Method for operating a surface measurement apparatus

Abstract

A method for operating a surface measuring apparatus for measuring a surface of a workpiece. Method includes operating surface measuring apparatus having a probe that includes a probe arm that is deflectable by an angle about a swivel axis, and that on its end facing away from the swivel axis bears a probe element. Probe is movable relative to a base body of surface measuring apparatus along a linear axis. In method, a workpiece is contacted by moving the probe along the linear axis by use of the probe element, and after workpiece is contacted, probe arm is moved by a specified travel distance along the linear axis. The resulting angular deflection of the probe arm about the swivel axis is measured, and based on the specified travel distance and measured angular deflection of the probe arm, the probe arm is classified with regard to its length.

Claims

1. A method for operating a surface measuring apparatus for measuring a surface of a workpiece, the method comprising: a) the surface measuring apparatus is provided, the surface measuring apparatus having a probe that includes a probe arm that is deflectable by an angle about a swivel axis, and that on its end facing away from the swivel axis bears a probe element, the probe being movable relative to a base body of the surface measuring apparatus along a linear axis; b) a workpiece is contacted by moving the probe along the linear axis by means of the probe element; c) after the workpiece is contacted, the probe arm is moved by a specified travel distance along the linear axis; d) the resulting angular deflection of the probe arm about the swivel axis is measured; and e) based on the specified travel distance and the measured angular deflection of the probe arm, the probe arm is classified with regard to its length.

2. The method according to claim 1, wherein: a) the length of the probe arm is calculated from the specified travel distance and the measured resulting angular deflection of the probe arm; and b) the classification of the probe arm is made by comparing the calculated length of the probe arm to the lengths of predefined probe arms.

3. The method according to claim 1, wherein: a) a measuring range of the surface measuring apparatus is automatically adjusted according to the classification of the probe arm with regard to its length.

4. The method according to claim 1, wherein: a) the surface measuring apparatus is a roughness measurement apparatus, a contour measurement apparatus, or a shape measurement apparatus.

5. The method according to claim 1, wherein: a) the linear axis is a vertical or horizontal axis.

6. The method according to claim 1, wherein: a) the linear axis is defined by a measuring column of the surface measuring apparatus.

7. The method according to claim 1, wherein: a) the probe is a tactile probe.

8. The method according to claim 1, wherein: a) the probe is connected to the base body of the surface measuring apparatus by a feed apparatus, and the feed apparatus defines a linear feed axis, wherein an inclination of the linear feed axis relative to the horizontal is determined and is included in the classification of the probe arm with regard to its length.

9. The method according to claim 1, wherein: a) a distance measuring system is associated with the linear axis.

10. A surface measuring apparatus for measuring a surface of a workpiece during a measuring operation, comprising: a) a base body; b) a probe that includes a probe arm that is deflectable by an angle about a swivel axis, and that on its end facing away from the swivel axis bears a probe element for sampling the surface of the workpiece, the probe being movable relative to the base body along a linear axis; c) an evaluation apparatus that is designed and programmed in such a way that angular deflections of the probe arm while sampling the surface of the workpiece are converted into measured values that represent the shape of the surface of the workpiece; d) a control apparatus for controlling the measuring operation; e) the control apparatus is designed and programmed in such a way that a workpiece is contacted by moving the probe along the linear axis by the probe element; f) after the workpiece is contacted, the probe together with the probe arm is moved by a specified travel distance along the linear axis; g) the resulting angular deflection of the probe arm about the swivel axis is measured; and h) based on the specified travel distance and the measured angular deflection of the probe arm, the probe arm is classified with regard to its length.

11. The surface measuring apparatus according to claim 10, wherein: a) the evaluation apparatus is designed and programmed in such a way the length of the probe arm is calculated from the specified travel distance and the measured resulting angular deflection of the probe arm; and b) the classification of the probe arm is made by comparing the calculated length of the probe arm to the lengths of predefined probe arms.

12. The surface measuring apparatus according to claim 10, wherein: a) the control apparatus is designed and programmed in such a way that a measuring range of the surface measuring apparatus is automatically adjusted according to the classification of the probe arm with regard to its length.

13. The surface measuring apparatus according to claim 10, wherein: a) the surface measuring apparatus is a roughness measurement apparatus, a contour measurement apparatus, or a shape measurement apparatus.

14. The surface measuring apparatus according to claim 10, wherein: a) the linear axis is a vertical or horizontal axis.

15. The surface measuring apparatus according to claim 10, wherein: a) the linear axis is defined by a measuring column of the surface measuring apparatus.

16. The surface measuring apparatus according to claim 10, wherein: a) the probe is a tactile probe.

17. The surface measuring apparatus according to claim 10, wherein: a) the probe is connected to the base body of the surface measuring apparatus by means of a feed apparatus, and the feed apparatus defines a linear feed axis, wherein an inclination of the linear feed axis relative to the horizontal is determined and is included in the classification of the probe arm with regard to its length.

18. The surface measuring apparatus according to claim 10, wherein: a) the surface measuring apparatus has a distance measuring system that is associated with the linear axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings show the following:

(2) FIG. 1 shows a perspective view of one embodiment of a surface measuring apparatus according to the invention for carrying out one embodiment of a method according to the invention; and

(3) FIGS. 2A and 2B show a schematic diagram for explaining the basic principle of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 illustrates a measuring station with one embodiment of a surface measuring apparatus 2 according to the invention in the form of a roughness measurement apparatus, having a probe 3 (measuring probe) with a probe arm 4 that bears a probe element, not discernible in FIG. 1, for contacting a surface of a workpiece to be measured. The surface measuring apparatus 2 has a feed apparatus 6 whose stationary base body 8 is situated in a height- and inclination-adjustable manner on a measuring column 10, which is mounted on a base plate 12 (base body). The probe arm 4 is exchangeably connected to a carriage 16 of the feed apparatus 6 via a mechanical interface 14.

