DE102019005692A1 - Cutting edge preparation - Google Patents

Abstract

The invention describes a device (1) for cutting edge preparation of cutting tools (5), in particular drills or milling cutters or similar tools (5), in particular hard metal cutting tools, the cutting tool (5) being provided with abrasive particles during a relative movement and flexibly bonded grinding body (2) interacts by cutting and the particles of the grinding body (2) influence the edge geometry of the cutting tool (5), in which the dimensions of the grinding body (2) are essentially adapted to the dimensions of the cutting tool (5) to be prepared and is received in an exchangeable holder (4) which is arranged in the working space of a tool grinding machine and is held in a machinable manner by the cutting tool (5) for cutting edge preparation. Furthermore, a corresponding method and a corresponding grinding tool (2) are specified.

Description

The invention relates to a device and a method for cutting edge preparation according to the preamble of claim 1 and a method according to the preamble of claim 16 and a machinable grinding body according to the preamble of claim 26.

For different machining tasks in machining, tools are required that achieve high manufacturing accuracy on the component and at the same time achieve a long service life in order to ensure economical and competitive product manufacture by the manufacturing company. In addition to good wear resistance of the tools, predictable wear behavior is required to ensure high process reliability. To improve the performance of cutting tools, especially in the field of hard metal tools, so-called cutting edge preparation has established itself as an important process step in the production chain. A cutting edge preparation is a fine machining, in particular of the tool cutting edge, after the grinding process to produce the actual tool macro shape. Due to the hard and brittle material behavior of hard metals, microscopic defects such as chipping along the cutting edge occur as a result of the grinding process. With the help of the cutting edge preparation, these defects can be eliminated and a cutting edge shape adapted to the specific machining process can be generated. With this load-appropriate design of the cutting edge, it is also possible in many machining cases to increase the stability of the cutting edges in such a way that increased metal removal rates can be selected without losing tool life. This can significantly increase the cost-effectiveness of production.

Previously known and in some cases established processes for cutting edge preparation are primarily based on processes with a geometrically undefined cutting edge such as jet cutting, magnet finishing, drag grinding and flow grinding. In addition, other cutting processes such as brushing, spark erosion and laser ablation as well as the grinding of fillets are known for the preparation of cutting edges. A common feature of the processes mentioned is that a special machine or device is usually required to carry them out, which is often associated with high investment costs. These investment costs represent a major hurdle, especially for small and medium-sized tool manufacturing companies. Another disadvantage that arises with the above-mentioned methods is a sometimes significant increase in the throughput time in tool manufacturing. On the one hand, this results from the additional process time that results from the preparation process. On the other hand, the use of a stand-alone machine usually requires additional handling. It should also be mentioned that, according to the current state of the art, none of the methods described above are used for the preparation of reground tools. Due to the lack of the possibility of preparing cutting edges in the reground state, these tools usually do not achieve the tool life of new tools.

Each of the processes mentioned has specific advantages and disadvantages, which on the one hand relate to the application of the process itself and to the resulting edge and surface shape of the tools. Due to the great relevance for the industry, the following only deals with the processes of jet cutting, brushing, drag grinding, grinding, in particular with the use of elastically bonded grinding wheels, as well as the drill polish similar to this process.

During blasting, a blasting agent consisting of an abrasive medium and a carrier medium is accelerated onto the workpiece surface via a blasting nozzle with high kinetic energy. The abrasive medium is differentiated according to grain type, grain size and grain shape. The carrier medium is often a liquid or air. The most important process influences on the process are, in addition to the choice of blasting agent, the beam feed speed, the blasting pressure and the blasting angle. The method allows flexible guidance of the jet nozzle or the tool to be prepared, which enables the targeted processing of individual cutting areas. It is therefore particularly suitable for producing complex cutting edge shapes with generally smaller rounding sizes, whereby the targeted control of the material removal is very difficult. Particularly with very small tool diameters and closely spaced cutting edges, so-called passive radiation can have an undesirable effect on other cutting edges that are not to be prepared. This has a negative impact on the process accuracy and the reproducibility of the process result. A characteristic dimple structure forms on the free and rake faces that border the blasted cutting edge and come into contact with the abrasive jet, which usually leads to an optical matting of the surface.

Brushing is also an established process in the industrial environment. The material is removed by moving a rotating brush with an abrasive medium along the cutting edge of the tool. The procedure is for efficient generation of larger and asymmetrical fillets. Process-side influencing factors of the method are the cutting speed, the feed speed, the infeed, the angle of inclination of the cutting edge and the brushing duration. The influences on the tool side are the thread diameter, the grain size of the abrasive medium, the bristle type and the bristle density. Because of this multitude of influencing factors, process control is complex and requires precise knowledge of the process and the interactions for precise implementation. In addition to process control, process reliability is negatively influenced by bristle wear. The creation of complex cutting edge shapes is also limited with smaller tool diameters.

Drag grinding, a variant of vibratory grinding, is also a widely used process in the industrial environment. The material is removed by passing the tools to be prepared through a loose and usually stationary abrasive medium. The tool movement is mostly rotary. The speed, the direction of rotation, the depth of immersion and the processing time as well as the selected abrasive medium are of particular importance for the processing result. Both smaller and larger roundings can be produced efficiently with the method. In addition, a significant improvement in the surface quality can be achieved. However, there are also some disadvantages due to its use. The immersion of the tool in the abrasive medium results in a very large contact surface between the medium and the tool. Material is removed in all of these contact areas, so that targeted preparation of individual cutting areas is almost impossible. Furthermore, form factors and graded roundings can only be set with great difficulty, and the rotational movement results in a large amount of material being removed, especially in the case of shank tools in the area of larger diameters.

Cutting edge preparation can still be implemented using a grinding process. It is common to create a single or double bevel along the cutting edge. In a more recent approach, the profile shape of the cutting edge is approximated to a rounding by creating more than two chamfers. In addition, the use of elastically bonded grinding wheels in tool preparation is known. One area of application is the fine machining of flutes on cutting tools.

