Research on a Novel Method for Measuring Volumetric Error of Coordinate Measuring Machine
CMM (Coordinate Measuring Machine) is used as an accurate measuring instrument in manufacturing and design of products. High accurate CMM is required by the development of super-finish, micro-machinery, micro-electronic mechanical systems (MEMS). The precision of CMM is influenced by its volumetric error and dynamic error. The volumetric error is the major component during slowly probing, but the dynamic error is not omitted during fast probing. Compensating the volumetric error is an effective approach to improve the precision of CMM. The volumetric error in the working space of CMM must be measured and the error model must be set up before compensating. In this paper, a novel method to measure 5 volumetric errors of a guide way at the same time by 3-beam laser interferometer is proposed. The error compensating model is validated by experiment. The method can also be used to measure the dynamical error of CMM and CNC machine in real-time. The research can be referred to design the super higher accurate CMM and the accurate CNC machine.
GUM Block for CMM Uncertainty Estimation
Coordinate measuring technique can be divided into 3 sections: for manufacture, for acceptance test and for application. The techniques for the first two sections are very developed. But the techniques for the 3rd section, measurement strategy optimization and uncertainty assessment is still in developing. GUM-Block can show the users of CMM the influences of the measurement strategy to the uncertainty. And it can be used to check the validity of uncertainty assessment by different users and different methods. This paper introduces the basic principle and the background of developing the block, and the result of block calibration comparison between NIM and NML.
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.