Manufacturing Processing Materials By P. Hennessy November 2007

Massachusetts State Frameworks Standards 7.1 Describe the manufacturing processes of casting and molding, forming, separating, conditioning, assembling, and finishing. 7.2 Identify the criteria necessary to select safe tools and procedures for a manufacturing process (e.g., properties of materials, required tolerances, end-uses). 7.3 Describe the advantages of using robotics in the automation of manufacturing processes (e.g., increased production, improved quality, safety).

What is manufacturing? The Manufacturing Process is used to change the size, shape, combination and composition of materials. Is the application of thermal, mechanical and electrical/chemical processes of a given starting material to make parts or products. Though manufacturing materials are transformed into items which have added value by means of one or more processing and/or assembly operation.

Types of Manufacturing Processes Thousands of manufacturing processes exist. Six classifications of manufacturing Casting and Molding Forming Separating Conditioning Assembling Finishing

Casting and Molding Casting and molding gives materials shape by introducing a liquid material to a mold. A casting is the pouring of the material into a mold. A mold is the cavity that has the shape of the desired object. Pouring molten aluminum into a sand mold A metal mold for a plastic toy A sand mold for a metal trivet

Extrusion Blow Molding Animation (from Fluent, CFD software) The material is injected between the mold halves 2. The mold closes 3. Air is used to inflate the material to the sides of the mold where it rapidly cools 4. Mold opens and the part is removed and extra material is trimmed www.fluent.com/software/ polyflow/blow.htm Plastic bottles are made using this method.

Where have you seen casting? Homework: Name at least 8 molding examples you know not shown here.

Forming Processes Forming process applies a force to a shaping device causing the material to change shape. Forming materials uses one of two types of devices which are harder than the material being formed. Dies or rollers A Die is in the shape of the object to be made, by using pressure it will form the object. Rollers working in pairs to form round objects from sheets.

The force applied to a material must be in a specific range for that material Elastic range – material will not hold the new shape. Yield point – the point that the material will permanently be deformed. Slide one of two

The force applied to a material must be in a specific range for that material Deformation range or Plastic range – material will retain the stretched, compressed, or bent form. Fracture point – the point that the material will fail or rupture. Slide two of two

Vacuum Forming Vacuum Forming is accomplished by heating a plastic sheet until it is pliable enough to be vacuumed into a mold.                        www.fluent.com/.../ thermoforming.htm www.pmwproducts.com/ thermoforming.html

Other forming processes Drawing - pulling Extrusion - pushing Rolling - squeezing

Separating Process Removing excess material to make an object of correct size and shape. Material is removed by either machining or shearing. Machining removes excess material in small pieces by the motion of the tool against the material. Shearing is cutting which is done by blades that slide by each other. Material is removed as one larger piece.

Machining examples Drilling Wood Lathe Shearing Milling machine Sawing Laser Cutting

What is the difference between the first two manufacturing methods forming and casting & molding and the third method, separating?

Conditioning Changing of internal properties is called conditioning. These processes can make the material harder, softer, stronger or more easily worked. Mechanical Conditioning Squeezing, stretching, pounding or bending Chemical Conditioning change the properties of a material like rain-x or glass etching Thermal Conditioning The most common conditioning aka Heat treating.

Thermal conditioning processes Hardening – used to increase the hardness of the material. Harden steel is made by heating to a specific temperature and soaked (wait until the entire part is at a uniform temperature) Once heated is rapidly cooling (quenching) in oil or water. Annealing - used to soften and remove internal stress in a part. The part is heated to a specific temperature and is allowed to soak. Once heated is then removed and cools slowly to room temperature. Page two of three

Thermal conditioning processes Tempering - used to relieve internal stress in a part. Hardening causes internal stress, which will cause the part to crack under use. Tempering temperatures are much lower than annealing temperatures. Used on glass and metal. Firing – a thermal conditioning process used for ceramics. This drives internal moisture out of the clay and the grains bond together to make a solid structure. Certain coatings are fired like porcelain enamels. Drying – is a common thermal conditioning process. It removes moisture from materials. Ceramics and wood must be dried before they are useful. Drying can happen naturally or be helped by adding heat. Lumber, for example is either dried by air or by kiln. Page three of three

Assembly Processes The word assemble means “to bring together.” Most of the things we see are made from two or more parts. A wood pencil is a total of five parts. The barrel is two pieces of wood glued together around the graphite. The eraser is held onto the wood barrel by a metal band. There are two methods of assembly. Bonding Mechanical Fastening Page 1 of 5

Bonding Fusion bonding – This method uses heat or solvents to melt the edges of a joint. The materials flow together to create a bond. Welding is an example of this type of bonding. Flow bonding – This method the base metals are cleaned and put together and an alloy is melted and flows between the two parts. When it cools the bond is complete. Soldering and Brazing are examples of this type of bonding Page 2 of 5

Bonding Pressure bonding – This method uses pressure and often heat to create the bond. Adhesives can be used also in this type and clamps apply pressure until the bond is complete. Spot Welding is an example where heat is used and wood glue to build furniture is an example of an adhesive bond. Page 3 of 5

Types of Joints Material Joints – Joints are where parts meet. Pieces of materials are fastened together at joints. By using different types of joints the strength or holding ability of the adhesive will improve. Page 4 of 5

Mechanical Fasteners Fasteners – Use mechanical forces to hold parts together. Friction between the parts can be used. Press fits are used to hold many parts together such as bearings on a shaft. Parts maybe interlocking such as a seam on sheet metal. Fasteners are the most widely method to hold parts together. Examples would be: staples, nails, screws, rivets, pins and nails. Page 5 of 5

Finishing Processes This is usually the last step of the secondary processes. These processes protect the product and enhance their appearance. Converted surface finish changes the surface to protect the product. Anodizing will cause aluminum products to oxide which will prevent further erosion. The other finishing method applies a coating to the product. These finishes applied to the product will protect it as well as add color. Finishes are applied by: Dipping Plating Spraying Flow Coating

Automating and Controlling Processes New machines can load materials, adjust tool feeds and speeds, and do many other tasks humans once did. These machines make up systems called automation. Automation includes robots, programmable logic controllers (PLCs), computer-controlled machines, and artificial intelligence (AI) systems. © Goodheart-Willcox Co., Inc.

Automation Parts Industrial robots are commonly used for welding, painting, assembling, moving materials and parts, and inspecting products. Programmable logic controllers (PLCs) have three basic functions: input, control, and output, all programmed by a technician. © Goodheart-Willcox Co., Inc.

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Blow Molding www.devco-design.com/ bl-mold.htm