|Application of three coordinate measuring machine in mold production|
|Date: 2015-01-07 Popularity: 2454|
| ---- With its high precision, high flexibility and excellent digitization ability, the coordinate measuring machine has become an important means for the design, development, processing and quality assurance of modern manufacturing, especially the mold industry. |
Tools for mold quality assurance
--- CMM is widely used in the mold industry. It is a modern intelligent tool for design, development, testing, and statistical analysis. It is also a tool for quality assurance of mold products. The three-dimensional measuring machines mainly used today are bridge measuring machines, gantry measuring machines, horizontal arm measuring machines and portable measuring machines. Measuring methods can be roughly divided into two types: contact and non-contact. At present, Metris LK's measuring machine ranks in the forefront of the world in two technologies. If there is a deviation between the matching of the core cavity of the mold and the guide post and guide sleeve, the deviation value can be found by a three-dimensional measuring machine for correction. After the core and cavity profiles of the mold are processed, many inserts and local curved surfaces are processed by electrodes on electrical pulses, so the quality of electrode processing and the quality of non-standard curved surfaces become the key to mold quality. Therefore, it is necessary to measure the shape of the electrode with a coordinate measuring machine.
--- The coordinate measuring machine can use the input of 3D digital mold to measure and compare the positioning, dimensions, related form and position tolerances, curves, and surfaces of the finished mold with the digital mold, and output a graphical report to reflect the mold intuitively and clearly. Quality, thus forming a complete mold finished product inspection report. When some molds are worn for a period of time and need to be corrected, but there is no original design data (that is, digital model), the point cloud can be collected by the cross-section method, output in a prescribed format, and the probe radius can be compensated for modeling. To achieve the original repair effect. When some surface contours are neither arcs nor parabolas, but some irregular surfaces, the surface can be made by hand using sludge or plaster as the base. Then use a coordinate measuring machine to measure the section line, feature line and parting line on each section, and output it in a prescribed format. The probe radius is compensated for modeling, and the curve is smooth during the modeling process to design and manufacture a brand new mold.
The correct use of the CMM plays a key role in its service life and accuracy. The following points should be noted.
(1) Before hoisting the workpiece, return the probe to the coordinate origin, leaving a large space for the hoisting position; the hoisting of the workpiece must be stable, and it must not impact any component of the CMM. (2) Install the parts correctly, and make sure to meet the isothermal requirements of the parts and the measuring machine before installation. (3) Establish the correct coordinate system, ensure that the constructed coordinate system meets the requirements of the drawing, and then ensure the measured data is accurate. (4) When the program is run automatically, it is necessary to prevent the probe from interfering with the workpiece, so it is necessary to increase the inflection point. (5) For some large and heavy molds and gauges, the worktable should be lifted off immediately after the measurement to avoid the worktable being in a load-bearing state for a long time. Ideal tool for digitizing molds. In 1974, Brown & Sharpe of the United States introduced a global CNC measuring machine. After that, PC-DMIS introduced the powerful YDD function into the measurement software. Since then, the coordinate measuring machine has become a high-precision, high-flexibility, and excellent digitization capability. Modern manufacturing, especially the mold industry, is an important means for design, development, manufacturing and quality assurance. I focus on two important functions of the measuring machine for the mold industry.
First, the measuring machine can provide quality assurance for the mold industry and is a good choice for measurement and inspection by mold manufacturing enterprises. The measuring machine's flexibility in handling different tasks and its own high precision make it a master arbiter. While providing dimensional data for process control, the measuring machine can provide additional features such as incoming product inspection, machine tool calibration, customer quality certification, gauge inspection, processing test, and optimization of machine tool settings. The highly flexible CMM can be configured in the workshop environment, and directly participates in all stages of mold processing, assembly, trial testing, and mold repair, providing necessary inspection feedback, reducing the number of rework and shortening the mold development cycle, thereby reducing molds. Manufacturing costs and control of production.
