DE102005037160A1 - Geometrical precision part e.g. optical ferrule, touching method, involves touching precision part with tactile structure, and optically measuring movement of body caused by measuring force at one position of body using interferometer - Google Patents

Abstract

The method involves touching a precision part with a tactile structure. A tracer (3) is connected with a reflecting body (1) having a reflecting surface. The reflecting body is flexibly connected with a fixed point by a spring joint. The movement of the body caused by measuring force is optically measured at one position of the body, where the movement of the body is measured by an interferometer (6). An independent claim is also included for device for tactile touching of a geometric precision part.

Description

The The invention relates to a method and a device for tactile Probing, in particular for probing geometrical precision parts.

The Invention is particularly suitable for probing geometric Precision parts, such as optical ferrules, precision mechanical parts, nozzles, micropumps and the like, in particular for Applications with adjustable and constant measuring force in connection with 3D precision coordinate measuring machines.

in the State of the art are various arrangements for tactile probing known by geometric parts.

In the pamphlets "Annals of the CIRP Vol. 50/1/2001, pp. 361-364 and WO 98/57121 are arrangements described for scanning in a coordinate measuring machine, in which at End of an optical fiber mounted a spherical probe element is that is illuminated by the fiber. The glowing ball will mapped to CCD sensors. This can be the contact of the probe element with the material surface be registered. The disadvantage is that the measuring forces are very high small and not adjustable, so that the sensor stick to the object can. Furthermore Anticipatory uncertainties in the nanometer range are not possible. Further is a return on national standards, what for Metrological precision measurements is required, not possible.

In tm 5/2003, pp. 238-243 a piezoresistive micro-probe is described in the piezoresistive resistors a silicon diaphragm interconnected to bridges are. The membrane is equipped with a stylus for probing the objects connected. Even with this solution reproducibility in the nanometer range is not achievable, there the Piezowider stood adversely affect the mechanical properties of the silicon membrane. Also no return occurs national standards.

in the Bulletin No. 1631 Mitutoyo is called a touch probe UMAP Vision System offered. The button, which is in a piezoelectric Element is held vibrates with resonant frequency. With workpiece contact the vibration is damped. The measuring force is not adjustable and not returned.

Of the Invention is based on the object, a method and an apparatus specify the type mentioned, the probing with high precision and adjustable measuring force allows.

According to the invention succeeds the solution the object with a method that specified in claim 1 Features and having a device which the in claim 7 features specified.

advantageous Embodiments are specified in the subclaims.

The Invention is characterized by a number of advantages.

The Probing of precision objects is possible with uncertainties in the nanometer range. The measurement of the force-dependent displacement A plate is made with the help of interferometers, which resolutions of 0.1 nm and less. So this measurement is national Normal returned and can be used as the basis for highest metrological precision serve. The deflection of the stylus is force proportional and is measured interferometrically with high precision and evaluated. By the different deflection of the stylus is the measuring force precise adjustable.

The unambiguous determination of three measuring force components F _x , F _y and F _z can be effected from three interferometer signals or from an interferometer signal and additional detection of two tilting movements by means of an autocollimator. So-called creep of the resilient elements and the stylus can be eliminated, that the Interferometeraus output signals y _a , y _b , y _c after a defined time, from the time of the first touch of the probe ball with the measurement object, queried.

The Invention will be explained in more detail below with reference to exemplary embodiments. In the accompanying drawings demonstrate:

1 a schematic representation of the tactile probing invention with ring spring and interferometer,

1.1 an embodiment according to 1 with meandering spring elements,

2 an embodiment for the interferometric measurement of the probe movement,

3 an arrangement with interferometer and autocollimator,

4 an arrangement for interferometric measurement of a spatially oriented probing force with parallel spring guidance for three translational components

5 an arrangement with a rotationally symmetrical solid-body joint,

6 a spring joint arrangement for two tilting movement components,

7 a spring joint arrangement for a translatory movement with one degree of freedom,

8th a crossed-type spring-joint arrangement for translational movement with one degree of freedom,

9 a crossed-type spring-joint arrangement for translational movement with one degree of freedom in two parallel planes,

10 a version with cylindrical spring joint arrangement for translational and rotational movements and

11 a version with cylindrical spring joint arrangement for translational movements.

