数控车床上磨削主轴的分析(2)

菜单

as well as complicated geometrical parts.

3. Applications

The above algorithm was used to create a subroutine (SPF 49) suitable for the Sinumeric (840-C) control. The complete software for this subroutine is shown in Appendix A. After loading the subroutine into the CNC unit, the subroutine will be used in all profiling and dressing operations for all taper type grinding wheels.

The shape is described in parameters and the programmer can change the values of these parameters according to need. For example, if the programmer wants to profile four grinding wheels at the same setting, he should fill in the parameters for subroutines SPF 201, SPF 202, SPF 203 and SPF 204. In this subroutine the programmer will define the taper angle, the value of the connection arc and the partial length of the taper zone. A typical procedure is shown in figure 3 for subroutine SPF 201.

After storing the subroutines SPF 49 and SPF 201-204 in the CNC unit, the CNC unit will also need a program like MPF 51 to call out different subroutines which are used on profiling and dressing operation. This program also contains all cutting conditions for profiling and dressing operations.

The above set-up was used for profiling and dressing four taper type grinding wheels with different profiles. They were used to finish the grinding zones of the combustion chamber for a large gun barrel, after the turning operation on the same machine. These grinding wheels are shown in figure 5. The time saving on preparing and testing the profiling and dressing program was almost 95%.

4. Conclusion

The presented algorithm offers an easy way to perform the profiling and dressing

operations for grinding wheels. The algorithm reduces the time required for preparing

the profiling and dressing of grinding wheel programs, as well as reducing programming error.

References

ABBAS, A. T., 2003, Enhanced CNC lathe capability by addition of a grinding spindle,

International Journal of Production Research, 41, 2699–2709.

GROOVER, M. P. and ZIMMERS, E. W., 1984, CAD/CAM Computer-Aided Design and

Manufacturing (Englewood Cliffs, NJ: Prentice-Hall).

LUGGEN, W. W., 1983, Fundamentals of Numerical Control (New York: Delmar Publishers).

SIEMENS, 1999a, Programming Manual for Sinumeric 840-C.

SIEMENS, 1999b, Operator Manual for Sinumeric 840-C.

Int J Adv Manuf Technol (2006) 28: 993-1005

DOI 10.1007/s00170-004-2449-0

S.Saravanan.G.S.Yadava.P.V.Rao

Condition monitoring studies on spindle bearing of a lathe

Received: 10 June 2004 / Accepted: 18 October 2004 / Published online: 16 November 2005 ©9 Springer-Verlag London Limited 2005

Abstract

In modern industry, machinery must become increasingly flexible and automatic. In order to increase productivity,enhance quality and reduce cost, machine tools have to work free of any failure. When a failure occurs in a machine tool, it is necessary to identify the causes as early as possible. Machine tool condition monitoring is very important to achieve this goal. Condition monitoring is generally used on the critical subsystem of any machine tool. This paper endeavors to focus on the condition monitoring aspects on the machine tool element. In the present study, a critical subsystem has been identified based on the failure data analysis. Condition monitoring techniques like vibration monitoring, acoustic emission, Shock Pulse Method (SPM) and surface roughness have been successfully used for fault identification.

1 introduction

Machine tool technology, the backbone of the world's manufacturing industry, is developing faster than ever. Despite these rapid advances, developments in the strategy and techniques of machine tool maintenance have fallen behind in the general pattern of progress. This is of serious concern, since it can be argued that present maintenance techniques will be unable to cope with new demands. In the modern automated manufacturing process,machinery has to become more flexible and automatic. The use of computer numerically-controlled machines has increased rapidly.Stoppage of these machines due to faults or failure to meet required performance has become very expensive. Therefore, it has become necessary to monitor the condition of the machine tool during its life so as to predict sudden failure or deterioration of performance. This is state-of-the art in machine maintenance. It is possible to measure the condition of elements like bearings and gears, but it is not yet possible to monitor the condition of all the machine elements from an economic point of view.