Publish Time: 2022-08-05 Origin: Site
With the development of modern manufacturing industry, the design requirements for mechanical manufacturing products are getting higher and higher, and the three-coordinate measuring instrument has been widely used in many industries. Improve the efficiency of the three-coordinate measuring instrument, which can make the detection results more effective.
The fixture used by the measuring instrument is composed of different parts, which are combined with each other to form a clamping mechanism for the measured parts of different shapes and different specifications.
1. Quick clamping device to realize rapid measurement of batch products
The clamping of parts is an important part of improving efficiency. Aiming at the problem of low clamping efficiency of three-coordinate measurement. Design a set of quick clamping devices. First, assemble the fixed splint, movable splint, guide column, hinge, spring, etc., and then fasten the fixed splint on the measuring platform of the CMM with bolts.
Next, place 6 parts with the same diameter between the V-shaped grooves, rotate the hinge to make it fall in the groove of the movable splint, push the movable splint, press the parts, and tighten the clamping nut to complete the clamping. After the measurement is completed, loosen the clamping nut, lift the hinge, and the movable splint moves in the opposite direction of the product along the guide column under the elastic force of the spring, and the product is automatically released.
In the clamping device, a vacuum rubber pad is attached to one side, and the fixed splint is designed to be in rigid contact to ensure that the fixed position of each workpiece is basically the same.
Features of the coordinate machine quick clamping device: the device is simple in structure, simple in production, convenient and flexible in clamping. The fixed position of the parts is basically the same after repeated clamping using this device, so there is no need to align the parts before each measurement, which saves a lot of time. Greatly improve the detection efficiency.
2. Flexible fixture, used for ball workpiece positioning
For the measurement of special-shaped structural components such as balls and space pipes, most of the existing combined fixtures cannot achieve effective clamping and positioning. Aiming at the positioning measurement of such parts on the CMM, based on the advantages of the combined fixture, a flexible positioning fixture is designed, which can realize the effective support of the spherical parts, and can be matched with the combined fixture. To achieve a multi-position positioning.
Solution: The specific structure of the flexible positioning clip, specifically the use of intensive multi-point support for the desktop structure. Make the surface contour of the workpiece to be tested as consistent and fit as possible with the contour of the support part of the fixture, so as to play a supporting role. The contour shape of the support part of the fixture can be changed with the change of the surface contour of the workpiece to be tested, so as to meet the requirements of flexible fixtures.
Features of flexible positioning fixture: This positioning fixture can automatically adjust the positioning joint surface according to its curved surface profile for ball parts, so that the workpiece can be stably supported on the three-coordinate worktable, and the fixture can be combined with the existing three-coordinate combined flexible fixture on the market. use to increase the value of use. The fixture has a wide range of use, which can effectively ensure the reliability of positioning, improve the measurement accuracy, and improve the measurement efficiency of the instrument.
3. Offline programming
The CNC CMM makes batch measurement more efficient, and by programming the measurement of a given workpiece, fully automatic and fast measurement can be achieved. Before the CAD function was introduced into the coordinate measurement software, the preparation of the measurement program required professionals to program corresponding drawings. This programming method was more complicated to use and had higher requirements for operators.
One way is to use the self-learning programming function of the three-coordinate measuring software to automatically generate a measuring program while actually measuring the workpiece. When measuring the same workpiece again, this program can be called for automatic measurement. This method is widely used in the industry due to its simplicity, ease of use and wide adaptability. However, since this kind of programming is inseparable from the actual workpiece, it also brings many insurmountable shortcomings.
First, since programming is inseparable from the hardware environment, it is necessary to open the gas source for the measuring machine so that the measuring machine can run normally before programming, which is cumbersome to compile.
Second, programming is inseparable from the workpiece, so programming must be performed after the workpiece is processed, which will reduce work efficiency and affect production. After the CAD function is introduced into the coordinate machine measurement software, the process of self-learning programming can be completed by virtual measurement of the CAD model in an offline state, thus solving the above problems. Whether production is in progress or not, programming can be done as long as the CAD drawing file designed by the design department is imported into the measurement software.
