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Unit 3: Introduction to Shop Practices. Unit Overview. This unit introduces students to shop practices and their interrelation to design. Generally , the purpose of doing a product design is to eventually fabricate a physical product for the end user.
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Unit Overview • This unit introduces students to shop practices and their interrelation to design. • Generally, the purpose of doing a product design is to eventually fabricate a physical product for the end user. • The transition from design blueprint to the final product requires that various materials be selected, processed and then fabricated. • We need to be aware of selection criteria, processing methods and fabrication techniques in choosing materials for product manufacture.
In this unit the student will be introduced to the physical/mechanical properties of wood, common metals and plastic and explore how these properties affect the cost, function and the required manufacturing processes. • They will also develop and appreciation for the effect of proper material selection and processing on quality assurance and costing of the final product. • Finally, production planning and production related careers are overviewed.
Topic 1 • Topic 1: Material Types and Properties (4 hours) • 3.1.1 Identify the common materials available for fabrication [1.403] • 3.1.2 Define the key physical/mechanical properties of common materials [1.403] • 3.1.3 Explain the relationship between material properties and product application [1.403] • 3.1.4 Explain the relationship of material type and properties to environmental impact [5.402, 5.403]
3.1.1 Identify the common materials available for fabrication [1.403]
Wood Types • Wood Properties: • All the woods are divided into two broad categories- hardwoods and softwoods. Before knowing about different types of wood, it is better to know the basic wood properties that distinguish one type from another
Some types of wood are very hard and durable and some are flexible enough to be bent. "Hardwood" is one of the common types of wood which is obtained from trees that lose their leaves in winter. • The other type of wood, the "Softwood“ (ever hear of the softwood lumber industry in BC?) is obtained from evergreen trees like fir, pine and redwood. All the woods fall between a range from very soft to very hard.
All types of wood have distinctive grain structure. Woods like white and red oak, ash and walnut have open-pores in the form of small holes on their surface that give a distinct textural quality to furniture pieces like wooden cupboards or wooden desks.
When the surface of this wood is stained, the color tends to collect in the "open-pores" and appears darker than the rest of the piece. There are other woods like maple, alder, and cherry which are tight grained woods. These woods are have smooth texture and can take finish evenly.
Hardwoods • Include: • Mahogany • Walnut • Oak • Maple • Cherry • Rosewood • Teak • Shesham
Softwoods • Include: • Pine • Hemlock • Fir • Redwood • Spruce • Cedar
Other Types • MDF (Medium Density Fibre Board): is made from powdered wood bonded with glue and compressed to form the sheets. It is quite soft and very easy to work with. It cuts, sands and finishes very easily. It is used widely for interior projects especially for cupboards and shelving.Chipboard: is made like MDF but from actual wood chips. It is used widely for kitchen furniture for which it is covered with a laminate. It is also used widely for low cost flooring.Plywood: is made from thin laminates of wood glued together. Each layer is at right angle to the grain of the other. It is very strong but also quite flexible, especially if there are thinner sheets. It is used widely in the building industry.
Newfoundland • Let’s look at some info on types of wood in our own province: • http://www.nr.gov.nl.ca/nr/forestry/statistics/forest/forest_types.html
Working with Wood Materials • The particular difficulties associated with working with wood in the shop include: • The presence of knots, warping, splitting, rotting and sawdust pollution. • Since wood is not a man-made material, it is impossible to have the uniformity and consistency of metals or plastics. Let’s discuss the fabrication challenges that this presents.
Assignment • You are to select one type of wood from Newfoundland, and discuss its uses and characteristics. Be sure to include: • Hardness • Tendency to warp • How easy it is to work with • Texture • Abundance • Main uses (where we see it being used the most) • http://www.nr.gov.nl.ca/nr/