From the DE 10 2011 054 276 B4 a method for cutting edge preparation of cutting tools is known, in particular of drills or milling cutters, in particular of hard metal cutting tools, the cutting tool, after the production of the desired cutting geometry, initially set or aligned to the necessary workpiece data according to the cutting geometry and / or cutting characteristics, set in a rotary movement and is then introduced or drilled into a grinding wheel with silicon carbide, tungsten carbide or diamond components, which is flexibly bound with a rubber-containing binder, at a depth selected according to the cutting edge geometry and at a position selected for this on the circumference of the grinding wheel while maintaining the rotational movement. Here, a rotating tool is moved into a grinding wheel with a defined drilling path and angle of attack. However, this kinematics can only be implemented on a very limited number of machines and therefore cannot be regarded as a universal preparation process. Furthermore, this method cannot be used to set any cutting edge roundings that run over the tool diameter. In addition, because of the drilling in solid material, there is always a strong rounding of the cutting edge and the cross cutting edge, for example on the twist drill, and the grinding wheel has to be dressed in a complicated manner after extensive use. Another disadvantage of this method is that long cantilever tools cannot be prepared due to the lack of guidance. With this method, complex programming must be carried out in order to know the position of the hole, the angle of incidence between the workpiece, here the ground cutting tool, and the tool, the grinding wheel to be cut. Furthermore, after complete, peripheral machining, the grinding wheel must be brought back to its original state by means of processes to be carried out externally. In addition, due to the grinding wheel assembly on a grinding mandrel, any grinding wheel magazine spaces required are occupied.

Cutting edge preparation has been shown to be an effective means of increasing the performance and processing quality of cutting tools, but it usually requires additional machines and equipment. This results in high investment costs for this equipment on the one hand, and additional workpiece handling costs on the other, which in a high-wage country like Germany can make up a significant part of the costs for the preparation. From the above-mentioned technological and economic aspects, there is a need to develop a further developed cutting edge preparation process, which is particularly suitable for use by small and medium-sized cutting tool manufacturers and in which in particular the requirements for low investment and operating costs, simple implementation and short lead times for tool preparation.

The object of the present invention is to provide a simple and inexpensive option for the targeted preparation of cutting edges on rotationally symmetrical cutting tools, in particular with clamping shanks (shank tools) with regard to their microscopic shape, without the tool-manufacturing company incurring additional investment costs for machines.

The solution to the object of the invention arises with regard to the device from the characterizing features of claim 1, with regard to the method from the characterizing features of claim 16 and with regard to the grinding wheel from the characterizing features of claim 26, each in cooperation with the features of the associated preamble. Further advantageous configurations of the invention emerge from the subclaims.

The invention with regard to the device is based on a device for cutting edge preparation of cutting tools, in particular drills or milling cutters or similar tools, in particular hard metal cutting tools, the cutting tool during a relative movement interacting with a flexibly bonded grinding body provided with abrasive particles and the particles of the grinding tool influence the edge geometry of the cutting tool. Such a generic device is further developed in accordance with the invention in that the dimensions of the grinding body are essentially adapted to the dimensions of the cutting tool to be prepared in each case and held in an exchangeable holder which is arranged in the working space of a tool grinding machine and can be machined by the cutting tool for cutting edge preparation is held. In contrast to known solutions for cutting edge preparation, the dimensions of the grinding wheel are adapted to the dimensions, e.g. the circumferential dimensions of the cutting tool to be prepared, whereby on the one hand a substantial saving in material of the grinding wheel can be achieved and on the other hand the technological implementation of the cutting edge preparation can be specifically influenced and can be improved. Thus, only as much material of the abrasive material to be processed into the grinding body is required as is actually required to carry out the cutting edge preparation and therefore the process of cutting edge preparation is made more economical. In addition, the otherwise necessary dressing of large grinding wheels between the respective processes for cutting edge preparation is no longer necessary. Furthermore, the dimensionally adapted grinding body is received in an associated exchangeable holder, which is arranged in the working space of a tool grinding machine and is held in a machinable manner by the cutting tool for cutting edge preparation. On the one hand, the exchangeable holder enables the holder to be pre-equipped with new or different grinding tools independently of the actual machining in the grinding machine, and thus significantly decouples the retooling of the grinding articles from the actual machining. On the other hand, the dimensionally adapted grinding wheel can be accommodated in a particularly space-saving manner and thus, for example, an upstream grinding process on the tool grinding machine with little disruption in the work area of the grinding machine and kept ready for performing the cutting edge preparation. This makes it much easier and less complicated, after the actual grinding of the cutting tool on the tool grinding machine, to also carry out the cutting edge preparation on the same tool grinding machine and ideally in the same set-up, since little or no additional equipment is required on the tool grinding machine and there is little or no space required take up no additional space in the work area of the tool grinding machine. This also makes it possible for smaller tool grinding shops to offer cutting edge preparation in addition to actual tool grinding without having to invest in expensive additional equipment on the tool grinding machine or having to purchase additional machines.

It is particularly advantageous if the exchangeable holder is kept insertable in a grinding wheel holder of the tool grinding machine. The installation space of the grinding wheel holder is a normally functionally unused area on the grinding wheel holder, which is usually arranged as an extension of the clamping cone or similar clamping holder in the area that is surrounded by the disk-shaped grinding wheel. This collar, onto which the grinding wheel is attached, is usually made of solid material and is otherwise unused. Therefore, precisely this space, which is arranged centrally in the working area of the tool grinding machine, can now be used to form an installation space for the exchangeable holder with the grinding wheel, in which the grinding wheel is held in a machinable manner by the cutting tool for cutting edge preparation. With such an arrangement of the grinding body, which is small in terms of volume and adapted to the dimensions of the cutting tool, no additional installation space is required for the cutting edge preparation and the cutting edge preparation is also required in an area of the working space of the Tool grinding machine feasible, which is easily accessible and does not require any changes to the kinematics for moving the grinding wheel or cutting tool. Of course, it is also conceivable to arrange the grinding body, which is small in terms of construction volume and adapted to the dimensions of the cutting tool, at a different point in the working space of the tool grinding machine.

