Comment by csours | Hacker News Reader

Comment by csours | Hacker News Reader

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Disclaimer up front: I work for a Tesla competitor.

People believe funny things about Tesla and Elon.

But before I talk about that, let me say: I've been extremely impressed with Tesla and Elon for their ability to eventually deliver, and to build unparalleled excitement around electric vehicles.

I believe Elon is truly a visionary.

Now for the funny things:

1. You can throw money at problems to fix them: If you do this you end up with a 1980's Jaguar - lovely and fast and fun, but unreliable, and overly expensive, and your competition will eat your lunch.

2. Tesla shouldn't be graded on cars or car production, they are an X company (X= software, technology, etc): Whatever kind of company you think Tesla is, right now they make cars and that's all you can grade them on right now. If you want to make a bet about the future, go for it, but realize that it is a bet.

3. Automation will solve this: GM spent about $60 Billion on advanced automation in the 1980's because they could not believe that Toyota was building cars at the cost and quality with human labor (this is a gross simplification). 10-15 years later, GM basically adopted the Toyota Production System. It may be possible to build quality cars in a cost effective manner with near 100% automation, but I do not believe it is possible to build them BECAUSE OF automation. You must have a good quality process first. Elon's previous comments about having a bed near the end of the production line rings alarm bells for anyone who has been in manufacturing. You cannot inspect your way to quality.

> You cannot inspect your way to quality.

I have to emphasize the sentence you ended your comment with. Anybody who has worked in volume production has heard this phrase too many times to count.

People who never learned the difference between QC and QA never seem to understand this phrase either. Doesn't mean they are dumb, but does mean they don't even understand the scope of what they don't know.

Another common misunderstanding is the dynamics of the learning curve. Costs of high volume production drop precipitously (and quality typically increases proportionally as well) but incrementally as volume goes up. A common misunderstanding is that that means you work incrementally to get better. But that is true for systems set up from the start as high volume systems. Tesla the company has been at it for almost 15 years (Musk has been there for 13 of them) and still appears to be in low volume manufacturing mode.

It's not super surprising when you consider that Space X makes small volume, bespoke hardware. A big backend system is still a one-off even if you run huge volume through it. Cars, phones, etc are a completely different game.

> People who never learned the difference between QC and QA never seem to understand this phrase either.

Can you please explain the difference?

QC means you don't sell duds, you test them, if they fail you don't send them for sale.

QA means you make sure that products aren't duds, you do that by finding what causes the failed products to be made and fixing it.

Meta: The focus on QC instead of QA brings to mind the UK government approach to education, adding more tests instead of using the time/resources devoted to tests to educate the children.

You need both; they serve different functions. QA is choosing to use flame-retardant material; QC is installing a fire alarm.

QA addresses your process, from repeatability (e.g. ISO9000 in the cases where it makes sense -- less often than it is used, but sometimes it's crucial), incoming materials inspection, choosing processes that error in directions you want (should you mill material away from a billet, potentially taking not enough, or cast and potentially have the part shrink? Some systems can handle a too-small part better than a too-big one; other systems are the opposite) etc.

QC can be thought of output validation (i.e. testing, which is a lot of it): are my products of the necessary quality/within spec etc? Sometimes you can do 100% inspection, sometimes you have to use statistical methods (there are whole ISO specs devoted to nothing but sampling algorithms).

If you are not clear in your mind about the differences, the jargon can confuse you more (e.g. incoming materials inspection is sometimes referred to as "incoming QC"). But from this you can see why you "can't test your way into quality": the tests happen too late in the process.

QA is like linting, having a style guide, having a strong type system and so on.

QC is looking for bugs for in the usual suspects for every output and fixing them as you discover. This can be automated and/or manual.

I am not they, but QA is process oriented and QC is product oriented. How you do it vs. what the results are.

QA is defect prevention. QC is defect detection and removal. If an activity causes rework then it's QC, not QA.

QA is about how you work to ensure you build a quality product QC is about the tests you do to ensure a quality product has been built.

