Topics:

• The first element of CIM -- product design
• The second element of CIM -- product manufacture
• The third element of CIM -- shop floor control and material handling
• Advanced technologies in CIM

The first element of CIM -- product design

1. What are involved in product design?

2. What is the importance of product design in manufacturing?

3. What is the CIM approach to product design?

4. What do the following acronyms stand for?

1. What are the input and output to the following postdesign activities?

3. What is the significance of the following preproduction activities?

5. How do the following technological developments change the way products are manufactured?

1. What is shop floor control and its relationship to production planning and control?

2. What are the major activities of shop floor control?

3. What kinds of technologies are developed in assisting shop floor control?

4. What is the significance of materials and tools handling in discrete-parts manufacturing?

5. What kinds of technologies are developed in streamlining materials and tools handling?

1. What are expert systems and their CIM applications?

2. What is computer vision technology and its CIM applications?

3. What is LASER technology and its CIM applications?

The first element of CIM -- product design

1. 6 steps in product design (Figure 6.1)

2. The importance of product design in manufacturing

• 70/30 rule: 70% of the manufacturing costs is determined at the design stage
• GM: 70% of the final production cost
• Rolls-Royce: 80% of the final production cost
• Reduce direct cost in manufacturing by reducing the no. of components and subassemblies, use new materials, and material processing techniques

• Rule of ten

• the design decisions should be integrated, informed, and balanced by involving manufacturing, repair, purchasing, and other knowledgeable personnel early in the process
• What good is it if it does not work
• What good is it if it does not sell
• What good is it if it is not profitable
• What good is it if it cannot be made
• Concurrent engineering/Simultaneous engineering:
• the 4 C's:
• Concurrence: design-production continuum
• Constraints: finance, marketing, quality, reliability, maintainability, machinability, assembly, schedulability
• Coordination: quality, cost & delivery
• Consensus: group decision

• Standardization of design data (geometry, dimensions, structures, surface finish, assembly instructions, etc.)
• DXF (Data eXchange Format)
• IGES (Initial Graphics Exchange Specification)
• PDES (Product Data Exchange Specification)

CAD Computer Aided Design (pg. 211)
use of computers in various facets of product design & its presentation

DFM Design For Manufacturability (pg. 209)
integrates product design, process planning & production to achieve ease of manufacture

DFA Design For Assembly (pg. 210)
devotes all the efforts at the product design stage to ensure ease of assembling

DFF Design For Functionality (Taguchi method)
a product is designed to be robust with respect to design parameters and tolerance parameters

DFD Design For Disassembly (design for the environment)
a product is designed for efficient disassembly

DFS Design For Schedulability
a product is designed with consideration of the operations aspect of its manufacture

• Min. the no. of machines involved
• Assign parts to machine cells
• Max. the no. of parallel operations
• Max. batch splitting
• Allow for alternative process plans

The second element of CIM -- product manufacture

1. Postdesign activities
 
 

Activities	Input	Output
Cost planning	Costs of material, labor, machining, etc.  Cost estimation formulas  What-if analysis  Part/product specification  Part demand	Product cost & delivery schedule
Process planning	Alternate production plans (sequence of operations to make the product)  Part/product specification  A standard process plan database (in Retrieval CAPP)	Route sheet
Production	Production instruction (routing, loading, scheduling)  Machines & tools availability  Testing/Inspection instruction	Finished product

 

2. Group technology

• Similar parts are grouped together to improve manufacturing effectiveness
• Production in cells of machines with associated tools, pallets, and fixtures (Cellular Manufacturing)

(a) Prototype testing/structural analysis

• Physical models ® iconic models on computers
• operation safety
• predict stress field, thermal distortion, vibration severity, noise emission, etc.

(b) Simulation - system behavior/performance

• SLAM, SIMAN

(c) Part programming - program codes that represent every movement, path, or action the machine tool must take to properly produce the part as described by the engineering drawing

• Cutter Location data (CLD): part geometry + operation & tooling requirements
• Machine control data (MCD or "G" code): machine-specific CLD

4. 4 common discrete manufacturing processes:

• Forming: use mechanical pressure to transform raw material into a useful part
• Machining: give the formed part its functional features, required tolerance & finish, e.g., milling, grinding, drilling, latheing, etc.
• Assembly: combining two or more fabricated parts in a predetermined relationship
• Auxiliary operation, e.g., welding, washing, heat treatment

Characteristics of discrete manufacturing ® NC technology

• Lot size < 50
• Complex part geometry
• Numerous processing operations
• Frequent changes in engineering design
• Costly process mistakes
• Narrow tolerance range
• 100% inspection is needed

