Wyniki wyszukiwania - BazTech

1

Process - machine tool thermal interaction

Jedrzejewski J., Grzesik W., Kwasny W., Modrzycki W.

Journal of Machine Engineering

|

2008

|

Vol. 8, No. 3

91--106

EN

Hereby paper shows the structure of mutually connected thermal interactions in a machine tool, a tool and a workpiece, which finally leave their traces on a machined workpiece in form of machining errors. Thermal interactions of a machine tool and the environment on own and workpiece errors were discussed. Thermal interaction cases were considered, connected with the varying environment and the main drive operation, as well as total influence of the varying environment, main drive and two drives of controllable axes. The interactions of the cutting process itself were discussed, assuming three basic mechanisms: thermal, physically-mechanical and tribological. On the example of turning it was proven that the character of changes in total influences between the tool and workpiece has the shape of a temperature curve.

2

Precise model of HSC Machining Centre for aerospace parts machining

Jedrzejewski J., Kwasny W., Kowal Z., Modrzycki W.

Journal of Machine Engineering

|

2008

|

Vol. 8, No. 3

29--41

EN

This article shows the aspects of precise modelling of precise High-speed Machining Centres for High-Speed Cutting (HSC) of parts used in the aerospace industry. The main focus was made on the thermal errors having a dominant influence on the precision of machining. Main assumptions for a hybrid thermal model of a centre thermal behaviour have been stated, taking into account the characteristics of heat sources. On the example of a 3-axis machining centre, measured runs of heating up and heat displacements have been shown, compared to these determined with the use of simulations of a behaviour in assumed working conditions. A special attention was drawn to the phenomena taking place in motorspindles, as well as to the displacements of a spindle face during high rotational speeds of spindles and step changes of rotational speeds. The significance and influence of the bearing preload and centrifugal forces on the spindle axial displacements was shown, which is decisive on the precision of part machining. Additionally, it was shown that the important component of a machining error is an error of spindle position identification by means of a linear encoder, resulting from the thermal deformation of a centre body, to which a quartz linear encoder is fixed.

3

Mechatronic approach to the development of an intelligent fixturing device test-bed

Bukowski A., Kwasny W., Jedrzejewski J.

Journal of Machine Engineering

|

2008

|

Vol. 8, No. 3

66--76

EN

In order to improve the process of designing mechatronic devices, an approach, based on a mechatronic model, is proposed. The structure of such model is presented, consisting of partial models of single elements in a system. Methods of creating these models and integrating them into one mechatronic model are discussed. In order to illustrate the approach, a case study is shown, consisting of a mechatronic alignment and fixing device for high-precision machine tools. A test bed of such device is under construction, which will allow experimental verifying partial models of components, as well as the entire system's mechatronic model. An extended set of monitoring sensors will provide accurate system behaviour data useful for such process.