Flexible Manufacturing Systems & Just-in-Time Production

This lesson covers advanced manufacturing strategies including flexible manufacturing systems (FMS) and just-in-time (JIT) production. These concepts are part of AQA GCSE Design and Technology (8552), Section 3.1.1, and relate directly to how modern factories organise production for maximum efficiency.

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Scales of Production

Before studying manufacturing systems, you need to understand the different scales of production:

Scale	Description	Example	Typical Cost per Unit
One-off (bespoke/prototype)	A single, unique product made to a client's specification	A wedding dress, a hand-crafted guitar	Very high
Batch production	A set number of identical products made together	500 school chairs, a bakery producing 200 loaves	Moderate
Mass production	Thousands or millions of identical products on an assembly line	Cars, smartphones, soft drinks	Low
Continuous production	24/7 manufacturing of a single product without interruption	Steel, paper, chemicals, electricity	Very low

AQA Exam Tip: When asked to identify the most suitable scale of production for a given product, consider the quantity required, the complexity of the product and whether it needs to be customised. Justify your answer with a reason, not just a label.

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Flexible Manufacturing Systems (FMS)

A Flexible Manufacturing System is a production setup that can be quickly reconfigured to manufacture different products or product variants with minimal downtime.

Key Components of an FMS

Component	Role
CNC machines	Programmable machines that can switch between tasks
Automated material handling	Conveyor systems, robotic arms and AGVs (Automated Guided Vehicles) move materials between stations
Central computer control	A master computer coordinates all machines and schedules production
Tool changers	CNC machines automatically swap cutting tools for different operations
Quality sensors	In-process inspection ensures defects are detected immediately

How FMS Works

1. The central computer receives a production order (e.g. 200 units of Part A, then 150 units of Part B).
2. CNC machines are automatically re-programmed with the correct G-code.
3. Tool changers load the appropriate cutting tools.
4. Material handling systems deliver the correct raw material to each workstation.
5. Production switches from Part A to Part B with minimal setup time.

The diagram below shows how an FMS coordinates the central computer, CNC cells and material handling to deliver finished parts:

graph LR
    A["Customer order"] --> B["**Central computer**\nschedules job"]
    B --> C["AGV delivers\nraw material"]
    C --> D["CNC mill\n(Part A)"]
    C --> E["CNC lathe\n(Part B)"]
    C --> F["Robot welding\ncell"]
    D --> G["Automated\ninspection"]
    E --> G
    F --> G
    G --> H["Finished part\ndispatch"]
    B -.feedback.-> D
    B -.feedback.-> E
    B -.feedback.-> F

Advantages of FMS

Advantage	Explanation
Quick changeover	Switching between products takes minutes rather than hours
Variety	One production line can manufacture multiple products
Responsiveness	Can react quickly to changes in customer demand
Efficiency	Machines are rarely idle because they can always be making something
Quality	Automated inspection reduces defects

Disadvantages of FMS

Disadvantage	Explanation
Very high capital cost	FMS setups require expensive CNC machines, robots and software
Complex to manage	The central computer system must be expertly programmed and maintained
Limited by machine capability	FMS cannot make products outside the range of its installed machines
Skilled workforce	Technicians and programmers are needed, not just operators

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Just-in-Time (JIT) Production

Just-in-Time (JIT) is a manufacturing strategy where components and materials are delivered to the factory exactly when they are needed — not before, not after. This eliminates the need for large warehouses full of stock.

How JIT Works

1. A customer order triggers a production schedule.
2. The factory orders materials from suppliers to arrive just before they are needed on the production line.
3. Components are assembled immediately upon arrival.
4. Finished products are shipped to the customer with minimal storage time.

Advantages of JIT

Advantage	Explanation
Reduced storage costs	No need for large warehouses — materials go straight to the line
Less waste	Materials are not sitting around deteriorating or becoming obsolete
Improved cash flow	Money is not tied up in stock that is not yet being used
Faster defect detection	Small batches mean problems are spotted quickly
Space efficiency	Factory floor space is used for production, not storage

Disadvantages of JIT

Disadvantage	Explanation
Supply chain vulnerability	If a supplier is late, the entire production line stops
No buffer stock	There is no safety net if demand suddenly increases
Reliance on reliable suppliers	JIT requires strong, trustworthy supplier relationships
Frequent deliveries	More delivery lorries on the road increases environmental impact
Not suitable for all products	Products with unpredictable demand are hard to manage with JIT

Real-World Example — Toyota

Toyota pioneered JIT as part of the Toyota Production System (TPS) in the 1970s. Their approach combined JIT with Kanban (a visual card system to signal when components are needed), Kaizen (continuous improvement) and Jidoka (automation with a human touch — machines stop automatically if a defect is detected).

AQA Exam Tip: JIT is one of the most commonly tested topics in the manufacturing systems section. Remember the key advantage (reduced waste and storage) and the key disadvantage (supply chain disruption). A good exam answer uses Toyota as a real-world example.

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Comparing Production Systems

Feature	Traditional (Push)	JIT (Pull)	FMS
Stock levels	High — large warehouses	Very low — materials arrive as needed	Moderate
Changeover time	Long — manual setup	N/A (related to scheduling)	Very short — automated
Product variety	Low — one product per line	Varies	High — multiple products per line
Waste	Higher — overproduction, excess stock	Lower — only make what is ordered	Lower — efficient scheduling
Risk	Low — buffer stock absorbs shocks	High — no buffer	Moderate

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Quality Control and Quality Assurance

FMS and JIT both depend on high-quality outputs with minimal defects.