At the in 1 schematically shown arrangement is a rigid reflective body 1 by means of resilient elements 7 with a fixed point 2 connected. At the bottom of the body 1 is a stylus in the middle 3 with a probe ball 4 arranged. Depending on the force components F _x , F _y and F _z with which the probe ball 4 on the test object 8th The body tilts 1 and / or is moved in parallel. The movement of the body 1 is done by means of three interferometers 6 measured with the interferometer beams a, b, c. The interferometer output signals y _a , y _b , y _c , are an unambiguous measure of the force components F _x , F _y , F _z . The force components are as follows: F x = k x (y b - y a ) F y = k y (y a - y c ) F z = k a · y a + k b · y b + k c · y c ,

Here, k _a, k _b, k _c, k _x, k _y calibration factors. Because with the interferometers 6 the movement of the body 1 with values of 0.1 nm and less can be reproduced, resulting in the probe ball 4 Reproducibility of only a few nanometers.

In the 1.1 illustrated embodiment corresponds to the formation of the resilient elements 7 according to the arrangement 1 , The resilient elements are designed for the purpose of a lower bending stiffness shaped.

2 shows a cylindrical design for interferometric measurement of the movement of the body 1 , At the festival point 2 are the interferometers 6 and a Kraftantastelement consisting of the rigid body 1 , resilient elements 7 , a stylus 3 a Tastkugel arranged thereon 4 , attached.

In 3 an arrangement with an interferometer and an autocollimator is shown. The tilting of the body 1 Here are using a high-resolution photo electric autocollimator 10 measured. The autocollimator 10 consists of the lens 10.1 and the deflecting mirror 10.2 where both have a central bore and the splitter cube 10.3 , the light source 10.4 and the position sensitive photodetector 10.5 , The tilting of the body 1 are a measure of the force components F _x and F _y . The force component F _z is determined by means of the interferometer 6 , whose measuring beam 9 in the middle of the body 1 hits, measured.

4 illustrates an arrangement for the interferometric measurement of a spatially-oriented probe force F (F _x , F _y , F _z ) in three translational components (x, y, z). The figure shows a parallel spring guide 11 that with a benchmark 2 is connected and out of the three leadership components 11.1 in X direction, 11.2 in the y direction and 11.3 is composed in z-direction. At the management component 11.3 is an end of a stylus 3 with a feeler element 4 attached and at the other end of the stylus 3 is a rigid reflective body 1 appropriate. The body 1 is here in the form of a measuring cube with three reflective surfaces ( 5.1 . 5.2 . 5.3 ). Furthermore, it is at the fixed point 2 an interferometer 6 appropriate. The interferometer 6 has the component 6.1 for measuring the translation in the x-direction, the component 6.2 for measuring the translation in the y-direction and the component 6.3 for measuring the translation in the z-direction. For this purpose, the interferometer beams a, b, c scan three reflecting surfaces 5.3 . 5.1 and 5.2 of the measuring cube.

For example, with the probe element 4 a measurement object 8th Touched in the x direction, then the probe element 4 , the stylus 3 and the measurement cube 1 due to the resilient properties of the parallel spring guide 11.1 offset parallel in the x-direction. This parallel offset is done with the interferometer 6.1 measured. In an analogous manner, a parallel offset of the parallel spring guides 11.2 and 11.3 detected when the probe ball in the y and z direction is touched. When probing the probe ball 4 with a spatially oriented probing force F (F _x , F _y , F _z ) all three parallel spring guides 11.1 . 11.2 and 11.3 depending on the force components F _x , F _y and F _z deflected.

An embodiment for measuring forces F with two force components F _x and F _y is in 5 shown. The from an interferometer 6 emitted interferometer beams a, b and c meet a rigid reflective body 1 that with a functional body 12 is connected. The cross section of the functional body 12 tapers to a plane E to a smallest and preferably circular cross-section D _min . This cross-section D _min forms a rotationally symmetrical one-body joint 7.1 , On the body 1 opposite end is the functional body ( 12 ) with a fixed point ( 2 ) connected. The functional body 12 is also by means of a connector 18 with a stylus 3 connected, at the end of which the feeler element 4 located. Acts on the probe element 4 a force F with the force components F _x , F _y in any direction of action, then the probe element 4 and thus also the bending-resistant, reflective body 1 in the direction of a resultant measuring force F deflected.

