Many manufacturers have already bought, or built, a production planning tool. Far fewer still use it six months later: the plan has gone back into an Excel workbook, and the ERP module is only opened to release manufacturing orders. The problem is almost never the software alone, but what was decided, or not, before choosing it.
This article describes how to implement a production planning tool that is actually used: the scope to define, the input data, the three horizons to tell apart (S&OP, MPS, scheduling), the routines that keep the plan alive and the classic mistakes. Whether the solution is Excel, custom development or production planning software for SMEs, the steps are the same.
A production planning tool: planning what, exactly?
Five questions are enough to define the scope, and their answers steer every technical choice that follows.
- What are we trying to plan? Production, but sometimes also maintenance, staffing or purchasing. A tool that tries to cover everything from the start covers nothing properly.
- Over what horizon? A few days, a few weeks, several months. The horizon sets the time bucket and the kind of decisions.
- In what time bucket? Day, week, month: the one in which real decisions are made, not the one the tool happens to display.
- Which horizon is frozen? The frozen window, during which nothing is replanned, protects the shop floor from constant change.
Three horizons, three tools: S&OP, MPS, scheduling
One confusion comes up in almost every project: a company talks about scheduling when it needs planning, or the reverse. Planning organises resources over a broad horizon; scheduling assigns manufacturing orders to work centres day by day. Supply chain practice distinguishes three levels.
| Level | Horizon and time bucket | Question asked | Who decides, how often |
|---|---|---|---|
| S&OP (sales and operations planning) | 6 to 18 months, by month, by product family | Do we have the capacity and the staff for the expected volumes? | Management, sales, production; once a month |
| MPS (master production schedule) | 2 to 12 weeks, by week or day, by item | What to make, in what quantity, by what date, with what projected stock? | Planner; once a week |
| Scheduling | 1 to 10 days, by hour, by manufacturing order and work centre | In what order should manufacturing orders run on each line, with which changeovers? | Scheduler, workshop manager; every day |
An effective production planning tool first covers one level, well, before expanding: wanting all three in the same grid from day one is the surest way to end up with none.
The input data without which nothing holds
A planning tool is only as good as its data. Take an honest inventory before choosing.
- Bills of materials: available, up to date, with the right quantities and scrap rates?
- Routings: standard times per operation and per work centre, even approximate ones?
- Stock: reliable, counted how often, with reserved stock kept separate?
- Demand: forecasts, sales history, or only an order book?
- Manufacturing orders and feedback: how is an order created, released, reported? Does the shop floor report actual quantities and times, or do you have to wait until the end of the week?
Then comes the question of where the data lives: ERP, MES, Excel workbooks, sometimes all three at once. Is an automatic extraction or an interface possible? A planner who has to re-enter stock every morning will drop the tool in the first busy month.
The constraints to model, and those to leave aside
Each business has its dominant constraints, and it is better to have a tool that adapts to them than to bend the business to fit the tool.
- Infinite or finite capacity? Standard MRP plans at infinite capacity. If two or three work centres are regularly overloaded, you need to apply load and capacity to them; we explain the method in this article on finite capacity production planning.
- Raw material availability, especially when it depends on an upstream flow that production does not control, such as slaughtering or a harvest.
- Human capacity: teams, skills, shift patterns, absenteeism.
- Machine capacity: run rates, maintenance, breakdowns, changeovers.
Not all of them deserve to be modelled: a good tool represents the two or three constraints that really make the plan fail.
The deliverable first, then the budget
A plan is only useful if it reaches the shop floor. So decide early what comes out of the tool: a paper sheet for team leaders, manufacturing orders created or updated in the ERP, or a real-time progress dashboard. Only once these questions are answered can the project timeline, the budget and the people to involve be set out seriously.
The routines that keep the plan alive
A production planning tool lives through its routines, not its features. Three meetings are enough in an SME.
- The weekly MPS review: the planner presents the plan for the coming weeks, projected stock and overloaded work centres; sales announce upcoming orders; production says what is achievable. The following week's plan is frozen at the end of the meeting.
- The daily scheduling meeting, short, at the start of the day: the order of manufacturing orders on each line, changeovers, missing materials.
- Feedback on actuals: quantities and times reported on the shop floor update the progress of manufacturing orders and, over time, the standard times. Without this feedback, the plan drifts silently.
Classic mistakes with planning tools
- Choosing the tool before the need. The demo looked good; the scope had not been defined.
- Confusing planning and scheduling, and buying a minute-by-minute scheduler when the problem was the weekly MPS.
- Ignoring data quality: missing routings, wrong stock, bills of materials from three years ago.
- Not naming an owner: a plan without a designated planner is kept up by no one.
- Throwing away existing rules. The workbooks in place hold years of business rules; carrying them over is safer than starting from scratch.
What we see on the ground in planning projects
On the projects we have carried out in food manufacturing, the tool that lasted was the one whose scope had been narrowed to one level and one dominant constraint. In a marinated poultry plant, an MRP run coupled with batch traceability. In a cutting plant, two separate files: a medium-term plan over fifteen days, driven by available raw material, and short-term scheduling line by line, driven by run rates and mould changes. Each has its owner and its routine.
We also see that the question "Excel, custom development or off-the-shelf software?" comes too early: once the scope, the data and the deliverable are set, the answer becomes obvious.
Conclusion: a planning tool chosen after the groundwork
Implementing a production planning tool is not just choosing software. You need to define what you plan and over what horizon, take stock of data and constraints, define the deliverable, then set up the routines that will keep the plan alive. A tool chosen after these steps gets used; a tool chosen before them gets worked around.
If your need sits at the level of the MPS and the net requirements calculation, Planiprod was designed for SMEs moving away from Excel without losing their rules: it reads your ERP every morning or your existing workbooks, calculates projected stock, net requirements and load per work centre, and every column can be programmed and explained. The ERP remains the master of manufacturing and purchase orders. To scope your project with us, book a demo or read our page on planning for SME manufacturers.