Furthermore, it is advantageous if the grinding body is essentially cylindrical. Since the cutting tools to be prepared usually also have at least fundamentally cylindrical dimensions, an extensive adaptation to the dimensions and shape of the cutting tools can be achieved by a likewise cylindrical configuration of the grinding body, whereby only the in connection with the dimensional adjustment of the dimensions of the grinding body to the dimensions of the Cutting tools a substantial saving of abrasive material for the grinding body can be achieved. For this purpose, in a further embodiment, the cylindrical circumferential dimensions of the grinding body are essentially adapted to the circumferential dimensions of the cutting tool to be prepared, so that the grinding body can be successively and largely completely machined in the course of the usually several cutting edge preparations to be machined one after the other and thus no unused residue of the abrasive material can be disposed of Need to become.

Furthermore, it is of considerable advantage that the grinding wheel can easily be exchanged for a new grinding wheel after it has been used completely. As a result, the times for machining a cutting tool are only insignificantly extended and the cutting edge preparation does not unnecessarily extend the time for producing the cutting tool due to conversions or the like that are otherwise necessary.

In a first embodiment, for this purpose, the grinding body is arranged in the exchangeable holder in an easily exchangeable manner, preferably pressed into the holder. For this purpose, for example, the rotationally symmetrical grinding wheel can be produced with a very small allowance adapted to the diameter of the cutting tool to be prepared and pressed into the exchangeable holder. By pressing in, a connection between the grinding body and the exchangeable holder that is easy to produce and that is sufficiently rotationally fixed is produced in order to safely absorb the machining forces during the preparation of the cutting edges.

In a particularly advantageous embodiment, it is conceivable to design the exchangeable holder so that it can be plugged into a preferably central bore in the grinding wheel receptacle, preferably in the receptacle collar for the grinding wheel. This easily accessible and, as already shown, largely unused volume can be made available by a simple modification of a conventional grinding wheel holder on a machine-side clamping element for the grinding wheel on almost every tool grinding machine and does not change the working space of the tool grinding machine, or only slightly.

In a further embodiment, the exchangeable holder can have an external thread which can be screwed into the bore provided with an internal thread in the grinding wheel holder. This allows the exchangeable holder to be installed and secured quickly and precisely in the hole in the grinding wheel holder. However, it is also conceivable to press or insert the replaceable holder into a preferably central bore in the grinding wheel holder and to hold it there in a rotationally fixed manner, for example by means of a type of bayonet or a clamp or the like.

Especially for cutting edge preparation, long cantilever cutting tools with a large length / diameter ratio can be arranged in the area of the exchangeable holder for the grinding body, through which such long cantilever cutting tools, guided by the guide bush, can be prepared and can thus be processed more precisely and safely than without additional ones Guide. Such long cantilever cutting tools can be, for example, asymmetrical deep drilling tools, single-lip drills, twist drills or the like with a large length / diameter ratio, which otherwise easily evade during machining or, due to their length, tend to vibrate during cutting edge preparation. For this purpose, in a further embodiment, the guide bushing can be arranged relative to the exchangeable holder, preferably arranged as an extension of the exchangeable holder, so that the guide bushing guides and supports the long cantilever cutting tool in front of the machining area of the grinding wheel.

Furthermore, it is conceivable that electrical conductor tracks and / or sensor elements can be introduced into the exchangeable holder, which provide information about the process of cutting edge preparation. For example, the processing sequence during the cutting edge preparation can be monitored and possibly influenced by means of contactless sensors or the like. In a further embodiment, it is conceivable that the sensor elements for the voltage supply with accumulators integrated into the exchangeable holder that can be loaded in the grinding wheel magazine or externally when not in use. As a result, enough energy can be stored in the accumulators in the non-productive times in which the exchangeable holder is not used in order to be able to carry out the above monitoring processes during cutting edge preparation when the respective exchangeable holder has been replaced.

It is particularly advantageous if the grinding body has abrasive particles, in particular made of silicon carbide, aluminum dioxide or diamond, and is successively completely machined by the cutting tools to be prepared. By choosing or mixing the abrasive particles processed into the grinding body and, in a further embodiment, also by mixing finer and / or coarser abrasive particles, the machining behavior of the grinding body and thus also the achievable cutting edge preparation can be influenced within wide limits. It is also conceivable here to make the distribution of finer and / or coarser abrasive particles within the grinding wheel inhomogeneous, e.g. to produce different preparation behavior, e.g. in the core area and in the outer area of the grinding wheel, and thus, adapted to the respective geometry of the grinding wheel to be prepared, different preparation results in individual areas of the cutting tool.

Furthermore, it is conceivable that the grinding body has an axially extending perforation which is matched to the cutting tool diameter and within which the cutting tool is not influenced by the particles of the grinding body. For example, when preparing the cutting edge of drills, it is advantageous to prepare the area of the cross cutting edge of the drill differently or not at all than the area of the main cutting edge. Because there is no material of the grinding tool in the area of the cross cutting edge due to the perforation, the area of the cross cutting edge is not changed either.

Furthermore, it is conceivable that the grinding body has sections with different degrees of hardness of the bond, in particular radial annular sections of different degrees of hardness. The binding of the abrasive particles of the grinding wheel has a direct effect on the machining behavior of the grinding wheel and thus on the local cutting edge preparation of the cutting tool. A further adaptation of the result of the cutting edge preparation to the requirements of the respective cutting tool can be achieved through different hardness or different ranges of hardness of the bond. For example, the core of the grinding wheel can have a higher bond hardness than the outer area in order to achieve a uniform cutting edge rounding due to the elastic deformation of the rotationally symmetrical grinding wheel.

The invention further relates to a method for cutting edge preparation of cutting tools, in particular drills or milling cutters or similar tools, in particular hard metal cutting tools, the cutting tool during a relative movement interacting with a flexibly bonded abrasive body provided with abrasive particles and the particles of the grinding body influence the edge geometry of the cutting tool, according to which the dimensions of the grinding body are essentially adapted to the dimensions of the cutting tool to be prepared in each case and held by an exchangeable holder arranged in the work area of a tool grinding machine in which the grinding body is successively completely machined from the cutting tools to be prepared becomes. Essential properties and advantages of the method are directly related to the device described and explained above, so the properties and advantages described can also be used to characterize the method according to the invention.

