U.S. patent application number 13/399202 was filed with the patent office on 2012-09-20 for method for providing an edge preparation on a cutting edge of a tool and a control and a processing machine for carrying out the method.
Invention is credited to Jurgen Schwagerl.
Application Number | 20120238184 13/399202 |
Document ID | / |
Family ID | 46604901 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120238184 |
Kind Code |
A1 |
Schwagerl; Jurgen |
September 20, 2012 |
METHOD FOR PROVIDING AN EDGE PREPARATION ON A CUTTING EDGE OF A
TOOL AND A CONTROL AND A PROCESSING MACHINE FOR CARRYING OUT THE
METHOD
Abstract
A method for providing an edge preparation on a cutting edge of
a tool by means of an edge processing operation includes clamping
the tool in a processing machine for providing the edge
preparation, recording as a reference value the position of the
cutting edge to be processed by means of a sensor arranged on the
processing machine, carrying out an edge processing operation by
means of a preparation tool, recording the position of the cutting
edge again by means of the sensor arranged on the processing
machine and storing the position as an actual value, monitoring the
edge processing operation on the basis of a comparison between the
reference value and the actual value, and comparing the actual
value with a desired value for material removed on the cutting
edge.
Inventors: |
Schwagerl; Jurgen;
(Vohenstrauss, DE) |
Family ID: |
46604901 |
Appl. No.: |
13/399202 |
Filed: |
February 17, 2012 |
Current U.S.
Class: |
451/1 ; 451/28;
451/59; 451/64 |
Current CPC
Class: |
G05B 19/4163 20130101;
B24B 29/005 20130101; B24B 3/16 20130101; B24B 3/24 20130101; G05B
2219/37602 20130101; B24B 3/02 20130101 |
Class at
Publication: |
451/1 ; 451/28;
451/59; 451/64 |
International
Class: |
B24B 49/00 20120101
B24B049/00; B24B 17/10 20060101 B24B017/10; B24B 19/00 20060101
B24B019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2011 |
DE |
102011011754.7-14 |
Claims
1. A method for providing an edge preparation on a cutting edge of
a tool by means of an edge processing operation, the method
comprising: clamping the tool in a processing machine for providing
the edge preparation; recording as a reference value the position
of the cutting edge to be processed by means of a sensor arranged
on the processing machine; carrying out an edge processing
operation by means of a preparation tool; recording the position of
the cutting edge again by means of the sensor arranged on the
processing machine and storing the position as an actual value;
monitoring the edge processing operation on the basis of a
comparison between the reference value and the actual value; and
comparing the actual value with a desired value for material
removed on the cutting edge.
2. The method of claim 1, wherein a plurality of tools are
successively processed on the processing machine and wherein wear
of the preparation tool is deduced on the basis of the progression
of the difference between actual value and reference value.
3. The method of claim 2, wherein when wear of the preparation tool
is detected, a desired control value for the preparation tool is
corrected in a control unit of the processing machine.
4. The method of claim 1, wherein desired value for the material
removal is within the range of 3 .mu.m to 200 .mu.m.
5. The method of claim 1, wherein the sensor is a probe.
6. The method of claim 1, wherein the preparation tool comprises a
brush.
7. The method of claim 1, wherein the processing machine comprises
a 5-axis CNC machine.
8. The method of claim 1, wherein an edge preparation is carried
out again in the event of an inadmissible deviation from the
desired value.
9. A processing machine for carrying out the method of claim 1, the
processing machine comprising: a clamping unit for clamping the
tool in place; a preparation tool for carrying out the edge
processing operation; a sensor for recording the position of the
cutting edge; and a control unit structured to monitor the edge
processing operation on the basis of a comparison between the
reference value and the actual value.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The invention relates to a method for providing a defined
edge preparation on a cutting edge of a tool for machining metals
by means of a rounding operation, in particular for providing a
defined edge preparation on a drilling, reaming, threading and/or
milling tool. The invention also relates to a control and to a
processing machine for carrying out the method.
[0003] 2. Background Information
[0004] Both drilling and milling tools are produced, inter alia, in
a plurality of production steps from a rough round bar. In this
case, modern high performance tools are produced from solid
carbide. In the process, the desired geometry with main cutting
edges is normally formed at the end face by a special point
grinding method. In continuation of the tool, flutes with secondary
cutting edges are often provided. The selection of the special
point grinding, the configuration of the cutting edge geometry and
of the flutes depend on the respective requirements. The cutting
properties of the tool are considerably influenced by the cutting
edge geometry. After the grinding operation, the cutting edges are
normally of very sharp design, and so the cutting edges are
regularly rounded via "edge rounding". This edge rounding, referred
to below as rounding operation, is carried out using a suitable
rounding tool, in particular by means of brushes. A high-precision
rounding process is important here in order to achieve the desired
cutting properties. The material removal is normally only within a
range of a few um. A deviation from desired material removal leads
to a deterioration in the cutting properties.
