computer integrated manufacturing

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INDIAN INSTITUTE OF TECHNOLOGY, BOMBAY Department of Mechanical Engineering

Course : ME-714Computer-Integrated Manufacturing Instructor : K.P. Karunakaran Date : January25, 2010 (Monday) 9:30PM

L-T-P-C : 3-0-0-6 II Semester 2009-10

Duration : 1 hr. Instructions:

Answer all the questions; answer as briefly as possible.

Roll No

Marks /??

TEST - 1 (Chapter 1: Introduction)

Part A

(1 mark each) 1. List the three fundamental requirements for implementing CIM.

1. Computer control of all functions 2. Networking of all these computer systems

3. Communication protocols and secure access control

2. Automotive components are mostly castings and forgings whereas aerospace uses mostly machined components. Do you agree or disagree? Justify your answer.

Automotive is cost-sensitive whereas aerospace is weight-sensitive. As castings and forgings can simultaneously realize several features, they are cheaper than machined parts.

3. Which is the most accurate casting method? Why?

4. Sort the following processes in the decreasing order of specific energy:

[i] sheet metal forming [ii] forging [iii] machining [iv] casting

5. Which of the following processes are suitable for objects with undercuts and deep features?

[i] 3-axis CNC machining [ii] forging [iii] casting [iv] RP

6. Which of the following processes are suitable for components/assemblies with high fatigue life?

[i] machining [ii] forging [iii] casting [iv] sheet metal forming

7. List the four significant applications of RP.

Conformal Cooling.

Components with Functionally Gradient Materials (FGMs)

Assemblies without joints

Shapes impossible or difficult by other processes.

8. Give an example for [i] fixed detachable assembly and [iii] movable permanent assembly.

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9. Distinguish between adjusted parts assembly and fitted parts

assembly.

Adjusted Parts Assembly Fitted Parts Assembly

Simple way of obtaining fine

fit.

Simple way of obtaining

tight fit.

The desired fit is achieved

during assembly using certain

adjustmentelements like, set

screws, washers, spacers,

wedges,shims, putty etc

The desired fit is achieved

during assembly by

adjusting one of the matching dimensions by

filing, cutting, chiseling,

scrapping, lapping etc

10. What category of assembly is usage of washers or shims?

Adjusted Parts Assembly

11. Distinguish between Product Design and Industrial Design.

12. Explain the significance of the figure in the context of product

design.

14. How is fixed-position layout different from job shop layout? Ans -

In fixed-position layout, the factory moves to the product’s place

15. List the contributions of F.W. Taylor

Part B (Weightage is given against each)

1. Define CIM comprehensively. Explain how it is different from CAD/CAM. [2]

1. CIM is the integration of the enterprise’s(imp plan’s) upstream, mainstream and downstream

activities of product development and life cycles into one self-regulating system with the help of connected computer systems and a common corporate data repository(a place where things

are stored and can be found ).

2. CIM is more often a strategy, direction, vision or a management(SDVM)philosophy.

3. CIM is a tool to achieve defined corporate goals or strategies. 4. CIM is a way of doing business that emphasizes(to show or state that something is very

important or worth giving attention to) an automated coordination of information and effort

throughout all the functional areas of a corporation. 5. CIM is the use of information technology to improve manufacturing.

6. CIM is rarely available as a product or system from a vendor. Each organization has to

build its own. At best, they may be able to hire consultants in selection and implementation.

2. Draw the block diagram of CIM that depicts all its building blocks. [2]

Any of the following will do.

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2. Discuss the positive and negative aspects of open sourcing.

Advantages: immense scope of improvement

It leads to better penetration of the biz in the market

Disadvantage: Security of the software is at question(hackers)

There’s no tab over how the software is used [2]

3. Define and distinguish between out-sourcing and in-sourcing. Use examples/ case studies to

explain.

Y2k vs UPS

out-sourcing in-sourcing

Getting things done where it is the best

and by whom does it the best. People retain

their core-competency with themselves and out-source all else as far as possible. This led

to lean and agile mfg’s

Complementing organizations working

together

It started with information processing. Thanks to Y2K problem which helped India

emerge as IT superpower. At that time, it

was “body-shopping”.

