Engineering Talk - DCS's Blog on Quality and Engineering

How is Excel Failing Your Tolerance Stack Ups? Now ON-DEMAND

[Webinar] How is Excel Failing Your Tolerance Stack Ups

Understanding the difference between 1D vs 2D vs 3D vs Worst Case Tolerance Analysis, and how you may become misled.

Tolerance Analysis can be a simple function. Using RSS and Excel, tolerances can be calculated as a stack-up to determine the range of variation. However, as soon as this method is used for real parts in an assembly, this method begins to lose its validity. Incorporating the variation from 3 dimensional effects can make the math extremely difficult and hard to reproduce quickly, leaving out variation that can cause expensive problems during manufacturing. 

Topics: CATIA 3DCS Tolerance Analysis Webinar Siemens NX 3DCS Creo PTC Creo

1D vs 2D vs 3D Tolerance Analysis, How is Excel Failing your Tolerance Stack Ups? [Webinar]

1D vs 2D vs 3D Tolerance Analysis Explained

Excel Stack-Ups do not include influences from 3D part associations, nor does it include process variation, that can greatly impact a design causing high costs to correct in scrap, rework and recalls. 

Topics: CATIA 3DCS Tolerance Analysis CATIA V6 Webinar Siemens NX 3DCS Creo PTC Creo Press Release

3DCS Version 7.6 NOW AVAILABLE - Learn About New Features in the First Webinar

Use GD&T to Put Tolerances on Your Model

3DCS Now Has a Complete GD&T Interface for Building PMI onto Your Simulation Model 

3DCS Version 7.6 is now available to all DCS Clients with active maintenance -- go to to download the new version. 

Topics: CATIA 3DCS Tolerance Analysis Webinar Siemens NX 3DCS Creo PTC Creo Press Release

Webinar Thurs, Feb 21st - NEW 3DCS Version 7.6 GD&T Interface and Application

NEW Version 7.6 for 3DCS Variation Analyst - CATIA, NX, CREO Integrated and Multi-CAD

Learn about the new features in 3DCS Version 7.6 and the updates to the software

Every major update of 3DCS includes some major features, which are demonstrated in the DCS Webinar Series for that version. To join the webinar, click below:

Topics: CATIA 3DCS Tolerance Analysis CATIA V6 Webinar Siemens NX 3DCS Creo PTC Creo Press Release

Upcoming Webinar - Pattern Move -- Setting Patterns of Holes and Pins and Then Some

Pattern Move - Floating & Fixed Fasteners, Gravity, Partial Pin, all with Model Variants 

Topics: CATIA 3DCS Tolerance Analysis CATIA V6 Webinar Siemens NX 3DCS Creo PTC Creo

Thank You for a Great 2018 - More to Come in 2019

Welcome to 2019 - Let's Get Started

Let's Talk About 2018 and What's In Store for 2019

2018 has been a good year. DCS is happy to welcome new clients, and work further with existing clients as Quality 4.0 and Tolerance Analysis continue to develop. 

Topics: CATIA 3DCS Tolerance Analysis T&T SPC FEA CATIA V6 Webinar Siemens NX 3DCS Creo PTC Creo

Is Cloud Computing Really Better for Business? Survey says...

Is Cloud Computing Really Better for Business? Survey says... 

Topics: CATIA 3DCS Tolerance Analysis SPC CATIA V6 Webinar QDM Siemens NX 3DCS Creo PTC Creo

Webinar Tomorrow - Iterative and Conditional Logic in Statistical Tolerance Analysis

Iterative and Conditional Logic, Iteration Move and Mechanical 

Understanding how to create, use and apply iterative and conditional logic in statistical tolerance analysis. 

DCS is hosting a webinar on the use and application of Iteration Move, Iterative and Conditional Logic and Mechanical Moves tomorrow, Thursday December 13th at 11 am EST. As part of the Digital GD&T Series, all current registrants will have access to the webinar and recording. 

Topics: CATIA 3DCS Tolerance Analysis CATIA V6 Webinar Siemens NX 3DCS Creo PTC Creo

3 Tools to Tackle Tough Tolerance Negotiations - Using Data to Support Tolerance Changes

3 Tools to Support Tough Tolerance Negotiations 

DCS Solutions offer a number of tools to support your tolerance discussions with customers. 

Tolerance Negotiations are never easy. Customers will try to hold their suppliers to difficult or over-engineered tolerances, or simply don't know that certain tolerances can be opened without affecting the assembly quality, or need to be opened (increased) in order to keep costs reasonable. 

