Summary
Summary 1CV50 Manufacturing integration course
- Course
- Institution
- Book
Summary of all lectures from the course 1CV50 and chapters 7, 8, and 9 from the book Factory Physics from Hopp and Spearman.
[Show more]
Connected book
Book Title:
Author(s):
- Edition:
- ISBN:
- Edition:
Seller
Follow
jonirensen00
Content preview
Summary 1CV50MANUFACTURING INTEGRATION COURSE
Written for college year 2021-2022
, Chapter 7
A manufacturing system is a goal-oriented network of processes through which parts flow. A plant is made up
of lines which in turn are made up of processes.
Throughput (TH): average quantity of good parts produced per time unit in a line.
Cycle time (CT): time the part spends as WIP
Lead time: time assigned for production of a part on a certain line
Service level: 𝑃(𝐶𝑇 ≤ lead time)
Fill rate: fraction of orders filled from stock
Turnover ratio: ratio of throughput to average inventory
Internal benchmarking: comparisons made inside systems
External benchmarking: comparisons made against outside systems
Parameters:
• 𝝀: arrival rate per time unit
• 𝒎𝒊: number of parallel identical machines at workstation 𝑊𝑖
• 𝒕𝒊𝟎 : raw process time of a machine in workstation 𝑊𝑖
• 𝜹𝒊 : throughput of workstation 𝑊𝑖
• 𝝋: average flow time in the system
Capacity:
• Upper limit on the throughput
𝑚𝑖
• Capacity =
𝑡0𝑖
Little’s law:
• Work in progress 𝑊𝐼𝑃 = 𝑇𝐻 × 𝐶𝑇
o 𝒘: average WIP level in the system
o So, 𝑤 = 𝛿𝜑
• Finished goods inventory 𝐹𝐺𝐼 = 𝑛 × 𝑇𝐻 with 𝑛 the planned inventory time.
Utilization: fraction of time a machine is not idle
𝛿𝑖 𝑡0𝑖
• 𝑢𝑖 = 𝑚𝑖
<1
Descriptors of a line:
• 𝒓𝒃 (bottleneck rate): capacity of the whole line
• 𝑻𝟎 (raw process time): sum of the long-term average process times of each station in the line
• Critical WIP (𝑾𝟎): WIP level in which a line without congestion achieves max TH and min CT
o 𝑊0 = 𝑟𝑏 𝑇0
o Critical WIP cannot exceed the nr of machines 𝑚.
▪ Balanced line: 𝑊0 = 𝑚
▪ Unbalanced line: 𝑊0 ≤ 𝑚
• 𝜶: congestion coefficient
o 𝛼 = 0: no variability, best case
o 𝛼 = 1: practical worst case
o 𝛼 = 0: worst possible case
Balanced line: all stations in a line have the same capacity
Ample equipment: processing is never blocked by lack of equipment
CONWIP: constant WIP meaning that the nr of parts in a line is kept at a constant level.
1
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller jonirensen00. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $6.96. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
50064 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now