5. 1950 Numerical Control (NC): use of coded numbers, letters, or symbols in the automatic control of equipment or tool positioning

1970 Computer Numerical Control (CNC): use of a computer to control several NC machines

Direct Numerical Control (DNC): the part programs are stored in the memory of the main-frame/mini and downloaded electronically when needed by the machine's NC controller

• Setup/Machine
• Process
• Convertibility/Product
• Routing
• Volume
• Expandability
• Operation
• Production

Acronym

CACE Computer Aided Cost Estimating (pg. 236)

a software tool (a data base of common workpiece material + machining cost + cost estimation formulas + what-if analyses) for product cost estimation

• Variant CAPP (e.g., MIPLAN): a new process plan is produced by modifying existing standard plans
• Generative CAPP (e.g., GENPLAN): a new process plan is developed from scratch each time according to its process sequence, part geometry, material and other related factor

CAM Computer Aided Manufacturing

use of computer to plan, manage, & control the operations of a manufacturing plant through direct/indirect computer interface with its production resources

1. Shop floor control as an activity of production planning & control

• Production planning & control deals with developing production plans, implementing these plans, monitoring the progress toward achieving these plans, and developing and implementing corrective actions when the original plans need modification. Management's strategic plans are translated into manufacturing plans for producing parts in the right quantities, at the right time, at the lowest possible cost, and with the highest possible quality
• Information flow in production planning & control
• Demand forecasting
• Aggregate production planning
• Master production schedule
• Material requirements planning
• Capacity planning
• Shop floor control

2. Shop floor control activities - acquire up-to-date information on the progress of manufacturing orders to control factory operations

• Order release
• Detailed assignment
• Data collection and monitoring
• Control/feedback
• Order disposition

3. Shop floor control technologies

• Factory data collection technologies
• Bar code
• Optical character recognition
• Vision/Image processing
• Radio frequency identification
• Magnetic identification
• Voice technology
• Computer control & monitoring technologies
• Programmable logic controllers ® logical control
• Measuring device, e.g., CMM (Coordinate Measuring Machine) ® physical control
• Sensors ® adaptive control (a control system that measures process variables, e.g., cutting force, temperature, horse power, hardness of material, width/depth of cut, air gaps in part geometry, etc. to manipulate feed and/or speed of a machining process to compensate for undesirable changes in the process variable)

4. Materials & tools handling - a major factor in manufacturing lead time

• Robot - reprogrammable & multi-functional
• Automated guided vehicles - 1st & 2nd generation AGVs
• Automated storage & retrieval system - computerization of material management at the shop floor
• Palletization - better utilization of expensive equipment

6. Other applications of robots

• Hazardous condition (heat, radiation, toxicity, weight)
• Repetitive tasks, e.g., pick-and-place, machine loading, multishift operation
• Material transfer
• Processing operations, e.g., welding, spray coating, drilling, etc.
• Assembly
• Inspection

Advanced technologies in CIM

Milestones in Machine Intelligence

1943 Do mathematics

1950 Large memories

1958 Play chess

1959 Beat humans at checkers

1965 1^st expert system

1975 Understand limited English

1976 Read printed text to blind

1979 Translate foreign language

1980 Beat world backgammon champion

1981 Synthesize speech

1983 Recognize restricted speech

1986 Beat human at table tennis

1988 Beat grand master at chess

1989 Read head writing

1993 Recognize continuous speech

1997 Beat world chess champion

2005 Translate international phone calls

2010 Understand unlimited English; serve dinner, clean house

2015 Use common sense

Source: Raymond Kurzweil, Maureen Caudill, American Association for Artificial Intelligence

Artificial Intelligence - the study of how to make computers to do things that are considered to require some level of intelligence - to learn/understand from experience, to acquire & retain knowledge, to respond quickly and successfully to new situations, to solve problems, etc..

 
 
 

Intelligent Computing	Conventional Computing
1.  Does not guarantee a solution to a problem	1. Guarantees a solution to a problem
2. Produces results that may not be reliable or consistent	2. Produces results that are consistent and reliable
3. Solves the given problem without specific program instructions	3. Solves the given problem according to the programmer's exact instructions
4. Can solve a range of problems in a given domain	4. Can solve only one problem at a time in a given domain

 

Characteristics of an Expert System

• solve problems that are difficult and require expertise;
• use descriptive facts and reasoning heuristics
• explain what it knows and its reasoning process

• Control governs system behavior to meet specifications
• Debugging recommends corrections to faults
• Design configuring objects under constraint
• Diagnosis locates sources of defects ** Predominant
• Instruction teaches
• Interpretation clarifies situations
• Planning develops goal-oriented schemes
• Prediction guesses
• Repair fixes