DCS provides 3 tools to support tolerance negotiation by using data to back up tolerance change requests: 

1. Tolerance Negotiator -- QDM Analyst Tool

2. 3DCS Variation Analyst Simulation Results

3. QDM Management Reports 


1. Tolerance Negotiator - QDM Analyst Tool 

How do I get it?

Tolerance Negotiator is built into the base QDM Analyst software, without the need for add-ons or additional purchases. If you have QDM Analyst, the standalone QDM template maker software, you have Tolerance Negotiator. 

Using Tolerance Negotiator

Tolerance Negotiator is under the Tools tab of QDM Analyst. 

After clicking Tolerance Negotiator, a table with all of the imported data measurements is generated.

Two types of data are usually used in Tolerance Negotiator.

Plant and Measured Data can be imported from any inspection device and used to demonstrate production tolerances and metrics. Suppliers use the first 30 parts in a production line, or prototype measurements to demonstrate measured values and whether they are meeting or failing to meet statistical objectives (Pp or Cp). 

Simulation data from an analysis tool can also be used before production. As a DCS Software, QDM is already configured to utilize 3DCS data. Importing 3DCS simulation results can show the risk of failure for given objectives. 

Tolerance Negotiator gives two sets of values:

1. Tolerance changes required to meet given Cp / Pp objectives

2. How Tolerance changes affect Cp and Pp 

This lets the user change tolerances, values and objectives and instantly see the results. For example, if your customer gave a required Pp of 1.33, you can show which tolerances in the provided design can actually meet that objective. With 3DCS, you can demonstrate how 3D stack ups affect those tolerances and further determine the final Pp or Cp values, and may affect the final range of variation. 

Tolerance Negotiator Demonstration

The video below demonstrates how the use of Tolerance Negotiator:


2. 3DCS Variation Analyst Simulation Results

3DCS Variation Analyst simulates assembly builds across a normal distribution (default) using Monte Carlo Simulation. Incorporating part tolerances and assembly processes, 3DCS provides outputs of simulated measurements that include the 3 dimensional variation stack of all parts and processes in the model. 

The results are the measured results of hundreds or thousands of virtual product builds compiled and analyzed statistically. Beneath the simulation results are the sensitivity results, which include the largest contributing tolerances to the given measure. 

In the simulation results window, upper and lower specification limits can be dragged to adjust and see the statistical outputs, Cp and Pp, change accordingly. It also demonstrates the expected failure rate for each given measurement with its given specification limits. This information can be valuable in showing the risk of build failure for each feature based on current design specifications, and how changes can affect either the Cp/Pp or the risk of failure. Adjusting a tolerance and re-running the analysis can show the change to the simulation results and whether an adjustment will positively or negatively affect the model outputs. 

Here is a video example of one method of how 3DCS simulation results can be used for tolerance negotiation: 


3. QDM Management Reports

QDM Management Reports are an effective way to present results to managers and business leaders. They summarize and display simulation or production results, giving visual context and information to make it easy to understand the content. 

Within the reports, as part of tolerance negotiation, a user can set specification limits or pass/fail criteria and color coding to show whether given measurements passed or failed inspection. 

This is a good way to show simulation results from 3DCS or production data in QDM and whether those simulation results will meet quality expectations. It can be helpful for pointing out trouble areas and leading into a tolerance negotiation on resolutions for those given measurements and tolerances. 

Learn more about Tolerance Negotiation and Supplier Quality with Supplier Quality for Suppliers Webinar - FREE On-Demand 

Click to View the Webinar

Topics: CATIA 3DCS Tolerance Analysis SPC CATIA V6 Webinar QDM Siemens NX 3DCS Creo PTC Creo

How to Simulate Material Thickness in 3DCS Tolerance Analysis

 How to Better Treat Thickness Tolerances in Sheet-Like Materials

We encounter many situations where there is a form tolerance on a primary surface and then the other side of the part has a thickness allowance. Often implicitly it is assumed to have the same form or a very local refinement. (i.e. stamped sheet metal, composite lay-ups)There are many situations in both aerospace and automotive I would think where sheet of material is stamped and parts are indexed to both sides and sheet metal is accepted using a spec tolerance. 

One method used in the past has been to use ghost parts but it seems like there should be an easier way. What am i missing?

Topics: CATIA 3DCS Tolerance Analysis T&T CATIA V6 Webinar Siemens NX 3DCS Creo PTC Creo