Manufacturing and fabrication are two different worlds. Manufacturing is all about reducing/eliminating variance, whereas fabrication (high-mix, low volume) is all about absorbing variance. Most of the things we build have never been built before, and most of them will never be built again. So the estimates on how long it will take to build one is just that: an estimate. And the process of fabricating it is affected by MANY variables, but I'll just list a few. Materials with long lead times. Materials not arriving on time. Wrong materials sent. A pareto distribution of time it will take to finish an operation depending on which employee I give it to. What else is in the queue for an operation. Whether customers put a hold on the part. And so on, and so on.
Every manufacturing person I've met thinks we're just idiots. Then they come to our shop and it takes them about 1-2 years of trying to "we just need to implement Lean, guys!" before they realize that fabrication has very little, if anything, in common with manufacturing and the only lean principle that really applies is keeping your work area tidy and your tools organized.
Our business model is built around our ability to absorb and manage variance, rather than eliminate it.
I agree that software and fabrication have much more overlap with regard to challenges faced than software and manufacturing. Unfortunately, manufacturing gets most of the academic attention, so job shop scheduling has basically stagnated since the 70s, when academia started becoming aware of Toyota's innovations in manufacturing. Some work has been done using genetic algorithms to try to tackle the subject, but nothing substantive has taken hold in the industry.
That being said, I've found a few resources that help you start to get a handle on fabrication (and software development) and how to manage it. Theory of Constraints by Goldblatt, and it's more executive-friendly companion volume called The Goal are a good place to start, but lacking on detail.
Understanding Variation by Donald J. Wheeler has proven to be a very useful resource.
It's About Time: The Competitive Advantage of Quick Response Manufacturing by Rajan Suri is the executive companion to the book Quick Response Manufacturing: a Compan-Wide Approach to Reducing Lead Times by the same author. Mr. Suri uses a system-dynamics approach to manage capacity and to manage batch sizing, which his research revealed as the keys to optimal lead time reductions, and thereby overall throughput.
The other interesting thing we've found by analyzing the data of our company is that the time it takes to ship a particular piece (measured in days) falls into a long-fat-tail distribution regardless of the scale we analyze. In other words, if we look at one employee's output, or one team's output, or one shop's output, or the company as a whole, the time to ship is in a long-fat-tail distribution.
Because of this, we basically manage by how long something has been in a particular department. The longer it's been sitting, the higher its priority becomes. What we're trying to do is basically manage the exceptions and let the system manage those that are in the normal bell curve.
Hope this helps. Feel free to ask further questions. I find the topic fascinating and not many people share this interest.
After I finished my comment, a thought occurred to me that I wanted to share. One big difference between fabrication and (most) software projects is scope creep. We manage scope quite fiercely, and the weapon we wield is the change order. We are in the fortunate contractual position of being able to charge our customers when they change/add scope.
One of the biggest challenges I've seen (as someone outside the industry, but familiar with it) in software development is feature/scope creep. That seems to really hobble a lot of projects. Star Citizen comes immediately to mind as an outlying, but illustrative example.
We don't really have a lot of feature/scope creep in most of our projects. We do, however, have shared resources between simultaneous projects, which poses a similar challenge.
Yes, we have much more in common with software development than we do with manufacturing. We have more stages of production than software, and we have a challenging situation of shared resources between projects (we are generally working anywhere from 25-50 projects at once in our shop using shared resources), but the variance factor of 1) not knowing exactly how long it will take to make something because it's never been made before, and 2) different employees taking vastly different amounts of time to accomplish the same task are both shared challenges that we face along with software development.
Anything made from steel. Everything from small machined parts all the way up to the swing arms on electric mining shovels. We have some parts we build that require two 60 ton cranes to lift. Everything in between, mostly for the energy industry.
