Scale of Production in Product Design: a guide for students

To become an effective designer, you must understand how the scale of production in product design (individual, small batch, and mass production) impacts the manufacturing process. Understanding these systems of production, as well becoming familiar with terms such continuous production and just-in-time manufacturing, helps you make better design decisions and anticipate manufacturing challenges.

Individual production (one-off items)

• Often involves a high level of craftsmanship, with high quality products;
• Often has motivated staff, because they have direct control over the creation of original products, with interesting and varied tasks;
• Products can be individually made to customer requirements;
• Products are unique and hence often considered more desirable;
• High cost per unit (takes lots of time to make each item);
• Skilled workers needed
• Not suitable for making many products that are exactly the same (hard to keep items perfectly consistent);
• Easier to manage – control of production sequence is often simple, because whole operation is small.

Batch production

This involves small batches of a product being made at once.

• More flexible than mass production;
• Can adjust to changes in product demand relatively easily (after each batch is complete, the process can be adapted as needed);
• Less expensive machinery than mass production;
• Faster than individual production, but slower than mass production;
• Needs careful budgeting – can involve bulk purchasing materials at the start – larger initial cost, but saves money overall (often discounts for purchasing larger volumes). Having all materials on-hand avoids production delays and helps ensure consistency, as quality control checks of materials can be undertaken at the start.
• Requires significant storage space and careful inventory management, which can create challenges.
• Changes between batches can be small (i.e. just a colour change).
• Can be complicated switching between batches – time-consuming changeovers, including cleaning, resetting, and recalibrating equipment, reducing overall production efficiency.
• Inspections, testing procedures, and other quality control measures can help ensure consistency between batches;
• The use of jigs and templates can help improve consistency.

Jig: a custom-made tool or device to guide the motion of another tool or hold a workpiece in a specific position while making it. Jigs help to ensure consistency when repeating a processes multiple times. For example, a drill jig might be used for precise placement, or to help hold timber while bending around a mould.

Mass Production

This involves the production of standardised items through a largely automated system.

• Separates each part of the manufacturing process – division of labour – using conveyor belts, machines and workers on production lines etc;
• Big cost to set up (purchase of all machines etc);
• Much cheaper long term due to economies of scale (faster to produce / low overheads per unit / low labour costs / better prices due to bulk purchasing of materials). This results in more affordable products and drives increased profit for manufacturers.
• Often involves manufacturing a very narrow type of product, as costly to suddenly start manufacturing something different;
• Quality control is easier because all units are likely to be very similar – much easier to have standardised systems with everything exactly the same;
• Harder to manage the whole operation and establish where errors are going on, because operation so large;
• Products may be ‘cheap and nasty’;
• Tasks are often repetitive, boring, and simple, leading to unmotivated staff and reduced job satisfaction
• Can be increased injury risk due to boredom / repetitive tasks / rapid pace of mass production. On the other hand, mass production methods can also improve workplace safety by removing workers from dangerous processes through the use of automated systems.
• Staff can become specialised / expert at their one task, leading to increased efficiency.
• Mass production methods can lead to loss of jobs as automation replaces human workers. However, mass production can create new types of skilled positions in areas such as machine maintenance, quality control, and production planning.
• Shift work and long hours: Continuous production can impact workers’ work-life balance and social relationships. Many mass production facilities operate 24/7, requiring workers to adapt to changing shift patterns.

Continuous Production is a type of mass production that never stops – it runs 24/7, and is often used when stopping the plant is costly.

Just-in-time manufacturing

Just-in-Time (JIT) is a production strategy where materials are delivered and products are made only as needed, reducing inventory costs and waste. Parts arrive “just in time” for use in production, rather than being stored in large quantities.

Amazon ‘print-on-demand’ facilities are an example of just-in-time manufacturing. When a customer orders a copy of self-published book via Amazon, for example, the book is printed right at that moment and shipped out to customers. There are no warehouses holding copies of these books. They are only printed as an when they are needed.

Note: Products can use more than one manufacturing process, i.e. have some parts mass produced and some parts batch produced.

Why do manufacturers consider the total number to be made before deciding the method of production to be used?

• Production volume affects material purchasing decisions and costs. This consideration is important because bulk material purchases often offer better rates but require higher initial investment.
• The total quantity produced affects storage requirements and associated costs.
• The number needed determines which production method will be most cost-effective. Different production methods have vastly different setup costs and per-unit costs. High setup costs must be spread across the total number of items produced.
• The production method directly impacts delivery schedules. Hand-cutting small quantities of a card product might be feasible, but for larger quantities, die-cutting becomes more time-efficient. Jigs and templates can speed up production if multiple copies are needed.
• Quality considerations: Production quantity influences the ability to maintain consistent quality across the batch. While hand-finishing might ensure high quality for small runs, automated processes become more reliable for maintaining consistency in large quantities.

Note: the content below is for A2 students only.

Concurrent Engineering

This is an approach where different stages of product development happen simultaneously rather than sequentially. Teams working on design, manufacturing, and other aspects collaborate from the start, reducing time to market and catching potential issues early.

Computer-Integrated Manufacturing (CIM)

This refers to the use of computer systems to control the entire production process, from design and engineering to manufacturing and quality control. Computer-Integrated Engineering (CIE) specifically focuses on using computer systems to integrate various engineering activities like design, analysis, and simulation.

Cell Production

This involves organising manufacturing into work cells – small, self-contained units where a team completes a whole product or major component. Each cell contains all necessary equipment and workers, improving efficiency and reducing material movement.

In-line Assembly

This method arranges production in a linear sequence where products move continuously from one workstation to the next, with each station performing specific tasks in order. This is common in automotive and electronics manufacturing.

Sample examination questions (AS Design & Technology)