Welcome to AS 2: Redesign Solutions and Development

Welcome to one of the most rewarding parts of your CCEA AS Level Technology and Design course! In AS 2: Coursework – Product Development, you step into the shoes of a professional design engineer.

Unlike GCSE projects where you often start from a blank sheet of paper, AS Unit 2 is all about product redesign. You will take an existing manufactured product, identify its real-world flaws, and re-engineer it to make it better, stronger, more ergonomic, and easier to manufacture. This unit counts for 50% of your total AS award (and 20% of your overall A Level), and this chapter covers the core creative and technical engine of your portfolio: turning initial ideas into fully resolved, workshop-ready solutions.

Quick Review: The AS 2 Journey
1. Investigation and Analysis of Product
2. Redesign Solutions and Development (our focus here!)
3. Making (Prototype/Model Manufacture)
4. Testing and Evaluation

1. Concept Generation: Exploring Redesign Solutions

Once you have analysed an existing product and established your Design Specification / Product Design Specification (PDS), your next task is to explore a wide range of creative redesign ideas.

What Makes an AS Level Redesign Concept?

Don't fall into the trap of just changing the colour or smoothing out a curved edge! A true engineering redesign addresses tangible issues identified in your initial product analysis, such as:

  • Functional limitations: Mechanisms that jam, poor mechanical advantage, or weak linkages.
  • Ergonomic shortcomings: Uncomfortable grips, poor balance, or awkward user interfaces.
  • Material failures: Parts that crack under stress, wear out quickly, or degrade under UV light.
  • Manufacturing inefficiencies: Products that have too many complex parts or are difficult to assemble.

Communication Standards for Initial Ideas

Your portfolio must present a wide range of distinct, viable 2D and 3D conceptual sketches. To score top marks, use clear graphical techniques:

  • Standard Graphical Projections: Use isometric, oblique, exploded views (showing how parts fit together), and orthographic sketches.
  • Detailed Technical Annotation: Never leave a drawing unannotated. Point out functional improvements, mechanical actions, potential materials, and assembly methods.

Analogy Time: Think of your concept sketches like a storyboard for a film. Anyone looking at them should understand exactly what is happening, how parts move, and why you changed a feature from the original product.

Key Takeaway: Redesign concepts must solve real functional, ergonomic, or mechanical problems identified in the original product—not just change its superficial style.

2. Concept Appraisal & Selection Matrix

How do you decide which concept is the best one to take forward? You must use an objective, systematic evaluation tool rather than just picking your personal favourite.

Using a Comparative Evaluation Matrix

A comparative appraisal matrix directly tests each concept against your Product Design Specification (PDS) criteria.

  • List your specification points along one axis (e.g., structural rigidity, ease of disassembly, production cost, user comfort).
  • Rate each redesign concept against these criteria using a clear scoring system.
  • Provide a written justification explaining why the winning concept best satisfies the brief and how it will be refined during development.

Key Takeaway: Concept selection must be evidence-based, directly linked to your initial specification criteria through a clear evaluation matrix.

3. Design Development & Iterative Modeling

Design development is not about drawing a single neat picture of your final idea. It is a step-by-step journey of iterative refinement—testing, modifying, and perfecting details before you step into the workshop.

A. Physical Sketch Modeling

Before committing to expensive materials or manufacturing, test your mechanisms and physical forms using rapid prototyping materials:

  • Cardboard & Foam Board: Ideal for quickly checking structural geometry, scale, and mechanical linkages.
  • Clay & Styling Foam: Perfect for testing handgrips and 3D surface contours.
  • 3D Print Mock-ups: Great for checking precision fit, snap-joints, and moving components.

B. Parametric 3D CAD Modeling

Computer-Aided Design (CAD) allows you to build virtual 3D models, test component clearances, simulate movement, and quickly adjust dimensions parametrically.

C. Ergonomics & Anthropometrics

Your redesign must fit the human body properly. When designing handles, buttons, or access panels, apply standard anthropometric percentiles:

  • 5th Percentile: Represents the smaller end of the population (e.g., reaching distances, grip spans for smaller hands).
  • 50th Percentile: The average human dimension.
  • 95th Percentile: Represents the larger end of the population (e.g., clearance heights, handle widths, door openings).

