DE102011108753A1 - Indexable insert has actuator that is provided for metrological detection of vibrations of cutting edge - Google Patents

Abstract

The indexable insert (1) has an actuator for metrological detection of vibrations of a cutting edge. The actuator comprises a piezo sensor, a bimetal or a shape memory alloy. A channel (3) and an annular duct allow flow to coolant to pass through the actuator to keep the temperature at moderate level. A hole (2) is provided at center of the insert for fastening the tool holder. A contact recess (8) is provided around the hole. Independent claims are included for the following: (1) a method for moving actuator; and (2) a method for manufacturing indexable insert.

Description

[Description and Introduction of the General Field of the Invention]

The present invention relates to the construction of an indexable insert. The main goal is to extend the service life of an indexable insert.

[State of the art]

In the DE19600172 An indexable insert is provided with a cooling channel, which is guided as a groove around the indexable insert.

In the US6447218 An indexable insert is provided on the top with an elevation and grooves. On these grooves, a coolant jet is directed from the outside.

In the DE3740814 An indexable insert with integrated coolant channel is described.

In the DE69914375 a tool holder is described, which dampens vibrations by a piezoelectric actuator.

In the DE60014591 will also describe a tool holder, which dampens vibrations by a piezoelectric actuator.

In the DE102007036002 a tool holder is described, which is equipped with a piezoelectric sensor and actuator.

For a longer service life, it is necessary to dissipate thermal energy where it arises directly. For a higher accuracy a vibration reduction is only interesting for long tool holders. A vibration reduction with short tool holders does not increase the accuracy. For this other solutions would be desirable. The listed writings have the disadvantage that they provide a higher service life but not a higher accuracy. When using piezoelectric actuators in holders, the vibrations are subsequently damped, but these have already occurred and thus adversely affect the cutting edge and the machining behavior or the entire machining process.

It would be desirable to achieve a combination of increasing service life and increasing accuracy.

[Task]

Object of the present invention is to eliminate or circumvent the disadvantages of the prior art.

[Solution of the task]

This object is achieved by an indexable insert comprising an actuator. The actuator is preferably made of material which has a piezoelectric effect (piezoelectric material) and performs a change of the geometric shape by the application of electrical voltage. Alternative actuators perform a change in the geometric shape due to thermal expansion, such. B. bimetallic strip or shape memory alloys. A further embodiment additionally contains a temperature control. The purpose of the temperature control is primarily to positively influence the dissipation, the spread and the height of the resulting heat flows during machining for the cutting process in terms of increasing the distance, increasing the accuracy and achieving the required surface quality. In the case of an actuator with bimetal strips or shape memory alloys, the temperature control can also be used to influence the temperature field of the bimetallic strip in order to increase the efficiency. The temperature includes cooling or heating.

The use of a piezoelectric actuator has the advantage that it can also act as a piezoelectric sensor. Depending on the control, it is decided whether the piezo component is a piezo actuator or piezo sensor. In one embodiment, the piezo component is cyclically switched as a piezoelectric sensor and piezoelectric actuator.

The piezo device is placed near a cutting edge of the indexable insert. The cutting edge is a cutting edge or corner of the indexable insert. The cutting edge is in a range of 10 to 150 °. In the indexable insert according to the invention, at least one, preferably a plurality of piezo components is used. The number of piezo components does not have to match the number of cutting edges. Preferably, a multiple in the range 1 to 8 in relation to the number of cutting edges is used for the number of piezo components.

In one embodiment, two piezo components per cutting edge are used. Here, a piezo device is switched as a piezoelectric sensor and the other as a piezoelectric actuator. This has the advantage that with each switching cycle a piezo sensor and a piezo actuator are available. Thus, measured data can be determined while the cutting edge is engaged or directly during the Cutting process. At least one piezoelectric component is arranged laterally to the cutting edge. Alternatively, at least one piezo component is arranged below the cutting edge. Due to the piezoelectric oscillation, a movement takes place parallel to the cutting direction and perpendicular to the cutting edge.