[0005] On account of the very hard material when using solid
carbide drills, the brushes are subjected to high wear during the
rounding operation, such that, during the processing of a
multiplicity of tools, the result of the rounding operation often
varies in an undesirable manner at the same machine settings.
[0006] A further conventional edge preparation in addition to such
edge rounding is the provision of a bevel on a cutting edge. Here,
too, reproducible high precision of the edge preparation is
important.
[0007] Accordingly, a need exists for a simple, reliable method for
producing a defined edge preparation, in particular during a
multiplicity of successive edge processing operations, and for a
processing machine for carrying out this method.
SUMMARY OF THE INVENTION
[0008] The present invention addresses such needs by providing a
method for providing an edge preparation on a cutting edge of a
tool by means of an edge processing operation, in particular for
providing edge rounding or a bevel. Accordingly, for providing a
defined edge preparation on a cutting edge of a tool, in particular
a drilling, reaming, threading and/or milling tool, the tool is
first of all clamped in place in a processing machine. The position
of the cutting edge to be processed is then recorded by means of a
sensor arranged on the processing machine and is stored as a
reference value. In the next method step, the edge preparation
operation is carried out by means of a preparation tool and the
position, which has then changed, of the cutting edge is then
recorded again by means of the sensor and stored as an actual
value. Finally, the edge preparation operation is monitored on the
basis of a comparison between the reference value and the actual
value and is compared with a desired value for the material removal
on the cutting edge. As a result, the edge preparation is
controlled overall in a simple and efficient manner.
[0009] In previous methods, it was regularly necessary for this
purpose to check the result of the edge preparation in a
complicated manner in separate measuring devices. To this end,
unclamping of the tool was necessary.
[0010] With the method now described herein, it is now possible to
determine the result of the edge processing operation directly at
the machine tool, and therefore no separate measuring operation in
a separate measuring device has to be carried out. The recording of
the relative change between the recorded reference value and the
actual value recorded after the edge processing operation is
especially important. It is therefore not important to determine
the actual absolute situation and position of the cutting edge in
the coordinate system of the processing machine. As a result of the
recording of the relative change, the material removal actually
effected can be determined in a highly precise manner.
[0011] In this way, in particular online process monitoring is made
possible and provided by the simple measuring operation. Normally,
a multiplicity of tools are processed one after the other on the
processing machine and are subjected to the edge processing
operation. The expression "online process monitoring" refers to the
fact that, in the course of this process, that is to say the edge
preparation of a multiplicity of tools, the result of a respective
edge processing operation is regularly monitored. The expression
"regularly" refers here to the fact that the edge processing
operation itself is monitored by the described comparison in each
case after a defined number of edge processing operations, for
example after 3 to 5 rounding operations (tools). In principle, it
is also possible, and provision is also made for this, to carry out
the measurement and monitoring and also to log the data at each
tool to be processed.
[0012] The edge preparation provided is in particular a rounding
operation. Alternatively, a bevel is provided using this method.
The invention is explained in more detail below with reference to
the rounding operation. The advantages and method features cited
also likewise apply to the provision of a bevel.
[0013] According to an expedient configuration, wear of the
preparation tool, designated below as a rounding tool, is deduced
on the basis of the progression of the difference between actual
value and reference value. Online monitoring of the wear of the
rounding tool is therefore also made possible by this measuring
method. When wear which exceeds an admissible tolerance value is
detected, provision is accordingly also made for a desired control
value for the rounding tool to be corrected in a control unit of
the machine tool. The wear is therefore taken into account for the
infeed movement of the rounding tool in order to ensure the desired
result, that is to say the desired material removal, for subsequent
rounding operations.
[0014] In an expedient configuration, the preparation tool is in
this case a brush and furthermore provision is made in particular
for the sensor to be a probe. Such probes are present in modern
processing machines, and therefore no additional measuring devices
have to be attached to a conventional processing machine.
[0015] As an alternative to the brush, other preparation tools or
preparation methods can also be provided, such as, for example, a
grinding tool or a blasting method, in which the edge to be
processed is processed in a wet blasting process, with abrasive
particles if required.
[0016] The processing machine is preferably a multi-axis, for
example 5- or 6-axis, CNC machine. Such machines are distinguished
by universal use for the most varied tool processing operations. In
particular, such machines are also used as universal machines for
the further production processes, such as, for example, grinding,
etc. It is therefore also possible to carry out a plurality of
production steps, in particular all the production steps, such as
the flute grinding or the end point grinding for producing the
tool, without resetting the tool on the processing machine.
