The invention relates to a measuring machine for measuring objects
is set up, and a corresponding procedure.
Measurement of workpieces are imaging measuring methods
known to work on an optical basis. The object is using
of a lens. The optical axis of the lens determines
the Z direction. At right angles X and Y measured values are determined.
For example, the WO 2005/108915 A1
In addition, a measuring system for microsystems technology, in which a white light interferometric measuring method is combined with an imaging measuring method. A lens that can be switched over from interference-optical measurement to imaging measurement is used for the implementation. With this device, both on the one hand in the X and Y direction areally and in the Z direction high resolution can be measured. In this way, the height structures can also be optically surveyed with a high level of precision even on stepped objects.
increasingly poses the task of small objects with inclined
Measure surfaces precisely and reliably.
For example, drilling tools with diameters become much smaller
manufactured as 1 mm down to tool diameters of 30 microns.
These drilling tools have defined cutting edges and others
Functional surfaces, such as clamping surfaces, open spaces
and the like, which must be precisely measured.
For example, rake angles and / or clearance angles are to be determined.
the determination of angles below those functional surfaces
are inclined, such as rake angle or clearance angle to the forehead
and scope of the drilling tool, is difficult.
It is an object of the invention, a possibility
for precise tool measurement especially for
Show micro tools.
This object is achieved with the measuring machine according to claim 1 and the method according to claim 19:
The measuring machine according to the invention is particularly suitable for measuring tools but also for measuring other objects, in particular objects with surfaces whose inclination is to be determined. The measuring machine has an imaging measuring head, which defines a first measuring plane. The imaging probe preferably serves to perform an XY measurement of the object. For example, object edges can be determined and measured in the recorded image by means of edge finding routines. The measuring machine also has an interferometric measuring head which defines a second measuring plane. The interferometric measuring head is used in conjunction with an evaluation device for determining the inclination of an object surface. With the interferometric measuring head, for example, it is possible to measure angles of functional surfaces of a tool, such as rake angle, clearance angle or the like.
interferometric measuring head is preferably a planar
Image capture set up. He thus allows the simultaneous
Recording Z positions of several points of the object. Becomes a
Z-scan performed, after performing the
Scans for each pixel of a selected frame,
a selected area of the object
or the entire image, a valid z-value, if
the object surface was in the scan area.
The evaluation device determines the number of such Z values
Inclination of the object surface.
interferometric measuring head is preferably as a white light interferometer
educated. It thus becomes a Z-resolution in the sub-micron range
and precise inclination determination even of small areas,
for example, only 200 microns by 200 microns
or smaller allows. Alternatively, however, can
Also interferometers are used that are not white
Light but for example with monochrome light or light at least
work two different wavelengths.
Both measuring heads are preferably structurally different from each other
separated. Neither for the design of the imaging measuring head
still for the design of the interferometric measuring head
compromises have to be made. They are in one
given spatial distance to each other,
wherein their two optical axes are preferably parallel to each other
are oriented. Likewise, their measurement levels are preferably parallel
oriented to each other. At least one of the two measuring heads,
preferably the interferometric measuring head is at an adjusting device
held the setting of a defined relative position
allowed to the other measuring head. In particular, it is advantageous
if the adjusting Justiermöglichkeiten for
the inclination of the interferometric measuring head about the X-axis and
about the Y-axis and a rotation about the Z-axis allowed. In order to
Both measuring levels can be aligned parallel to each other
become. Furthermore, the X and Y axes of the measurement planes can
of the interferometric measuring head and the imaging measuring head in parallel
aligned with each other.
For the object to be measured is an ob provided jekthalteeinrichtung which preferably defines at least one pivot axis by means of which the object surface whose inclination is to be determined, to bring in a certain orientation relative to the measuring plane.
the object to be measured is a tool such as a drill
is preferably, the object holder means a pan or
The axis of rotation, with which the object is rotatable about its central axis.
Furthermore, at least one pivot axis is preferably provided,
with which the object is rotatable about a transverse axis. Through this pivoting possibilities
can determine the object surface whose angle is to be determined in
be placed in a position where they have no angle with the
Includes trade fair level that is greater than
for example 30 °. Preferably, everyone is
included angles no larger than, for example
25 °. This applies z. B. for a lens 50 × 0.5.
This can be achieved that the area to be measured
does not leave the numerical aperture of the interferometric probe
and thus detected correctly during the measurement.
Measuring heads are preferably connected to an image evaluation device
connected. This is used to determine the X-Y measured values
the images supplied by the imaging probe. Furthermore
the image evaluation device can determine the angle using the
perform images supplied by the interferometric probe.
The evaluation device can for this purpose a separate angle determination module
contain. This module can be implemented in terms of hardware or software
be and extract the desired angles from the pictures, the
the interferometric measuring head supplies.
Determination of the angle is preferably carried out in a predetermined
Direction. The direction of the angle to be determined can be automatic
or, if desired, also be manually specifiable. To
An input device may be provided by means of which in the
Measuring plane of the interferometric measuring head to specify a line
is where the angle is measured.
interferometric measuring head delivers after performing his
Z-scans a stack of images that can be processed immediately.
