JPH0472164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high precision, automatic master alignment method and apparatus for comparative measurement when successively measuring a large number of objects having the same design dimensions. For example, in comparative measurements using an electric micrometer method using a differential transformer or an air micrometer method using pneumatic pressure, so-called master alignment is performed in which the zero point and magnification of the measuring device are adjusted using large and small ranges of reference dimensions. When it is necessary to start a measurement and to improve the reliability of the measurement, it is necessary to correct errors in the measurement value caused by changes in the state of the measurement device, such as zero point drift and changes in magnification. , it is necessary to frequently repeat the master matching operation. To do this, conventionally, a large number of main and small master pieces were manufactured accurately according to the design dimensions, the values were memorized as master values, and master matching was performed manually or automatically using this. was. Therefore, it was necessary to prepare, store, and manage a large number of master pieces made with high precision for one design dimension, which was expensive and required trouble to handle. Furthermore, since the master alignment is performed with the measuring machine in operation temporarily stopped, there was a question as to whether or not the correction was performed in accordance with the necessary correction while the measuring machine was in operation. In other words, the master alignment included dimensional errors due to the master shape and repetition errors inherent in the machine.

The present invention improves this point and makes correction by performing master alignment under exactly the same conditions as the operating conditions of the measuring machine, without requiring the design and manufacture of a master piece.

In the present invention, a large number of processed finished products (hereinafter referred to as workpieces) are used as master pieces. First, from among them, we randomly select multiple items that are close to the dimensions of the large master as a large group, and those that are close to the dimensions of the small master as a small group, and measure each of them with a reliable measuring machine. Prepare multiple units as a general group and multiple units as a small group, and store them in series. For example, when measuring the diameter, let the upper limit dimension P + α and the lower limit dimension P - α for the approximately central design dimension P,
A plurality of values close to P+α are defined as a large range group, and a plurality of values close to P−α are defined as a small range group. Let D ₁ and D ₂ be the average values of the large group, for example, 10 items selected in this way, and the 10 items of the small group. Then, the workpieces of the large and small groups that are stored in series are continuously fed into the continuous dimension measuring device that is actually in operation, and each of the 10 workpieces is measured separately for the large and small groups. Calculate the average of the 10 measured values to create D ₁ ′ and D ₂ ′. Next, the large and small range average values D ₁ , D ₂ and D ₁ ′ of the standards set as above,
A comparison is made with D ₂ ′, and the measurement circuit system of the measurement device is corrected based on the calculation results of (D ₁ ′−D ₁ ) and (D ₂ ′−D ₂ ).

Figures 1 and 2 show an example of a specific device for carrying out the above method using a sorting device. The work pieces are stacked vertically and supplied to 12 comb bars located within the circumference of the comb bar, and are sequentially rotated by a control unit (not shown) to measure the workpieces being fed to the comb bars one by one. Large and small master pieces are connected and supplied to any of the comb rods, and master matching can be performed at any time according to instructions from the control unit.
In the figure, the master pieces of the large and small groups selected as described above are housed in series E for each large and small group. It should be noted that the distinction between large and small ranges is made by a control unit (not shown) by counting. B is a workpiece takeout/delivery device that takes out workpieces one by one from the supply section and transfers them to the measurement section C, and transfers the workpieces for which measurement has been completed to the classification and sorting section D. The sorting section accommodates workpieces to be sorted according to the measured values at predetermined sorting positions. In such a configuration, when master matching is required, the storage section E for the large and small groups, which are accommodated in series at any time during operation, is positioned in the take-out section, and the large and small groups are sequentially stored.
Send each small group to the measurement department. Then, while performing normal measurements, the large/small range judgment circuit, average value calculation circuit, and comparison correction circuit built into the control section (not shown) are activated. On the other hand, in the sorting section D, there is a position F where only the large and small groups are received and accommodated.
and set it at the receiving position during that time,
Receive only large and small group workpieces. Then, when the large and small ranges pass through the measuring section (D ₁ '-D ₁ ) and the correction is completed by (D ₂ '-D ₂ ), normal measurement and sorting operations are continued. The large and small group workpieces stored in F are transferred to E in the supply section manually or automatically (not shown) during operation.

