By Dr. Lisa Lang, TOCICO Certified Expert and developer of the Velocity Scheduling System
How many lean job shop events has your shop run in the last five years? 5S implementations. Value stream mapping sessions. Kaizen blitzes. Setup reduction workshops. Standard work documentation.
Now tell me: which of those moved your on-time delivery by more than 5 points and held it there for more than six months?
Take your time. Be honest.
If you’re like most job shop owners I talk to, the answer is uncomfortable. You can point to the 5S tags on the toolboxes, the before-and-after photos from the Kaizen, the reduced setup times on two machines. And your scheduling is still chaotic. Your lead times are still longer than you want. Your expediting hasn’t stopped.
And you’ve decided the problem is you. You didn’t implement well enough. You didn’t sustain it. You need to try harder.
Here’s what nobody told you: it’s not an execution problem. It’s an environment problem.
Table of Contents
The Job Shop Environment
These are good shops. Committed operators. People who actually follow through.
And the results still don’t hold.
The easy explanation: they didn’t try hard enough. More training. Better accountability. A harder push next time.
But that story has a problem: the pattern is too consistent.
When I see the same result across shops with different teams, different consultants, different budgets, different levels of commitment, I stop asking what’s wrong with the execution. I start asking what’s wrong with the logic.
If execution were the cause, some shops would have fixed it through better execution. Not a few. Many. You’d see success stories scattered evenly across the population.
You don’t. You see partial wins that don’t compound. 5S that holds, standard work that doesn’t. Setup reductions on a few machines, scheduling chaos that never resolves. The same ceiling, over and over, in shop after shop.
That’s not an execution pattern. That’s a structural one.
The Lean Job Shop Mismatch
Here’s the part that’s never in the Lean training materials.
Lean was engineered for a specific environment. Toyota’s production system was designed for specific vehicles on specific lines. The same work repeats every day. The same products flow through the same paths. The same constraints exist in the same places at the same times.
That stability isn’t incidental to Lean. It’s required by it.
Lean’s core tools are built on repetition. Value stream mapping assumes the same product flows the same stream repeatedly. Standard work requires the same work to repeat. Takt time is calculable only when demand is predictable and product mix is controlled.
Remove the repetition, and the tools lose their mechanism. There’s nothing left to map. Nothing to standardize. No takt time to calculate.
A custom job shop makes different things in different ways every week. The mix changes. The constraint moves. What was waste last month is critical this month. The value stream for a hydraulic manifold looks nothing like the one for a bracket, and next week you might not be making either of them.
You cannot map a value stream that changes every week. You cannot standardize work that is, by definition, custom. You cannot calculate takt time when the product mix shifts daily.
The consultant was competent. The team executed well.
Lean fixes the assembly line. You don’t run one.
Tricia Gerak, CEO of Precision Component Industries, put it more directly than I could: “Ninety percent of lean is useless to us.” Not poorly implemented. Useless. Because it was never designed for this environment.
The 10% that does work in custom shops – mistake-proofing, some visual management principles, systematic waste identification, shares a common characteristic: it doesn’t require stable, repeating work to function. The 90% that doesn’t work all shares the same dependency: repetition your shop doesn’t have and never will.
The failure was never execution. It was category error. A tool applied to an environment it was never designed for.
Knowing the Wrong Answer Doesn’t Give You the Right One
So now you see what Lean was built for. And what it wasn’t.
The question is: what do you use?
Knowing Lean is wrong doesn’t tell you what’s right. Stopping the wrong tool doesn’t solve the job shop scheduling problems or cut your lead times. You need something designed for your environment, not adapted for it, not “applied carefully” to it, but built from the start for high-mix, variable-demand, custom manufacturing.
That thing exists. And it was developed specifically in response to what Lean left behind in shops like yours.
The Mechanism That Works Without Repetition
In a lean job shop, Lean tries to create flow by standardizing the work. When the same work repeats in the same way, you can systematically eliminate waste, reduce variation, and improve predictability. That mechanism requires repetition. Take it away, and there’s nothing to standardize.
The Velocity Scheduling System creates flow by managing moving constraints – a scheduling approach rooted in Theory of Constraints. It identifies the resource limiting your throughput right now, protects that resource, and controls the release of work to keep jobs moving. Whether or not the work repeats.
That difference matters more than it sounds.
In a custom shop where the constraint moves, because your mix changes, because your volume shifts, because different jobs hit different resources differently, you need a scheduling logic that watches what’s actually happening and responds to it. Not one that assumes stability and fails when that assumption breaks.
The Velocity Board makes this concrete. Every job in process is on the board. Every operator on the floor can see – at a glance – what to work on next. Not based on a schedule that was updated 4 hours ago and is already out of date. Based on what’s actually moving right now, and what’s stalling. Red means highest priority. The priority system is visible to everyone, without a manager having to call a morning meeting to sort out who works on what.
Lean would have you standardize how work flows through the shop. VSS shows you where it’s actually flowing – and where it’s piling up.
