True Position Calculator

Position Parameters

Theoretical X coordinate
Theoretical Y coordinate
Measured X coordinate
Measured Y coordinate
Allowed deviation

Calculation Results

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True Position Calculator: Your Complete Guide to Geometric Tolerancing

Accurately calculating true position is essential for quality control, manufacturing, and engineering. Our True Position Calculator helps you determine the deviation of actual positions from their theoretical locations.

Understanding True Position Calculations

Proper true position calculation is crucial for several reasons:

  • Quality Control: Ensures parts meet specifications
  • Manufacturing Precision: Maintains assembly tolerances
  • Cost Efficiency: Reduces scrap and rework
  • Design Verification: Validates part functionality
  • Standards Compliance: Meets industry requirements

How to Use the True Position Calculator

  1. Enter Nominal Position: Input theoretical X and Y coordinates
  2. Enter Actual Position: Input measured X and Y coordinates
  3. Specify Tolerance: Enter allowed position deviation
  4. Click Calculate: Get true position results

True Position Calculation Formula

True Position Formula:
True Position = 2 × √((X_actual - X_nominal)² + (Y_actual - Y_nominal)²)
Where:
X_actual = Measured X coordinate
X_nominal = Theoretical X coordinate
Y_actual = Measured Y coordinate
Y_nominal = Theoretical Y coordinate

Common Applications

  • Manufacturing:
    • Hole patterns
    • Mounting features
    • Assembly points
  • Quality Control:
    • Inspection reports
    • Process validation
    • Part verification
  • Engineering:
    • Design reviews
    • Prototype testing
    • Production planning

Real-World Examples

Example 1: Standard Hole Pattern

Nominal Position: (100mm, 100mm)
Actual Position: (100.2mm, 99.8mm)
Tolerance: 0.5mm
Results:
- True Position: 0.283mm
- Within Tolerance: Yes
- Deviation: 56.6% of tolerance

Example 2: Precision Mounting

Nominal Position: (50mm, 50mm)
Actual Position: (50.1mm, 49.9mm)
Tolerance: 0.2mm
Results:
- True Position: 0.141mm
- Within Tolerance: Yes
- Deviation: 70.5% of tolerance

Frequently Asked Questions

What is true position tolerance?
True position tolerance is a geometric dimensioning and tolerancing (GD&T) specification that defines the allowed deviation of a feature's actual position from its theoretical position.
How do I interpret true position results?
The result shows the actual deviation from the nominal position. If this value is less than the specified tolerance, the part is within specification. The percentage of tolerance used helps assess the margin of safety.
What factors affect true position accuracy?
Key factors include measurement equipment accuracy, part stability during measurement, environmental conditions, and operator skill. Proper fixturing and measurement techniques are essential.
How do I improve true position accuracy?
Use precise measurement equipment, maintain stable measurement conditions, implement proper fixturing, and follow standardized measurement procedures. Regular calibration and training are also important.
What are common true position applications?
Common applications include hole patterns, mounting features, assembly points, and any feature where precise positioning is critical for function or assembly.

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