Etymologically, Quality Control implies some sort of feedback. Quality Assurance merely implies a filter at the end of some process.

Interestingly, your inference is almost opposite to the commonly accepted definitions.

That's really interesting and quite counter-intuitive to me!

Actually QA applies from the beginning of the process while QC is the check.

QA is checking that your output is good.

QC is making sure that your output is good before it gets to QA.

It's actually the reverse.

Either you or I have it back to front.

Just to 3

Unknown to analysts, investors and the hundreds of thousands of customers who signed up to buy it, as recently as early September major portions of the Model 3 were still being banged out by hand, away from the automated production line, according to people familiar with the matter.”

https://www.wsj.com/articles/behind-teslas-production-delays...

> major portions of the Model 3 were still being banged out by hand

Reminds me of some other automotive companies when a new car is launched..

Good to see "do things that don't scale" being applied to the very definition of things that need to scale.

I feel the need to correct the record. You do the things that don't scale in order to better realize/appreciate where to put the effort to fix them. Tesla has the equivalent of an mvp/poc production line. You'd be kidding yourself if you think they're not improving it every minute. And you know the improvements they're making are the ones with the biggest impact, in that exact order of priority.

If you try to make the perfect assembly line before you deliver 1 car, you'll be making huge over-engineering expenditures and costly assumptions which result in even greater net production losses.

> still being banged out by hand, away from the automated production line, according to people familiar with the matter.”

The press is up and running:

https://www.instagram.com/p/BaInXGBg9G7/

Based on a 3.7 second cycle time, they can bang out 5,837,837 body panels per year (assuming some math an automotive engineer on /r/teslamotors provided that takes into account downtime and typical automotive labor scheduling: 50 weeks/year * 5 days/week * 24 hours/day * 3600 seconds/hour)/3.7 second panel cycle

EDIT: csours: Thanks! I removed my grossly inaccurate prediction of per-vehicle pressed components.

in_cahoots: Original response was to comment that Tesla is still banging out components by hand; this is possible, my rebuttal is that they do have parts of the line that are fully operational.

I’m not sure how this is relevant? Production is only as fast as its slowest component; it doesn’t matter if you can bang out a billion body panels per year if you don’t have enough human labor to put the pieces together.

6 is much too few. You have floorpan, roof (even if the roof is glass you still have to hold it), hood, liftgate/trunk, each door inner, each door outer. Thats 12 big ones, then all of the little ones that stiffen the big ones, and the other little ones that make things like the door pillars. There's probably like 70 stamped metal parts in all.

There are probably a number of press lines and the press lines would be changing dies periodically to make different parts.

That's what stamping looks like. Here's Subaru banging out car doors.[1] About the same cycle time, using automated loading and unloading.

[1] https://youtu.be/r9byGJtbCws?t=63

”You cannot inspect your way to quality.”

Exactly.

Once you understand (grok) this, a lot of efforts become obviously silly. Like standardized testing regiments for K-12 public education.

Source: Former QA/Test manager, back when we still pretended to care about quality, eliminating defects, reducing costs.

"2. [...] right now they make cars and that's all you can grade them on right now. If you want to make a bet about the future, go for it, but realize that it is a bet."

This. But the potential is huge compared to other vendors for being more biased to research than production. Other vendors are forced to keep time, people and money allocated to maintain their 19th century gas engines production while Tesla can use all its resources for new things. Having a lot of brain power devoted to new ideas will inevitably bring achievements in other fields, which won't necessary become Tesla products. A serendipitous discovery could lead to a patent for something they cannot produce or aren't interested in producing (say a new medical machine) but could license to others.

> Other vendors are forced to keep time, people and money allocated to maintain their 19th century gas engines.

GM had to sell 600,000 high-margin trucks to raise the same amount of funding that Tesla got from investors (VERY ballpark numbers). With those funds, GM also had to invest in over 30 assembly plants around the world and 12 or so product launches, not including engine and transmission programs.

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