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
what are 4 major classifications of cold working
- squeezing
- bending
- shearing
- drawing
what are 4 conditions of cold rolled sheet and strip
- skin rolled
- quarter-hard
- half hard
- full hard
Why is cold rolling for rods and bars more appealing?
- uniform cross section
- increased yield strength
what is peening
mechanical working of surfaces by repeated blows of impelled shot or a round tool
what is burnishing
rubbing a smooth, hard object under pressure over the minute surface irregularities
what is roller burnishing used for
used to improve the size and finish of internal and external cylindrical and conical surfaces
what are two stages of shearing
deformation and fracture
what is process capability
ability to consistently hit “bulls-eye”
define tolerance
an undesirable but permissible deviation from a desired dimension
define allowance
the intentional desired difference between the dimensions of two mating parts
what are some sources of variation when determining process capability
- variations in materials
- operator variability
- vibrations or chatter
- machine or tool wear
what are some assignable causes for process capability
- multiple machines making the same product
- operator blunders
- defective materials
- progressive tool wear
what is a histogram
- a bar chart where the width of each bar is represents a measurement size interval and the height of each bar represents the frequency of parts within that interval
what are some limitations of a normal curve and histogram analysis
- needs at least 50 measurements for a basic pattern
- samples are taken at random
- don’t show a change with time
define mean value
an average
what is a median value
the middle value
What are some joining processes
- mechanical fastening
- soldering/brazing
- welding
- press shrink or snap fittings
- adhesive bonding
- assembly processes
what are some surface treatments
- finishing operations
- cleaning
- removing burrs after machining
- provide a protective/decorative coating
What are some characteristics of Process Technology
- mechanics (static or dynamic)
- Economics
- Time spans
- constraints
- skills
- process capability
what two consumers are involved in the manufacturing system design
Internal - consumer who manufactures the product
External - consumer who buys the product
Describe properties of the Toyota Production System
- lean manufacturing system
- 100% good units flow without interruption
- integrated quality control
- responsibility for quality is given to the manufacturing
- constant quality improvement
what are the critical control functions of a manufacturing system
- production rate
- production mix
- inventory control
- quality control
- machine and tool control
what is a lean shop
- employs U-shaped cells or parallel rows
- more responsive to customer demand
- minimizes rework, waste, handling and inventory
what are the steps of design
- conceptual
- functional
- production
when selecting a material, describe the method of general sequence of product design
- design
- material selection
- process
- selection
- production
- evaluation
- redesign
what are some pitfalls of the case-history method for material selection
- variations in service requirements
- doesn’t consider new technology or new materials
what are common geometric considerations
- relative size
- shape complexity
- precision
- tolerances
- surface finishes
what is an ANSI Class 1 Fit
loose fit
what ANSI class is a free fit
Class 2
what is an ANSI Class 8 fit
Heavy force and shrink fits
what ANSI class is a tight fit
Class 6
what is an ANSI Class 3 fit
Medium Fit
what is an ANSI Class 7 fit
Medium Force Fit
what ANSI class is a Snug fit
Class 4
what ANSI class is a wringing fit
Class 5
What are 3 ISO Classes of fit
- Clearance
- Transition
- Interference
what are 4 ways to tolerance
- bilateral
- unilateral
- limits
- geometrical
What is nominal size
Desired theoretical size
what is Basic Size
the theoretical size or the nominal standard size from which variations are made
what is Design Size
the size from which the limits f size are derived by applying tolerances
For design Size, what is HBS
hole is the basic size
- shaft is the basic size minus allowance
For Design Size, what is SBS
shaft is basic size
-hole is the basic size plus allowances
What is Actual Size
the actual size of the part after it is produces
What is LMC
Least Material Condition is the lower limit for an external feature and the upper limit for an internal feature
what is MMC
Maximum Material Condition is the upper limit for an external feature and the upper limit for an internal feature
In casting, what is the pattern
A duplicate of a part to be made from plastic, wood, metal
What is the molding material
The material packed around the pattern to produce a mild cavity
Define flask
The rigid metal or wood frame that hold the molding aggregate
In a horizontally 2-part mild what is the top half of the pattern called?
