AQA GCSE Design and Technology 8552 - Unit 5B

AQA GCSE Design and Technology 8552 - Unit 5B: Timber-Based Materials

• Unit focus: Sources, origins, and properties of timber-based materials, including forestry management, timber conversion, seasoning, faults, and manufactured boards.

Objectives

• Students should understand the processes involved in creating workable timber - conversion, seasoning, and manufactured timber creation.
• Students should be aware of the sustainability and ethical factors in timber production and use.
• Students should understand the advantages and disadvantages of manufactured board compared to natural wood.

Trees

• Wood has been used as a material and fuel for thousands of years.
• Wood is durable.
• Planet Earth has over 23,000 tree species.
• What wooden products/objects were used this morning?

Forestry Management

• Proper forestry management creates a sustainable cycle.
• Well-managed forests offer benefits: leisure, employment.
• What other benefits do students think managed forests offer?
• The cycle includes cultivation, planting, resource recycling, harvesting, wood chip fuel use, and waste management.

Thinning Forests

• Managed forests contain trees of various ages.
• When a tree is felled, it's replaced with new seedlings.
• Young trees are typically thinned around five years old.
• Why is thinning trees every five years common?
• What is the typical use for the thinned timber?

Felling

• Felling occurs when a tree is cut down.
• Traditional methods used an axe or long saw.
• Modern felling utilises chainsaws or agricultural machinery to fell, de-branch, and cut trees into equal-length logs.
• Compare advantages/disadvantages of mechanised vs. manual methods.

Product Mileage

• How much mileage does wood take from tree to end user?
• What stages are in the journey from tree to end product?

Timber Conversion

• What does PAR stand for? (Planed All Round)
• How is PAR timber used?
• Where is PAR most commonly used? (Exterior tasks, or interior spaces requiring a smooth finish)
• What happens to offcuts?

Green Timber

• Newly felled, unseasoned trees are called "green timber."
• Green timber has high moisture content (over 50%).
• Green timber is harder to work with for interior projects.
• Exterior timber should have a moisture content below 20%.
• Domestic furniture timber moisture content should be below 10%.

Seasoning

• Seasoning reduces timber's moisture content.
• Seasoning methods: air drying, kiln drying.
• What are the advantages of air drying compared to kiln drying?
• What are the environmental advantages of air drying?

Faults

• Faults occur during drying. Examples: bowing, splitting/cracking, springing, cupping, twisting.
• How do the different faults visually appear?

Reducing Faults

• Faults can make timber unusable (increase wastage).
• Why is kiln-dried timber less prone to faults than air-dried timber?
• Why are end grains of timber planks sealed?

Sustainability

• Trees are valuable resources but often overused.
• The rate of timber use has sometimes exceeded trees' growth rate.
• High demand for exotic woods (teak, mahogany) has fuelled illegal logging.

Consequences of Illegal Logging

• Illegal logging destroys rainforest areas.
• Illegal logging causes desertification.
• Deforestation influences global warming.
• What are the potential consequences of rainforest destruction, desertification, and global warming?

Timber Provenance

• Timber provenance is regulated by organizations like FSC (Forest Stewardship Council) and PEFC (Programme for the Endorsement of Forest Certification).
• In the UK, sustainably managed forests must be FSC or PEFC accredited.
• How do FSC and PEFC organizations regulate the timber industry?

Kit House Construction

• Complete Task 1 of Worksheet 1 (likely a worksheet within the course materials).

Manufactured Boards

• Manufactured boards are made from waste/recycled wood using adhesives and lamination/compression techniques.
• Higher-quality timber veneers are used for manufactured board aesthetic appeal.
• Why can manufactured boards be classified as composite materials?

Laminated Boards

• Lamination involves layering materials using heat, pressure, and adhesives.
• Veneers (thin layers) are layered with their grain at 90° angles to each other to for structural strength.
• Why are odd numbers of layers used in lamination?
• Discuss lamination's impact on material properties.
• Mention any aesthetic benefits of laminated manufactured boards.

Compression

• Compression uses adhesives, heat, and pressure to combine wood shreds, chips, or pulp into larger boards.
• Commonly used in oriented strand board (OSB), chipboard, and medium-density fiberboard (MDF).
• These products may be coated with melamine or Formica® laminates.
• Where are raw materials for compression boards obtained?
• Why are compressed boards weaker than laminated ones?

Rotational Veneer Production

• Veneer is created by rotating a tree trunk on a machine (like a wood lathe).
• The process produces a continuous ribbon of veneer that can then be cut to the desired lengths.

Using Manufactured Board

• Advantages: Available in large sheets, less prone to defects, aesthetic flaws are covered, little finishing required, made from otherwise wasted wood, wide range of surface finishes.
• Disadvantages: Adhesives can be hazardous (inhalation), dulling tools, unsuitable for woodworking joints, prone to absorbing moisture.

Worksheet 1

• Complete task 2 of Worksheet 1.

Plenary

• Forestry: managing tree growth.
• When mature, trees are cut down using tools such as chainsaws or industrial machinery.
• What happens to felled timber after being cut?
• Discussion of environmental and ethical factors (sustainability).