[0017] In a preferred development, in the event of an inadmissible
deviation from the desired value being detected on account of wear
of the rounding tool, a rounding operation is carried out again
before the tool is unclamped. However, this is expediently avoided
by a timely correction of the desired control value for the
rounding tool.
[0018] The present invention further addresses such needs by
providing a processing machine for carrying out the methods
described herein. The machine includes a clamping unit for clamping
the tool in place, a preparation tool for carrying out the edge
processing operation, a sensor for recording the position of the
cutting edge, and a control unit structured to monitor the edge
processing operation on the basis of a comparison between the
reference value and the actual value.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] An exemplary embodiment of the invention is explained in
more detail below with reference to the drawings, in which:
[0020] FIG. 1 shows a greatly simplified illustration of a
processing machine for carrying out edge rounding on a tool;
and
[0021] FIG. 2 shows a greatly simplified schematic illustration of
a cutting edge before and after the edge rounding.
[0022] Equivalent parts are provided with the same reference
numerals in the figures.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] According to FIG. 1, a processing machine 2 has a clamping
unit 4 which is designed for clamping a tool 6 in place. The
processing machine 2 is shown in its entirety in FIG. 1 by the
dot-dash line. Furthermore, the processing machine 2 comprises a
tool unit 8 for the defined guidance of a tool, in particular a
rounding tool, which in the exemplary embodiment is designed as a
brush 10. Finally, the processing machine 2 comprises a control
unit 12 which controls the individual processes of the processing
machine 2. A sensor designed in particular as a probe 14 is
arranged on the tool unit 8. The individual components of the
processing machine 2, which in particular is designed as a CNC
machine tool, are adjustable in a controlled manner along various
axes, as indicated by the arrows. In addition to linear adjustments
in the direction of axes, rotary adjustments about axes of rotation
are also possible. The individual adjusting movements can be
superimposed in a suitable manner if required.
[0024] To carry out the actual rounding operation, first of all, in
a first step, the probe 14 is brought up to a cutting edge 16
(shown in solid lines in FIG. 2), in particular a main cutting edge
of the tool 6. In this initial state, the cutting edge 16, as
shown, is still of extremely sharp design. As soon as the probe 14
touches the tip of the cutting edge 16, this position is
established as a reference position. The corresponding measured
values define reference values of the reference position.
[0025] The reference position is expediently recorded at an
appropriate point on the main cutting edge or also on a secondary
cutting edge of the tool 6. The position is preferably merely
recorded at one point, since the rounding operation over the
cutting edge length leads within sufficient tolerances to identical
material removal d.
[0026] The probe 14 is then retracted again and the brush 10 for
carrying out the rounding operation is advanced to the tool 6 in a
manner known per se. A desired control value, up to which the brush
10 is advanced to the tool 6, is stored in the control unit 12.
[0027] After the rounding process is carried out, which is carried
out according to a process sequence stored in the control unit 12,
the probe 14 is again brought up to the then rounded cutting edge
16 (shown in dashed line in FIG. 2). The (rounded) position, then
recorded by the probe 14, is evaluated as an actual position and
the associated actual value is compared with the reference value
recorded beforehand. The difference between the actual value and
the reference value in this case determines the material removal d
effected during the rounding operation. If material removal d is
within a desired range, that is to say corresponding to a desired
value with predetermined tolerances of, for example, .+-.5%, the
rounding operation is all right. In a preferred configuration, if
the material removal d effected is too little, a rounding operation
is carried out once again by advancing the brush 10 again.
[0028] Preferably provided within the control unit 12 is a
comparison module which continuously compares the recorded
reference and actual values with one another and deduces the wear
of the brush 10 on the basis of the progression of the difference
between the reference values and actual values (during successive
rounding operations on various tools 6). If the wear exceeds a
predetermined tolerance value, the desired control value stored in
the control unit is accordingly corrected. During the next rounding
process, the brush 10 is then brought up to the tool in accordance
with the new desired control value. As a result of this measure,
online process monitoring is made possible and provided overall in
a continuous manner during the rounding operation.
[0029] Instead of carrying out the rounding operation by means of a
brush 10, other rounding tools, such as, for example, blasting
methods, etc., can also be used. The rounding operation itself,
with the online process monitoring described, can be carried out on
a special processing machine 2 provided only for the rounding.
[0030] Further measures, such as, for example, coating measures,
etc., can also be carried out if required.
[0031] The method described here and the processing machine 2 with
the control algorithm stored in the control unit 12 in accordance
with the method are distinguished by reliable edge rounding and
online monitoring of the same during a multiplicity of successive
edge rounding operations without the need for a separate external
measuring operation for recording the result of the respective edge
rounding operation.
* * * * *