A movement parallel to the cutting direction causes a forward and backward movement of the cutting edge. This includes the particular advantage that vibrations of the workpiece are compensated by the cutting edge. This makes it possible to swing the cutting edge and the workpiece in the same phase. These vibrations also occur laterally, so that even for a lateral swing an equal phase of the cutting edge and workpiece can be achieved. Thus, a chip can be produced with the same thickness and a smoother surface can be produced.

In an alternative application, the vibration behavior is exploited in such a way that vibrations with a deliberately defined phase shift are produced, which leads to rougher surfaces. There are thus structurings of the surface produced.

By a simultaneous tempering the service life can be further increased. The temperature causes a positive influence on the thermal conditions during the cutting process. The oscillation movement through the actuator also takes place in the absence of temperature control.

The indexable insert is produced by sintering. Preferably, a template is inserted into the mold. The template represents the tempering channels and contains the at least one actuator. In addition, the template contains the contacts for the actuator. The template is preferably made of a fusible material z. As plastic or wax. After sintering the indexable insert, the template can be melted out. The actuators remain in the indexable insert.

For piezoelectric actuators the following materials can be used: silicon oxide, lead zirconate titanate, Berlinite (aluminum orthophosphate), gallium orthophosphate, tourmaline, barium titanate, zinc oxide, aluminum nitride.

For shape memory alloys, alloys of metals such as NiTi (nickel-titanium, nitinol), CuZn (copper-zinc), CuZnAl (copper-zinc-aluminum), Cu-AlNi (copper-aluminum-nickel), FeNiAl (iron-nickel Aluminum). Indexable inserts with such a structure can also be produced directly by laser sintering or jet melting.

Another possibility is the melting out of the sintered material with a laser and the subsequent introduction of the actuator (piezo component). The embodiment according to the invention is explained below, wherein the invention comprises all the following preferred embodiments individually and in combination.

[Embodiments]

In the 1 is an indexable insert 1 shown with cutting edges (corners). This has a hole 2 which serves for attachment to the tool holder. Furthermore, in the indexable insert Temperierkanäle 3 available. The fluid flow is guided from the underside of the indexable insert. This is an annular channel 7 created. From this ring channel 7 a line carries the fluid (coolant or heating medium) between the two piezo elements 5 by. Near the surface and the cutting edge, the fluid passes through a nozzle 9 pressed and distributed in two return channels. These lead the fluid to the bore 2 where it comes out.

The piezo components 5 are arranged laterally to the cutting edge (in this case a corner). Two piezo elements are connected by an electrical conductor 6 connected with each other. In the 1 a curved sheet represents the electrical conductor 6 dar. The curved, electrically conductive sheet 6 is located below the cutting edge. Alternatively, the electrical conductor is designed as a wire between the piezo components. The control of the piezo components is by an electrical contact 4 that as a contact pin 4 was built up realized. This contact pin 4 gets close to the hole 2 guided and can then be contacted with an insert ring, not shown. This indexable insert has four cutting edges. The cutting edges are the same and the internals are repeated per cutting edge. Therefore, in the drawings, only the label of a cutting edge.

In 2 the same indexable insert is shown from the side. In 1 and 2 are also the cuts for the 3 to 6 located.

In 3 is a section through the insert in the diagonal direction shown. It can be seen here that the fluid passes through an annular channel 7 and is passed over other leads to below the cutting edge. The L-shaped feed lines are alternatively guided by one or more direct diagonal channels to below the cutting edge.

In the 4 is a section through the piezo device 5 and the contact pin 4 placed. The piezo element is with the piezo element on the other Side of the cutting edge through an electrical conductor 6 connected. The contact pin 4 ends in a contact recess 8th which was passed around the hole. Through an insert ring the electrical contact is feasible. For the sensor circuit is a single contact per pin 4 mounted in the insert ring. This should be the contact pins 4 not as close together as shown here. In addition, an orientation recess in the contact recess 8th bring in and provide the insert ring with a corresponding Orientierungsausprägung.

In a piezosensor circuit, the piezoelectric actuator is permanently, temporally limited or cyclically alternately switched as a piezoelectric sensor. With a piezoelectric sensor circuit vibration data of the cutting edge are determined. These are used for targeted deflection of the cutting edge. Thus, the cutting edge is exposed to high deflections in areas with high vibration amplitudes. This ensures that the cutting edge vibrates with the workpiece in phase or specifically in different phases. This causes a smoother or a rougher surface.