It is particularly advantageous here that the cutting edge preparation can be carried out in the same set-up immediately after the first production of the shape of the cutting tool or also after regrinding the cutting tool on the same tool grinding machine. On the one hand, this eliminates the need for additional devices for separate cutting edge preparation, and the cutting edge preparation can also be carried out directly in the same clamping and on the same tool grinding machine on which the basic shaping of the cutting tool is also carried out. In addition, the cutting edge preparation can also be carried out after a regrinding of a cutting tool that has already been used, whereby the advantages of cutting edge preparation can also be used in such regrinded cutting tools.

It is particularly advantageous that the relative movement between the grinding body and the cutting tool, in particular by superimposing the directions of rotation and the rotational speeds, enables a broad adjustment of the cutting speeds when machining the grinding body. Many parameters of the cutting edge preparation are influenced by the cutting speed during the cutting edge preparation and can therefore be used with large The possibility of varying the cutting speed can be used specifically to control the results of the cutting edge preparation.

It is also conceivable that the grinding body and / or the cutting tool carry out rotary movements during the machining of the grinding body. In addition to the usual rotation of the cutting tool, the grinding body can also rotate, possibly in opposite directions or at different rotation speeds. As a result, the superimposing of the rotational movement of the grinding body and / or cutting tool can cause targeted rounding and / or tilting of the cutting edge of the cutting tool or the production of asymmetrical cutting edge profiles and / or cutting edge profiles that are variable over the tool diameter.

Furthermore, it is conceivable that only the cutting tool to be prepared performs the required translational and rotational movements during the cutting edge preparation.

It is also conceivable that the abrasive body with sections with different degrees of hardness of the bond produces variable roundings over the cutting area of the cutting tools. For this purpose, the grinding body can be manufactured specifically and adapted to the cutting tool to be prepared with locally or section-wise variable degrees of hardness of the bond, which influences the local machining by the cutting tool and thus the local cutting edge preparation

Furthermore, it is conceivable that the grinding tool only subjects certain areas of a cutting tool, in particular e.g. the main cutting edges of a drilling tool, to a cutting edge preparation through an axially extending perforation in which the cutting tool is not influenced by the particles of the grinding tool other areas, in particular the cutting edge of a drilling tool, are not rounded.

The grinding body can also have external dimensions that are matched to the cutting tool diameter, by means of which only areas of the cutting edges of the cutting tool are subjected to cutting edge preparation.

For certain cutting tools to be prepared, it is conceivable that the cutting tool with main and secondary cutting edges, in particular milling tools, reaming tools and / or stepped boring tools, for cutting edge preparation with its main and secondary cutting edges machine each successively assigned grinding bodies of different properties. For example, the main cutting edges of a reamer can be prepared with a differently shaped or dimensioned grinding tool than the secondary cutting edges, in order to be able to achieve the optimum preparation result for the main or secondary cutting edges.

The invention further relates to an abrasive body for carrying out the method according to claim 16, in which the cylindrical circumferential dimensions of the abrasive body are essentially the same as the circumferential dimensions. adapted to the cutting tool to be prepared.

A particularly preferred embodiment of the device according to the invention is shown in the drawing.

• 1 - in einer prinziphaft ausgebildeten Darstellung den grundsätzlichen Aufbau und die Funktion einer erfindungsgemäßen Vorrichtung, angeordnet in der Schleifscheibenaufnahme einer Schleifscheibe vor der Schneidkantenpräparation eines Bohrers,
• 2 - eine erfindungsgemäße Vorrichtung gemäß 1 mit einer zusätzlichen Führungsbuchse vor der Schneidkantenpräparation eines lang auskragenden Einlippenbohrers,
• 3a-3c - Ansichten und Schnitte durch verschieden aufgebaute Schleifkörper der erfindungsgemäßen Vorrichtung gemäß 1,
• 4a-4d - geschnittene Detailansichten der auswechselbaren Halterung und darin angeordneter Schleifkörper für die Schneidkantenpräparation verschiedener Schneidwerkzeuge.

Show it:

• 1 - in a basic representation of the basic structure and function of a device according to the invention, arranged in the grinding wheel holder of a grinding wheel before the cutting edge preparation of a drill,
• 2 - A device according to the invention according to 1 with an additional guide bush in front of the cutting edge preparation of a long protruding single-lip drill,
• 3a-3c - Views and sections through differently constructed grinding bodies according to the device according to the invention 1 ,
• 4a-4d - Cut detailed views of the interchangeable holder and the grinding bodies arranged therein for the preparation of the cutting edges of various cutting tools.

In the 1 is in a basic representation of the basic structure and function of a device according to the invention 1 to be recognized, arranged in the grinding wheel holder 3 a grinding wheel 14th before the cutting edge preparation of a cutting tool 5 here in the form of a drill. The device 1 is attached to a commercially available, here as a cone mount 10 a grinding wheel 14th trained tool holder arranged, as is common for commercially available tool grinding machines. The specific design of the mounting of the device on the grinding machine side 1 is secondary and can include all types of mechanical interfaces to the tool grinding machine.

At the cone mount 10 is a mounting collar in the work area of the tool grinding machine 3 to hold the grinding wheel 14th arranged on which the grinding wheel 14th with their perforation attached and with the help of a thread 8th by a union nut 9 is secured in a conventional manner. This reception alliance 3 is usually made of a solid material and has, in addition to the bearing of the grinding wheel 14th no other task.

According to the invention, a part of this receiving collar, which otherwise consists of solid material, is used 3 , which is centrally located in the work area of the tool grinding machine, used the device according to the invention 1 record. For this purpose, a central longitudinal bore is made from the work area of the tool grinding machine 11 as a blind hole in the receiving collar 3 introduced into which a sleeve-like and easily replaceable bracket, which will be explained in more detail 4th for a grinding wheel 2 can be plugged in. This arrangement of the device 1 interferes with the device 1 the normal mode of operation of the tool grinding machine does not and still provides the holder for a grinding wheel 2 available for the preparation of the cutting edge of a cutting tool 5 can be used.