(5) During operation of the surface measuring apparatus 2, the carriage 16 of the feed apparatus 6 moves relative to the base body 8 along a linear feed axis, so that a workpiece to be measured may be sampled by means of the probe element mounted on the probe arm 4. The basic design of such a surface measuring apparatus, including a probe and a feed apparatus, is generally known to those skilled in the art, and therefore is not explained in greater detail.

(6) During sampling of the workpiece, the probe 3 outputs probe raw data that represent the surface shape of the workpiece. The probe raw data are evaluated in an evaluation apparatus 18 that is in, or may be brought into, data transmission connection with the probe 3. The evaluation apparatus 18 is illustrated in FIG. 1 in a strictly symbolic manner, and the data transmission connection between the probe 3 and the evaluation apparatus 18 is symbolized by a dashed line 20.

(7) The evaluation apparatus 18 is designed and programmed in such a way that angular deflections of the probe arm during the sampling of the surface of the workpiece are converted into measured values that represent the shape of the surface of the workpiece.

(8) A control apparatus 22 is provided for controlling the measuring operation.

(9) The probe arm 4 is supported on the probe 3 so as to be deflectable by an angle about a swivel axis 24 (see FIG. 2A), and on its end facing away from the swivel axis bears a probe element 26, for example in the form of a probe tip, for sampling the surface of the workpiece, the probe being movable relative to the measuring column along a linear axis, symbolized by a dash-dotted line 28 in FIG. 1. In the illustrated embodiment, the linear axis 28 is the z axis.

(10) The probe arm 4 is exchangeable for adapting to different measuring tasks; the probe arms have different lengths, and a measuring range of the surface measuring apparatus 2 is associated with each probe arm length.

(11) According to the invention, after a probe arm 4 is changed, the associated measuring range of the surface measuring apparatus 2 is automatically adjusted by means of a method according to the invention for operating the surface measuring apparatus 2.

(12) For this purpose, in the illustrated embodiment the control apparatus 22 is designed and programmed in such a way that a) a workpiece is contacted by moving the probe 3 along the linear axis 28 by means of the probe element, b) after the workpiece is contacted, the probe arm 4 is moved by a specified travel distance along the linear axis 28, c) the resulting angular deflection of the probe arm 4 about the swivel axis is measured, d) based on the specified travel distance and the measured angular deflection of the probe arm 4, the probe arm 4 is classified with regard to its length, and e) a measuring range of the surface measuring apparatus 2 is automatically adjusted according to the classification of the probe arm 4 with regard to its length.

(13) One embodiment of the method according to the invention takes place as follows:

(14) FIG. 2A and FIG. 2B show a schematic diagram for explaining the basic principle of the method according to the invention. In FIG. 2B, for purposes of illustration, a probe arm 4′ is depicted whose length is twice the length of a probe arm 4 according to FIG. 2A.

(15) FIGS. 2A and 2B illustrate a probe element 30 that bears the probe arm 4 or 4′ on its end facing away from the swivel axis 24.

(16) A workpiece to be measured is symbolically illustrated in FIGS. 4A and 4B and is denoted by reference numeral 32.

(17) For carrying out a measuring operation in which the surface of the workpiece 32 is measured, the workpiece 32 is initially contacted by moving the probe 3 along the linear axis 28 (step a) of the method according to the invention). FIG. 2A illustrates by way of example that the probe element 30 rests against the surface of the workpiece 32, and the probe arm 4 is situated approximately horizontally.

(18) After the workpiece 32 is thus contacted, the probe 3 together with the probe arm 4 is moved along the linear axis 28 (z axis) by a specified travel distance z1, and in particular in the illustrated embodiment in FIG. 2A, upwardly (step b) of the method according to the invention).

(19) The probe element 30 remains in contact with the surface of the workpiece 32, so that the angular deflection of the probe arm 4 about the swivel axis 24 changes. This change in the angular deflection (angle α1 in FIG. 2A) is measured, and recorded by the evaluation apparatus 18 (step c) of the method according to the invention).

(20) In the configuration illustrated in FIG. 2B with a probe arm 4′ having twice the length, moving the probe 3 together with the probe arm 4 by the same linear travel distance z1 results in a smaller angular deflection of the probe arm 4 (angle α2 in FIG. 2B).

(21) Thus, since for a specified travel distance along the linear axis 28, the resulting angular deflection of the probe arm 4 or 4′ is a direct function of the length of the probe arm 4 or 4′, the length of the probe arm 4 or 4′ may be deduced directly from the measured angular deflection.

(22) In step d), the probe arm 4 or 4′ may thus be classified with regard to its length, based on the specified travel distance and the measured angular deflection of the probe arm 4 or 4′.

(23) In the illustrated embodiment, the evaluation apparatus is designed and programmed in such a way that in step d) d1) the length of the probe arm is calculated from the specified travel distance and the measured resulting angular deflection of the probe arm; and d2) the classification of the probe arm is made by comparing the calculated length of the probe arm to the lengths of predefined probe arms.

(24) After the probe arm 4 or 4′ has been classified by calculating its length and comparing the calculated length to the lengths of predefined probe arms, and has been identified by recognizing its length, the measuring range of the surface measuring apparatus 2 may be correspondingly automatically adjusted.

(25) The invention thus allows, in a particularly simple manner and without additional hardware, automatic recognition of probe arms of different lengths and a corresponding automatic adjustment of the associated measuring range of the surface measuring apparatus 2. Measuring errors resulting from an adjustment of the associated measuring range of the surface measuring apparatus that is not made, or is made incorrectly, after a change of the probe arm are thus reliably avoided.

(26) While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention.