I'm a broadcast engineer and I worked for the world's largest manufacturer of broadcast antennas during the USA's television spectrum repack.
Essentially the federal government told television stations that they would have to move to a different frequency so the government could sell the open RF spectrum to wireless providers. Most of the expenses incurred by the TV stations were reimbursed by the government. So business at this antenna company was exceptionally good but with some pain in scaling up of the operations. I worked in the sales department and attended the weekly production meetings. There was a recurring theme of production instance holdups due to lack of parts or materials. After months of sitting silent in these meetings I got to a point were I couldn't hold back anymore and said something like "I'm just a broadcast engineer but I think we should at least build up some stock in these things". Everybody sitting in the meeting around the big table on the phone conference just burst out in laughing. I was then told about the concept of Slim or Lean inventory (I don't remember the exact terms). Everybody gathered themselves up and told me that they agreed with me on my point and then the production manager summed it all up with "Our Hands Are Tied".
Looking at the distributed lean inventory concept from afar: It looks like a house of cards.
I have always been burnt by the JIT concept ... simply because it often fails.
A small delay at ANY link in the chain throws it out of sync, big time.
Or buying a little today, little more tomorrow makes me pay full list price, while buying a sizable batch at once gives me WAY better prices.
Sometimes I even do the conceptually opposite: I get an offer which is too good to pass, then first buy and then think or design some product to use it.
As in: I was offered 100 ECC189 for $100
My counter offer was "I want to pay U$500 for 1000 of them, if you have them"
Which he did, so we closed the deal.
Now I am designing a 40W Hybrid Guitar head (think Orange Microterror but higher power) which I guess I will sell like hot cakes.
Also built an acrylic/plastic sheet thermal bending machine, to make brick sized Guitar amp covers (chassis is made out of bent and punched aluminum),currently designing a 50W Guitar amplifier which will fit there.
So you see, the absolute opposite path: FIRST get components or machines, THEN design a product round them.
Has worked so far in the last 50 years 😉
A small delay at ANY link in the chain throws it out of sync, big time.
Or buying a little today, little more tomorrow makes me pay full list price, while buying a sizable batch at once gives me WAY better prices.
Sometimes I even do the conceptually opposite: I get an offer which is too good to pass, then first buy and then think or design some product to use it.
As in: I was offered 100 ECC189 for $100
My counter offer was "I want to pay U$500 for 1000 of them, if you have them"
Which he did, so we closed the deal.
Now I am designing a 40W Hybrid Guitar head (think Orange Microterror but higher power) which I guess I will sell like hot cakes.
Also built an acrylic/plastic sheet thermal bending machine, to make brick sized Guitar amp covers (chassis is made out of bent and punched aluminum),currently designing a 50W Guitar amplifier which will fit there.
So you see, the absolute opposite path: FIRST get components or machines, THEN design a product round them.
Has worked so far in the last 50 years 😉
Use finned tubular heaters, and a PID action temperature controller, sensor a little away from heat source.
A fan on extended shaft, like from old window a/c units to ensure even heating.
Stress relieve after bending the acrylic sheet.
Had a stupid failure at a friend, the oven was made with poor connections at the heater end.
Got studs, like those used for motherboard stand offs, with a nice thicker thread, so the other heaters could be used in parallel.
Builder had used 12 or so heaters, with three phases distributed, that is okay.
But he used tiny crimps, and the heater studs were like 4 mm, and all the current was going through them.
Stand off had 1/4" thread, and we changed the lugs.
Now it works perfectly.
My friend makes acrylic models, and sometimes bends 10 mm sheets.
A fan on extended shaft, like from old window a/c units to ensure even heating.
Stress relieve after bending the acrylic sheet.
Had a stupid failure at a friend, the oven was made with poor connections at the heater end.
Got studs, like those used for motherboard stand offs, with a nice thicker thread, so the other heaters could be used in parallel.
Builder had used 12 or so heaters, with three phases distributed, that is okay.
But he used tiny crimps, and the heater studs were like 4 mm, and all the current was going through them.
Stand off had 1/4" thread, and we changed the lugs.
Now it works perfectly.
My friend makes acrylic models, and sometimes bends 10 mm sheets.
