Very nice Brian. Being a polymer Physicist doing product market development over 45 years, I've been in ans out of probably a 1000 manufacturering plants. From sand going into to make sheet glass, to progressive die electronic terminals, wire covering and drawing, bumpers injection molded, car windows, laptops, LCD displays, lithograph Semiconductor optics.. Always interesting.
Not a believer in JIT as we saw the brittleness in supply chains..
At BigCorp we used Variable Cost, and VC productivity making most things.
Great topic.
Sheet glass is one production they don't shut down as the cost of tearing out and rebuilding the sand to glass refractory (with 40 ft gas jets!) is super high. like every dozen years. They slow the line and just break the glass and dump it mostly back into the prime melt.
I learned early in my Lean journey that "JIT" meant "Just-in-time" plus "just-in-case". In other words, some buffer to handle variation. The size of the buffer needs to be Goldilocks: not too large, not too small.
I learned years later that JIC is but one of the three levers outlined in Hopp & Spearman's Factory Physics: Inventory, capacity, and time.
It's all a good way to go, except when supply chains are very distant and subject to disruptions. Then it is a complete disaster. It was all founded on the basic theory of freeing up cash tied up in WIP and inventory. Alas we live in an imperfect world for such tightly bounded structures. The best idea is an "eco-system-supply-chain" predominately built around the final product assembly.
Basic raw materials from the dirt are never near final assembly - but because of their scale usually are well stocked by the 1st step refineries.
We didn't see supply issues in basic copper, aluminum, coal, or oil, in the US anyway if recall correctly.
But the upstream processing into Steel coil, wire, sheet, basic chemicals into plastic pellets - into single parts into sub assemblies into sub systems and then final product - weak links are not having buffers between.
Not a fan of JIT. I am a fan of Value analysis/engineering, process consolidation efficiency (DFMA etc)..
And thus we blotted out the stars from the sky. We confined our selves to see only what is bathed in the glow of our lights. Most people will never see the full glory of the lights of the universe.
The just in time part is interesting, because an ideal process has no slack, but at my facilities we usually try to design in lots of storage between steps, for food packaging for example the machines that prepare the packages are faster than the actual filling, and a coupe minutes of boxes sit on conveyor so if the machine in back goes down things keep flowing while you prepare, of course in an ideal facility you would hope for no unplanned downtime.
Very nice Brian. Being a polymer Physicist doing product market development over 45 years, I've been in ans out of probably a 1000 manufacturering plants. From sand going into to make sheet glass, to progressive die electronic terminals, wire covering and drawing, bumpers injection molded, car windows, laptops, LCD displays, lithograph Semiconductor optics.. Always interesting.
Not a believer in JIT as we saw the brittleness in supply chains..
At BigCorp we used Variable Cost, and VC productivity making most things.
Great topic.
Sheet glass is one production they don't shut down as the cost of tearing out and rebuilding the sand to glass refractory (with 40 ft gas jets!) is super high. like every dozen years. They slow the line and just break the glass and dump it mostly back into the prime melt.
I learned early in my Lean journey that "JIT" meant "Just-in-time" plus "just-in-case". In other words, some buffer to handle variation. The size of the buffer needs to be Goldilocks: not too large, not too small.
I learned years later that JIC is but one of the three levers outlined in Hopp & Spearman's Factory Physics: Inventory, capacity, and time.
It's all a good way to go, except when supply chains are very distant and subject to disruptions. Then it is a complete disaster. It was all founded on the basic theory of freeing up cash tied up in WIP and inventory. Alas we live in an imperfect world for such tightly bounded structures. The best idea is an "eco-system-supply-chain" predominately built around the final product assembly.
Basic raw materials from the dirt are never near final assembly - but because of their scale usually are well stocked by the 1st step refineries.
We didn't see supply issues in basic copper, aluminum, coal, or oil, in the US anyway if recall correctly.
But the upstream processing into Steel coil, wire, sheet, basic chemicals into plastic pellets - into single parts into sub assemblies into sub systems and then final product - weak links are not having buffers between.
Not a fan of JIT. I am a fan of Value analysis/engineering, process consolidation efficiency (DFMA etc)..
Cheers Mike
JIT is more "glassy" and adding buffers makes the process more "metallic" — different materials are optimal for different purposes. :-D
Nicely done!
Glad you thought so. Brian's casual mentions of "synchronization" sent me down a rabbit hole that I sense you may appreciate... https://x.com/riemannzeta/status/1990072369759801546?s=20
It’s a great book, written in a way that makes these topics rather accessible. I highly recommend it.
Become a mission to get this ex Aus to NZ! It has been back n forth across the ditch!
There should also be a buffer at the top of Fig.3.
Very interesting. I assume you talk about Jevons' Paradox in the book? I look forward to reading more. And "I, Pencil" is such a classic!
Your book just arrived! Looking forward to reading it. Chapter 1 is a great beginning!
And thus we blotted out the stars from the sky. We confined our selves to see only what is bathed in the glow of our lights. Most people will never see the full glory of the lights of the universe.
Finally arrived moments ago. So looking forward to reading it.
The just in time part is interesting, because an ideal process has no slack, but at my facilities we usually try to design in lots of storage between steps, for food packaging for example the machines that prepare the packages are faster than the actual filling, and a coupe minutes of boxes sit on conveyor so if the machine in back goes down things keep flowing while you prepare, of course in an ideal facility you would hope for no unplanned downtime.