4 Some things to think about, and who might think about them: Materials (MSE, Chem E) Processes (ISE, WE, Chem E, ME) Tooling: molds and dies (ME, ISE) Production setup and plant layout (ISE)
5 Some questions a designer might ask: What’s the best material for this part? Given the best material, how do I form it? How will my design affect how the part is manufactured? How does the manufacturing process affect my design? Can I make this using fewer parts?
6 Some things a manufacturing engineer might think about: How can I make this component most efficiently? How can I make it with the least amount of material, energy, and labor? What manufacturing process is best suited to this component?
7 Today we’ll look at three important manufacturing processes: Thermoplastic injection molding is used for almost every part of the camera, except the circuit board, shutter, and springs. Sheet metal forming is used to make the shutter, springs, contacts Machining is used to make the molds for injection molding, and the dies for metal forming.
8 Injection molding Injection molding is a widely used process used for forming the groups of polymers known as thermoplastics. Thermoplastics undergo a physical change during molding, and can be remelted and reused. The other group of polymers, thermosets, change chemically when processed, and can’t be reused.
9 To form polymer resin into components, we need to: Bring it to a liquid state Inject it under high pressure into a mold Let the resin cool and solidify Open the mold and eject the part Close the mold and start again
10 The injection molding machine: Heats the polymer until it’s liquid Clamps the mold shut Injects polymer into the mold cavity Holds it under pressure until it’s cool enough to retain its shape, and Ejects the part and starts the process again...
11 chemical The injection molding machine:
12 The injection molding machine:
13 The injection molding machine:
14 If we look at injection pressure vs. time:
15 Some problems: Filling the mold before the plastic freezes Designing the mold so that the part can be ejected easily Designing the part and mold so that we can produce the parts and make a profit.
16 What about the metal parts? There are several different ways of forming metal: forging extruding drawing (the aluminum can!) bending rolling
17 Today, we’ll look at blanking: Blanking occurs when we punch a hole in a sheet of metal, and keep the piece (blank) that we punch out. When we punch a hole and “keep the hole”, then the process is called piercing.
18 The blanking process:
19 The piercing process:
20 The punch press:
21 How do we make the tools that form the metal and plastic? By machining: Milling Turning Grinding Sawing Electric discharge machining
22 Probably the most important machining process is milling. Milling machines: Can make a variety of complex shapes Can machine essentially any material Can be computer controlled Are widely used to make molds and dies Use a rotating cutter to machine a fixed work piece.
23 A CNC vertical milling machine:
24 Machining parameters:
25 What we’ll do today: Form into supergroups of 12 Go to Baker Systems 090 (basement) Your supergroup will move through four different stations: injection molding, sheet metal forming, machining, and fixed- assembly. See handout for memo discussion questions.