.

Being able to visit your manufacturing partner, as a small startup, is essential when launching a product. Too often physical product startups try to run before they can walk. You can always ship a tool back to China once you are up and running, but realistically at that point you know what v2 should be and retooling is required.

I was OK with the section because includes "at scale", "consumer devices" and it ends with "Figure out a way to cast your metal parts." The advice is not wrong, just not complete. It would be better if it said "Machining might not be the best process, figure out the best way to make your parts -cast metal parts, use plate, sheet metal or simple extrusions, change metal for reinforced plastic, etc."

Based on my meager experience in this area (mostly having been involved in the mechanical keyboard enthusiast scene where there's a lot of small-batch [e.g. 50-5,000 units] manufacturing), the killer for CNC machining is the complexity of the shape being machined and the tolerances desired. A simple flat rounded rect is relatively easy/cheap, but if you go for a more 3D sort of shape with complex curves cost will go through the roof. It's similar with tolerances, with large margins being cheap and low being high.

It’s so easy to turn a cheap part into an expensive part!

The classic example, internal corners: Dimension them with convenient big radius and your feature needs a single pass with a big end-mill. Inadvertantly specify them “sharp” and suddenly it’s off for broaching (if you’re lucky) or maybe a custom EDM sinker tool.

For what it's worth the article is 8 years old. Has the CNC situation evolved since then?

If anything, it should have become better with improved machinery. Not sure what impact Covid had so...

Same experience here. When I needed to manufacture our product I quickly discover that casting at our scale would just ruin us financially. Meanwhile I shopped around and found very decent CNC deals. So CNC it was for me.

Even startups can hire manufacturing and industrial design consultants, then rent time at the same factories Apple uses.

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