Geometric Dimensioning and Tolerancing (GD&T) basics in Solidworks - Dashboard Guide

Dashboard Mode - Geometric Dimensioning and Tolerancing (GD&T) basics

Goal

Understand how GD&T symbols are used to control part quality and ensure proper assembly in manufacturing.

Sample Data: GD&T Inspection Results

Feature	Symbol	Tolerance (mm)	Measured Value (mm)	Pass/Fail
Hole Diameter	Ø	10.00 ±0.05	10.02	Pass
Flatness of Surface A	Flatness	0.02	0.015	Pass
Position of Hole B	Position	0.1	0.12	Fail
Perpendicularity of Surface C	Perpendicularity	0.05	0.04	Pass
Profile of Surface D	Profile	0.03	0.025	Pass
Concentricity of Shaft E	Concentricity	0.02	0.018	Pass
Parallelism of Surface F	Parallelism	0.04	0.05	Fail

Dashboard Components

• KPI Card: Total Features Inspected = 7
• KPI Card: Features Passed = 5
• KPI Card: Features Failed = 2
• Bar Chart: Count of Features by GD&T Symbol
  Formula: Count features grouped by Symbol from data table
• Pie Chart: Pass vs Fail Ratio
  Formula: Count of Pass and Fail from Pass/Fail column
• Table: Detailed Inspection Results
  Shows all columns from sample data

Dashboard Layout

+----------------------+----------------------+----------------------+
| Total Features       | Features Passed      | Features Failed      |
| Inspected: 7         | Passed: 5            | Failed: 2            |
+----------------------+----------------------+----------------------+
|                      Bar Chart: Count of Features by GD&T Symbol       |
|                      (Symbols on X-axis, Count on Y-axis)             |
+-----------------------------------------------------------------------+
| Pie Chart: Pass vs Fail Ratio           | Detailed Inspection Results Table |
| (Pass and Fail slices)                  | (All data rows and columns)        |
+---------------------------------------+---------------------------------+

Interactivity

User can filter by GD&T Symbol using a dropdown filter. Selecting a symbol updates the bar chart, pie chart, and detailed table to show only data for that symbol. KPI cards update to reflect counts for the filtered data.

Self Check

If you filter to show only the 'Position' symbol, which components update and what are their new values?

• KPI Cards: Total Features = 1, Passed = 0, Failed = 1
• Bar Chart: Shows only 'Position' with count 1
• Pie Chart: Shows 0% Pass, 100% Fail
• Table: Shows only the row for 'Position of Hole B'

Key Result

Dashboard shows GD&T inspection results with pass/fail KPIs, symbol counts, and detailed data.

Practice

1. What is the main purpose of Geometric Dimensioning and Tolerancing (GD&T) in SolidWorks?
GD&T helps to:

easy

A. Define allowable variations to ensure parts fit and function together

B. Create 3D models faster

C. Improve the color scheme of the design

D. Reduce the file size of CAD models

Solution

1. Step 1: Understand GD&T purpose

   GD&T is used to specify allowable variations in part features to ensure proper fit and function.

2. Step 2: Compare options to GD&T role

   Only Define allowable variations to ensure parts fit and function together correctly describes this purpose; others relate to unrelated CAD tasks.

3. Final Answer:

   Define allowable variations to ensure parts fit and function together -> Option A

4. Quick Check:

   GD&T = Allowable variations for fit [OK]

Hint: GD&T controls fit and function, not modeling speed [OK]

Common Mistakes:

• Confusing GD&T with modeling tools
• Thinking GD&T changes visual styles
• Assuming GD&T reduces file size

2. Which of the following is the correct symbol for a flatness tolerance in GD&T?

easy

A. A straight horizontal line inside a rectangle

B. A circle with a diagonal line

C. A parallelogram

D. A triangle

Solution

1. Step 1: Recall flatness symbol

   The flatness symbol is a straight horizontal line inside a rectangular frame.

2. Step 2: Match options to symbol

   A straight horizontal line inside a rectangle matches the flatness symbol; others represent different or incorrect symbols.

3. Final Answer:

   A straight horizontal line inside a rectangle -> Option A

4. Quick Check:

   Flatness symbol = horizontal line in rectangle [OK]

Hint: Flatness symbol looks like a flat line in a box [OK]

Common Mistakes:

• Confusing flatness with circularity symbol
• Selecting shapes unrelated to GD&T
• Mixing up symbols for different tolerances

3. Given a part with a datum feature frame referencing datum A and a positional tolerance of 0.1 applied to a hole, what does this imply about the hole's location?

medium

A. The hole's depth tolerance is 0.1 units

B. The hole diameter must be exactly 0.1 units

C. The hole can be anywhere on the part surface

D. The hole's center must be within 0.1 units of the true position relative to datum A

Solution

1. Step 1: Understand positional tolerance with datum

   Positional tolerance controls the allowable deviation of a feature's location relative to a datum.

2. Step 2: Interpret 0.1 positional tolerance

   The hole's center must lie within a 0.1 unit zone around the true position defined by datum A.

3. Final Answer:

   The hole's center must be within 0.1 units of the true position relative to datum A -> Option D

4. Quick Check:

   Positional tolerance = location within 0.1 units [OK]

Hint: Positional tolerance limits location, not size [OK]

Common Mistakes:

• Confusing positional tolerance with size tolerance
• Ignoring datum reference
• Assuming tolerance applies to hole depth

4. A GD&T feature control frame is missing the datum reference after the positional tolerance symbol. What is the likely issue?

medium

A. The tolerance is ignored by inspection software

B. The tolerance applies globally without reference

C. The tolerance is incomplete and may cause manufacturing errors

D. The feature is automatically datum A

Solution

1. Step 1: Identify role of datum references

   Datum references specify the exact location or orientation basis for the tolerance.

2. Step 2: Understand missing datum impact

   Without datum reference, the tolerance lacks context, making it incomplete and risky for manufacturing.

3. Final Answer:

   The tolerance is incomplete and may cause manufacturing errors -> Option C

4. Quick Check:

   Missing datum = incomplete tolerance [OK]

Hint: Always include datum references in feature control frames [OK]

Common Mistakes:

• Assuming tolerance applies without datum
• Thinking software ignores missing datum silently
• Believing default datum is assigned automatically

5. You have a cylindrical part with a diameter tolerance of 50 ±0.1 mm and a concentricity tolerance of 0.05 mm relative to datum A. What does this combination ensure about the part?

hard

A. The cylinder can have any diameter but must be concentric within 0.05 mm

B. The cylinder's diameter is within 49.9 to 50.1 mm and its axis is within 0.05 mm of datum A's axis

C. The cylinder's diameter is exactly 50 mm and concentricity is ignored

D. The part's length is controlled by these tolerances

Solution

1. Step 1: Interpret diameter tolerance

   The diameter must be between 49.9 mm and 50.1 mm, allowing ±0.1 mm variation.

2. Step 2: Interpret concentricity tolerance

   The cylinder's axis must be within 0.05 mm of the axis of datum A, ensuring alignment.

3. Final Answer:

   The cylinder's diameter is within 49.9 to 50.1 mm and its axis is within 0.05 mm of datum A's axis -> Option B

4. Quick Check:

   Diameter ±0.1 and concentricity 0.05 ensure size and alignment [OK]

Hint: Diameter controls size; concentricity controls axis alignment [OK]

Common Mistakes:

• Ignoring diameter tolerance range
• Confusing concentricity with diameter size
• Assuming length is controlled by these tolerances