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Comment by kenjackson | Hacker News Reader

If this impacts the total time to make each car, wouldn't that impact your production volume? It seems weird that something that should make you slower is what allows you to hit your target? Unless they're saying the target doesn't take this into account -- which would just seem stupid.

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I think what it means is that they gave up on correcting the automation process in favor of just pumping out cars and fixing them up manually. The former having longer-term benefits, but stalling car production until its complete. In other words, they just threw more bodies at the problem to get it out asap

If your production line has 10 machines that break the car windscreen, the long-term most efficient thing would be to fix those 10 machines.

But that'll take time, and in the short term putting a guy at the end of the line replacing all the windscreens gets cars out the door today.

Classic case of throughput (i.e., how many cars are completed per month) v. latency (i.e., how long it takes one car from start to end) — the targets are almost always about throughput and not latency.

I think the title "Tesla hit Model 3 target by reworking thousands of cars" should be read as "Tesla hit Model 3 target by not only producing the cars, but also reworking them in time".

It's confusing, I prefer the article's headline "Internal documents reveal the grueling way Tesla hit its 5,000 Model 3 target" (the submission title is from the URL)

I'm wondering if what they're saying is that there was a large enough quantity of to-be-reworked assemblies from a prior week that reworking them and calling them done gave them enough "completed" vehicles to put them over the target for a later week.

It's not that it affected the time to make each car, it's that a large majority of the cars needed to have some issue addressed after they were manufactured (86% according to the article).

Tesla was always accused of some chicanery when they claimed to hit a 5000/week of "factory gated" cars -- a term they had never used before. Also, last quarter, they had more than 10,000 cars "in transit" between the factory and delivery, which they didn't fully explain how much re-work might be needed on before a customer can accept delivery. It's part of a pattern of a company being misleading with its metrics.

Rework can happen in parallel with production, so it won’t necessarily affect your rate.

It definitely affects labor productivity.

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