16-10-2010, 12:02 PM
Why Improve
Machine Tool Volumetric Accuracy? Measuring machine performance
Allows process improvements before parts are made.
Allows predictive repairs of machines.
Why Improve
Machine Tool Volumetric Accuracy?
Measuring finished part dimensions
Can only be done after the part is completed.
Causes reject parts to be repaired or thrown way.
What are the Tools?
Machine Error Budgets
Machine Parametric Measurement
How did these tools evolve?
For over 90 years, the builders determined machine performance standards.
Dr. Georg Schlesinger recognized the need to do measurements on machine tools.
How did these tools evolve?
Schlesinger’s book, Testing Machine Tools, contains parametric tests, such as
limited to the characterization of machine spindles and moving components
roundness
straightness
How did these tools evolve?
Engineers at Lawrence Livermore National Labs found these methods inadequate for specifying their machines.
How did these tools evolve?
The ISO 230 Specifications were for the assembly of machine tool components not the capability of machines to make parts.
“parametric error budgeting”
“parametric error measurement”
What were their solutions?
They developed techniques to aid in specification, design & production of the world’s most accurate machine tools.
Identify machine axis relation parameters
Identify machine thermal error parameters
Identify machine environmental error parameters
Sum error parameters
Parametric Error Budgeting
Identify machine motion error parameters
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