6 shows a further embodiment possibility for an arrangement for measuring forces F with the force components F _x and F _y . The from an interferometer 6 emitted interferometer beams a, b, c meet a rigid body reflective 1 that with a functional body 12 is connected. The cross section of the functional body 12 tapers in two mutually parallel planes E ₁ , E ₂ to a smallest and preferably rectangular cross-section with a smallest web width S _min . Each of these cross sections forms a spring joint 7.2 and 7.3 with defined axis of rotation. The axes of rotation of the swivel joints 7.2 and 7.3 are preferably arranged in angularly offset directions at 90 °. On the body 1 opposite end is the functional body 12 with a fixed point 2 connected. Furthermore, that is with the body 1 connected end of the functional body 12 with a stylus 3 and arranged thereon probe element 4 connected. Acts on the probe element 4 a force F with the force components F _x and F _y in any direction of action, then the spring joints 7.2 and 7.3 deflected in the ratio of the force components.

In the 7 shown symmetrical design of a joint group consists of a succession of spring joints. It is with respect to a symmetry line 13 built mirror-symmetrically and on both sides with a fixed point 2 connected. From the benchmark 2 starting are a first spring joint 7.2 , a second spring joint 7.3 and a third spring joint 7.4 arranged. The spring joints 7.2 and 7.3 are arranged on an imaginary construction line K, with respect to the symmetry line 13 preferably oriented vertically. The spring joint 7.4 is offset with respect to the construction line K above or below. By this up or down parallel offset arrangement of the spring joint 7.4 creates a lever that a positive-free and preferably translational movement of the joint group in the direction of symmetry line 13 allows. The conclusion of the joint group forms the middle piece 15 through whose middle the symmetry line 13 runs. Beyond the line of symmetry 14 the arrangement is continued by the spiegelsym merische arrangement of the spring joints 7.4 ' . 7.3 ' . 7.2 ' to the fixed point 2 ' , The arrangement is suitable for measuring forces in the z-direction.

8th shows an arrangement in which the in 7 explained joint group was used in a crossed version. The articulated group described there is arranged a second time at an angle α, preferably at an angle of 90 ° to the first joint group. At the location of the symmetry line 13 is the stylus 3 with the probe element 4 arranged. The crossed translational joint group is deflected exclusively by forces in the z-direction.

At the in 9 illustrated embodiment is in 8th described joint group arranged in a plane parallel to the first plane E ₁ second plane E ₂ again. The connection between the planes E ₁ and E ₂ forms the middle piece 15 , This joint group is deflected only by forces in the z direction.

The execution after 10 relates to an arrangement for 3D force measurement. The interferometer beams a, b and c of the interferometer 6 meet on the reflective rigid body 1 that with the functional body 12 is firmly connected. The cross section of the functional body 12 tapers at one point and forms the rotationally symmetrical spring joint 7.1 , The spring joint 7.1 connects the functional body 12 with the joint group 7.2 . 7.3 . 7.4 in crossed execution. Above the rotary spring joint 7.1 are at the functional body 12 Support 16 fixed, which pass through holes, which in the middle of the joint group 7.2 . 7.3 . 7.4 are attached. The pillars 16 are below the joint group with a plate 17 connected. Below the plate 17 is at this the stylus 3 with the probe element 4 attached. With this arrangement spatially directed probing forces F (F _x , F _y , F _z ) can be determined interferometrically.

A further embodiment for the interferometric measurement of spatially directed contact forces F (F _x, F _y, F _z) is in 1 shown. The interferometer beams a, b and c of the interferometer 6 meet on the reflective rigid body 1 that with the functional body 12 is firmly connected. At the function body 12 are the spring joints 7.2 and 7.3 , as well as the spring joints 7.4 . 7.5 and 7.6 in crossed execution. At the body 1 opposite side of the functional body 12 this is with the stylus 3 and with the probe element 4 connected.

1

bending Stiff reflective body, measuring dice

2

benchmark

3

feeler

4

scanning element

5

reflective area (Interferometerplatte)

5.1

reflective area (Measurement cube (X))

5.2

reflective area (Measurement cube (Y))

5.3

reflective area (Measurement cube (Z))

