DK172962B1 - Perforated plate for calibration of optical/mechanical co- ordinate measuring machines - Google Patents

Description

DK 172962 B1 7 *

CALIBRATION CALENDAR

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OPTICAL / MECHANICAL COORDINATE PAINTING MACHINES

The invention relates to a hole plate for verification of coordinate measuring machines using both optical and mechanical impact and which can be calibrated by a so-called wrapping method.

Plate normals are two-dimensional calibration objects upon which are placed a plurality of elements in a particular pattern, usually square or rectangular. In known plate norms for the verification and calibration of mechanical coordinate measuring machines, the elements are typically spheres, ball bushings or cylindrical bores. The elements have a typical diameter of 20-25 mm and the cylindrical bores a height of approx. 30 mm (example of patents 15 DE19507805 and DE 4036181). For the verification and calibration of optical coordinate measuring machines, plate norms have been proposed, the elements being made up of chrome structures on glass (VDI / VDE 2617, Blatt 5, 1994). These elements only allow optical measurement, which means that for combined optical-mechanical coordinate measuring machines one must have several different kinds of 20 norms. Furthermore, the optical plate norms cannot be calibrated by the same method as ball, ball sleeve and hole plates for mechanical coordinate measuring machines. The wrapping method involves four cover measurements where the elements are measured from both sides of the plate and this is not possible using chrome structures on glass. The actual wrapping calibration principle is described in patent DE 4006835.

The invention provides a hole plate which can be used for verification and calibration of both optical and mechanical coordinate measuring machines, and which can simultaneously be calibrated by the cover method described. This is achieved according to the invention by using an element which is characterized by being a thin disc containing a circular hole with small mold defects and low roughness, the edges of which appear sharp without burrs. In addition, the element has a sufficient hardness which makes it suitable for impact with a measuring key on a coordinate measuring machine.

By using the element in a hollow plate, the thickness of the disc (about 0.1 mm) ensures that the element can be measured from both sides with the same center coordinates as 10 results. This ensures that the hole plate can be calibrated according to the wrapping method.

The edge of the hole is made without burrs, ensuring that the hole appears the same from both sides of the element. The roundness of the hole is crucial for the reproducibility of the center coordinates of the subject. In addition, a uniform surface on both sides of the element ensures that an optical measurement can take place under optimal conditions.

In a particular clamping form, the element is clamped vertically and horizontally in the hole plate by means of a nut. This ensures that the element is clamped and that mechanical impact can be made.

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The invention is explained in more detail below with reference to the drawings, wherein

Figure 1 shows a sketch of the overall hole plate 25

Figure 2 shows a sketch of the element itself (the disc)

Figure 3 shows a sketch of an element clamped in a plate

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Claims (2)

10 PATENT REQUIREMENTS 1. Hollow plate (Fig. 1) for verification of coordinate measuring machines using both optical and mechanical impact and which can be calibrated by a so-called wrapping method characterized in that the elements for impact (Fig. 2) are ~ 15 formed as thin slices of sufficient hardness, wherein a circular hole having a small mold defect and having sharp, free-edge edges is formed, and further having a surface in the area immediately around the hole of such a condition that the element is suitable for impact with an optical probe based on edge detection. 20 Hollow plate (Fig. 1) according to claim 1, characterized in that the elements (Fig. 3a) are clamped against a ground surface (Fig. 3b) in the hollow plate by means of a nylon disc (Fig. 3c) and a nut (Fig. 3d). . in E =