System Performance Characterization Specification Document

Version 1

October 1, 2008

Evan Malone

1. Category: General positioning system performance

   1. Metric: Positioning Accuracy

      1. Description: Over a large number of moves, how closely do commanded distances match measured distances?

      2. Instrumentation:

      3. Measurement:

      4. Calculation: Mean of N repetitions (measured distance – commanded distance) for each velocity and acceleration setting

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   1. Metric: Positioning Repeatability

      1. Description: Over a large number of identical moves, how much variation in measured distance is observed?

      2. Instrumentation:

      3. Measurement:

      4. Calculation: Standard Deviation of N repetitions (measured distance – commanded distance) for each velocity and acceleration setting

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   1. Metric: Velocity Accuracy

      1. Description: Over a large number of constant velocity motions, how closely does measured velocity match commanded velocity?

      2. Instrumentation:

      3. Measurement:

      4. Calculation: Mean of N repetitions of ((measured distance / measured time) – commanded velocity)

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   1. Metric: Velocity Regulation

      1. Description: Over a long constant velocity motion, how much variation is there in the measured velocity?

      2. Instrumentation:

      3. Measurement:

      4. Calculation:

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   1. Metric: Acceleration Accuracy

      1. Description:

      2. Instrumentation:

      3. Measurement:

      4. Calculation:

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   1. Metric: Maximum Velocity

      1. Description:

      2. Instrumentation:

      3. Measurement:

      4. Calculation:

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   1. Metric: Maximum Acceleration

      1. Description:

      2. Instrumentation:

      3. Measurement:

      4. Calculation:

1. Category: Tool control performance

   1. Tool: Standard syringe deposition tool

      1. Metric: Flow start/stop accuracy

         1. Description:

         2. Instrumentation:

         3. Measurement: Test pattern of lines on grid paper with range of lengths: VCT file

         4. Calculation:

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      1. Metric: Flow start/stop repeatability

         1. Description:

         2. Instrumentation:

         3. Measurement: Test pattern of lines on grid paper with range of lengths: VCT file

         4. Calculation:

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      1. Metric: Flow regulation

         1. Description:

         2. Instrumentation:

         3. Measurement: Deposit onto a laboratory balance and plot mass vs. time

         4. Calculation:

1. Category: Single material additive fabrication performance

   1. Metric: Dimensional accuracy

      1. Description: What is the error in the dimensions of finished manufactured parts relative to the nominal input model dimension?

      2. Instrumentation: Calipers

      3. Measurement: Manufacture test parts and measure them and or fit them together

         1. Rectangular block

         2. Pegs and holes

         3. 3D Puzzle

      4. Calculation:

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   1. Metric: Max overhang angle

      1. Description: What is the maximum unsupported overhang angle that can be produced by the system for a given material?

      2. Instrumentation: Calipers

      3. Measurement: Manufacture set of pillars with flared sides of increasing overhang. Identify pillars which fail and determine allowable overhang.

      4. Calculation:

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   1. Metric: Smallest feature size (different orientations)

      1. Description: What are the smallest interior and exterior features that can be controllably produced in the XY plane and in the Z planes?

      2. Instrumentation:

      3. Measurement: Produce set of test parts with holes and pillars at different scales and different orientations. Identify sizes at which manufacture fails or dimensional errors become large.

      4. Calculation:

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   1. Metric: Build environment uniformity

      1. Description: How much do the dimensional accuracy, repeatability, and feature sizes vary with position of the part on the build surface?

      2. Instrumentation: Caliper

      3. Measurement: Build test part in grid pattern on build surface to check for uniformity

      4. Calculation:

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   1. Metric: Maximum part height / Maximum aspect ratio

      1. Description: What is the maximum height of object with maximum height to horizontal cross-section ratio?

      2. Instrumentation: Caliper

      3. Measurement: Build set of pillars of constant cross section and maximum height allowed by work volume, each pillar with smaller cross section than the prior. Find pillar cross section at which full height fails to be achieved.

      4. Calculation:

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   1. Metric: Clean Break of Deposited Road

      1. Description: Combination of tool control and tool translation to break deposited road cleanly where desired, leaving minimal peak

      2. Instrumentation:

      3. Measurement:

      4. Calculation:

1. Category: Multiple material additive fabrication performance

1. Instrumentation

   1. Table truing

      1. Displacement gage

      2. Opto-ranger

      3. Tip position measurement