6

interferometer

6.1

interferometer (X) direction

6.2

interferometer (Y) direction

6.3

interferometer (Z) direction

7

spring joint

7.1

rotationally symmetric spring joint

7.2

spring joint

7.3

spring joint

7.4

spring joint

7.5

spring joint

7.6

spring joint

8th

measurement object

9

Interferometermessstrahl

10

autocollimator

10.1

lens

10.2

deflecting

10.3

subcube

10.4

light source

10.5

PSD

11

Parallelfederrührung

11.1

Parallel spring stir (x) direction

11.2

Parallel spring stir (y) direction

11.3

Parallel spring stir (z) direction

12

function body

13

line of symmetry

14

contact plate

15

centerpiece

16

support

17

plate

18

joint

a, b, c

interferometer

F

measuring force

F _x, F _y, F _z

components the measuring force

k _a , k _b , k _c , k _x , k _y

calibration

y _a , y _b , y _c

Interferometerausgangssignale

K

construction line

α

angle between two simple translational joint groups

Claims (13)

Method for tactile probing of a part, in particular for probing geometrical precision parts, characterized in that the part is provided with a feeler element ( 4 ) is touched, wherein the probe element ( 4 ) on a stylus ( 3 ) arranged with a rigid, reflective body ( 1 ) with at least one reflective surface ( 5 ), and the reflective body ( 1 ) by means of at least one spring joint ( 7 ) with a fixed point ( 2 ) and wherein the movement of the body caused by the measuring force ( 1 ) in at least one location of the body ( 1 ) is measured optically. Method according to claim 1, characterized in that the movement of the body ( 1 ) by means of at least one interferometer ( 6 ) is measured. Method according to claim 1 or 2, characterized in that the movement of the body ( 1 ) in three places of the body ( 1 ) by means of three interferometers ( 6 ) is measured. Method according to one of claims 1 to 3, characterized in that three measuring force components F _x , F _y and F _z by means of three interferometer beams (a, b, c), which are evaluated photoelectrically and interferometer output signals y _a , y _b and y _c form, be determined. Method according to claim 1, characterized in that tilting of the body ( 1 ) and with the help of an autocollimator ( 10 ) Are determined and therefrom two measuring force components (F _x, F _y) are determined, and a third force component (F _z) is detected by interferometry. Method according to one of claims 1 to 5, characterized in that the output signals y _a , y _b , y _c , after a defined time from the time of the first touch of the probe element 4 with the measurement object 8th to be queried. Device for tactile probing of a part, in particular for carrying out the method according to one of claims 1 to 6, characterized in that a probe element ( 4 ) on a stylus ( 3 ) arranged on at least one reflective surface ( 5 ) having rigid Kör by ( 1 ), whereby the body ( 1 ) by means of at least one spring joint ( 7 ) with a fixed point ( 2 ) and with the fixed point ( 2 ) at least one interferometer ( 6 ), with which the movement of the rigid reflective body are detected. Device according to claim 7, characterized in that an autocollimator ( 10 ) and an interferometer ( 6 ) with respect to the body ( 1 ) are arranged so that an interferometer measuring beam ( 9 ) in the optical axis of the autocollimator ( 10 ) and on the middle of the surface of the body ( 1 ). Device according to claim 7, characterized in that the body ( 1 ) three reflective surfaces ( 5.1 . 5.2 . 5.3 ) and the stylus ( 3 ) with the probe element ( 4 ) on a parallel spring guide ( 11 ) with three guides ( 11.1 . 11.2 . 11.3 ) and three interferometer beams (a, b, c) of three interferometers ( 6.1 . 6.2 . 6.3 ) on the three reflective surfaces ( 5.1 . 5.2 . 5.3 ) of the body ( 1 ) are directed. Device according to claim 7, characterized in that the rigid body ( 1 ) with a spring joint ( 7 ) formed functional body ( 12 ) is firmly connected to which the stylus ( 3 ) is arranged. Apparatus according to claim 10, characterized in that the functional body ( 12 ) as a rotationally symmetrical spring joint ( 7.1 ) is trained. Apparatus according to claim 10, characterized in that the functional body ( 12 ) two orthogonal spring joints ( 7.2 . 7.3 ) having. Apparatus according to claim 10, characterized in that the functional body ( 12 ) a middle piece ( 15 ), on which the stylus ( 3 ) and which is connected via a spring joint arrangement with the fixed point ( 2 ), wherein the spring joint assembly consists of at least two connecting elements, which three series spring joints ( 7.2 . 7.3 . 7.4 ) whose axes of rotation parallel and perpendicular to the line of symmetry of the center piece ( 15 ), wherein two spring joints ( 7.2 . 7.3 ) relative to the third spring joint ( 7.4 ) are arranged offset in parallel.