Welcome to AS 2: Redesign Solutions and Development

Hello and welcome to your guide for Unit AS 2: Coursework – Product Development in CCEA GCE Technology and Design (8900)! If you are feeling a little overwhelmed about how to take an existing product apart, figure out what is wrong with it, and develop a completely new and improved version, do not worry. This guide breaks down the entire Redesign Solutions and Development stage step by step.

In this unit, you produce a 10-page A3 design folder and a 3D physical model or functional prototype. This coursework unit is worth 50% of your total AS Level (and 20% of your full A Level), so mastering this chapter is a massive boost toward securing top marks.

The Big Picture: What is "Redesign Solutions and Development"?

In the first part of your AS 2 portfolio, you investigated a commercial product and uncovered its flaws—maybe it breaks easily, hurts the user's hand after five minutes, uses expensive materials, or cannot be repaired. In this chapter, your job is to turn those problems into solutions.

Analogy Time: Think of a car mechanic who also happens to be an inventor. You do not just paint the car a shiny new colour (which is a superficial cosmetic change); you re-engineer the engine mount, redesign the door handle so it fits hands better, and make the panels snap together without ten different screws. Redesign is about functional, ergonomic, material, and structural innovation.

Part 1: Generating and Exploring Redesign Concepts

1. The Design Brief and Development Specification

Your redesign must never start out of nowhere. It has to connect directly back to the findings of your initial product analysis.

The Design Brief: A clear statement outlining what you intend to design and the core problem you will solve.
The Development Specification: A detailed list of measurable criteria your redesign must achieve. This includes ergonomic targets, structural needs, manufacturing constraints, and design for disassembly/recycling.

2. Creating a Range of Alternative Solutions

Examiners want to see that you have explored a wide range of creative ideas rather than latching onto your very first thought. Aim to generate multiple, distinctly different concepts.

Top Tip: Avoid "false variety." Changing the colour from blue to red or rounding off a single corner does not count as two different concepts. Instead, try completely different mechanical approaches, different component layouts, or distinct modular configurations.

3. Design Communication and Graphical Techniques

To score in the highest mark bands, you must communicate your ideas using a rich variety of industry-standard graphic techniques across your A3 portfolio pages:

• 2D and 3D Freehand Sketching: Use isometric, oblique, and perspective sketching techniques. Apply tone, shadow, and thick-and-thin line work to make sketches pop off the page and look three-dimensional.
• Section Views: "Slice" through your product to reveal internal gears, clips, batteries, or electronic boards that would otherwise be hidden.
• Exploded Views: Draw the components pulled apart along an axis to clearly communicate how sub-assemblies connect, join, and fit together.
• Computer-Aided Design (CAD) & 3rd Angle Orthographic Projection: Produce 3D solid models alongside standard 3rd angle projection working drawings complete with dimensions and hidden detail lines.
• Comprehensive Technical Annotation: Never leave a drawing unlabelled! Annotate every sketch with notes explaining the working principles, chosen materials, manufacturing processes, tolerances, and ease of recycling/disassembly.

Section Takeaway: Strong concept pages combine distinct, creative ideas with rich technical annotations and varied graphical styles—from freehand 3D sketches to CAD exploded views.

Part 2: Detailed Development and Iterative Refinement

Development is the bridge between a rough initial sketch and a fully realised product ready for manufacture. It is an iterative process—a repeating cycle of designing, modelling, testing, spotting a problem, and refining the design.

1. Iterative Modelling and Prototyping

Do not wait until the final making stage to pick up materials. Use fast, low-cost workshop models to test your ideas as they evolve:

• Card and Foam Models: Perfect for testing physical proportions, scale, hand grip, and form factors.
• 3D Printed Test Pieces: Excellent for testing tight mechanical tolerances, snap-fits, and interlocking joints.
• Breadboards and Digital Simulations: Ideal for proving that your electronic circuits or mechanical linkage simulations function before building them for real.

2. Applying Ergonomics and Anthropometric Data

Ergonomics is the study of how products interact with human users, while anthropometrics refers to the measurement of human body sizes.

In your redesign, you must justify dimensional changes using standard anthropometric data tables. Most design tasks aim to accommodate the \(5^{\text{th}}\) to \(95^{\text{th}}\) percentile of the target user population:

• The \(5^{\text{th}}\) Percentile: Represents the smaller end of the population (only \(5\%\) of people are smaller). Use this for minimum reach distances, slot sizes, or handle grip diameters so smaller hands can still grasp them securely.
• The \(50^{\text{th}}\) Percentile: Represents the exact median or average measurement.
• The \(95^{\text{th}}\) Percentile: Represents the larger end of the population (only \(5\%\) of people are larger). Use this for clearance dimensions, such as head clearance or handle width, ensuring that larger users do not get stuck.