If only one Aktorschaltung is realized, it is possible to make the insert ring so that at the four contact points corresponding voltages applied opposite points have the same potential). All piezo actuators are operated simultaneously, although only one cutting edge is active. Alternatively, a contacting of one or more outer sides or of the upper or lower side can be carried out instead of an insert ring. The corresponding contact pins 4 are then executed as lines with contact fields, so that electrical contacts are feasible.

Furthermore, the temperature control channels 3 and the ring channel 7 shown.

In the 5 gets around the hole 2 the contact recess 8th guided. The contact pins 4 lead from the contact recess 8th to the piezo component 5 , This is done with the other piezobauelement arranged laterally of the cutting edge 5 through a curved electrical conductor 6 contacted. Between the piezo components 5 is a fluid channel 3 arranged.

In 6 is the continuation of the tempering channel 3 shown below the surface of the cutting edge. In this case, the temperature control medium through a nozzle 9 guided and then divided into two fluid streams. These are going to bore 2 returned again.

In 7 is an alternative form of indexable insert 1 shown. Here are the piezo components 5 also arranged laterally of the cutting edge. For a better lateral movement are side of the cutting side recesses 10 brought in. The piezo components 5 are through contact pins 4 , which are designed here as a contact ring, contacted each other.

Alternatively, the piezo components 5 replaced by shape memory alloys. The resulting during the processing of a workpiece heat energy causes a deflection of the shape memory alloy. The cutting edge is deflected and thus generates less heat. By tempering the heat is dissipated more effectively and the shape memory alloy returns to its original state. The return of the cutting edge now produces heat again. The particular advantage is that in this embodiment no electrical contacts are needed. Only a sufficiently optimized temperature control must be guaranteed. For this purpose, temperature control channels are introduced into the indexable insert. The tempering channels must be arranged in the immediate vicinity of the actuators (shape memory alloys, bimetallic strip). The fluid flow is preferably not performed uniformly but pulsed. This makes it possible to ensure sufficient heating and cooling of the actuator.

Here, vibrations of the cutting edge are generated with a deliberately defined phase shift, which leads to rougher surfaces.

[Illustration legends and reference list]

1 Indexable insert from above with markings for cuts

2 Indexable insert on the side with markings for cuts

3 Indexable insert side cut AA

4 Indexable insert side cut BB

5 Indexable insert from above section CC

6 Indexable insert from above section DD

7 Indexable cutting insert

LIST OF REFERENCE NUMBERS

1

Indexable insert

2

Hole for attachment to the tool holder

3

tempering

4

electric contact

5

piezo device

6

curved electrical conductor

7

annular channel

8th

contact recess

9

jet

10

side recess

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 19600172 [0002]
• US 6447218 [0003]
• DE 3740814 [0004]
• DE 69914375 [0005]
• DE 60014591 [0006]
• DE 102007036002 [0007]

Claims (8)

Indexable insert with cutting edge characterized in that the indexable insert comprises an actuator. Indexable insert according to claim 1, characterized in that the actuator comprises a piezoelectric material, bimetal or shape memory alloy. Indexable insert according to one of claims 1 to 2, characterized in that the actuator is arranged laterally or below the cutting edge. Indexable insert according to one of claims 1 to 3 characterized in that the indexable insert comprises an additional temperature. Indexable insert according to one of claims 1 to 4, characterized in that the piezoelectric actuator is a piezosensor. Method for moving a cutting edge in an indexable insert according to one of claims 1 to 5, characterized in that the actuator is controlled so that the cutting edge performs movements parallel to the cutting direction and perpendicular thereto in addition to the cutting movement. A method according to claim 6, characterized in that the actuator of piezo material is controlled as a piezoelectric counter permanently, temporally limited or cyclically between the piezoelectric actuator and the piezoelectric sensor. Production of the indexable insert according to claim 1 by means of sintering, laser sintering, jet melting or melting out.

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