The interchangeable bracket 4th has such an outer diameter that it is largely free of play in the longitudinal bore 11 of the reception federation 3 can be plugged in. A definition of the interchangeable bracket 4th in the longitudinal bore 11 can through an end thread 6th on the outside surface of the interchangeable bracket 4th done in a corresponding mating thread on the longitudinal bore 11 can be screwed in. It would also be conceivable to use the replaceable bracket 4th by pressing in or some other form-fitting or force-fitting manner in the longitudinal bore 11 determine if on the one hand a non-rotatable definition with easy interchangeability of the exchangeable bracket 4th is guaranteed.

Inside the sleeve-like, replaceable holder 4th there is also a hole 23 into which a cylindrical grinding wheel 2 can be inserted or rotatably pressed in to interact with the cutting edges 7th of the cutting tool 5 as part of the cutting edge preparation of the cutting tool 5 can be used. The grinding wheel 2 consists of a flexibly bound abrasive particle matrix, for example rubber-bound abrasive particles made of hard materials.

The grinding wheel 2 is in terms of its cylindrical outer dimensions to the circumferential dimensions of the cutting tool 5 , here the outer diameter of the drill, and has a slightly larger outer diameter than the outer diameter of the cutting tool 5 on to allow the cutting edge of the cutting tool 5 When preparing the cutting edge, in any case only with the grinding tool and not with the exchangeable holder 4th get in touch.

Now about the cutting edge preparation of the cutting tool 5 perform the cutting tool 5 in the form of the drill, for example after the basic grinding of the tool shape by means of the grinding wheel 14th so in front of the device 1 in the longitudinal bore 11 of the reception federation 3 positioned that the axis of the cutting tool 5 and the longitudinal bore 11 and with it the interchangeable bracket 4th align with each other. The cutting tool 5 becomes during a relative rotation between the cutting tool 5 and grinding wheels 2 then on the grinding wheel in the feed direction 2 advanced until the cutting edge of the cutting tool 5 in the intended manner with the cutting edge of the cutting tool 5 interact and machine them and thereby be prepared. This is where the grinding wheel 2 Machined at least a bit and thus shorter in the longitudinal direction. After the cutting edge preparation of the cutting tool 5 becomes the cutting tool 5 against the delivery direction 24 from the interchangeable bracket 4th moved out and can be removed ready.

The process can then be done with the next cutting tool 5 repeated, creating the abrasive 2 is successively more and more machined and must be replaced when a consumption limit is reached. To do this, the whole interchangeable bracket 4th with the rest of the grinding wheel 2 from the longitudinal hole 11 removed and put through one with a fresh grinding wheel 2 Pre-equipped interchangeable bracket 4th exchanged. Due to the quick interchangeability of the interchangeable bracket 4th with the grinding wheel 2 you can continue working immediately. Other similar interchangeable brackets 4th can be stored as a depot in other grinding wheel holders, for example, so that they can be used with the same preparation. This allows the replacement of the grinding tool 2 until the order is completed or the wear limits of the grinding slide 14th be delayed.

In the 2 is a modified device 1 according to 1 shown, for the cutting edge preparation of a long cantilever cutting tool 13 , here an example of a single-lip drill was modified. Because such long cantilever cutting tools 13 During the grinding process and also when preparing the cutting edge, the cutting tool becomes slightly pushed away to the side and begins to swing 13 here by one on the exchangeable bracket 4th Guide bushing arranged on the front 12 Guided and supported, so that the negative effects of the long overhang do not come into play or not at all.

In the 3a to 3c are views and sections through differently structured grinding tools 2 the device according to the invention 1 according to 1 shown, the exemplary conceivable modifications of the grinding wheel 2 represent.

In the 3a is a homogeneous over the entire machining area of the grinding tool 2 trained grinding wheel 2 to recognize how this also in the 1 is shown.

The 3b shows a grinding wheel 2 with a central hole 15th , for example for the cutting edge preparation of a drill as a cutting tool 5 can be used. In the area of the perforation 15th the drill then does not interact with the grinding wheel 2 because there is no abrasive material there. This creates the cutting tool designed as a drill 5 in the area of the sensitive cross-cutting edge and retains that of the previous grinding process with the grinding wheel 14th existing shape. Only in the area of the main cutting edges are due to the sleeve-like shape of the grinding tool 2 the main cutting edges prepared.

It is also like in 3c pictured conceivable, the outer area 17th and the core area 16 of the grinding wheel 2 from different abrasive particles or the same abrasive particles with different bond hardness and thus different machining properties. For example, the core area 16 of the grinding wheel 2 a higher bond hardness than the outer area 17th have to minimize elastic deformations on the inner cutting edge of the cutting tool 5 to bring about. Here are many modifications to the grinding wheel 2 depending on the cutting tool to be prepared 5 and its shape is conceivable.

In the 4a to 4d are cut detailed views of the exchangeable bracket 4th and grinding wheel arranged therein 21st , 22nd for the cutting edge preparation of various cutting tools 18th , 19th and 20th shown. All tools 18th , 19th and 20th What they have in common is that they have different main cutting edges and secondary cutting edges to be prepared, which cannot be prepared easily or not at all in a single pass.

For example, the reamer 18th in the 4a with the sub-area 22nd of the grinding wheel 2 at the main cutting edges and simultaneously with the sub-area 21st of the grinding wheel 2 be prepared at the secondary cutting edges. But it is also conceivable to use the secondary cutting edges according to 4b in one of the individual machining operations following the preparation of the main cutting edges, only on the partial area 21st of the grinding wheel 2 to prepare at the secondary cutting edges.

In the 4c is the cutting edge preparation of a step drill 19th to recognize its two levels at two differently bound sub-areas, for example 21st and 22nd of the grinding wheel 2 is prepared at the same time.

The 4d shows a cutting edge preparation of a milling cutter 20th only on the ancillary cutting edges with a partial area 21st of the grinding wheel 2 interact.