3. Material and Component Selection

Every material choice in your portfolio must be backed up by a clear engineering reason. Link the material's mechanical properties directly to its manufacturing process:

• Polymers (Plastics): Select polymers like ABS or Polypropylene based on properties such as high impact resistance and suitability for injection moulding or 3D printing.
• Metals: Select metals like Aluminium or Mild Steel based on high tensile strength, stiffness, or electrical conductivity, matched with processes like CNC milling or turning.
• Woods: Select manufactured boards or hardwoods based on aesthetic warmth, grain strength, and suitability for laser cutting or CNC routing.
• Compliant and Smart Materials: Select flexible elastomers or responsive materials where natural flexibility or state-changing behaviour improves product function.
• Standard Bought-In Components: Select standard fixings, bearings, microswitches, or gears to reduce production costs and enable straightforward servicing.

4. Design for Manufacture (DfM) and Design for Assembly (DfA)

A brilliant idea is useless if a factory cannot make or assemble it. Show examiners your commercial awareness by including:

• Draft Angles: Tapered vertical walls (typically \(1^{\circ}\) to \(2^{\circ}\)) that allow moulded parts to be cleanly ejected from tooling without getting stuck.
• Uniform Wall Thickness: Constant wall thickness to prevent sink marks, uneven cooling, and warping in polymer moulding.
• Reinforcing Ribs: Thin internal structural supports that increase stiffness without adding unnecessary solid material.
• Snap-Fits and Standard Fasteners: Self-locating clips and standardised screws that make assembly quick and keep disassembly for repair or end-of-life recycling simple.
• Tolerances: Clearly stated allowable dimensional limits (e.g. \(\pm 0.5\text{ mm}\)) to ensure mating parts fit together reliably.

Section Takeaway: Development is not just drawing more pictures. It is proving that your product fits the human body (anthropometrics), works physically (modelling), uses the right materials, and can actually be built in a real factory (DfM/DfA).

Part 3: Memory Aid – The "CRATER" Checklist

Before submitting your development pages, check them against the CRATER checklist to guarantee full specification coverage:

C – Concepts: Did you generate multiple, distinctly different redesign concepts?
R – Real-world DfM: Have you added draft angles, uniform walls, ribs, and snap-fits?
A – Anthropometrics: Have you justified dimensions using the \(5^{\text{th}}\) to \(95^{\text{th}}\) percentile tables?
T – Technical Annotation: Are all materials, processes, tolerances, and joints clearly labelled?
E – Exploration & Modelling: Have you shown intermediate card/foam/3D-printed trial models?
R – Root Cause Solved: Does the redesign directly fix the initial product analysis flaws?

Part 4: Pitfalls and Examiner Warnings

Examiners routinely highlight the following recurring errors. Make sure you steer clear of them:

1. Purely Cosmetic Modifications: Do not just change the exterior shape or colour. If your redesign does not solve functional, mechanical, or ergonomic problems, it will not access higher mark bands.
2. The "Instant CAD" Trap: Do not jump directly from an initial idea straight to a finished 3D CAD render. Examiners award marks for the evolution of your idea through step-by-step iterations, physical trial models, and refinements.
3. Disconnection from Initial Analysis: If your investigation in section 1 found that the handle caused hand fatigue, your redesign must demonstrate an improved ergonomic handle. Never lose track of your initial findings.
4. Inadequate Technical Annotation: Avoid vague labels like "made of plastic" or "glued together." Use precise technical terms: "Injection-moulded ABS casing with a \(1.5\text{ mm}\) wall thickness and snap-fit cantilever joints."
5. Impossible CAD Geometry: CAD lets you draw shapes that cannot physically be manufactured or assembled. Ensure your models have realistic parting lines, draft angles, and clearance for internal components.

Quick Review: Essential Chapter Summary

1. Assessment Overview: AS 2 is assessed via a 10-page A3 portfolio and a 3D prototype outcome, worth 50% of AS Level (20% of full A Level).
2. Conceptual Range: You must present genuinely varied functional concepts using high-level graphics: 2D/3D sketches, exploded views, section views, and 3rd angle orthographic projections.
3. Scientific Ergonomics: Dimension decisions must be supported with anthropometric data tables (\(5^{\text{th}}\) to \(95^{\text{th}}\) percentiles).
4. Iterative Testing: Show your working! Document low-cost study models (card, foam, 3D prints, breadboards) to prove that mechanisms and forms work.
5. Manufacturing Realism: Integrate DfM principles (ribs, draft angles, wall uniformity, standard fixings, and disassembly considerations) to demonstrate real-world engineering thinking.