17.5 Line Balancing Algorithms 生產線平衡算法
To distribute the total workload as evenly as possible. 儘可能平均分發總工 作量
w
Minimize (wTs Twc ) or Minimize (Ts Tsi )
-Line pacing生產線步調
- Maintain production rate by a mechanized conveyor. 透過機械化的輸送裝置保持生產率
17.1 Fundamentals of Manual Assembly Lines人工裝配線的基礎
Figure 17.1 (圖17.1)
efficiency
重新定位效率
Er
Ts Tc

Tc Tr Tc
17.4.2 The Line Balancing Problem 生產線平衡問題
Assigning the individual work elements to workstations so that all workers have an equal amount of work. 把個別的工作項目分發到工作站，以便全 部工人有相等的工作量。
Concepts概念
-Minimum rational work elements 最小合理的 工作項目 -Precedence constraints先後順序限制條件
17.4.2 The Line Balancing Problem
Minimum rational work elements
Introduction
Why is it productive?為什麼它是有生產力 的？
-Specialization of labor勞工的專業化
- Learning curve學習曲線
-Interchangeable parts可互換零件 -Work principle工作原則
- Applied to make smooth material handling可應用來 達到平順的物料處理
where Ts = max { Tsi }
-Eb = 0.9 ~0.95
-Balance delay 平衡延遲
d

wTs Twc wTs
Labor efficiency (勞工效率) = E Er Eb Revised number of workers 修正工人的數量
w minimum integer RpTwc Twc Twc 60 EEr Eb Er EbTc EbTs
Mechanized work transport 機械化的工作
運輸
17.1.3 Line Pacing 生產線步調
Rigid pacing 硬性步調
- 固定時間完成工作
Pacing with margin 有範圍的步調
- Allowing queues 允許等候線 - Designing the station to be longer length 設計工作站 有較長的輸送帶長度
-Synchronous transport 同步運輸
- Move simultaneously 同時移動(例如轉盤)
-Asynchronous transport非同步運輸
- Move independently、Small queues 獨立移動、小量等 候
17.1.2 Work Transport Systems 工件運輸系統
人工方法的工件運輸
-Starving and blocking buffers 缺料和阻擋現象 緩衝區
Mechanized work transport 機械化的工作運輸
-Continuous transport 連續的運輸
- Work units may be fixed or removable工件可能是固定 的或可移動的 - 例如輸送帶 (汽車或電子產品)
17.1.4 Coping with Product Variety 對應於產品種類
Single model 單一模型
-No variety
Batch model 批量模型
-Hard variety
Mixed model 混合模型
-Soft variety -Vs. batch model
- No production time lost 沒有生產時間浪費 - Lower inventories 較低的存貨 - Adjustable production rate 可調整的生產率 - Line balancing problem 生產線平衡問題 - difficult scheduling and logistics困難的排程和運籌
17.3 Design for Assembly (DFA) 為方便組裝的設計
During product design:在產品設計階段
- Fewer parts 更少的零件 - Easy to assembly. 容易組裝
General principles 一般通則
- Use the fewest number of parts possible儘可能的使用 最少的零件數量
最小合理的工作項目
-A small amount of work having a specific limited objective (required time: Tek)
ne
Twc
Tek
k 1
ne：number of work elements 工作項目的數量
-The task time at station I 在工作站i 的工作時間
17.4 Analysis of Single Model Assembly Lines
(Hourly) Workload (每小時)工作量
WL Rp Twc
Minimum number of workers 至少工人的數
量
w* WL minimum integer Twc
AT
i 1
subject to (1) Tek Ts
ki
(2) precedencereqirements are obeyed
Tc
-Theoretical formula because of:此乃理論公式因為
- Repositioning losses: 重新定位之損失
- E.g. workers walk from the ending position to the starting position.
- The line balancing problem 生產線平衡問題 - Task time variability 工作時間變化性 - Quality problem品質問題
Da: Annual demand 每年需求
Rp

Da 50SH
plant operates 50 wk/yr 工廠一年運作50週 S:每週班次 H:每班次工作時數
Cycle time週期時間(min/cycle) and cycle rate週期率
(cycles/hr 對於生產線而言)
Tc

60 E Rp
17.4.2 The Line Balancing Problem Example 17.1
Example 17.1
17.4.2 The Line Balancing Problem
Measures of line balance efficiency
Eb

Twc w Ts
生產線平衡效率的測量
workers i
assigned
-Utility workers
- Helping workers - Relieving workers - Maintenance
17.1.2 Work Transport Systems 工件運輸系統
Manual methods of work transport
Assembly workstations 組裝工作站
-Workers stand or sit. 工人站或坐 -Average manning level 平均人工化水準
n
wu wi
M
i1 w
n
n
wu: number of utility workers
wi
:
number of to station
- For fixed work unit with continuous moving.
- Allowing to move beyond the boundaries 允許在邊界 以外移動
No pacing 無步調
- No time limit 沒有時間限制
- Manual transport, removable work unit or asynchronous conveyor. 人工運輸、可移動的工件或非同步輸送帶 - Motivating workers to achieve a certain pace.激勵工人達到一 定步調
17.4.1 Repositioning losses . 重新定位的損失
M大的可允許的服務時間
Ts Max{Tsi} Tc Tr Tr: repositioning time
-Figure 17.4
Repositioning
- Symmetrical features 對稱的特徵
- Avoid parts that tangle 避開纏結的零件
- Less hooks, holes, etc. 較少鉤，洞等等
17.4 Analysis of Single Model Assembly Lines單一模型裝配線的分析