It is also possible to use the image stack or parts of it
or the z-values determined from the image stacking or parts thereof
between store to the desired evaluation later
make. This way you can stack with a picture
several angles, z. B. several clearance angle at different locations
a surface are determined.
the interferometric measuring head and the imaging measuring head
physically different working optical measuring heads
combined together. White light interferometers work independently
from their optical arrangement always in reflected-light brightfield illumination.
With this lighting is on for a data logging
specular surfaces reflect the slope of the surface
limited to the numerical aperture. Because worked technical
Surfaces usually diffuse diffusely, the actual
Limit angle of the data acquisition greater than the
be numerical aperture of the lens. The numerical aperture of the
Lens is a geometric parameter,
in the case of objectives of identical dimensions, for example microscope objectives,
from the measuring distance and the opening radius of the lens
certainly. Large numerical apertures require small measuring distances. complex
shaped, in particular twisted rotation measuring objects, such as
Micro drills require a compromise between numerical aperture
and working distance. In the present embodiment
This compromise is for the measurement of micro tools by means of Mirau lenses
20 × 0.4 / 50 × 0.5 and the measuring distances
3.6 mm / 1.7 mm found. Makeware tools usually require one
much larger measuring distance, so that the mentioned
Mirau lenses a measurement in the flute of macro tools
geometrically impossible. Here can white light interferometer after
Linnik be used. These allow an enlargement
the measuring distance at the expense of the numerical aperture.
Measuring method according to the invention is advantageously suitable
for measuring chip and clearance angles on transverse and longitudinal cutting
a micro drill. Other angles, such as helix angle,
can be measured with the imaging probe.
Features and benefits are for the invention
Procedure to record. Further details emerge
the drawing, the description or claims. The description
is limited to essential aspects of the present
Invention and other circumstances. The drawing is supplementary
consulted. In the drawing is an embodiment
of the invention illustrated. Show it:
1 a measuring machine according to the invention in a fragmentary perspective view,
2 the measuring machine after 1 in another fragmentary perspective view in different size rendering,
3 the fixation of the interferometric measuring head of the measuring machine 2 in another perspective view,
4 the measuring machine after 1 (without interferometric measuring head) in a perspective overall view,
5 the object-holding device of the measuring machine after 1 in a perspective view in a first position for measuring the first clearance angle of the transverse cutting edge,
6 the object-holding device after 5 in a second position for measuring the radius-dependent rake angle of the transverse cutting edge in a perspective view,
7 the measuring heads and an evaluation device in a schematic block diagram and
8th a graphical representation illustrating a measurement process.
In 1 is a measuring machine 1 in the neckline illustrating an arm 2 for storage of two measuring heads 3 . 4 having. The arm 2 is in at least one direction, z. B. mounted adjustable in the vertical direction. For adjustment, for example, serves an engine control device, which is also referred to as "axis" or "vertical axis".
The measuring head 3 is an imaging probe having a preferably vertical optical axis 5 sets. It contains a lens, a camera and if necessary a lighting device. The illumination device may also be of the measuring head 3 be formed and arranged separately. He sets a measurement level 6 firmly, on the optical axis 5 and thus also the Z direction designated by an arrow is vertical. The X-direction and the Y-direction, however, are in the measurement plane, as in 1 indicate further arrows.
The arm 2 is from a Z-pillar 7 worn vertical from a base. The interferometric measuring head 4 is between the Z-pillar 7 and the imaging probe 3 arranged. The interferometric measuring head 4 is from an adjustment device 8th worn him with his arm 2 combines. The adjustment device 8th allowed, as indicated by arrows 9 . 10 . 11 is indicated, an adjustment of the measuring head 4 around three different perpendicular axes. The arrow 9 indicates an adjustment possibility rotating around the optical axis 12 of the measuring head 4 at. The optical axis 12 is preferably parallel to the optical axis 5 to orient. Thus, the direction Z1 coincides with the Z direction. By rotation about the optical axis 12 the directions Y1, X1 of a measuring plane agree 13 of the measuring head 4 with the directions X and Y of the measurement plane 6 match.
The 2 and 3 illustrate the adjustment 8th , The measuring head 4 is in a holder 14 rotatably mounted about the Z-axis. An extension 15 a rotatably mounted ring 16 , with the measuring head 4 is connected, engages in a recess 17 and is in this with set screws 18 . 19 adjustable.
As 3 shows is the holder 14 also by means of further adjustment screws 20 . 21 . 22 against the arm 2 curious; excited. The tension is achieved, for example, by a slotted adjusting sleeve and two spherical washers per adjusting screw 20 to 22 generated.