There are various types of automatic conveyance measuring and sorting machines, and as another example, one that moves along an inclined chute will be explained with reference to FIG. Here, A is a supply section, in which the workpiece 1 is conveyed through an inclined chute 2. A large and small case 3 is separately connected to the chute, and stoppers 4 and 5 are provided at the outlet of the chute and the case. Further, a case 7 is also provided in the conveying section in a branched manner in the middle of the chute 6 heading toward the sorting section D, and a direction switching plate 8 is provided at the branching section. Case 7 will be used to accommodate large and small groups. Normally, the stopper 5 is closed, the stopper 4 is opened, the workpiece 1 is supplied to the measuring section C, the workpiece is measured, and the workpiece is sent to the passage C to the sorting and sorting section. When master alignment is required, stopper 4 is closed and stopper 5 is opened to send the workpieces of the large and small groups to the measuring section.When the measurement has been completed, the workpieces of the large and small groups are moved by raising the plate 8. Place it in storage case 7. After the master alignment is completed, the cases 7 and 3 are replaced manually or automatically (not shown) in preparation for the next master alignment.

As described above, according to the present invention, the values obtained by measuring a plurality of workpieces with a reliable measuring machine are stored as master values, and the values obtained by measuring a plurality of workpieces with a reliable measuring machine are stored at any time in the same state and manner as the actual operation of the device. Perform a master measurement, find the difference between the measured value and the master value,
Since this difference is used as an instrumental error to correct the zero point and magnification of this device, it is possible to always perform highly accurate measurement and sorting, and without stopping the operation of the device.
No human intervention is required after the Master Piece is supplied. Also,
Since the average values of a plurality of groups are used as master values for the large range and the small range, reliability is further increased. Furthermore, since the material extracted from the workpiece is used as the master piece, there is no need to design or manufacture a master piece, and storage and management can be simplified, resulting in economical effects, and other great effects.

[Brief explanation of the drawing]

FIG. 1 is an explanatory plan view showing an example of the implementation of the present invention, FIG. 2 is a side design drawing thereof, and FIG. 3 is an explanatory view showing another embodiment. 1... Workpiece, 2... Inclined case, 3,
7... Large/small group case, 4, 5... Stopper, 8... Switching plate.

Claims (1)

[Scope of Claims] 1 Work groups with approximate dimensions (average dimensions) measured in advance using a measuring device as a reference.
A plurality of workpieces classified into workpiece groups with average dimensions (D ₁ ) and workpieces with average dimensions (D ₂ ) are prepared for each group, and during the operation process of the continuous measuring device, these large and small groups are separated. The workpieces are successively fed into the measurement section in groups, and each
Measure the workpieces of the small group one after another, store them separately from the general workpiece measurement path, and calculate the average values D ₁ ′, D ₂ ′ of the measured values of the large and small groups on the equipment. Making (D ₁ ′−D ₁ ),
(D ₂ ′−D ₂ ) is a high-precision master matching method that corrects the error of the device. 2 Work groups with approximate dimensions (average dimensions) that have been measured in advance using a standard measuring device.
D ₁ ) and workpiece groups close to the small size (average size D ₂ ), each group is prepared with a plurality of workpieces arranged in series, and the workpieces in the measuring device in operation are generally stored. and a storage device that only accommodates the master pieces, and when performing master alignment, the transfer of the general workpieces in operation is stopped and the large and small master pieces stored in series are sequentially fed into the measuring device in operation. and a device that measures the dimensions of each master piece fed in and stores it separately from the path of the general workpiece, and calculates the average of the measured values of each of the large and small groups D ₁ ′, D Standard average values D _{1 , D 2 of} large and small work groups measured using a calculation circuit that calculates ₂ ′ and a measuring device that serves as a reference.
A high-precision master matching device that has a comparison correction circuit that corrects the measurement system circuit by comparing with the