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> What happened when Apple wanted to CNC machine a million MacBook bodies a year? They bought 10k CNC machines to do it. That can’t be right. 1M / 10K = 100 Ma

by rlt 4y ago

> What happened when Apple wanted to CNC machine a million MacBook bodies a year? They bought 10k CNC machines to do it. That can’t be right. 1M / 10K = 100 MacBooks per CNC machine per year. Surely it’s at least an order of magnitude or two off?

rjzzleep 4y ago
Sounds like something a friend told him, who heard it somewhere. I'd be interested in the real story and the real numbers behind it as well.
paulsutter 4y ago
Apple sells hundreds of millions of iphones per year with CNC cases, and does indeed use tens of thousands of CNC machines The real problem with the point in the article is that it’s easy to get CNC work done
- rlt 4y ago
  Maybe true, but I was doubting the specific numbers of 10K CNC machines for 1M MacBooks. I’m curious how long it takes a single CNC machine to machine a MacBook body.
  - hef19898 4y ago
    I didn't see a naked body, but I'd guess max. one hour including polishing of the visible surfaces (and that is on the upper end, because you put more than one body in the jigs). Edit: The tact time per casing is somewhere around 30 seconds (assuming 24/7 operations). Which is absolutely doable, not just for apple but for everyone with a demand of 1 million units per year for the same part.
    - Retric 4y ago
      I have read 10 hours per Mack book initially split across multiple machines, but I don’t know how accurate that was. Or if that was adjusted for scrap rate and downtime etc. Presumably they wanted to create rumors to improve peoples perception of quality. On the other hand it’s several fairly large complicated parts and their removing a lot of material from the blanks.
      - hef19898 4y ago
        Difficult to tell without having the naked housing parts, or ideally the drawings. 10 hours is more in aerospace territory so, if it really is that, something seems a bit of. But you never know, some designers come up with the strangest ideas.
  - deleted 4y ago
    [deleted]
- hef19898 4y ago
  Dead easy, especially in Southern Germany there are littetally thousands of small, independent CNC shops doing nothing but sub-cobtracting work for everything from cheap, rapid prototyping to serial parts, visible and not, for Premium automotive OEMs. And all of those are happy to get your start-up scale CNC part contracts. Get a good one, and they will even tell how to improve your part design to make it easier and cheaper to manufacture.
  - dalbasal 4y ago
    Know any good ones?
schuke 4y ago
Seems more realistic when the K is put on the other end of the equation?
Retric 4y ago
The original quote was it would take thousands of CNC machines do do X and apple saying that’s fine. 2k machines to make 200k laptop bodies for an initial sales rush over a month is 3.3 laptops per day per machine but each laptop uses multiple parts front and backplate for top and bottom. Assuming 4 major components per laptop and 5 different CNC machines per component you might be at say 3.3 * 4 * 5 = 66 parts per CNC machine per day. Which doesn’t sound that far off when they are discarding such a large percentage of the initial blank, though it’s likely some stages are much faster than others. The equipment would be extremely expensive, but it’s also going to last for a long time.
hjnilsson 4y ago
There was a dearth of CNC machines on the market back in 2011-2012 due to Apple buying so many (via Foxconn, https://appleinsider.com/articles/11/10/21/catcher_hoping_to_reopen_chinese_macbook_unibody_case_plant_in_november https://appleinsider.com/articles/11/10/21/catcher_hoping_to... ). But they were shared for iPhone production etc. This is the source for the 10 000 machines number. I however recall that they claimed in a keynote it took 10 hours to machine a single unibody MacBook, which would make the capacity for a single machine about 700 cases a year.
- fmajid 4y ago
  Plus they need to ramp up production quickly to have sufficient inventory at launch time, so overcapacity is inevitable.
quartesixte 4y ago
You’re assuming 0% scrap rate, and discounting setup time, teardown time, general down time. Also, most likely they don’t run them for a full year. They need 1mm Macbooks in a window of a few months. In which case, 10,000 machines making 100 macbooks each makes sense. Edit: also, this is assuming every machine is the same machine doing the same thing. Which most likely is not (unless the unibodies are made in one go on a 5-axis mill)

by rlt 4y ago

rjzzleep 4y ago

Sounds like something a friend told him, who heard it somewhere. I'd be interested in the real story and the real numbers behind it as well.

