How do MRP and JIT view inventory?

MRP accepts needed buffer; JIT sees it as waste to be minimised

MRP sees it as waste; JIT accepts it as buffer

Where is JIT most suitable?

Repetitive, high-volume production with stable demand and reliable suppliers

Products with many BOM levels and erratic demand

For which production is MRP better suited?

Complex products with many BOM levels and variable demand, job-shop or batch

Very simple one-level products with constant demand

Production with zero set-up time

Continuous process plants with no components

Which pair correctly contrasts lot size and flow?

MRP: computed lots, push; JIT: very small lots, pull

MRP: very small lots, pull; JIT: computed lots, push

Practice · 5 marks

MRP compared with JIT

Short answer

MRP is a computer-based push system planning from forecasts, accepting inventory and fixed lead times. JIT is a pull philosophy that reacts to actual consumption, aiming for zero inventory, small lots, and continuous improvement. MRP suits complex, variable-demand products; JIT suits stable, high-volume repetitive production.

Compare MRP and Just-in-Time (JIT) concepts. In what situations is each suitable?

MRP is a computer-based push system that plans orders from the master schedule, BOM and inventory records. JIT is a pull philosophy aimed at zero inventory and continuous elimination of waste, in which parts are produced only when the next stage uses them.

Basis	MRP	JIT
Basic idea	Plan using forecasts and schedule	React to actual consumption
Flow of material	Push	Pull (kanban)
Inventory	Accepted as needed buffer (safety stock)	Seen as waste; to be minimised
Lot size	Computed (lot-for-lot, EOQ)	Very small, ideally one
Lead time	Fixed, planned	Continuously reduced
Set-up	Accepted as given	Reduced (SMED)
Information	Computer, complex	Visual cards, simple
Suppliers	Arm's length, many	Long-term partners, few, frequent small deliveries
Quality	Some defects allowed for	Zero defects required
Demand pattern	Variable, complex products	Stable, repetitive, levelled
Cost of system	Software, data accuracy	Discipline, training, supplier cooperation

Suitability

MRP: complex products with many levels in the BOM, variable demand, job-shop or batch production (aircraft, machinery).
JIT: repetitive, high-volume production with stable demand, short set-ups and reliable suppliers (automobile, electronics assembly).
Combined: many firms use MRP for planning and JIT/kanban for shop-floor execution.

✓ Answer checked by Claude Opus 5.5 (high effort)

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MRP compared with JIT

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