Example: If you are redesigning an enclosed carry-handle, you size the opening for the 95th percentile hand breadth so that \(95\%\) of users can fit their hand through comfortably!

Key Takeaway: Development must show clear iteration. Document your physical mock-ups, CAD tests, and anthropometric choices to prove that your design evolved logically.

4. Material and Manufacturing Process Selection

In AS Unit 2, every material and manufacturing method you choose must be technically justified based on mechanical properties and commercial feasibility.

Material Justification

Avoid vague terms like "plastic" or "metal". Specify exact material categories and justify them based on their properties:

  • Timbers: Natural hardwoods/softwoods or manufactured boards (e.g., assessing grain strength, dimensional stability, moisture resistance).
  • Metals: Specific alloys such as 6061 Aluminium alloy (lightweight, corrosion-resistant) or mild steel (high tensile strength, easily welded).
  • Polymers: Thermoplastics like ABS (high impact resistance, rigid) or High Impact Polystyrene (HIPS) (easy to thermoform, lightweight).
  • Composites & Smart Materials: Materials engineered for specific strength-to-weight ratios or responsive behaviours.

Properties to discuss: Strength-to-weight ratio, durability, thermal resistance, electrical conductivity, and resistance to environmental/UV degradation.

Manufacturing Process & Scale of Production

Explain how your redesigned components would be produced commercially, considering:

  • Scale of Production: One-off, batch, or mass/continuous production.
  • Commercial Feasibility: Incorporating standard design rules such as draft angles for injection moulding, tool clearances for CNC machining, and integrating standard off-the-shelf fasteners.

Key Takeaway: Always name specific materials and production processes, backing up your choices with clear mechanical and commercial reasons.

5. Final Working Drawings & Technical Specification

The final step of the development section is preparing technical drawings that allow someone else to manufacture your prototype accurately.

Standards and Requirements

  • Standard: Drawings must comply with BS 8888 standards.
  • Projection: Fully dimensioned 3rd Angle Orthographic Projection showing front, plan, and end elevations.
  • Details Included: Hidden detail (dashed lines), section views (to reveal internal mechanisms), and strict tolerances (e.g., \(\pm 0.5\text{ mm}\)).
  • Parts & Cutting Lists: A complete breakdown listing part names, quantities, exact dimensions, and materials ready for workshop manufacture.

Key Takeaway: Your final working drawings must be precise, fully dimensioned to BS 8888 standards, and include cutting lists so your prototype can be built without guesswork.

Common Examiner-Reported Errors to Avoid

Keep these common pitfalls in mind as you work through your portfolio:

  • Superficial Styling vs. Real Redesign: Do not just change the exterior casing style. Focus on resolving mechanical, ergonomic, or manufacturing weaknesses.
  • The "Magic Leap": Avoid jumping directly from a raw sketch to a finished CAD model without showing the messy, realistic middle steps (cardboard mock-ups, size adjustments, failed ideas).
  • Disconnected Specification: Ensure your development steps directly answer the constraints set out in your initial PDS.
  • Vague Material Callouts: Replace labels like "tough plastic" with specific materials like "Injection-moulded ABS" and explain why.
  • Incomplete Drawings: Avoid missing dimensions, omitted tolerances, or missing cutting lists on your final orthographic sheets.

Chapter Summary Checklist

Before moving on to the workshop making phase, ensure your portfolio includes:

  • [ ] A diverse range of 2D/3D concept sketches showing real functional and ergonomic redesigns.
  • [ ] Clear technical annotation on all concepts (materials, mechanics, joints).
  • [ ] A completed comparative appraisal matrix evaluating ideas against the PDS.
  • [ ] Evidence of iterative development using physical models (card, foam, 3D prints) and CAD.
  • [ ] Anthropometric calculations using appropriate percentiles (5th, 50th, 95th).
  • [ ] Justified material selections and commercial manufacturing considerations.
  • [ ] BS 8888 3rd angle orthographic working drawings with dimensions, tolerances, and cutting lists.