engineering

Material requirements planning

Material requirements planning is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Material requirements planning rather than just read about it. In short: Material requirements planning (MRP) is a production planning, scheduling, and inventory control system used to manage manufacturing processes. Most MRP systems are software-based, but it is possible to conduct MRP by hand as well.

Key takeaways

Material requirements planning belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Material requirements planning to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Material requirements planning from memory before moving on to harder problems.

Reference excerpt

Material requirements planning (MRP) is a production planning, scheduling, and inventory control system used to manage manufacturing processes. Most MRP systems are software-based, but it is possible to conduct MRP by hand as well. An MRP system is intended to simultaneously meet three objectives:

Ensure raw materials are available for production and products are available for delivery to customers. Maintain the lowest possible material and product levels in store Plan manufacturing activities, delivery schedules and purchasing activities.

History Prior to MRP, and before computers dominated industry, reorder point (ROP)/reorder-quantity (ROQ) type methods like EOQ (economic order quantity) had been used in manufacturing and inventory management. MRP was computerized by the aero engine makers Rolls-Royce and General Electric in the early 1950s but not commercialized by them. It was then 'reinvented' to supply the Polaris program and then, in 1964, as a response to the Toyota Manufacturing Program, Joseph Orlicky developed material requirements planning (MRP). Early MRP users in the 1960s and 1970s included Black & Decker, Twin Disc, Markem, Steelcase, and American Sterilizer. The first company was Black and Decker in 1964, with Dick Alban as project leader. Orlicky's 1975 book Material Requirements Planning has the subtitle The New Way of Life in Production and Inventory Management. By 1975, MRP was implemented in 700 companies. This number had grown to about 8,000 by 1981. In 1983, Oliver Wight developed MRP into manufacturing resource planning (MRP II). In the 1980s, Joe Orlicky's MRP evolved into Oliver Wight's manufacturing resource planning (MRP II) which brings master scheduling, rough-cut capacity planning, capacity requirements planning, S&OP in 1983 and other concepts to classical MRP. By 1989, about one third of the software industry was MRP II software sold to American industry ($1.2 billion worth of software). MRP's appeal is greater financial improvement than other business software. While automating payroll reduces the need for payroll clerks but requires computer equipment and staff, Computerworld said in 1986 that "In companies getting the full benefits of MRP II, however, the return on investment averages 200%". While accounting software automates manual functions, MRP allows analyses of updated material requirements impossible without computers. By then a variety of MRP software was available for mainframes and minicomputers, such as ASK's Manman and IBM's MAPICS.

Worked examples

Example 1 — a first encounter with Material requirements planning

Start with the simplest possible case. Write down what Material requirements planning claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Material requirements planning before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Material requirements planning ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Material requirements planning

In research: Material requirements planning appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Material requirements planning in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Material requirements planning is common in secondary-school and first-year university syllabi. It links to neighbouring topics Business intelligence terms, Computer-aided engineering, Enterprise resource planning terminology, so understanding it makes those chapters shorter.
In everyday life: Look for Material requirements planning outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Material requirements planning in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Material requirements planning means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Material requirements planning out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Material requirements planning in simple terms?

Why does Material requirements planning matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Material requirements planning?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Material requirements planning.