Tolerance Stack Ups for Mechanical engineers with Six-Sigma

Name: Tolerance Stack Ups for Mechanical engineers with Six-Sigma
Rating: 4.6 (365 reviews)

Estimate the quality level of your assembly as a PRO to predict Defects + Examples + Homeworks + Templates

Highest Rated

Created bySantiago Aguillón

Last updated 12/2022

English

What you'll learn

Worst-Case approach
Statistical approach (RSS)
Six-Sigma approach
Create the loop for tolerance analysis in 2D
Estimate the quality level of the assembly
Estimate the expected Defects Per Million of Opportunities (DPMO)
Inflation factors for non-normal distributions (Ci)
Process capablity index (Cp) from manufacturing
Dynamic shift (k) for loss of performance over time
Understand trade-offs for tolerance analysis
Customer requirements (LSL, USL)

Course content

5 sections • 41 lectures • 4h 16m total length

Intro2:40
Explore practical tolerance analysis with Six Sigma, from worst-case and statistical methods to inflation factors and process capability, using hands-on assembly problems and an Excel template to predict defects.
What is tolerance analysis (Stack up)?6:18
Apply tolerance analysis to determine critical dimensional limits and final clearance gaps in assemblies, using linear stack ups and methods like worst case, statistical, and Six Sigma.
Fundamentals & definitions10:10
Standard deviation10:54
Dimensioning methods6:18
Steps to perform a tolerance analysis7:10
Example of sketch creation8:16
Explore tolerance stack ups in a mechanical assembly, illustrating sketch creation and direct versus chain dimensions, and apply worst-case or Six Sigma methods to the critical gap.

What is the Worst-Case approach?2:30
Explore the worst-case approach for tolerance analysis by examining extreme size variations to determine maximum or minimum gaps. Apply the bolt length example to illustrate the method without probability.
Mathematical definition of WC4:19
Example WC6:01
Template in excel for WC4:32
Practice problems WC (watch before the following videos)5:15
Solution: Assembly I8:16
Apply six-sigma tolerance stack-ups to meet a 6.5–7.9 mm critical distance in assembly i, center the process, and optimize tolerances to balance variation and manufacturing cost.
Solution: Assembly II6:51
Solution: Assembly III12:44
Solution: Assembly IV9:54
Redesign item one and item six to extend nominal lengths, then assess interference and critical credence in assembly iv. Propose nominal distance changes or larger overall distance.
Solution: Assembly V8:12
Apply the worst case approach to assembly v, setting all components to the same tolerance and ensuring the critical distance exceeds 0.35 mm while evaluating the impact on manufacturing cost.

What is RSS approach?3:35
Apply the rss approach to tolerance analysis, using a normal distribution to capture the most likely variations and connect three-sigma limits to defects per million.
Mathematical definition of RSS10:57
Example RSS14:31
Template in Excel for RSS8:41
Practice problems RSS (watch before the following videos)3:11
Solution: Assembly I5:03
Solution: Assembly III8:42
Solution: Assembly IV7:16
Solution: Assembly V3:57

What is Six-Sigma approach?4:19
Mathematical definition for mixed distributions6:07
Explore the mathematical definition of mixed distributions for tolerance stack-ups, applying inflation factors to convert component standard deviations from various distributions to the overall normal approximation.
Example using mixed distributions4:34
Mathematical definition for process capability7:11
Explore the mathematical definition for process capability, linking specification width to six-sigma process width. Learn how process capability index uses tolerance and standard deviation to relate to defects per million.
Example using process capability2:54
Compare suppliers with different process capabilities to show how higher capability reduces standard deviation and increases assembly sigma, while noting higher manufacturing costs from better quality control.
Mathematical definition for dynamic shift4:30
Example using dynamic shif3:11
General equation for tolerance analysis6:06
Delve into the general equation for tolerance analysis, examining mixed distributions, inflation factors, and dynamic shift to relate process capability to assembly quality.
Template in Excel for Six-Sigma approach7:15
Practice problems Six-Sigma (watch before the following videos)5:15
Solution: Assembly I3:20
Explore tolerance stack-ups for assembly one, comparing normal and uniform distributions to compute quality levels at 3 sigma, 2.67 sigma, and 1.53 sigma, including dynamic shift and fixed tolerances.
Solution: Assembly III5:38
Solution: Assembly IV2:58
Solution: Assembly V0:02

Requirements

We start from the basics, but some fundamentals of statistics are recommended
Please note: This course WILL NOT cover GEOMETRIC tolerances, ONLY plus/minus tolerances

Description

Stack up and Tolerance Design is all about quality, or in other words, the allowable parts to be rejected during the process. In escence, this results in an iterative process between the design department, manufacturing and the customer. In this course you will learn the concepts to master plus/minus tolerance stack ups in 2D. At then end, you will become a valuable member for your company because you will be capable to assess assemblies and propose changes to meet critical requirements. Although currently there are several software which run complex tolerance analysis in 3D, in my experience, most of the times you can simplify the problem with a 2D analysis, so as mechanical designer YOU MUST be capable of performing 2D analysis in order to save valuable resources to the company.

First, you will learn the basics: The definition of nominal value, tolerance, standard deviation, normal distribution and the importance of tolerance analysis in mechanical design.

Then. you will learn how to create the sketch (loop) to follow in the calculation of tolerance analysis. Several exercises will be provided so you can practice this process.

Next you will Learn how to perform a linear stack ups with three approaches:

Worst Case: When no rejections are allowed. This apporach results in the most expensive, but it is used in critical applications.
Statistical: Some rejections are allowed. The costs are reduced because some defects will always be presented.
Six-Sigma: Complex considerations such as process distributions, process caapability and loss of performance are taken into account to improve the design at different quality levels.

Finally, for each approach I will provide you five assemblies with different requirements. You will need to apply the concepts to find the suitable design which meet the quality levels and solve the critical clearances. A template in excel will allow you to perform these calculations.

Please note: We will cover ONLY plus/minus tolerances. But the knowledge is also applicable for geometric tolerances.

This course is based in my own experience as designer in the aerospace industry for 10 years. I used this methods everyday to discuss initial changes with customer, find a suitable provider and reduce costs with manufacturing.

Who this course is for:

Mechanical designers (entry level)
Mechanical engineers
Students of mechanical engineering

Tolerance Stack Ups for Mechanical engineers with Six-Sigma

What you'll learn

Explore related topics

Course content

Introducción7 lectures • 52min

Sketch creation1 lecture • 7min

Worse-Case approach (WC)10 lectures • 1hr 9min

Root Sum Square approach (RSS)9 lectures • 1hr 6min

Six-Sigma approach14 lectures • 1hr 3min

Requirements

Description

Who this course is for: