I Need Help In Manufacturing System. I Attached The Assignment

1

Chapter 16- Automated Production Lines

Fixed-routing manufacturing system that consists of multiple workstations linked together by a material handling system to transfer parts from one station to the next

• A raw work part enters one end of the line, and the processing steps are performed sequentially as the part progress forward

• Each station performs a different operation, so all operations must be performed to complete each work unit.

1

Automated Production Lines

• Where to Use Automated Production Lines • High product demand: Requires large production quantities

• Stable product design: Difficult to change the sequence and content of processing operations once the line is built

• Long product life: At least several years

• Multiple operations required on product: The different operations are assigned to different workstations in the line

• Benefits of Automated Production Lines • Low direct labor content, Low product cost, High production rates,

Production lead time and work-in-process are minimized, and Factory floor space is minimized

• Applications • Transfer lines used for machining, Robotic spot welding lines in automotive

final assembly, Sheet metal stamping, Electroplating of metals

• Fixed automation

2

3 4

5

Work Part Transport

• The workpart transfer system moves parts between stations on the line. Transport mechanisms are usually synchronous or asynchronous, but rarely continuous.

• Asynchronous transport is more flexible, easier to rearrange or expand the production line, and permits queues of parts to form between workstations to act as storage buffers.

• The term palletized transfer line is sometimes used to identify a transfer line that uses pallet fixtures or similar work-holding devices.

• Uses pallet fixtures to hold and move work parts between stations

• Free transfer line • Part geometry allows transfer without pallet fixtures

6

2

System Configuration

• The work flow can actually take several different forms • In-line: consist of a sequence of stations in a straight line arrangement. This

configuration is common for machining bug workpieces, such as engine blocks. These parts require a large number of operations. In-line system can also be designed with integrated storage buffers along the flow path

• Segmented in-line: consists of two or more straight-line transfer sections, where the segments are usually perpendicular to each other. • Available floor space may limit the length of the line

• A workpiece in a segmented in-line configuration can be reoriented to present different surfaces for machining

• The rectangular layout provides for swift return of work-holding fixtures to the front of the line for reuse

• Rotary: the work parts are attached to fixtures around the periphery of a circular worktable, and the table is indexed to present the parts to workstations for processing

7

Segmented In-Line Configurations

L-shaped layout

U-shaped layout

Rectangular configuration

8

Two Machining Transfer Lines

9

Rotary Indexing Machine

10

Storage Buffers in Production Lines

• Automated production lines can be designed with storage buffers.

• A location in the sequence of workstations where parts can be collected and temporarily stored before proceeding to subsequent downstream stations

• Reasons for using storage buffers: • To reduce effect of station breakdowns

• To provide a bank of parts to supply the line

• To provide a place to put the output of the line

• To allow curing time or other required delay

• To smooth cycle time variations

• To store parts between stages with different production rates

11

Storage Buffer

12

Storage buffer between two stages of a production line

3

13

Control Functions in an Automated Production Line

• Sequence control • To coordinate the sequence of actions of the transfer system and workstations

• Safety monitoring • To avoid hazardous operation for workers and equipment

• Quality control • To detect and possibly reject defective work units produced on the line

14

Analysis of Transfer Lines

• Three problem areas must be considered: 1. Line balancing

• To divide the total work load among workstations as evenly as possible

2. Processing technology • Theory and principles about the manufacturing or assembly processes used on the line

3. System reliability - two cases: • Transfer lines with no internal parts storage

• Transfer lines with internal storage buffers

15

What the Equations Tell Us – Lines with No Storage Buffers

• As the number of workstations increases • Line efficiency and production rate are adversely affected

• As reliability of individual workstations decreases • Line efficiency and production rate are adversely affected

16

What the Equations Tell Us – Lines with Storage Buffers

• If E0 and E are nearly equal • Then little advantage is gained by adding a storage buffer

• If E is much greater than E0 • Then adding a storage buffer may improve line performance significantly

• Storage buffers should be located so that production rates of the stages are about equal

• During operation, if any buffers are always empty or always full, then the buffer is serving little purpose

17

What the Equations Tell Us - Lines with Storage Buffers

• The maximum possible efficiency is achieved by: • Setting the number of stages = number of stations

• Using large buffer capacities

• The “law of diminishing returns” operates in multi-stage automated lines: • As the number of storage buffers is increased, line efficiency improves at an ever-

decreasing rate

• As storage buffer capacity is increased, line efficiency improves at an ever- decreasing rate

18