Push System: Forecast-Driven Production Control

A push system is a production control method in which work is scheduled and released from a plan: a forecast, an MRP calculation or a master production schedule, rather than from actual downstream consumption. Material is pushed through the factory on a predetermined timetable, whether or not the next operation is ready for it.

Almost every ERP system in the world is a push system, which is why this is the default way manufacturing runs rather than a choice anyone made. This manufacturing glossary entry explains the mechanics, where push genuinely fits, where it breaks, and the numbers from one plant that fixed it. For the direct comparison with pull, see push against pull inside a finite capacity engine, which is where that comparison lives on this site.

What Is a Push System?

In a push system, production decisions are made centrally - typically by a planning department using MRP (Material Requirements Planning) or ERP software. The system calculates what to produce, when to produce it, and in what quantity based on:

• Sales forecasts
• Customer orders already received
• Bill of materials (BOM) requirements
• Current inventory levels
• Lead times for purchased and manufactured items

The resulting production orders are "pushed" to the shop floor according to the schedule. Each work center processes its assigned orders and pushes the output to the next operation, regardless of whether that operation is ready for it.

This is how the vast majority of manufacturing has operated for decades, and it works reasonably well in certain environments. The honest way to judge it is by environment rather than by principle.

Read down the "why" column and a pattern appears. Push is sound wherever a decision has to be made before the information exists, and weak wherever the information exists and is being ignored.

How Push Systems Work in Practice

A typical push system cycle:

1. Demand planning generates a forecast for the next 3 to 12 months.
2. Master Production Schedule (MPS) converts the forecast into a production plan by time period.
3. MRP explosion breaks the MPS into component requirements, netting against inventory and generating planned purchase orders and production orders.
4. Order release: Production orders are released to the shop floor with due dates.
5. Execution: Work centers process orders in due-date or priority sequence. Completed work is pushed to the next operation.

The fundamental assumption: the forecast is accurate enough that building to plan will meet actual demand. This assumption holds reasonably well for stable, repetitive products with predictable demand.

Where Push Systems Struggle

Push systems create problems when:

• Forecasts are wrong (they always are to some degree): Overforecasting creates excess inventory; underforecasting creates stockouts.
• Too much work is released at once: When MRP releases all orders based on planned start dates without considering current shop floor conditions, WIP explodes. Twenty jobs competing for the same machine create queues, confusion, and expediting.
• Batch sizes are large: Large batches pushed through the system create lumpy demand on downstream operations, causing alternating overload and starvation.
• No feedback loop: Push systems do not inherently respond to shop floor conditions. If a machine breaks down, the upstream operations keep pushing work - building WIP that has nowhere to go.

Example with Numbers

A make-to-stock manufacturer of industrial fittings measured its pure-push baseline, then measured again after putting a finite capacity schedule in front of the MRP output, and once more after moving its 50 most repetitive part numbers onto Kanban.

The middle column is the interesting one, because nothing in it changed what the plant made or what MRP calculated. The only change was which orders were allowed onto the floor and when. Open work orders fell by 59 percent, lead time by 44 percent, and on-time delivery rose 15 points, from release discipline alone.

That is the practical conclusion: the improvement did not come from abandoning push. It came from controlling push with capacity constraints, and then removing from push the handful of items that pull handles better.

Why Push Systems Matter for Production Scheduling

Understanding push systems is essential for schedulers:

• Most ERP systems are push-based: MRP generates production orders based on planned dates. Without finite capacity scheduling overlaid on MRP, the push system will overload the shop floor.
• A capacity filter in front of MRP adds intelligence to push: instead of releasing everything MRP calculates, RMDB and its successor EDGEBIC (RMDB 2.0) apply capacity constraints to decide when work should actually be released, turning a naive push into a controlled, capacity-aware release. This is the role of software that decides which orders the floor can actually start, and the reason BAE Systems discontinued its ERP scheduling in favour of RMDB.
• Hybrid is usually best: Use push (MRP) for planning, purchasing, and long-lead-time activities. Use pull (Kanban) for repetitive shop floor execution. Use finite scheduling (RMDB) to control the boundary between planning and execution.
• WIP control is the key: the biggest scheduling improvement available in a push environment is controlling how much work hits the floor at once. It needs no new equipment and no change to the ERP system.
• The requirements still have to be right: a capacity filter cannot rescue a bill of material that nets the wrong quantities, so netting requirements correctly down every level remains the foundation under any push plan.

Where the push plan has to respect finite machine hours, labor and tooling at the same time, that filter is a schedule that loads every resource against the hours it actually has. GE Railcar Services went from 30 percent to over 90 percent on-time shipping after putting its ERP-driven plan on that footing.

The lean manufacturing guide explains the evolution from push to pull and how finite capacity scheduling bridges the gap.

Common Questions About Push Systems

Is MRP a push system?

Yes. MRP calculates requirements from a forecast and a master schedule, then releases planned orders by their planned start dates without asking whether the floor has capacity on those dates. That is the definition of push, and it is why MRP output is usually filtered through a finite capacity schedule before anything is released.

What is an example of a push system?

Any build-to-forecast operation. A seasonal goods maker building stock in January for a June selling season is running push, and so is any plant whose ERP drops every planned order onto the floor on its planned start date. In both cases the work is authorized by a plan rather than by downstream consumption.

What are the disadvantages of a push system?

Excess WIP, longer lead times and overproduction, all of which trace back to forecasts that are never perfectly accurate. The sharper problem is release volume: when many orders arrive at the same work center at once, queues form, every job slows down, and the schedule loses its meaning. The fitness table above shows where that cost is worth paying and where it is not.

Can you fix a push system without replacing the ERP?

Yes, and it is the usual path. The ERP keeps calculating requirements, and a finite capacity schedule sits between its output and the floor, deciding which of those orders can actually start. The plant in the example above took 44 percent out of its lead time without changing a single MRP setting.

Related Terms

• Pull System - The demand-driven alternative to push, where production is triggered by actual consumption rather than forecasts.
• Kanban - The visual signaling system that implements pull on the shop floor, often replacing push-based production orders for repetitive items.
• Work-in-Progress (WIP) - The inventory that accumulates when push systems release more work than the shop floor can process.

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See all lean and scheduling terms in the Manufacturing Glossary.