Taking measurements with MCG
Taking measurements when using MCG Tools
Renishaw have simplified the implementation of using an MCG by providing on-line MCG Tools on the Renishaw website:
Using the MCG has never been easier with Renishaw's online MCG service. In three easy steps, we help you to measure, analyse and track the volumetric performance of your CMM:
- Create an MCG test program to run on your CMM - a DMIS program is generated for you from a set of parameters that you specify. You can run this on your CMM to generate a set of measurement results.
- Analyse your MCG test results - the MCG test generates a set of measurement results, again in DMIS format. You can upload these and have them analysed online. We provide guidance to help you interpret the data.
- Store and retrieve previous results to spot trends - you can store your MCG test results online and retrieve them at a later date, allowing you to identify changes in the performance of your CMM over time.
Taking measurements when not using MCG Tools
- Arm elevation 0° - measure the arm radius R at 45° intervals in the horizontal plane (a total of eight measurements).
- Arm elevation -45° - measure the arm radius R at 45° intervals in the horizontal plane (a total of eight measurements).
- Arm elevation +45° - measure the arm radius R at 45° intervals in the horizontal plane (a total of eight measurements).
- Repeat steps 1 to 3 twice to obtain repeatability measurements. This provides a total of 72 (3 × 24) measurements for evaluation of volumetric measuring performance and system repeatability.
- Remove the counterbalanced arm carefully and re-datum the pivot ball using a minimum of ten readings (refer to the ‘Setting-up' section). If the pivot ball centre has moved significantly more than the maximum measured repeatability, re-datum the pivot ball ensuring that:
- The seating faces between the pivot , pillars and baseplates are perfectly clean and that these parts are firmly tightened.
- The stated pillar thermal stabilising period (2 minutes minimum) is observed.
- The utmost care is taken when placing the counterbalanced arm of the pivot.
Eight points of measurement: