Summary
Summary 1CV50: Manufacturing integration course
- Course
- Institution
A summary of all material needed for the final exam of 1CV50
[Show more]
Seller
Follow
julidekok
Reviews received
Content preview
Chapter 7 Balanced line: when all machines in the line have the same rate
Capacity of a station (per hour) = number of machines * (1/process time)
Congestion Coefficient (α): A unitless measure of congestion
- Zero variability: α=0
- Practical worst-case: α=1
- Worst possible case: α=W(o)
Effective production rate: the maximum average rate at which the workstation can
process parts
Fill rate: the fraction of orders that are filled from stock immediately
Inventory turns / Turnover ratio: the ratio of throughput to average inventory
Lead time: time allocated for production of a part on a routing or line
Service level = probability of (cycle time ≤ lead time)
Touch time: the actual working time
Utilization: fraction of time a workstation is not idle = arrival rate/effective production
rate
Little’s Law
WIP = Throughput * Cycle time
Cycle time / Flow time / Throughput time (CT): the average time from release of a job
at the beginning of the routing until it reaches an inventory point at the end of the routing
Throughput (TH): the average quantity of good parts produced per unit time
Cycle time: Throughput:
,Work in Progress
Work in progress (WIP): inventory between start and end points of a product routing
Critical WIP (Wo): the WIP level for which a line with given values of r(b) and T(o) but
having no variability achieves maximum throughput with minimum cycle time
W(o) = rb * To
Raw process time (To): the sum of the long-term average process times of each
workstation in the line
Bottleneck rate (rb): the rate of the workstation having the highest long-term utilization
When we have two machines we can calculate the bottleneck rate by calculating the
utilization. Because some parts are scrapped we should take this into account. The
percentage of rate r scrapped is 1-y so the percentage kept is r*y. Therefore the utilization of
machine 2 is different than machine 1.
Performances
1. Best-case performance: maximum throughput and minimum cycle time (no randomness)
o In a balances line: W(o) = number of machines
o In an unbalanced line: W(o) is always less than number of machines
, 2. Worst-case performance: maximum cycle time and minimum throughput (no
randomness)
3. Practical worst-case performance: considers randomness, represents the maximum
randomness case
Every possible state occurs with equal frequency. In order for all states to be equally likely,
three conditions are required:
1. The line must be balanced
2. All stations must consist of single machines
3. Process times must be random and occur according to the exponential distribution
(memoryless)
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 julidekok. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.97. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
62555 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now