The Velocitizer™ controls what enters production. Instead of pushing work in on a schedule, it releases jobs when the system is ready for them – continuously accelerating flow and adapting as shop conditions change minute-to-minute. The constraint finishes work; more work comes in at the right rate. The floor stays workable even when your mix changes completely week to week.
And when something disrupts flow – which in a custom shop it always will – the system automatically captures it and prompts for a why. The AI then validates whether the reason captured is actually useful for improvement or just noise – ensuring good categories, good data, a POOGI record worth acting on. Once the data is in, the Correlizer™ runs in the background, finding patterns across your production history that no scheduler working under pressure would catch on their own. It doesn’t replace the scheduler’s judgment. It amplifies it – surfacing correlations that point to the flow improvements worth pursuing, so the POOGI team focuses on what the data actually shows instead of guessing.
That’s the gap Lean can’t close. Lean’s continuous improvement cycles need stable, repeating work to find a signal. VSS captures disruptions in real time and uses AI to find the pattern. The result isn’t a Kaizen event that fades. It’s a discipline that gets sharper the longer the shop runs it.
VSS was developed and refined across 550+ custom job shops over more than 15 years. Not high-volume plants. Not repetitive manufacturing facilities. Custom shops, where the work changes weekly.
Tim has been implementing Lean for more than 30 years. 5S, Kaizen blitzes, 2-second lean. He knows what Lean can do as well as anyone. After going through VSS, he said:
“When I tell you that your system is the most impressive, all around system that I have ever come across, I have over 30 years of experience implementing lean ideas and have seen much success. This system is by far the best all-around way to reach our goal of getting product to move smoothly and consistently through our shop.”
That’s not someone who gave up on Lean because they didn’t understand it. That’s someone who understood it thoroughly, and found VSS to be in a different category entirely.
The Right Architecture for Your Environment
The difference between Lean and VSS isn’t about which system is “better.” It’s about which one was built for your problem.
Lean was built for a factory that makes the same things in the same way, repeatedly. If that’s your operation, Lean is the right tool. The results speak for themselves in that environment.
You don’t run that kind of operation.
VSS was built for shops where the constraint moves, the mix changes, and the scheduling logic has to work whether or not the work repeats. Where the goal isn’t to standardize the work. It’s to get work through faster, on time, with less chaos and less WIP backed up on the floor.
The question “how do I make Lean work in my shop?” has no good answer. It was never designed to work here.
The question “what tool was built for my shop?” has a clear one.
The answer isn’t more discipline. It’s the right architecture.
If This Resonates
If you’re trying to be a Lean job shop and wondering why the results don’t hold, VSS+iVSS is worth a closer look.
VSS+iVSS combines the Velocity Scheduling System with job shop scheduling software built specifically to automate its execution. Same constraint-management methodology. Same logic designed for high-mix, variable-demand shops. Now with tools that handle the manual work of maintaining it at scale: automatic release, real-time visibility, and AI-assisted pattern detection that catches what schedulers working under pressure will miss.
550+ custom job shops have implemented VSS. The results above are theirs.
If your scheduling methodology came from a different kind of manufacturing, it may be time to ask whether you’ve been in category error this whole time, and what it would mean to finally use a tool built for you.
Start here: The 9 Challenges of Scheduling a Custom Job Shop and Why Your Schedule is Dead on Arrival
Frequently Asked Questions: Lean Job Shop
Why doesn’t lean work in job shops?
Lean was engineered for repetitive, stable manufacturing where the same products flow the same paths every day. In a custom job shop, the mix changes weekly, the constraint moves, and the work content varies job to job. Lean’s core tools – value stream mapping, standard work, takt time – all require repetition that custom shops don’t have and never will.
What percentage of lean tools are actually useful in a job shop?
Roughly 10%. The tools that work in custom shops – mistake-proofing, some visual management, systematic waste identification – share one characteristic: they don’t require stable, repeating work to function. The 90% that doesn’t work all shares the same dependency: repetition your shop doesn’t have.
What is the alternative to lean for a job shop?
The Velocity Scheduling System (VSS) was built specifically for high-mix, variable-demand custom manufacturing. Unlike lean, VSS manages moving constraints rather than standardizing work. It has been implemented in 550+ custom job shops and doesn’t require repetition to function.
Why do lean improvements fade in job shops?
Lean improvements fade because lean’s mechanisms require repetition to sustain. 5S holds because it applies to physical organization. But scheduling improvements, standard work, and flow-based methods require stable, repeating production. When the mix shifts – which it always does in a custom shop – lean-based improvements lose their foundation.
What is a category error in lean manufacturing?
A category error means applying a tool to an environment it was never designed for. Lean was designed for assembly-line manufacturing. Using lean in a job shop is a category error – the tool’s core requirements (stable mix, repeating work, fixed constraints) don’t exist in a custom shop, so results can’t hold regardless of execution quality.
