Erdem Tubun - 503101306 - 1st Week Unanswered Words (04.03.2012)

1-COMPUTER AIDED PRODUCTION MANAGEMENT (CAPM)

Manufacturing Method

(New Answer - Better)

Computer aided production management  is the use of computers to improve the efficiency and the effectiveness of the production management. It is concerned with what to manufacture, in which order and by when. CAPM as being concerned with the executing of costumers' orders, efficiently, economically. Its concerned with:
1. Knowing at all times what delivery dates can be offered realistically, taking account of existing commitments.
2. Planing future capacity to meet sales opportunities
3. Ensuring te right materials are ordered.
4. ensuring that work in progress proceeds through the manufacturing stages in the righ sequence.
5. providing the flexibility to meet changing costumer requirements or priorities without incuring excess inventory.

(Stephen J. Childe, An Introduction to computer aided production management. P.34)

(Previous Answer)

CAPM is the use of the computers to improve the efficiency and effectiveness of production management. It is concerned what the manufacture ,in which order and by when.CAPM concerned with the executing of customers orders,efficiently and economically.Purpose of the CAPM is use of computer-based information to support production management functions and to coordinate flows of orders ,materials and finished goods.

(An Introduction to Computer Aided Production Management-1st Edition-Stephen J. Childe-P.34)

5-DATA INPUT FOR NC MACHINES

Control

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For a numerically controlled machine to accomplish the required operations, the necessary data have to be entered into the MCU (Machine Control Unit). The MCU than convert the data into commands that can be issued to the appropriate motors for the necessary functions to be executed.

The series of data that is fed into the MCU to generate the required tool commands is referred to as an NC part program. The commands are input to the controller in units called blocks or statements. The structure of an NC part program can include three different block formats:

• Fixed- sequential format
• Tab sequential format
• Word address format

(Singh N., Systems Approach to Computer Integrated Design and Manufacturing, p. 194-197)

(Previous Answer)
The numerical information is read and stored in computer memory.

(Kalpakjian S., Schmid S.R.,Manufacturing Engineering and Technology, 5th Edition, pg.1155)

6-DATA OUTPUT FOR NC MACHINES

Control

(New Answer - Better)

The data that input is transferred into commands by MCU. These converted output data,  can be issued to the appropriate motors (servo/stepping) for the necessary functions to be executed.

These functions can be listed as:

• Determining the cutting speed for the machining,
• Determining the spindle speed for the machining,
• Changing or loading the appropriate machine tool,
• On/off action for the coolant liquid

 (Singh N., Systems Approach to Computer Integrated Design and Manufacturing, p. 194-197)

(Previous Answer)

This information is translated into commands(typically pulsed commands) to the servo motor. The servo motor then moves to work table (on which the workpiece is mounted) to specific positions through linear or rotary movements by means of stepping motors, leadscrews, and other similar devices.

(Kalpakjian S., Schmid S.R.,Manufacturing Engineering and Technology, 5th Edition, pg.1155)

7-NUMERICALLY CONTROLLED ROBOT

Control Systems

(New Answer)

Numerically controlled robots (also known as playback robot) are instructed to perform tasks through the receipt of information on sequences and positions in the form of numerical data. Such robots are typically used for making precision machinery.

(Branwyn G., Absolute Beginner’s Guide to Building Robots, p. 16)

(Previous Answer - Better)

The numerically controlled robot is programmed and operated much like a numerically controlled machine.The robot is servocontrolled by digital data and its suquence of movements can be changed with relative ease.As in NC machines, ther are two basic types of controls:point-to-point and continuous-path.

Point-to-point robots are easy to program and have a higher load-carrying capacity and larger work envelope,which is the maximum extent or reach of the robot hand or working tool in all directions.
Continuos-path robots hace greater accuracy than point-to-point robots,but they have lower load-carrying capacity.Advanced robots have a complex system of path control,enabling high-speed movements with great accuracy.

(Kalpakjian S.,Schmid S.R.,Manufacturing Engineering and Technology 5th edition,p. 1169)

10-DERIVATIVE SYSTEM FOR CAPP SYSTEMS

Manufacturing Method

(New Answer - Better)

Derivative CAPP systems, also known as variant CAPP systems or retrieval CAPP systems; are Computer Aided Process Planig systems, based on group technology and parts classification and coding. In these systems, a standart process plan is stored in computer files for each part code number. The standart plans are based on current part routings in use in the factory, or on an ideal plan that is prepared for each family.

In derivative CAPP systems, the user begins by identifying the GT code for the component for which the process plan is to be determined. A search is made of the part familiy file to determine if a standart route sheet exists for the given part code. If the file contains a process plan for the part, it is retrieved and displayed for the user. The standart process plan is examined to determined wheter modifications are necessary. Although the new part has the same code number, minor differences in the process might be required to make the part. The standart plan is edited accordingly. The capacity to alter an existing process plan is why retrieval CAPP systems are also called variant systems.

If the file does not contain a standart process plan for the given code number, the user may search the file for a similar code number for wich a standart routing exists. By editing the existing process plan, or by starting from scratch, the user develops the process plan for the new part. This becomes the standart process plan for the new part number.

The final step is the process plan formatter, which prints the route sheet in the proper format. The formatter may call other application programs; determining cutting conditions for machine tool operations, calculating standart times for machining operations, or computing cost estimates.

(Groover M.P, Fundamentals of Modern Manufacturing, 3rd edition, p. 944)

(Previous Answer)

It also called the variant system.These computer files contain a standart process plan for the part to be manufactured.A search for a standard process plan for rhe part to be manufactured.A research for a standard plan is made in the database by a code number for the part.The plan is retrieved,displayed for review and printed as a routing sheet.

The variant-process plan includes information such as the types of tools and machines to be used the squence of manufacturing operations to be performed,the speeds,the feeds and the time required for each sequence.Minor modification of an existing process plan also can be made.In the variant system,if the standard plan for a particular part is not be computer files,a plan that is close to it is retrieved.If a routing sheet does not exist,one is made for new part and stored in computer memory.

(Kalpakjian S.,Schmid S.R.,Manufacturing Engineering and Technology 5th edition,p. 1205)