Technical field

The invention concerns a milling cutter which consists of insert holders that project from a carrier disc which is adapted for clamping onto the spindle of a machine tool and is provided with a cutting fluid supply system.

Background art

Milling of certain materials with the use of solid tools or tools with exchangeable cutting inserts requires cooling/lubrication to be applied during the cutting process. Besides well-known steels, such materials may include nickel or titanium superalloys with a low thermal conductivity which precludes effective heat removal from the cut. Generally, heat is generated during cutting by friction between the tool and work, and by plastic deformation at the point of chip formation. Heat dissipation plays a key role in the tool durability and in the quality of machined surface, mainly in the sense of surface integrity.

Several possible routes have been defined in terms of cooling/lubrication of the cutting part of tool during the cutting process. The fluid is either supplied at normal pressure or at increased pressure, which is known as high-pressure cooling, helping the fluid enter the gap between the chip and the face/flank of the cutting part of the tool. Superalloys are also machined with cooling provided by freezing or, often, with minimum quantity lubrication, and also by dry machining with freezing or cooled air being supplied to the cut. Background art includes coolant supply to a milling tool, where one of the options is internal cooling when coolant is supplied to cutting parts of the tool through the spindle or shaft of the machine-tool via a suitable channel system provided in the tool. For instance, there are disc milling cutters on whose wheel-shaped bodies there are cutting inserts arranged in shaped recesses on the wheel perimeter, beside which there are, for instance, recesses for chip removal. A method is known for connecting these recesses for chips via radial channels with an axial through-hole in the tool body, which enables the fluid to reach individual recesses for chips, and therefore the cutting inserts as well. To achieve this, very deep holes of relatively small diameters must be bored or electrical discharge machined laboriously in the cutting tool body. Such procedures are very costly and even then the coolant is often delivered to the cutting inserts in a suboptimal manner.

Patent no. 303363 describes a chip cutting tool which is provided with at least one central internal hole for the cooling or lubricating medium and whose major or minor flank has near the associated cutting edge at least one communicating channel for supplying the cooling or lubricating medium, which communicates with the distribution channel. A groove is connected to the communicating channel on the major and/or minor flank. The face may be provided with at least one additional channel for supplying the cooling or lubricating medium.

EP 1897642T3 patent file describes a disc-shaped milling tool with a central bore for inserting a central pin sealed with a movable sealing. The mid-length part of the central pin is splined and the pin is inserted in the tool body which is provided with individual slots. This invention enables flow control of the fluid through channels directed at the face of the cutting part of the cutting tool. It uses the option of fitting the component in question in the space between the inner cavity of the milling cutter and its clamping part, as in the present invention. It can be used for tools with multiple exchangeable cutting inserts arranged in the direction of the tool axis as well as for stepped tools. This invention, however, does not enable the fluid to be supplied on the flank of the cutting part.

Patent file no. DE 102004055377 describes a tool which is provided with a distribution system comprising cooling or lubrication channels of various cross-sections communicating with the means of coolant supply.

The arrangement known from patent file no. EP 1897642 involves a disc-shaped milling tool in which cooling of cutting inserts is provided with the use of two and more structural parts of the entire cutting tool, where individual discs contain channels and attachment plates for the supply of the fluid to the cut.

These solutions are very costly to manufacture and maintain. In addition, the tool must be modified in an irreversible manner in such cases.

Disclosure of Invention

The invention concerns a milling cutter which consists of insert holders that project from a carrier disc which is adapted for clamping onto the spindle of a machine tool and is provided with a cutting fluid supply system.

The face of the carrier disc is provided with a reservoir surrounded by cutting inserts, the height of which is greater than that of the reservoir, so that the machining process is possible. This reservoir communicates with the cutting fluid supply system and includes cutting fluid outlets which are directed at the flanks of cutting inserts. In a preferred arrangement, the channel is of toroidal shape for the reason of uniform distribution of the coolant during machining, and does not obstruct the central bore of the carrier disc. The reason is that cooling of the tool flank reduces friction between the cutting inserts and the machined surface. Preferably, they are directed at tool flanks to which it is usually difficult to supply the cutting fluid.

Description of figures

Fig. 1 is an isometric view of a milling tool.

Fig. 2 is an isometric view of a toroidal channel.

Fig. 3 and Fig. 4 show cross-sectional views of a milling cutter.

Example embodiment

A milling cutter consists of holders 2 of cutting inserts 3 where the holders 2 project from a carrier disc 1 which is adapted for clamping onto the spindle of a machine tool. The carrier disc 1 is provided with a cutting fluid supply system 11 In the carrier disc 1, the cutting fluid supply system 11 is provided with orifices 12 for directing the cutting fluid at the faces of the cutting inserts 3. The face of the carrier disc 1 is provided with a torus-shaped reservoir 4 surrounded by cutting inserts 3, the height of which is greater than that of the reservoir, so that machining process is possible. The reservoir 4 communicates with the cutting fluid supply system IJ.. The reservoir 4 is provided with outlets 4 for the cutting fluid. These outlets 4 are directed at the flanks of the cutting inserts 3.

The milling cutter is clamped by means of the carrier disc 1 onto the machine-tool spindle, and the supply system H delivers cutting fluid to the faces of the cutting inserts 3. The cutting fluid supply system 11 communicates with the reservoir 4 which is provided with outlets 41 Thanks to the rotational motion of the tool, the cutting fluid is distributed equally to the flanks of the cutting inserts 3.

Industrial utility

The tool described in this invention finds use predominantly in rotational chip cutting of predominantly difficult-to-machine materials, predominantly in milling.