Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C3/00—Milling particular work; Special milling operations; Machines therefor
  • B23C3/002—Milling elongated workpieces
  • B23C3/005—Rails
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
  • E01B31/00—Working rails, sleepers, baseplates, or the like, in or on the line; Machines, tools, or auxiliary devices specially designed therefor
  • E01B31/02—Working rail or other metal track components on the spot
  • E01B31/12—Removing metal from rails, rail joints, or baseplates, e.g. for deburring welds, reconditioning worn rails
  • E01B31/13—Removing metal from rails, rail joints, or baseplates, e.g. for deburring welds, reconditioning worn rails by milling

Definitions

• the invention relates to a method for milling a strip-shaped workpiece surface with the aid of at least one milling tool guided parallel to the processing strip, the cutting edges of which are distributed over the circumference and have a length that exceeds the width of the processing strip.
• grinding tools are generally used, which are pressed onto the machining strips with a pressing force that is matched to the removal in order to take into account the grinding wheel wear.
• This pressure adjustment of the grinding tools means that the respective longitudinal profile of the processing strip is copied during grinding and therefore undesired deviations in the longitudinal profile are retained during grinding processing.
• a considerable warming of the workpiece to be machined and a flying sparks are to be expected, which leads to a considerable environmental pollution and a fire hazard when machining laid rails.
• the feed speed that can be achieved in practice is limited to a few kilometers per hour, so that when long track systems are being worked on, schedule rail traffic is impeded.
• the invention is therefore based on the object of improving a method for milling a strip-shaped workpiece surface of the type described at the outset with simple means such that the advantages of milling can be exploited even at high feed speeds without reducing the surface quality of the machined To fear the workpiece surface.
• the invention solves this problem in that the milling tool designed as a face milling cutter, the cutting edges of which lie in a common plane perpendicular to the milling cutter axis, is guided from the edge of the machining strip closer to the milling cutter axis at an axis distance which is larger than the inner radius but smaller than the outer radius reduced by the width of the machining strip is the circular ring area swept by the cutting edges during a milling cutter revolution.
• the cutting engagement of the individual cutting edges is limited to a comparatively small angle of rotation of the milling tool and the cutting edges in the machining surface are rotated about an axis perpendicular thereto, high cutting performances can be ensured in the area of the cutting engagement, which result in a large feed and a high surface quality allow because the cut interventions of the individual teeth overlap in the longitudinal direction of the processing strip, so that the processing strip is machined several times per unit length by successive teeth. Because of the course of the cutting edge, this multiple machining operation produces a particularly good surface finish only in the machining plane. quality with itself. The roughness depths are many times smaller than with grinding.
• the radial distance of the edge of the processing strip closer to the milling cutter axis from the inner circle of the circular ring area swept by the cutting edges should be chosen to be as small as possible.
• This inner cutting edge section corresponding to this distance in contrast to the outer cutting edge end, does not come into cutting engagement with the workpiece. It is therefore advisable to guide the milling tool from the edge of the machining strip closer to the milling cutter axis at a center distance which corresponds to the inner radius de increased by a safety distance, which corresponds to the circular area swept by the cutting edges.
• FIG. 1 shows a milling tool for milling a rail head according to the invention in a schematic axial section
• FIG. 2 shows the basic engagement conditions for a milling tool used according to the invention when milling strip-shaped workpiece surfaces according to the invention.
• the rail head profile is approximated by a polygon train which determines the individual processing strips 3, which are machined by one of the milling tools 2 arranged one behind the other in the longitudinal direction of the rail.
• the milling tool 2 used according to the invention has an axis 4 perpendicular to the surface of the associated machining strip 3, the cutting edges 5 of the cutting tips 7 distributed over the circumference of the milling head 6 being in a common plane which determines the machining surface 8 lie. This results in an end mill, the cutting edges 5 of which have a length which is greater than the width b of the machining strip 3.
• the axis 4 of the milling tool 2 has shifted as a result of the feed, as is shown by the milling cutter axis 4 'of the dot-dash line in the rotational position for the central engagement position of the cutting edge 5b' Neten milling tool is indicated, so that there is a machining section for the subsequent tooth 5b, as illustrated by the dash-dotted line 15 in Fig. 2.
• the displacement of the cutting edge 5b to 5b ' corresponds to the simultaneous displacement of the cutting edge 5a to 5a'.
• the inner end 16 of the cutting edges 5 does not come into cutting engagement with the processing strip 3.
• the center distance a of the milling tool 2 from the closer edge 9 of the processing strip 3 therefore only needs to be increased by a slight safety distance 17 than the inner radius r of the annular surface 10.
• the protrusion 18 of the outer cutting edge 19 with respect to the width b of the machining strip 3 should, however, be larger with regard to the machining length I in order to ensure a corresponding overlap of the individual machining sections 11 of successive teeth. In the case of a given cutting edge projection, this overlap is determined by the number and the rotational speed of the cutting edges 5 and the feed speed of the milling tool 2, which runs in the direction of cutting of the individual cutting edges 5 in the sense of synchronous milling.
• the invention is of course not limited to the illustrated embodiment.
• two or more milling tools arranged one behind the other in the machining direction could be used for milling a machining strip if the thickness of the layer to be machined increases.
• the use of this milling process is not limited to the machining of rail heads, although it is of particular importance for this area of application due to the high feed speeds.
• the described milling process can be used to advantage wherever narrow processing strips have to be processed at high feed rates without having to forego a particularly good surface quality, as is the case, for example, when processing the longitudinal edges of metal sheets.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Milling Processes (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=3481168

Family Applications (1)

Country Status (2)

Cited By (9)

Citations (2)

• 1995
  • 1995-01-18 EP EP95905479A patent/EP0740722A1/de not_active Ceased
  • 1995-01-18 WO PCT/AT1995/000009 patent/WO1995020071A1/de not_active Application Discontinuation

Patent Citations (2)

Also Published As

Similar Documents

Legal Events