• Grundidee des erfindungsgemäßen Verfahrens ist die Nutzung eines flexibel gebundenen Schleifkörpers 2 aus Abrasivpartikeln, welcher in einer speziell entwickelten Schleifscheibenaufnahme 3 installiert ist. Bei der definierten Zerspanung eines solchen Schleifkörpers 2 kommt es zu einem Materialabtrag an der Schneidkante des Schneidwerkzeugs 5, der zur gezielten Präparation genutzt werden kann. Dieses Verfahren wird auf einer konventionellen Werkzeugschleifmaschine durchgeführt und ist somit ohne weiteren Handhabungsaufwand am Ende der Prozesskette zur Werkzeugherstellung bzw. dem Werkzeugnachschleifen integrierbar. Der zur Präparation erforderliche Materialabtrag entsteht durch die Relativbewegung zwischen Schleifkörper 2 und Schneidwerkzeug 5. Der zylindrische Schleifkörper 2 wird hierbei z.B. ortsfest in der Schleifscheibenaufnahme 3 gespannt, während die erforderlichen translatorischen und rotatorischen Bewegungen vom zu präparierenden Schneidwerkzeug 5 ausgeführt werden.

Essential properties and advantages of the invention are briefly explained below:

• The basic idea of the method according to the invention is the use of a flexibly bonded grinding tool 2 from abrasive particles, which in a specially developed grinding wheel holder 3 installed. During the defined machining of such a grinding wheel 2 material is removed from the cutting edge of the cutting tool 5 that can be used for targeted preparation. This process is carried out on a conventional tool grinding machine and can therefore be integrated at the end of the process chain for tool manufacture or tool regrinding without any further handling effort. The material removal required for preparation is caused by the relative movement between the grinding wheels 2 and cutting tool 5 . The cylindrical grinding wheel 2 becomes stationary in the grinding wheel holder 3 tense while the required translational and rotational movements of the cutting tool to be prepared 5 are executed.

Furthermore, there is a targeted superimposition of the directions of rotation of the cutting tool 5 and grinding wheel holder 3 the possibility of setting specific rounding and tilting of the cutting edge. Furthermore, a structure of the grinding body 2 with different degrees of hardness variable roundings over the cutting edge area of the cutting tool 5 produce. Also the rounding of the cross cutting edge of the cutting tool 5 due to established preparation processes poses a known problem. By using a grinding tool 2 with one to the tool diameter 5 coordinated perforation 15th , there are possibilities to use the main cutting edges, for example of a drilling tool 5 to be adapted to the preparation process, but avoid rounding the cross cutting edge. The same applies to the exact coordination of the diameter of the Grinding wheel 2 the diameter of the cutting tool to be prepared 5 .

Furthermore, due to the free process kinematics, there are other areas of application, such as the preparation of reamers, micro-milling tools and stepped drilling tools.

From the machining of the grinding wheel 2 this results in material being removed from the cutting edge of the cutting tool 5 , which makes it rounded. The advantage of the method according to the invention is that the tool production (grinding of the macro shape) and the defined generation of the microscopic cutting edge shape can be carried out on the same tool grinding machine. By machining the grinding tool 2 Fresh abrasive medium is constantly used, which means that the preparation conditions are constant over the duration of the process. The tool influence is limited to that with the grinding wheel 2 areas of the cutting tool coming into contact 5 , which is an advantage over other preparation methods, such as drag grinding or blasting. In addition to the low investment costs, the preparation costs per tool are low, since the grinding wheel has to be exchanged 2 can be done quickly and easily.

In particular, the rounding of the cutting edge of long cantilever cutting tools 13 with a high length-to-diameter ratio (I / d ratio) requires special handling and complex process management according to the current state of the art, if a suitable cutting edge preparation is to be created. The inventive device offers the potential that such long cantilever cutting tools 13 Thanks to the simple kinematics, machining can be prepared in a single clamping and within existing production processes on the tool grinding machine in the shortest possible time. Besides cutting tools 13 with a high I / d ratio, however, can also be achieved by a slight change in the grinding wheel 2 Prepare conventional rotationally symmetrical cutting tools using this process.

In addition to the rounding of the cutting edge on new tools 5 the method according to the invention also allows cutting tools 5 that have been reground and are therefore already coated with a hard material layer on certain functional surfaces. According to the current state of knowledge, this is not specifically possible using currently available methods, which reduces the performance of reground cutting tools 5 is usually significantly less than that of new cutting tools 5 .

Relevant for the implementation of the device according to the invention 1 is the receptacle for the interchangeable bracket 4th in the grinding wheel holder 3 . The grinding wheel holders usually used on tool grinding machines 3 have corresponding interfaces to the tool grinding machine spindle. These are usually designed as hollow shank taper (HSK), shank taper (SK) or other, mostly standardized interface, in order to enable a high degree of flexibility and accuracy when changing the grinding wheel. Here, the grinding wheels for tool grinding are mostly on a mandrel 3 , e.g. with a diameter d = 20 mm, set, positioned by spacer rings and by a clamping nut 9 fixed. The core of the thorn 3 previously had no function. By installing the interchangeable bracket 4th , here in a hole 11 with internal thread, becomes the mandrel 3 an additional function is given and the grinding wheel holder 3 significantly upgraded in terms of their operational capabilities. Besides setting the interchangeable bracket 4th the connection, which can be screwed or joined in some other way, could also be used to implement other functional elements that do not serve the purpose of cutting edge preparation.

The grinding tools specially developed for the application of cutting edge preparation 2 have an elastic bond of the abrasive particles with a degree of hardness to be determined for the respective application. This involves a rotationally symmetrical grinding body interspersed with fine or coarser abrasive particles, for example silicon carbide, aluminum dioxide or diamond 2 which of the cutting tools to be prepared 5 is successively completely machined. The rotationally symmetrical grinding tools 2 are based on the diameter of the cutting tool to be prepared 5 adapted and manufactured with very little oversize and in the exchangeable retaining element 4th pressed in. Thus, the exposed cutting corners of the cutting tools can be rounded 5 avoided or significantly minimized compared to existing processes. In addition to the rotationally symmetrical base bodies with a fixed bond hardness, grinding bodies can also be used 2 produce that have different degrees of hardness and are accordingly adapted to the application and the diameter to be processed. Particular mention should be made here of the possibilities that there are with cutting tools 5 may be necessary that the core 16 of the grinding wheel 2 a higher hardness than the outer area 17th has to provide a uniform cutting edge rounding due to the elastic deformation of the rotationally symmetrical grinding wheel 2 to reach.