Logistic companies such as FedEx, UPS train their customers in packaging so as to

minimize transit damages. They tie up with

insurance companies and offer insurance

along with transport charges. UPS’s slogan is “Your world is synchronized”

India’s problems of huge population, lack of

a common Indian language and democracy turned into our advantage. Setting up of IITs,

NITs and thousands of Govt and

UPS even repairs of Toshiba computers and

returns to the customers

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pvt.Colleges enabled us to churn out good

quality engineers (10 lac/yr)

This was further enabled by connecting continents through fibre-optic cables. Speed

and bandwidth increased

The banks depute people to builders and automobile outlets

It is no longer body-shopping. It happens within the same country

All automotive companies working together on mutually beneficial projects like alternate

fuel systems etc

Now this has extended to product

development and manufacturing also

[4]

4. Define off-shoring and discuss its implications. Also explain how it is different from out-

sourcing.

Setting up factories abroad where it is cheaper to make. Another approach is to produce in

locations closer to the customer which is cheaper due to less transportation cost, tax benefits

and better service. Companies become global.

This is an offshoot(something which has developed from something larger which already

existed) of out-sourcing. The difference between out-sourcing and off-shoring is just the ownership

[4]

5. Give two examples for the primary industries, [two + two] examples for the secondary industries identifying them with its two types and two examples for tertiary industries. [3]

Primary Secondary Tertiary

Discrete Process

Agriculture Aerospace Paper Education

Fishing Automotive Cement Entertainment

6. What is selective assembly? When is it used? What are its limitations?

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tight tolerances that go beyond the process capability - More time spent on inspection

No interchangeability

Definition: Most practicable for extremely tight tolerances that go beyond the process capability. Produce both matching parts in large number. Measure each and fit. Eg.: Ball bearings, slip gauges Advantages: + Cheap to manufacture individual parts. Limitations: - More time spent on inspection - No interchangeability. Hence, both mating parts shall be replaced. - If the process of the individual components are not under control, one may land up accumulating more unused components. [3]

7. Reproduce the following table and fill in the empty cells. [2]

Type of Manufacture Type of Layout Type of Automation

Job shop production Job shop and Fixed position layout Fixed Automation

Batch production Process layout Flexible Automation

Mass production Flow & fixed layout Programmable Automation

8. What are the considerations in selecting a layout? Compare the three layouts based on these. [2]

Consideration –

The goal in layout is primarily minimization of material movement and WIP(work in progress). For

the same product, different layouts are feasible for different subassemblies and components

Job shop and Fixed position layout Process layout Flow & fixed layout

material movement &

WIP

?? High Low

9. Present the comparison of stationary manufacturing or quantity production and progressive

manufacturing or flow production. [2]

Stationary manufacturing or Quantity

production

Progressive manufacturing or flow production

All tools required come to the same place

and perform their task

Workstations are spread out and the raw material

of the part/ assembly-in-progress moves from one

station to the next till all operations are over

This is more suitable for discrete parts

manufacture wherein the volume keeps

reducing as the activities progress.

Limited to simple parts/assemblies only due to the limited number of

operations/tools

This is more suitable for assemblies since the

volume keeps increasing and becomes unwieldy as

the activities progress. Furthermore, the assembly

tools are large and varied in shape. Suitable for

complex

Eg.: Consider assembling a book from its pages available as bundles. Arrange the

bundles of the pages around you with a

table in the middle. Take one page after the

other and place on the middle table to assemble the book. Finally staple it

Eg.: Consider assembling a book from its pages available as bundles. Arrange the bundles of the

pages in line on a long table. Move from one end to

the other picking one page each and assemble the

book. Finally staple it

Eg.: CNC machining (tools stored in ATC

come to the blank one after the other to do

Eg.: Assembly of automotive engines or bodies.

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the job; PCB assembly

10. Any manufacturing process requires the continuous control of slide motions and the control of

switching functions such as spindle control, tool change, coolant control etc. Fill the 4 boxes in

the following table: [2]

Function

Element(s) used to control this

function in hard automation is

(are)

Element(s) or code(s) used to

control this function in soft automation is (are)

Slide motion

Switching functions

computer integrated manufacturing

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