The cope
What is the bottom half of a casting mold called
Drag
Define core print
A feature that is added to a pattern, core, or mold and is used to locate and support a core within the mold
Define core box
The box in which the core is produced
What is a mold cavity
Includes the mold material and the cores then the combine to produce a complete mold cavity
What is the riser used for
An addition void in the mold that also fills with molten metal, used to provide a resubmit of additional liquid that can flow into the mold cavity to account for shrinkage
What is a network of connecting channels used to deliver the molten metal from the pouring vessel?
The gating system
What is the pouring cup used for?
The portion of the gating system that receives the molten metal from the pouring vessel and controls delivery to the rest of the mold
What is a Sprue
The portion of the gating system that connects the pouring cup and the runners
What are runners
Horizontal channels that ensure travel of molten metal
Describe what a parting line is
The interface that separates the cope and drag half of the mold flask
Describe casting
A process that exploits the properties of a liquid as it flows into and assumes the shape of its prepared container and then solidifies upon cooling
What is quality
Quality is defined as the degree to which a set of inherent characteristics fulfills requirements
What are two dimensions of quality
Features and freedom of deficiencies
How are features of quality relevant to manufacturing
- performance
- reliability
- durability
- ease of use
- serviceability
How do freedom of deficiencies play into quality
They affect cost
- redundancy of delivery, usage, service
What is the little q, regarding quality
Manufactured
- goods
- processes
- industries
When regarding quality, what is the big Q
- all goods and services
- all processes
- all industries
What are the three roles within Total Quality
- The customer receiving info and goods as inputs
- The processor converting inputs into products as outputs
- The supplier delivering outputs to customers
What are three universal processes involved with managing quality
- planning
- control
- improvement
What is quality assurance
The activity of providing evidence to establish confidence that quality requirements will be met
What are two types of quality standards
Product related standards and quality system standards
What are 3 quality system standards in Canada
- CAN3Z299
- ISO9000
- AQAP-1
What are the nine required steps in ISO 9000 registration
- management decision
- ISO Team
- internal audit
- quality manual
- procedures
- registrar selection
- pre-assessment
- registration audit
- registration decision
What are the benefits of adopting a quality system standard
- develop a comprehensive quality program
- promote customer confidence in you quality program
- understand your suppliers quality program
- improved quality
- expanded market share
- increase profits
What are some advantages of casting
- complex shapes
- parts can have hallow sections
- large parts
- intricate shapes
- different mold materials
- different pouring methods
What are the three cast regions or zones
Chill-zone
Columnar zone
Equiaxed zone
What are two basic categories for casting process
Expendable mold process and permanent mold process
What are the 6 basic requirements of casting
- mold cavity produced
- melting process
- pouring techniques
- solidification process
- mold removal
- cleaning/finishing and inspection
What are some typical disadvantages of casting
- porosity
- oxidization
- hot spots
What are some casting mold materials
Sand
Ceramics
Metals
What are some different cast materials
Aluminum Copper Magnesium Zinc Low or high carbon steel White or gray cast iron
What are the 8 principles for ISO9000
- customer focus
- leadership
- involvement of people
- process approach
- system approach to management
- continual improvement
- factual approach to deduction making
- mutually beneficial supplier relationships
What three categories of moods are there
- single use moods with multiple use patterns
- single use mold with single use patterns
- multiple use molds
What are the four types of pouring that can be used in casting
- high pressure
- low pressure
- vacuum
- gravity
Which type of casting is the most versatile?
Sand casting
What types of patterns are used in sand casting
- one piece or solid
- split patters
- match-plate patterns
- cope and drag patterns
What are the four requirements of sand used in casting
Refractoriness-ability
Cohesiveness-ability
Permeability-ability
Collapsibility-ability
What is the % mixture of green sand
88% silica
09% clay
03% water
What are some testing parameters for sand?
- grain size
- moisture content
- clay content
- permeability
- compressive strength
- hardness
- compactibility
What are some sand defects
- gas related voids
- sand expansion defects
- phase changes at temperature
What is used to strengthen cores and molds
The addition of 3-6% sodium silicate
