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It means not carrying needless excess work-in-progress that cannot be delivered to the customer but may very well go stale or never be sold at all. This is a b

by mpyne 5y ago

It means not carrying needless excess work-in-progress that cannot be delivered to the customer but may very well go stale or never be sold at all. This is a balance point, not an optimization problem where you're supposed to go to the extreme. In fact, one of the books that popularized Lean manufacturing, Eli Goldblatt's "The Goal", explicitly makes the point throughout the book that making work centers within a plant locally optimal will cause your overall operation to fail to deliver efficient outputs. To make global efficiency improvements you have to accept that individual work centers may be inefficient. Rather, just like a developer optimizing their software program, you need to look at your entire organization and find where the actual bottlenecks are, and improve those specific bottlenecks, potentially by running "inefficient" (but non-bottlenecked) work centers to assist the teams that are the current bottleneck. And then as you change things you'll have to be willing to address a different bottleneck. Moreover, unavoidable variances (which the book describes in a story about a Boy Scout camping trip) means it will be potentially disastrous to 'optimize' even your critical path, just like you wouldn't want a network router to be consistently near max capacity.

Aeolun 5y ago
So it’s like Factorio? If you accidentally fuck up your critical path you suddenly find that all your production dies.
- mpyne 5y ago
  I've studiously avoided Factorio because I don't need to get hooked on any more video games, but yes it's about thinking of your organization's workflow in terms like a critical path (Goldblatt would describe 'critical chain' in a later book), and then discovering where your bottlenecks are. To be honest I would recommend a separate book for software practitioners, Reinertsen's Principles of Product Development Flow, because it gives you methods to look at which are more applicable to creative work where you can't easily turn your work into "production lines" to then use Lean manufacturing/JIT principles on. Either way none of this works if you let every local work center just produce produce produce up to its peak output or most efficient point. At that point it becomes impossible to find the bottleneck because there are so many bottlenecks (including bottlenecks not on the critical path). That's a key reason why all the methods (Goldblatt, Reinertsen) focus on reducing the amount of work-in-progress and reducing batch sizes of each individual work package or work item.
jjk166 5y ago
> needless excess work-in-progress that cannot be delivered to the customer but may very well go stale or never be sold at all. And what exactly is a big stockpile of raw materials and components that aren't intended to be delivered to the customer under normal circumstances?
- mpyne 5y ago
  "Inventory" (ideally), "Overhead" or "Waste". Raw materials can at least be resold in concept, but half-assembled gear (i.e. "work-in-progress") can easily end up in a sort of parallel universe where it's not easily sold without the additional investment of time and effort (either to break it back down into components or finish it for sale) but you have to pay each month to maintain it properly until it can be finished. It's important to remember that in traditional manufacturing at the time, each work center wasn't graded on its ability to contribute to customer sales, they were graded on things like local efficiency on a per sub-assembly basis. The "customer" wasn't the end user, the "customer" was the plant manager or the PMO or some other stand-in. The work centers were structured around functional tasks like "heat treat" or "machining" rather than an end user product, so your "high priority" customer product had to make it through multiple independent backlogs before it could be shipped, even in theory. God forbid rework would be needed! Quality issues were the job of customer service to address, not the work center that introduced the defect (as after all, it might be years before the sub assembly finally ends up in a user's hands).
jiveturkey 5y ago
> one of the books that popularized Lean manufacturing, Eli Goldblatt's "The Goal", Turns out it's Goldratt. Very difficult to read as it is in the form of a melodrama. I suppose the point was to make it light reading, but to me it's a difficult slog through the protagonist's personal life to get to the data I want.
- mpyne 5y ago
  Thanks for the correction. You're right, the point is to make it easier to approach for business minded readers (his son even recently got someone to turn it into a graphic novel). Same tradition later picked up by Unicorn Project and Phoenix Project by Gene Kim.

by mpyne 5y ago

Aeolun 5y ago

So it’s like Factorio? If you accidentally fuck up your critical path you suddenly find that all your production dies.

mpyne 5y ago
I've studiously avoided Factorio because I don't need to get hooked on any more video games, but yes it's about thinking of your organization's workflow in terms like a critical path (Goldblatt would describe 'critical chain' in a later book), and then discovering where your bottlenecks are. To be honest I would recommend a separate book for software practitioners, Reinertsen's Principles of Product Development Flow, because it gives you methods to look at which are more applicable to creative work where you can't easily turn your work into "production lines" to then use Lean manufacturing/JIT principles on. Either way none of this works if you let every local work center just produce produce produce up to its peak output or most efficient point. At that point it becomes impossible to find the bottleneck because there are so many bottlenecks (including bottlenecks not on the critical path). That's a key reason why all the methods (Goldblatt, Reinertsen) focus on reducing the amount of work-in-progress and reducing batch sizes of each individual work package or work item.

jjk166 5y ago

> needless excess work-in-progress that cannot be delivered to the customer but may very well go stale or never be sold at all. And what exactly is a big stockpile of raw materials and components that aren't intended to be delivered to the customer under normal circumstances?

mpyne 5y ago
"Inventory" (ideally), "Overhead" or "Waste". Raw materials can at least be resold in concept, but half-assembled gear (i.e. "work-in-progress") can easily end up in a sort of parallel universe where it's not easily sold without the additional investment of time and effort (either to break it back down into components or finish it for sale) but you have to pay each month to maintain it properly until it can be finished. It's important to remember that in traditional manufacturing at the time, each work center wasn't graded on its ability to contribute to customer sales, they were graded on things like local efficiency on a per sub-assembly basis. The "customer" wasn't the end user, the "customer" was the plant manager or the PMO or some other stand-in. The work centers were structured around functional tasks like "heat treat" or "machining" rather than an end user product, so your "high priority" customer product had to make it through multiple independent backlogs before it could be shipped, even in theory. God forbid rework would be needed! Quality issues were the job of customer service to address, not the work center that introduced the defect (as after all, it might be years before the sub assembly finally ends up in a user's hands).

jiveturkey 5y ago

> one of the books that popularized Lean manufacturing, Eli Goldblatt's "The Goal", Turns out it's Goldratt. Very difficult to read as it is in the form of a melodrama. I suppose the point was to make it light reading, but to me it's a difficult slog through the protagonist's personal life to get to the data I want.

mpyne 5y ago
Thanks for the correction. You're right, the point is to make it easier to approach for business minded readers (his son even recently got someone to turn it into a graphic novel). Same tradition later picked up by Unicorn Project and Phoenix Project by Gene Kim.