The measuring machine has powerful reverse engineering capabilities and is an ideal digital tool. Through the combination of different types of probes and measuring machines with different structural forms, three-dimensional data and geometric features of the workpiece surface can be obtained quickly, which is particularly useful for mold design, sample replication, and repair of damaged molds. In addition, the measuring machine can also be equipped with contact and non-contact scanning probes, and use the powerful scanning function provided by PC-DMIS measurement software to complete the replication of YDD models of complex workpieces with free-form shape features. Without any conversion, it can be directly identified and programmed by various YDD software, which greatly improves the efficiency of mold design. Specifically, when applying a measuring machine to complete design and inspection tasks in a mold manufacturing enterprise, it is necessary to pay close attention to the selection of the measurement reference, the calibration and selection of the probe, the planning of the number of measurement points and measurement positions, the establishment of the coordinate system, and the environmental impact. , The influence of local geometric features, CNC control parameters and other factors. Each of these factors is sufficient to affect the measurement results and efficiency. Hexagon has long-term experience in operating training for more than 3,000 customers in China, forming a complete system from elementary, intermediate to training. Our understanding of the correct use of measuring machines is as follows.
First, choose the right equipment and the correct detection strategy. And must pass the necessary demonstration, from the aspects of accuracy, efficiency and measurement methods to measure whether the measuring machine meets the needs of the work goals. Secondly, surveyors need to be trained to be familiar with the measurement goals and be competent for the job. In addition, the technical indicators of all measurement equipment and measurement processes should be regularly evaluated and summarized. Demonstrate consistency of measurement results. With the rapid development of modern manufacturing industry, especially the development of automobile manufacturing industry, the requirements for mold design and manufacturing are also increasing. CMM has become an indispensable key in mold manufacturing. device.
--- CMM is a precision CNC testing equipment, its accuracy is higher than that of ordinary CNC machine tools, and it is widely used in mold, automobile, aviation, aerospace, machinery and other manufacturing industries. Check it out. Industrial development in the United States and Europe, measuring machines have become very popular, about every seven CNC machine tools to be equipped with a coordinate measuring machine. In addition to the conventional geometric size and shape and position tolerance detection functions, the coordinate measuring machine has special advantages in reverse engineering technology and surface coordinate detection, which is very suitable for mold manufacturing. Reverse engineering technology is the process of reversely pushing out product design data (digital models or design drawings) based on existing product models or samples through the measurement of various geometric dimensions and surfaces by a coordinate measuring machine. Therefore, using reverse engineering technology, you can easily manufacture molds or directly process products based on samples provided by customers. This has a wide range of applications in mold manufacturing, automotive, and motorcycle industries.
As a digital measuring device, the three-dimensional coordinate measuring machine can obtain the three-dimensional coordinate data of the workpiece surface through the measurement of curves and curved surfaces, and then use the reverse engineering YDD technology to obtain the YDD mathematical model of the product, and then use the YDM system to complete the product manufacturing. Reverse engineering technology uses computer digital graphics technology to express complex workpiece shapes, which can replace the traditional shape-based transfer method based on physical objects, shorten the product development trial production cycle, and reduce costs. In the mold manufacturing industry, most molds are manufactured on CNC machine tools according to the YDD mathematical model. Compared with the original YDD mathematical model, to determine the errors generated in processing and manufacturing, you need to use a coordinate measuring machine to measure .
--- In the software system of the coordinate measuring machine, the original YDD mathematical model can be displayed graphically, and then the measured points can be determined from the graphics in a visual way, the X, Y, Z coordinate values of the measured points and the normal vector, An automatic measurement program can be generated. The coordinate measuring machine can measure the workpiece according to the normal direction to obtain accurate coordinate measurement results. It can also be compared with the original YDD mathematical model and displayed graphically, and generate coordinate detection reports (including text reports and chart reports). The process is intuitive and fast, which cannot be done with traditional detection methods. The use of CMMs can reduce measurement errors, ensure the accuracy and quality of products, meet the needs of design and manufacturing, and play an important role in improving the market competitiveness of products. It has a great effect on the technological progress of the mold manufacturing industry. CMM has a very broad application prospect in the mold manufacturing industry.
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