Comments
Manufacturing and fabrication are two different worlds. Manufacturing is all about reducing/eliminating variance, whereas fabrication (high-mix, low volume) is all about absorbing variance. Most of the things we build have never been built before, and most of them will never be built again. So the estimates on how long it will take to build one is just that: an estimate. And the process of fabricating it is affected by MANY variables, but I'll just list a few. Materials with long lead times. Materials not arriving on time. Wrong materials sent. A pareto distribution of time it will take to finish an operation depending on which employee I give it to. What else is in the queue for an operation. Whether customers put a hold on the part. And so on, and so on.
Every manufacturing person I've met thinks we're just idiots. Then they come to our shop and it takes them about 1-2 years of trying to "we just need to implement Lean, guys!" before they realize that fabrication has very little, if anything, in common with manufacturing and the only lean principle that really applies is keeping your work area tidy and your tools organized.
Our business model is built around our ability to absorb and manage variance, rather than eliminate it.
Interesting, maybe we should drop the manufacturing metaphors in software? Is there any good reading about fabrication?
I agree that software and fabrication have much more overlap with regard to challenges faced than software and manufacturing. Unfortunately, manufacturing gets most of the academic attention, so job shop scheduling has basically stagnated since the 70s, when academia started becoming aware of Toyota's innovations in manufacturing. Some work has been done using genetic algorithms to try to tackle the subject, but nothing substantive has taken hold in the industry.
That being said, I've found a few resources that help you start to get a handle on fabrication (and software development) and how to manage it. Theory of Constraints by Goldblatt, and it's more executive-friendly companion volume called The Goal are a good place to start, but lacking on detail.
Understanding Variation by Donald J. Wheeler has proven to be a very useful resource.
It's About Time: The Competitive Advantage of Quick Response Manufacturing by Rajan Suri is the executive companion to the book Quick Response Manufacturing: a Compan-Wide Approach to Reducing Lead Times by the same author. Mr. Suri uses a system-dynamics approach to manage capacity and to manage batch sizing, which his research revealed as the keys to optimal lead time reductions, and thereby overall throughput.
The other interesting thing we've found by analyzing the data of our company is that the time it takes to ship a particular piece (measured in days) falls into a long-fat-tail distribution regardless of the scale we analyze. In other words, if we look at one employee's output, or one team's output, or one shop's output, or the company as a whole, the time to ship is in a long-fat-tail distribution.
Because of this, we basically manage by how long something has been in a particular department. The longer it's been sitting, the higher its priority becomes. What we're trying to do is basically manage the exceptions and let the system manage those that are in the normal bell curve.
Hope this helps. Feel free to ask further questions. I find the topic fascinating and not many people share this interest.
After I finished my comment, a thought occurred to me that I wanted to share. One big difference between fabrication and (most) software projects is scope creep. We manage scope quite fiercely, and the weapon we wield is the change order. We are in the fortunate contractual position of being able to charge our customers when they change/add scope.
One of the biggest challenges I've seen (as someone outside the industry, but familiar with it) in software development is feature/scope creep. That seems to really hobble a lot of projects. Star Citizen comes immediately to mind as an outlying, but illustrative example.
We don't really have a lot of feature/scope creep in most of our projects. We do, however, have shared resources between simultaneous projects, which poses a similar challenge.
Would this apply to "Software Fabrication" as well?
Yes, we have much more in common with software development than we do with manufacturing. We have more stages of production than software, and we have a challenging situation of shared resources between projects (we are generally working anywhere from 25-50 projects at once in our shop using shared resources), but the variance factor of 1) not knowing exactly how long it will take to make something because it's never been made before, and 2) different employees taking vastly different amounts of time to accomplish the same task are both shared challenges that we face along with software development.
Can you share what kind of products you are in fact fabricating?
Anything made from steel. Everything from small machined parts all the way up to the swing arms on electric mining shovels. We have some parts we build that require two 60 ton cranes to lift. Everything in between, mostly for the energy industry.
Very interesting - thanks!