4 further illustrates the object storage. The object is here by a tool, for example in the form of a drill 23 illustrated. For storage of this object 24 serves z. As a cross table with two to the optical axes 5 . 12 right-angled directions. The two in the example horizontal positioning directions are in 4 symbolized by arrows. They form the basis of an object holder 25 with the object 24 is also mounted pivotably about at least one, preferably two axes. These axes are in 4 through arrows 26 . 27 symbolizes. One of the axes is concentric to the drill 23 aligned while the other ( 26 ) Radially or transversely to this and preferably horizontally and thus transversely to the optical axes 5 . 12 is oriented.
The 5 and 6 illustrate various pivotal positions of the drill 23 , In the position after 5 is the central axis 28 of the drill 23 pivoted so far upwards that the front cutting edge 29 of the drill 23 parallel to the exhibition levels 6 . 13 is oriented. In 6 is the drill 23 so swung that its rake surface 30 with the trade fair levels 6 . 13 includes only a small acute angle.
The measuring heads 3 . 4 each contain cameras connected to an image evaluation device 31 are connected as they are in 7 is indicated schematically by a dot-dashed block. It contains a module 32 for XY measurement. This module 32 may be, for example, a software program with edge finder routines and the associated hardware. The interferometric measuring head 4 is on the other hand an angle measuring module 33 connected, which serves to determine the surface tilt angles. The angle measuring module 33 can be realized by one or more software routines in conjunction with the associated hardware. To the image evaluation module is an input module 34 connected. This serves z. B. for specifying the measuring direction for determining the desired angle by the angle measuring module 33 ,
The measuring machine described so far 1 works as follows:
First, the measuring machine 1 adjusted. These are the measuring heads 3 . 4 by means of the adjusting device 8th aligned in parallel, so that the measurement levels 6 . 13 are parallel to each other. In addition, the measuring head 4 around the optical axis 12 turned so that its X1 direction coincides with the X direction of the measuring head 3 matches. The same applies to the Y1 direction.
As an object 24 to measure serves to further illustrate the drill 23 , This becomes, for example, first in the field of view of the measuring head 3 positioned. For example, its cutting edge 29 Be measured, the drill becomes 23 in the position after 5 pivoted. The measuring head 3 is now adjusted in the Z direction until the measuring level 6 exactly on the cutting edge 29 lies. The XY measurement can now be performed by image acquisition and edge finding and edge measurement.
Below is the inclination of the cutting edge 29 subsequent open space 35 Be measured, the drill becomes 23 without pivoting in the field of view of the measuring head 4 linear procedure. His exhibition level 13 is at the same height as the exhibition level 6 , The interferometric measuring head 4 Now perform a Z-scan by looking at the measurement plane 13 in several stages in the direction of the optical axis 12 adjusted. This is the open space 35 scanned. 8th illustrates the process. In each step of the scan, an interferometric image of the free space is taken. Only those parts of the open space that are right down to the smallest fractions of a micrometer in the measurement plane 13 lie, provide a valid Z-measure for each pixel. Thus, a height profile can be extracted from the image stack obtained in the Z-scan 8th through contour lines 36 are indicated. These serve only to illustrate the measuring process. They do not coincide with the individual Z steps of the measuring head 4 together and are not necessarily visible in the picture.
Via the input module 34 becomes a line 37 predetermined, on which the searched angle, in the present example a clearance angle, is to be determined. The line 37 can be specified by entering two or more points or removed from a library containing typical tool shapes and their form elements, such as cutting edges and functional surfaces, such as rake surfaces and / or open spaces and the like. Along the line 37 Now the existing z-values are extracted from the image stack. These Z values obtained with great accuracy can be approximated by a straight line, the angle of which to the reference plane is ne 13 determined and as an angle value at an output of the image evaluation module 31 is issued.
6 illustrates the measurement process using the example of measuring a rake face. After the rake angle at the drill 23 is relatively large, the drill, for example, as in 6 shown, inclined so that the rake face 30 with the trade fair level 13 an angle smaller than 30 °. After carrying out the Z-scan, the Z-values of the rake face are extractable from the image stack and the radius-dependent rake angles can be extracted therefrom, ie both the axial rake angle and the radial rake angle as well as the effective rake angle. The Axialspanwinkel lies in an imaginary axially oriented plane, the Radialspanwinkel in a radially oriented plane and the effective rake angle in a plane perpendicular to the cutting edge plane.
According to the invention
for the measurement of complex 3D objects, such as
Micro drills, an areal measuring X-Y measuring system
with a high-resolution Z-scanning white light interferometer
combined. The imaging measuring system is used as a monitor system for
used the white light interferometer. It will be a planar Z-height scan
of the white light interferometer without mechanical movement
the axes of the coordinate measuring machine performed.
The X, Y, Z readings are better with a resolution
as a micrometer in the X and Y directions and with a resolution
much better than a micrometer in the Z direction. To the spatial
Angle measurement will only be the Z height readings
used by the white light interferometer.
- measuring machine
Axis of the imaging probe
- measuring plane
of the imaging probe
- z column
- adjusting screws
- adjusting screws
- Object holder
- central axis
- End cutting edge
- clamping surface
- Angle measuring module
- input module
- open space
- contour lines
QUOTES INCLUDE IN THE DESCRIPTION
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Cited patent literature