paulsutter 4y ago

Apple sells hundreds of millions of iphones per year with CNC cases, and does indeed use tens of thousands of CNC machines The real problem with the point in the article is that it’s easy to get CNC work done

rlt 4y ago
Maybe true, but I was doubting the specific numbers of 10K CNC machines for 1M MacBooks. I’m curious how long it takes a single CNC machine to machine a MacBook body.
- hef19898 4y ago
  I didn't see a naked body, but I'd guess max. one hour including polishing of the visible surfaces (and that is on the upper end, because you put more than one body in the jigs). Edit: The tact time per casing is somewhere around 30 seconds (assuming 24/7 operations). Which is absolutely doable, not just for apple but for everyone with a demand of 1 million units per year for the same part.
  - Retric 4y ago
    I have read 10 hours per Mack book initially split across multiple machines, but I don’t know how accurate that was. Or if that was adjusted for scrap rate and downtime etc. Presumably they wanted to create rumors to improve peoples perception of quality. On the other hand it’s several fairly large complicated parts and their removing a lot of material from the blanks.
    - hef19898 4y ago
      Difficult to tell without having the naked housing parts, or ideally the drawings. 10 hours is more in aerospace territory so, if it really is that, something seems a bit of. But you never know, some designers come up with the strangest ideas.
- deleted 4y ago
  [deleted]
hef19898 4y ago
Dead easy, especially in Southern Germany there are littetally thousands of small, independent CNC shops doing nothing but sub-cobtracting work for everything from cheap, rapid prototyping to serial parts, visible and not, for Premium automotive OEMs. And all of those are happy to get your start-up scale CNC part contracts. Get a good one, and they will even tell how to improve your part design to make it easier and cheaper to manufacture.
- dalbasal 4y ago
  Know any good ones?

schuke 4y ago

Seems more realistic when the K is put on the other end of the equation?

Retric 4y ago

The original quote was it would take thousands of CNC machines do do X and apple saying that’s fine. 2k machines to make 200k laptop bodies for an initial sales rush over a month is 3.3 laptops per day per machine but each laptop uses multiple parts front and backplate for top and bottom. Assuming 4 major components per laptop and 5 different CNC machines per component you might be at say 3.3 * 4 * 5 = 66 parts per CNC machine per day. Which doesn’t sound that far off when they are discarding such a large percentage of the initial blank, though it’s likely some stages are much faster than others. The equipment would be extremely expensive, but it’s also going to last for a long time.

hjnilsson 4y ago

There was a dearth of CNC machines on the market back in 2011-2012 due to Apple buying so many (via Foxconn, https://appleinsider.com/articles/11/10/21/catcher_hoping_to_reopen_chinese_macbook_unibody_case_plant_in_november https://appleinsider.com/articles/11/10/21/catcher_hoping_to... ). But they were shared for iPhone production etc. This is the source for the 10 000 machines number. I however recall that they claimed in a keynote it took 10 hours to machine a single unibody MacBook, which would make the capacity for a single machine about 700 cases a year.

fmajid 4y ago
Plus they need to ramp up production quickly to have sufficient inventory at launch time, so overcapacity is inevitable.

quartesixte 4y ago

You’re assuming 0% scrap rate, and discounting setup time, teardown time, general down time. Also, most likely they don’t run them for a full year. They need 1mm Macbooks in a window of a few months. In which case, 10,000 machines making 100 macbooks each makes sense. Edit: also, this is assuming every machine is the same machine doing the same thing. Which most likely is not (unless the unibodies are made in one go on a 5-axis mill)