Having worked in the electronics industry for 40 years, I took all the quality training (Which by the way did not originate in Japan, it was developed in the USA, ignored, and adopted first by Japan. Both Deming and Juran were from the USA.)
JIT should not be confused with quality process.
JIT only applies to large scale manufacturing (auto industry,, Industrial controls, consumer products manufacturing, etc) where annual contracts determine stock availability and delivery schedules.
Even then there are disruptions such as when one of two plastic manufacturers for IC Packaging had a fire which disrupted the entire IC industry about 10 years back.
Another example is when the MLC cap shortage hit about four years ago.
With large scale manufacturing, JIT is a boon for keeping stock low and minimizing overhead.
Again It does not apply to small scale manufacturers who have to buy stock from distributors It can only apply to companies which purchace directly form the component manufacturer where contracts dictate delivery schedules and stock is guaranteed by contract. Even then there are pitfalls.
JIT should not be confused with quality process.
JIT only applies to large scale manufacturing (auto industry,, Industrial controls, consumer products manufacturing, etc) where annual contracts determine stock availability and delivery schedules.
Even then there are disruptions such as when one of two plastic manufacturers for IC Packaging had a fire which disrupted the entire IC industry about 10 years back.
Another example is when the MLC cap shortage hit about four years ago.
With large scale manufacturing, JIT is a boon for keeping stock low and minimizing overhead.
Again It does not apply to small scale manufacturers who have to buy stock from distributors It can only apply to companies which purchace directly form the component manufacturer where contracts dictate delivery schedules and stock is guaranteed by contract. Even then there are pitfalls.
That.
For us mere mortals, pre-buying and stocking as needed is the realistic. way to go.
JIT can be a (bad) joke.
We always have fun at my transformer wire supplier.
He has a huge shop, "only sells by full 8 to 25 kg rolls direct to Manufacturers" BUT he has a couple old customers since he had a struggling small shop which he gives attention to, just out of courtesy and old memories.
So there is this real old customer from around the corner, think mid to late 80´s (if not more) who rewinds small appliance motors, think food processors, hand drills, desktop fans, etc.
He comes 2 or 3 times a week and always , with very rare exceptions, buys the same: "please give me 300 grams - 250 grams - 350 grams of 0.40mm enamelled wire" ... the exact quantity to rewind ¨one motor.
They oblige only because of his advanced age and longstanding as a customer, but always suggest:
"hey, Don Cosme, why don´t you buy a full 8 kg roll once a Month?" (which he ends up using anyway, if you add all his purchases up)
"eeehhhhh!!!!! WHAT will I do with ALL that wire????" 🙂 🙂 🙂
Can I call that JIT? 😉
For us mere mortals, pre-buying and stocking as needed is the realistic. way to go.
JIT can be a (bad) joke.
We always have fun at my transformer wire supplier.
He has a huge shop, "only sells by full 8 to 25 kg rolls direct to Manufacturers" BUT he has a couple old customers since he had a struggling small shop which he gives attention to, just out of courtesy and old memories.
So there is this real old customer from around the corner, think mid to late 80´s (if not more) who rewinds small appliance motors, think food processors, hand drills, desktop fans, etc.
He comes 2 or 3 times a week and always , with very rare exceptions, buys the same: "please give me 300 grams - 250 grams - 350 grams of 0.40mm enamelled wire" ... the exact quantity to rewind ¨one motor.
They oblige only because of his advanced age and longstanding as a customer, but always suggest:
"hey, Don Cosme, why don´t you buy a full 8 kg roll once a Month?" (which he ends up using anyway, if you add all his purchases up)
"eeehhhhh!!!!! WHAT will I do with ALL that wire????" 🙂 🙂 🙂
Can I call that JIT? 😉
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Therein lies the rub... that's a big assumption.
It can be mitigated by having multiple sources - vendors, manufacturers, geographical, political...- but sometimes it fails. And when it fails, it can fail spectacularly:
(1) Japanese quake
(2) Semiconductor production
Sometimes the engineering needs to take such things into account and design accordingly, but they don't because the customer wants the doodahs...
..why should a door latch require a computer to operate?
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