In addition, the process kinematics result in possibilities, for example by superimposing the directions and speeds of rotation, regardless of the performance of the workpiece and tool spindles, a wide range of parameters with regard to the cutting speeds when machining the grinding wheel 2 to cover. Furthermore, by means of differently oriented, counter-rotating and synchronous movements of the grinding wheel holder 3 with integrated grinding tool 2 and the cutting tool to be prepared 5 , Influences of the cutting edge tilt, the form factor κ, enable and set. By making holes 15th , the introduction of cores 16 with different hardnesses, abrasive particles and grain sizes and the flexible shape of the grinding media 2 this method offers the possibility of transferring it to many other variants of cutting tools 5 . In addition, the axes of the grinding wheel holder can be superimposed 3 Develop and implement different kinematics that come close to milling and thus also the preparation of different milling tools 5 allows targeted at the front and / or circumferential cutting edges.

In addition to the already described use for grinding tools 2 the device can be used for cutting edge preparation 1 can also be expanded by using measurement technology or sensors. By introducing electrical conductors and sensors into the exchangeable bracket 4th It would even be possible to implement electronic monitoring electronics equipped with accumulators and charge them using suitable charging technology when not in use in the grinding wheel magazine or externally.

Due to the integration of the device 1 into the grinding wheel holder 3 the acquisition costs are only marginally higher compared to conventional grinding wheel holders 3 . Linked to this is that it is integrated into the grinding wheel holder 3 the concept can be used on almost any tool grinding machine. This eliminates the investment required for most of the previously known processes for additional systems, including the resulting maintenance and repair costs, as well as workpiece handling after the grinding process. Complete machining on the tool grinding machine results in times when the machine cannot be used for its primary purpose, but these are marginal due to the very short process times of <5 s per preparation. A tool change can be carried out with a skilful combination of the grinding wheel packages on the grinding mandrel or by equipping each grinding wheel holder 3 with the device according to the invention 1 avoid, whereby the productivity increases overall and the manufacturing costs can be reduced significantly.

Adjusting the grinding wheel 2 to the diameter of the cutting tools 5 and the previously defined maximum oversize of the grinding wheel to be machined 2 guarantee an almost irrelevant influence on the cutting edges and the ancillary cutting edges of the cutting tools 5 . In addition, the contact surface between the cutting tool is limited by the chip thickness 5 and grinding wheel to be machined 2 no influence on the peripheral surfaces of the cutting tool 5 . Due to the defined length of the rotationally symmetrical grinding wheel 2 inside the interchangeable bracket 4th a number of cutting tools depending on the diameter and target rounding can be used 5 Process with the help of the presented concept until the grinding wheel to be machined 2 is completely used up. By replacing the interchangeable bracket 4th or changing to a different grinding wheel holder 3 with the same grinding tool 2 seamless processing close to the process chain is possible. The free kinematics through assembly in the grinding wheel holder 3 furthermore offers the potential to implement different process kinematics on the tool grinding machine similar to milling. This results in options for the main and secondary cutting edges of the cutting tools 5 to prepare with different cutting edge fillets and form factors.

Besides the variation of the shape of the grinding wheel 2 and bond hardness, it is possible to create different shapes of the cutting edge rounding by adapting the kinematic engagement ratios. The direction of rotation of the cutting tool is of particular importance here 5 , the direction of rotation of the grinding wheel 2 , the dwell time at the bottom of the hole and the feed per revolution.

For long protruding deep drilling tools 13 With different diameters, it is necessary to guide the tool tip in order to enable cutting edge preparation without damaging the cutting tool 13 to result in. This requires an adaptation of the exchangeable bracket 4th necessary. The guidance of the cutting tool 13 is to be dimensioned so that the grinding wheel 2 coincides with the workpiece axis and the elastic deflection of the cutting tool 13 is compensated. The complexity of the preparation results from the demands on the cutting edge. In addition to the stronger rounding of the outer cutting edge, when using single-lip deep drilling tools, there is also a to achieve significantly less rounding of the inner cutting edge.

List of reference symbols

1 -

device according to the invention

2 -

Grinding wheel

3 -

Support collar grinding wheel support

4 -

interchangeable bracket

5 -

Cutting tool

6 -

Thread interchangeable bracket

7 -

Cutting cutting tool

8th -

Clamping thread for grinding wheel

9 -

Clamping nut for grinding wheel

10 -

Tool cone

11 -

Hole in the grinding wheel holder

12 -

Guide bush

13 -

Single-lip bur

14 -

Grinding wheel

15 -

Perforation

16 -

Core with higher bond hardness

17 -

Circumferential area with lower bond hardness

18 -

Reaming tool

19 -

Step drill

20 -

Milling tool

21 -

surrounding abrasive

22 -

internal grinding wheel

23 -

Hole bracket

24 -

Infeed direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011054276 B4 [0009]

Claims (26)