After the workpiece is processed, the program measurement can be performed, which greatly improves the production efficiency. The specific method is to first open the CAD model of the workpiece to be measured in the three-coordinate measurement software, and then open the self-learning function of the measurement program. After the coordinate system is established, the measurement of the workpiece can be simulated.
The system will automatically generate the measurement program. After the programming is completed, the program can also be called in the CAD environment to perform simulated measurement, to verify the program, to find out the wrong measurement path and sampling points during the running process, and to revise the program to correct the possible errors in the actual measurement. The problem is reduced to a very low level and safety during the measurement is also guaranteed.
4. Virtual measurement
Virtual measurement is to measure the CAD model in software without the actual workpiece. The ac-dmis measurement software has powerful CAD functions. To perform virtual measurement, open the software, select the offline working mode, and then import the CAD model to be measured, and then measure the CAD model by corresponding it to the selected coordinate system.
According to the geometric elements to be measured, use the mouse to click the position of the point to be collected on the CAD model, and the position of the point to be collected and its vector direction will be displayed on the CAD model at this time. According to the needs of the measured geometric elements, multiple points can be collected.
When the required number of points is collected, then confirm the point in the point-collecting window, the system will drive the virtual probe to collect points, and draw out the geometric elements to be measured and their graphics. Virtual measurement can determine various dimensional parameters by measuring CAD models without dimensional data. But this is not the main purpose of virtual measurement. The main function of virtual measurement is to serve the automatic measurement programming in offline state.
5. Make the position tolerance evaluation more convenient
In the previous three-coordinate measurement software, to evaluate the position tolerance of geometric elements, the theoretical position of the geometric elements must be manually input, and then compared with the actual measured value, which is very inconvenient to evaluate the position tolerance.
When the CAD function is introduced into the coordinate measuring machine software, the CAD model can be measured in the software. Since the model is designed, the measured value of the measurement is the theoretical value of the geometric element. After the theoretical value is obtained, the actual workpiece is measured in the corresponding coordinate system, that is, the actual value of the required geometric element is obtained. This makes it possible to evaluate the positional tolerances of the measured geometric elements.
It can be seen that the importance of CMM in CAD design is no longer the use of an isolated measuring machine, but is more used in conjunction with other things.
6. CAD output for reverse engineering
In the current production and manufacturing, it is often encountered in such a situation that the customer can only provide the manufacturer with the real object without any drawings or CAD data, especially if there are curves and curved surfaces in the sample, it is difficult to obtain its accurate information through measurement. Complex models of data.
In this case, the traditional processing method is to use engraving or other methods to make a one-to-one mold, and then use the mold for production. This method cannot obtain accurate dimensional drawings of the workpiece, and it is difficult to modify its appearance. Reverse engineering is a set of theories proposed to solve the above problems. Reverse engineering refers to the process of generating drawings or various related dimensional data from workpieces, which is relative to the traditional process of generating workpieces from drawing data.
The CAD function is introduced into the CMM software for reverse engineering, so that the function of the traditional CMM for finished product inspection has been greatly expanded. In reverse engineering, the three-coordinate measuring machine is used to accurately measure the appearance of the sample, and then the measured data is processed with the CAD function to generate one or several CAD format data files.
For example, the three-coordinate measurement software of Xi'an Edward Company generates data in IGS format, and you can also use the functions attached to this software to convert the data between various CAD formats. These data files can be accepted by general CAD/CAM software systems. Using these software systems, the data can be modified, or the CNC machine tool processing method can be programmed directly to guide the CNC machine tools to process.
These data can also be sliced to guide the laser prototyping machine for rapid prototyping. Reverse engineering not only enables the workpiece to enter mass production quickly, but also obtains the CAD data of the workpiece. With these data, the three-coordinate measuring machine can be used to detect the produced workpiece to ensure the quality of the product.