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How to Manage Product Cost With Geometric Dimensioning and Tolerancing (GD&T)

 | February 20, 2024

Key Takeaways:

  • Tighter geometric tolerances add cost and complexity to manufacturing
  • Geometric dimensioning and tolerancing improve quality and cost outcomes by providing greater control and standardization
  • Optimize GD&T with aP Design’s robust features, including direct tolerance editing and scenario comparisons

The Full Article:

Geometric dimensioning and tolerancing (GD&T) is a system that helps to control variations in manufacturing. This approach utilizes GD&T symbols and measurements to describe the geometric characteristics of a 3D engineering drawing, such as its dimensions and shape. As a result, organizations can ensure that their product designs are manufactured precisely as intended and within target costs.

Our overview of GD&T will examine how geometric tolerances impact product cost and manufacturability. Additionally, we will outline GD&T’s role in striking the optimal balance between quality and cost efficiency.

How Geometric Tolerances Impact Product Design Intent

Geometric tolerances are specified during product design to define the allowable variation in the dimensions of a manufactured part. This ensures the proper functioning and perfect fit of critical product components and assemblies.

Manufacturers who work with tighter tolerances manage a smaller range of allowable variation, which results in higher precision. However, tighter tolerances may potentially necessitate higher costs due to more complex manufacturing processes and increased labor requirements.

Alternatively, components with looser geometric tolerances have a wider range of acceptable variation, making it easier and more cost-effective to manufacture. Further, less stringent quality control is required to inspect the basic dimensions of a component, leading to lower costs associated with the equipment needed for this process. While components with looser tolerances have wider allowable variations, they may compromise fit and function.

The optimal component tolerance level depends on its requirements and the trade-off between cost, precision, and functionality. Moreover, manufacturers who specify tolerances early in the product design process are more likely to avert downstream problems that require late-stage engineering change orders (ECOs).

Watch this presentation to learn more about how form tolerances affect cost and manufacturability.

Applying Geometric Dimensioning & Tolerancing (GD&T) Effectively

Our most recent Manufacturing Insights Conference featured a session titled “The Price of Precision: How Tolerances Shape Cost and Manufacturability.” This presentation highlighted the following three methods for applying tolerances:

  • Feature-targeted tolerance application: This approach focuses on applying precise tolerances to a component’s features while carefully considering both 2D and 3D drawings. This provides manufacturers with greater control over dimensions, enabling them to enhance production and assembly efficiency by minimizing variation within the tolerance zone. This includes managing angularity, circularity, flatness, parallelism, and other geometric characteristics with greater precision.
  • Generic policy application: This method enables companies to apply standard tolerances based on a feature’s nominal size, dimensions, and manufacturing process when specified tolerances are absent. Although this method provides a baseline level of tolerance, it may not effectively address critical features, potentially resulting in fitment problems.
  • No tolerance application: This “do-nothing” approach leaves room for interpretation because machines have varying tolerances. Failing to apply tolerance can result in poorly controlled products with form and fit issues, which may require rework activities and additional costs.

It is crucial to note that excessive tolerance application is not beneficial, as it requires additional specialized tools. This results in increased cycle time, scrap material, and significant costs for product manufacturers.

Using aP Design to Optimize Geometric Dimensioning and Tolerancing (GD&T)

aPriori’s automation-driven aP Design solution allows manufacturers to optimize tolerances and geometric designs through the following capabilities:

Direct Tolerance Editing

aP Design empowers product development teams to add and edit tolerances directly within the platform. The process is further streamlined as users can select specific features to work with, enabling tolerance modifiers to be added more seamlessly. Additionally, the platform automates the product evaluation process and filters out unsuitable tolerance types based on the selected features.

Importing Tolerances From CAD Models

The aP Design application facilitates the direct import of tolerances from 3D CAD prototypes using product manufacturing information (PMI) and CAD tolerance policies.

Actionable Design Feedback

Product teams can employ aP Design to gain detailed and precise insights into the cost, carbon footprint, and Design for Manufacturability (DFM) implications of tolerance decisions. This enables manufacturers to make informed, data-driven decisions to optimize their product designs for cost and sustainability.

Project Progress Tracking

Users can now use aP Design to track the progress of their design iterations and visualize the impact of different tolerance scenarios using biaxial graphs. This feature allows users to make informed decisions by providing insights into key metrics such as cost and cycle time.

Scenario Comparisons

With aP Design, teams can effectively build, compare, and save various tolerance scenarios. This functionality provides a granular breakdown of each scenario’s performance, making it easy to identify the most cost-effective and efficient design solutions.

Learn more about aPriori’s early design guidance for geometric dimensioning and tolerancing (GD&T).

Streamlining GD&T Processes for Enhanced Productivity and Cost Optimization

Establishing the optimal tolerance is crucial in balancing precision and cost efficiency during the product design process. Tighter tolerances require more precise processes and equipment, leading to higher expenses. Alternatively, looser tolerances allow for simpler production but may compromise the functionality of the product.

To optimize geometric design decisions, product teams can employ digital solutions such as aP Design. The platform provides valuable features like direct tolerance editing to enhance productivity, accuracy, and cost efficiency in designing cutting-edge innovations.

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