In the AI Job Shop Scheduling article I shared last week, I broke down why ERP scheduling keeps failing job shops and why they often get abandoned. Let’s make the logic airtight.
Each flaw triggers the next, creating this chain reaction built into requirements-planning logic:
- Backwards schedule from due date to calculate “start dates” → create dispatch lists → reality strikes and jobs are not where they are supposed to be → Dispatch lists are out of date
- Releasing new work continues → WIP grows → Dispatch lists are MORE out of date
- Replan → Reschedule → Keep releasing, we’re late!
- System releases too many jobs → mountains of WIP → longer lead times and slower flow velocity.
- Mountains of WIP → cherry-picking and working out of dispatch order → due date performance suffers.
- Dispatch lists go stale within hours → reschedule AGAIN → “nervousness” and firefighting.
- When firefighting dominates → no one has time to follow “the process” → chaos thrives.
It’s exhausting. I’m tired after writing that.
While there are typically compliance issues—people don’t always follow the process—not following the process is not the CAUSE of this chain of pain, it’s the EFFECT.
This isn’t user error. It’s what the logic guarantees.
Why would you keep doing something that is so much work for so little or no benefit? You wouldn’t.
That’s why so many ERP scheduling modules end up abandoned.
Industry reviews note that ERP scheduling often requires perfect data and constant tweaking, leading shops to abandon it in favor of Excel or whiteboards.¹ ²
This is exactly why one Practical Machinist forum user noted: ERP scheduling modules often go unused, with most shops relying on Excel instead.³
VSS alumni sum it up bluntly:
“We struggled with ERP (M1) and tried add-ons like LillyWorks’ Protected Flow. All abandoned. VSS was the only thing that worked.” — Robert S.
“Global Shop sold me in a demo. The sales guy explained they support Theory of Constraints scheduling concepts. After signing up and getting started, the guy doing the training, looked at me like I was crazy for asking about TOC. We’ve had to abandon their scheduling module. It’s unusable.” R. L.
👉 Read full article: https://www.velocityschedulingsystem.com/blog/ai-scheduling-vs-erp-job-shops/
— Dr. Lisa
P.S. Do you have a story of trial and error with scheduling? What worked? What didn’t? I would love to hear YOUR story.
¹ Paraphrased from Practical Machinist forum (MRP Production Planning Software Costs thread): users reported that most ERP users in the job shop world avoid those modules and run their own Excel applications for scheduling. Link
² Sc_Book_2021: “Many ERP scheduling modules … unable to generate a feasible schedule … job shops download data and schedule in Excel.” Link
³ Paraphrased from Practical Machinist forum (Job Scheduling Software thread): users noted that most job shop users ignore the scheduling modules and run their own Excel applications. Link