Device (1) for cutting edge preparation of cutting tools (5), in particular drills or milling cutters or similar tools (5), in particular hard metal cutting tools, the cutting tool (5) being provided with abrasive particles and flexibly bonded grinding body during a relative movement (2) interacts by cutting and the particles of the grinding body (2) influence the edge geometry of the cutting tool (5), characterized in that the dimensions of the grinding body (2) are essentially adapted to the dimensions of the cutting tool (5) to be prepared and in an exchangeable holder (4) is accommodated, which is arranged in the working space of a tool grinding machine and is held in a machinable manner by the cutting tool (5) for cutting edge preparation. Device (1) according to Claim 1 , characterized in that the exchangeable holder (4) is kept insertable in a grinding wheel holder (3) of the tool grinding machine. Device (1) according to one of the Claims 1 or 2 , characterized in that the grinding body (2) is essentially cylindrical Device (1) according to Claim 3 , characterized in that the cylindrical circumferential dimensions of the grinding body (2) are essentially adapted to the circumferential dimensions of the cutting tool (5) to be prepared. Device (1) according to one of the preceding claims, characterized in that the grinding body (2) can easily be exchanged for a new grinding body (2) after complete use, in particular is arranged in the holder (4) so as to be easily exchangeable, preferably in the exchangeable one Bracket (4) is pressed in. Device (1) according to one of the preceding claims, characterized in that the rotationally symmetrical grinding body (2) can be produced with a very small allowance adapted to the diameter of the cutting tool (5) to be prepared and can be pressed into the exchangeable holder (4). Device (1) according to one of the preceding claims, characterized in that the exchangeable holder (4) can be inserted into a preferably central bore (11) in the grinding wheel holder (3), preferably in the holder collar for the grinding wheel (14). Device (1) according to Claim 7 , characterized in that the exchangeable holder (4) has an external thread (6) which can be screwed into the bore (11) provided with an internal thread in the grinding wheel holder (3). Device (1) according to Claim 7 , characterized in that the exchangeable holder (4) can be pressed or plugged into a preferably central bore (11) in the grinding wheel holder (3) and is held there in a rotationally fixed manner. Device (1) according to one of the preceding claims, characterized in that a guide bushing (12) is arranged in the area of the exchangeable holder (4) for the grinding body (2), through which long cantilevered asymmetrical cutting tools (13), preferably deep drilling tools, single-lip drills, Twist drills or the like can be prepared in a guided manner with a large length / diameter ratio, the guide bushing (12) in particular being arranged relative to the exchangeable holder (4), preferably in an extension of the exchangeable holder (4) on the latter, that the guide bushing (12) guides and supports the long cantilever cutting tool (13) in front of the machining area of the grinding tool (2). Device (1) according to one of the preceding claims, characterized in that electrical conductor tracks and / or sensor elements can be introduced into the exchangeable holder (4), which provide information about the process of cutting edge preparation, with the sensor elements in particular also being in the exchangeable holder (4 ) integrated accumulators that can be charged in the grinding wheel magazine or externally when not in use. Device (1) according to one of the preceding claims, characterized in that the grinding body (2) has abrasive particles, in particular made of silicon carbide, aluminum dioxide or diamond, and can be successively completely machined by the cutting tools (5) to be prepared. Device (1) according to Claim 12 , characterized in that the grinding body (2) has a mixture of finer and / or coarser abrasive particles, the distribution of finer and / or coarser abrasive particles within the grinding body (2) being in particular inhomogeneous. Device (1) according to one of the preceding claims, characterized in that the grinding body (2) has an axially extending perforation (15) which is matched to the cutting tool diameter (5) and within which the Cutting tool (5) is not influenced by the particles of the grinding tool (2). Device (1) according to one of the preceding claims, characterized in that the grinding body (2) has sections (21, 22) with different degrees of hardness of the bond, in particular radial annular sections (21, 22) of different degrees of hardness, with the core (22 ) of the grinding body (2) has a higher bond hardness than the outer area (21) in order to achieve a uniform cutting edge rounding due to the elastic deformation of the rotationally symmetrical grinding body (2). Method for cutting edge preparation of cutting tools (5), in particular drills or milling cutters or similar tools, in particular hard metal cutting tools, wherein the cutting tool (5) interacts during a relative movement with a flexibly bonded grinding body (2) provided with abrasive particles and the particles of the grinding body (2) influence the edge geometry of the cutting tool (5), characterized in that the dimensions of the grinding body (2) are essentially adapted to the dimensions of the cutting tool (5) to be prepared and by a replaceable one in the work space Tool grinder arranged holder (4) is received, in which the grinding body (2) is successively completely machined by the cutting tools (5) to be prepared. Procedure according to Claim 16 , characterized in that the cutting edge preparation is carried out in the same clamping immediately after the first production of the shape of the cutting tool (5) or the regrinding of the cutting tool (5) on the same tool grinding machine. Method according to one of the Claims 16 or 17th , characterized in that the relative movement between the grinding body (2) and the cutting tool (5), in particular through the superimposition of the directions of rotation and the rotational speeds, results in a broad adjustment of the cutting speeds when machining the grinding body (2). Procedure according to Claim 18 , characterized in that the grinding body (2) and / or the cutting tool (5) perform rotary movements during the machining of the grinding body (2), in particular a superimposition of the rotational movement of the grinding body (2) and / or cutting tool (5) targeted rounding and / or tilting of the cutting edge of the cutting tool (5) and / or the production of asymmetrical cutting edge profiles and / or cutting edge profiles that are variable over the tool diameter. Procedure according to Claim 18 , characterized in that the cutting tool (5) to be prepared executes the required translational and rotational movements during the cutting edge preparation. Method according to one of the Claims 16 to 20th , characterized in that the grinding body (2) with sections with different degrees of hardness of the bond produces variable roundings over the cutting area of the cutting tools (5). Method according to one of the Claims 16 to 21st , characterized in that the grinding body (2) through an axially extending perforation (15) matched to the cutting tool diameter (5) and in which the cutting tool (5) is not influenced by the particles of the grinding body (2), the axial areas of the cutting tool (5), in particular the main cutting edges of a drilling tool, does not subject the cutting edge preparation, in particular does not subject the cross cutting edge to rounding. Method according to one of the Claims 16 to 22nd , characterized in that the grinding body (2) has outer dimensions matched to the cutting tool diameter (5), by means of which only areas of the cutting edges of the cutting tool (5) are subjected to cutting edge preparation in a targeted manner. Method according to one of the Claims 16 to 23 , characterized in that the cutting edge preparation is carried out on new tools (5) or on cutting tools (5) which have been reground and are therefore already coated with a hard material layer on certain functional surfaces. Method according to one of the Claims 16 to 24 , characterized in that the cutting tool (5) with main and secondary cutting edges, in particular milling tools (20), reaming tools (18) and / or stepped boring tools (19), for the cutting edge preparation with its main and secondary cutting edges respectively assigned grinding bodies (2 ) machined with different properties. Abrasive body (2) for performing the method according to Claim 16 , characterized in that the cylindrical circumferential dimensions of the grinding body (2) essentially the Circumferential dimensions of the cutting tool to be prepared (5) are adapted.

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