Topic 4 – Manufacturing Processes and Techniques

Fall 2006

4.1 Manufacturing Processes and Techniques

• Manufacturing Process• Manufacturing Technique• Shaping

– Bending - http://manufacturing.stanford.edu/hetm.html (Forming Shaping)

– Molding - – Casting - http://manufacturing.stanford.edu/hetm.html (casting Metal)– Weaving

• Joining– Fasteners – screws, nail, rivets, welds, etc. http://

manufacturing.stanford.edu/hetm.html (welding)– Adhesives– Fusing– Stitching

• Wasting - http://manufacturing.stanford.edu/hetm.html (machining)– Machining– Cutting– Abrading

4.2 Selecting Materials and Techniques

• The selection of materials takes into account economic processing and service requirements.

• Successful products should be evaluated in term of efficiency and economy of manufacture as well as performance

Techniques

• Injection Molding - • Lamination• Sintering• Extrusion• Cutting and Machining

Injection MoldingThe direct introduction of molten plastic under pressure into a die which

then cools rapidly allowing the formed object to be released from the mold

• Advantages– No finishing required, volume production, use

of different molds• Disadvantages

– Set up costs reduce suitability for low volume production, limitations to the size, shape

• Design Considerations – must consider thermal expansivity and toughness

Laminationbuilding up a thick layer of material using thin layers of the material

joined with adhesives includes mold or former and a method of cramping

Advantages – no finishing required, able to form complex shapes and surfaces, can suit large surfaces, able to combine different materials

Disadvantages – labor intensive, may require production of a mold, limitations to the glue, size, clamping, shape and angles of curvature.

Design Considerations – Good when needing a tough and high tensile strength.

SinteringThe fusing of solid particles together by heat and pressure without

completely liquifying the particles

AdvantagesDisadvantagesDesign Considerations

ExtrusionForcing material through a shaped die to produce a shaped rod or tube

of material, eg: wire, pasta, toothpaste

Advantages

Disadvantages

Design Considerations

Cutting and MachiningCutting a material into shape and finishing it by machines

Advantages

Disadvantages

Design Considerations