Midterm Flashcards
Give examples of a Job Shop, Flow Shop and a Project Shop?
Job Shop - an injection mold manufacturing shop
Flow Shop - automobile assembly
Project Shop - diesel-electric locomotive production
How does a system differ from a process? From a machine tool? from an operation?
a manufacturing system is a collection of people, tools and material moving systems working together to accomplish a specific task. A process is one part of the system, a way to get something done. A machine tool is used directly to produce the product, and an operations is a process in work.
What are the major classifications of basic manufacturing processes?
- casting or molding
- forming
- heat treating
- metal removal
- finishing
- assembling
- inspection
Could casting be used to produce a complex-shaped part to be made from a hard-to-machine metal? How else could the part be made?
the desired shape could be obtained by casting. This greatly reduces the necessity for machining the hard-to-machine metal. less machining required when the raw material is close to the finished part size and shape.
How is the railway station like a station on an assembly line?
trains stop at the station to load and unload people or materials. In an assembly like, product stops at the job station to take on materials or have operations performed on them
What forming processes are used to make a paper clip?
conventional paper clips, wire is cut to length, then formed in three bending operations
In the production system, who usually figures out how to make the product?
the manufacturing engineer is responsible for selecting or designing the manufacturing processes
What costs make up manufacturing cost (factory cost)?
- materials
- direct/indirect labor
- energy
- depreciation
What are producer goods?
intermediate goods used to manufacture the producer or consumer goods.
What are goods
Material things
What is a service
Non-material things
What is an SPSs
Service Production Systems
- non-material systems that do not produce a product
What is manufacturing
The ability to make goods and services to satisfy societal needs
What is a production system
The system is the total company and includes manufacturing
What are the interactive factors in manufacturing
- Product design
- materials
- labour costs
- equipment
- manufacturing costs
What are manufacturing systems
-complex arrangement of physical elements characterized and controlled by measurable parameters
What are manufacturing processes
Converts unfinished materials to finished products
What is the responsibility of a manufacturing engineer
Select and coordinate specific processes and equipment
What is the responsibility of an industrial engineer
Manufacturing system layouts
What do materials engineers do
Specify ideal materials or develop new or better ones
How much of the selling price of the product does the manufacturing cost account for?
40%
Define Job
the total of the work or duties a worker performs
Define Station
a location or area where a production worker performs tasks or their job
Define operation
a distinct action performed to produce a desired result or effect
what is fabricating
the manufacture of a product from pieces such as parts, components or assemblies
what is processing
the term processing referst to the manufacturing of products by continuous means, or by continuous series or operations
what are finishing processes used for
used to clean, remove burrs left by machining and provide a protective/decorative surface on the work piece
what are heat treatments used for
the heating and cooling of metal is done to alter its metallurgical and mechanical properties
What type of production system is the Toyota Production System
it is a Lean Production,
What role does manufacturing play relative to the standard of living of a country?
The availability and cost of manufactured products are important part of our cost of living and the wealth of a nation. Reducing cost of producer and consumer goods improves the productivity while holding down inflation.
explain how all goods are really consumer goods
by defining the customer as anyone who has used the output from a process, including all intermediate steps
In Lost-Wax (or foam) Casting what happens to the wax (or foam)?
The foam/wax is melted and vaporized and so it moves to the atmosphere around the process
in making a gold medal casting, what is meant by “relief image” cut into the die
the cavity in the die that the work material is deformed into when the die is pressed into the work piece.
Concave on the die results as a raised surface on the finished product
in the production system who usually figures out how to make the product?
All members involved in designing the part should be involved with determining the manufacturing process.
What is the objective of a manufacturing operation, and what are some of the details in meeting this objective?
Exceed Product Requirements
- Different Materials
- Different manufacturing processes
- knew knowledge/experiences
What are some undesirable features of significantly exceeding the requirements of a product?
- cost and price
- re-evaluations
- environmental concerns
- competition and demand
- review and evaluations
- product liability
What is the interrelation between engineering materials and the fabrication processes used to produce the desired shape and properties?
More than likely a change in material will lead to a change in manufacturing processes. and a change in processes will often lead to a re-evaluation of materials.
What is design?
- what to produce based on quantitative performance measures
- required material and geometric properties
- material to use
- related issues for manufacturing process selection
what are the three primary stages of product design and how does the consideration of materials differ in each?
- conceptual ( material selection is not a concern)
- functional (suitable materials will be selected and checked for availability)
- production (exact material is chosen)
What should the first step in any material selection problem be?
MUST define needs
What are some advantages to the customer of standardization and of interchangeable parts
- must be manufactured in the same standards of measurement
- mass production
- repetition
Explain the difference between attributes and variables inspection.
Attribute - determines if a part is good or bad
Variables - requires measurements to determine how good or how bad (more informative)
What are gage blocks and why do they come in grades and sets?
The grades of gage blocks are - laboratory - precision - working Blocks come in sets so that they can be "wrung" together into any length needed
What is the difference between an allowance and a tolerance?
Allowance - determines desired basic fit between mating parts
Tolerance - takes into account any deviations from a desired dimension and fit
Explain the difference between accuracy and precision
Accuracy - measured by distribution means
Precision - measured by variances or standard deviation
What are 6 factors when selecting inspection equipment?
- gage capability
- linearity
- repeat accuracy
- stability
- magnification
- resolution
What is the length range for gage blocks?
0.1001 to over 25 inches in increments of 0.0001 inch
Why are air-gages particularly well suited for gaging the diameter of a hole?
- detect linear size deviation and out-of-round conditions of a hole
- fast and virtually no wear on the gage or part
Explain how a go/no-go ring gage works to check a shaft.
the go ring should slip over the shaft if it doesn’t the shaft is to large
the no-go ring should not slip over the shaft, if it does the shaft is to small
What tolerances are added to gages when they are being designed?
if gage errors, it will reject a good part rather than accept a bad part, a tolerance is added for manufacturing and for wear
what is the primary precaution that should be taken when using a dial gage
- axis of the spindle is parallel with the dimension being read
- multiple readings are recommended
how can the no-go member of a plug gage be easily distinguished from the go member
the no-go member is usually made shorter because it undergoes less wear
what are the 5 basic families of shape-production processes? List 1 advantage and 1 disadvantage of each.
Casting - complex shapes but may have defects Material Removal - precision but lots of waste Deformation Processes - high production rates but require powerful equipment Consolidation - large/complex shapes but different materials = different properties
Describe the capabilities of the casting process in terms of size and shape of the product
- wide range of size (fractions of an inch to 30ft)
- complex shapes
- hollow sections
- internal sections
- irregular curved surfaces
Why would one choose to use single use versus multiple use molding processes?
Multiple use is generally used for large production jobs where upfront cost isn’t an issue. single use for a smaller production.
What kind of defect can occur if the mold material provides to much restraint to the solidifying and cooling metal?
the casting may crack
What is draft and why is it used?
Draft is a taper on a pattern to permit the pattern to be withdrawn from the mold
What is dross or slag and how can it be prevented from becoming part of a finished casting
- oxidized metal which can be carried with the molten metal during pouring.
- prevented by fluxes, skimming, protective atmosphere
what are two stages of solidification and what will occur during each?
Nucleation
- stable solid forms, beginning of a crystal or grain structure
Growth
- heat of fusion extracts from liquid metal and the nucleated solid increases in size
What are hot spots and what causes them?
- poor design
- spots that cool slower than the rest of the casting
- localized shrinkage
