An international comparison of geometrical roundness measurements using error separation has been arranged between five European laboratories. In order to test the error separation in high precision roundness measurements, a glass hemisphere with a low roundness error was used. Measurements were made in two directions: perpendicular to the axis of rotation and perpendicular to the spherical surface. The measured departure from roundness varied from 5.6 nm to 20 nm and the calculated En < 1. The reason for the big variation in values of departure from roundness is believed to be unstability of the artefact. However, by removing the 2nd harmonic component from the roundness curves, similar features in some details are seen when comparing originally differently shapes.
| Original language | English |
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| Place of Publication | Helsinki |
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| Publisher | Centre of Metrology and Accreditation (MIKES) |
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| Number of pages | 28 |
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| ISBN (Print) | 952-5209-60-1 |
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| Publication status | Published - 2001 |
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| MoE publication type | D4 Published development or research report or study |
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| Series | MIKES Julkaisu |
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| Number | J4/2001 |
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| ISSN | 1235-5704 |
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