Mecanizado Alta Velocidad

——————————

International

Workshop

CA Systems And Technologies

——————————

HIGH SPEED MACHINING (HSM) – THE EFFECTIVE WAY OF MODERN CUTTING
Pasko, R. - Przybylski, L. & Slodki, B.
Rafal Pasko Eng., Research assistant. Lucjan Przybylski Prof. Eng., Cracow University of Technology, Production Engineering Institute, Al. Jana Pawla II 37, 31-864 Cracow, Phone +48 12 648 01 30, Fax +4812 648 20 10. Bogdan Slodki Ph.D Eng., Cracow University of Technology, Production Engineering Institute.
Summary: In this study the idea of HSM (High Speed Machining) including some different definitions, is presented. The requirements referred to the machine tools, tools and machining data are defined. Some examples of milling caves are described. Some economical advantages of productivity,accuracy in terms of tool and toolholder unbalancing are d iscussed.

1 Introduction Machining with high speeds (HSM) is one of the modern technologies, which in comparison with conventional cutting enables to increase efficiency, accuracy and quality of workpieces and at the some time to decrease costs and machining time [9]. Even though High Speed Machining is known for a long time (first trieswere made in early twenties of the past century) there are still a lot of questions and less or more complicated definitions of HSM. The first definition of HSM was proposed by Carl Salomon in 1931. He has assumed that at a certain cutting speed which is 5 –10 times higher then in conventional machining, the chip tool interface temperature will start to decrease (Fig. 1).

Fig 1. Temperature as afunction of cutting speed [2, 9].

- 72 -

——————————

International

Workshop

CA Systems And Technologies

——————————

It is not possible to verify this theory to its full extent based on recent experimental results. There is a relative decrease of the temperature at the cutting edge that starts at certain cutting speeds for different materials. Actually there are many differentways to define HSM, upon them HSM is said to be [2]: ?? high cutting speed machining (vc), ?? high rotational speed machining (n), ?? high feed machining (vf), ?? high speed and feed machining, ?? high productive machining. Practically, it can be noted that HSM is not simply high cutting speed. It should be regarded as a process where the operations are performed with very specific methods andproduction equipment [2]. HSM is not only machining with high spindle speed because many applications are performed with conventional spindle speeds. HSM is often used in finishing in hardened steels with both high speeds and feeds. HSM can be called rather the High Productive Machining when machining components in roughing to finishing and also in finishing to super-finishing in components of allsizes. 2 Applications of High Speed Machining The use of HSM allow us to shorten the production time and to increase the accuracy of machined parts. High Speed Machining is being mainly used in three industry sectors due to their specific requirements [1].

= Manual finishing
A) Traditional process. Non-hardened (soft) blank (1), roughing (2) and semifinishing (3). Hardening to the final servicecondition (4). EDM process – machining of electrodes and EDM of small radii and corners at big depths (5). Finishing of parts of the cavity with good accessability (6). Manual finishing (7). B) Some process as (A) where the EDM-process has been replaced by finish machining of the entire cavity with HSM (5). Reduction of one process step. C) The blank is hardened to the final service condition (1),roughing (2), semifinishing (3) and finishing (4). HSM most often applied in all operations (especially in small sized tools). Reduction of two process steps. Normal time reduction compared with process (A) by approximately 30 – 50%.

Fig. 2. Improvement of production process when using HSM [2]. - 73 -

——————————

International

Workshop

CA Systems And Technologies

——————————...