The coordinate measuring machine is one of the most effective methods to measure and obtain dimensional data, because it can replace a variety of surface measurement tools and expensive combination gauges, and reduce the time required for complex measurement tasks from hours to minutes. This is Effects that cannot be achieved by other instruments.
The coordinate measuring machine can be divided into contact measurement and non-contact measurement as well as contact and non-contact measurement according to the measurement method. Contact measurement is often used to measure machined products, pressed products, metal films, etc. This article takes a contact measuring machine as an example to illustrate several methods of scanning the surface of an object to obtain data points. The data point results can be used for processing data analysis and can also provide original information for reverse engineering technology.
Mainly used for the measurement of boxes, racks, gears, cams, worm gears, worms, blades, curves, curved surfaces, etc. in machinery, automobiles, aviation, military industry, furniture, tool prototypes, machines and other small and medium-sized accessories, molds and other industries. It can also be used in electronics, hardware, plastics and other industries to accurately detect the size, shape and form tolerance of the workpiece, so as to complete tasks such as part inspection, shape measurement, and process control.
The CMM is widely used in the mold industry. It is a modern intelligent tool for design, development, testing, and statistical analysis. It is also an effective tool for unparalleled quality and technical assurance of mold products. The three coordinate measuring machines mainly used today include bridge measuring machines, gantry measuring machines, horizontal arm measuring machines and portable measuring machines. Measurement methods can be roughly divided into two types: contact type and non-contact type.
If there is a deviation in the matching between the core cavity of the mold and the guide pin and sleeve, the deviation can be found by a coordinate measuring machine for correction. After the core cavity profile of the mold is processed and formed, many inserts and partial curved surfaces need to be processed on electric pulses through electrodes, so the quality of electrode processing and non-standard curved surface quality become the key to mold quality. Therefore, it is essential to use a coordinate measuring machine to measure the shape of the electrode. The coordinate measuring machine can use the input of 3D digital model to measure and compare the positioning, size, related form and position tolerances, curves, and curved surfaces of the finished mold with the digital model, and output a graphical report, which can intuitively and clearly reflect the quality of the mold, thereby Form a complete mold product inspection report. In the case that some molds have been worn for a period of time and need to be corrected, but there is no original design data (ie digital model), the point cloud can be collected by the section method, output in the specified format, and the probe radius will be compensated for modeling. Achieve the restoration effect as intact.
When the contours of some curved surfaces are neither arcs nor parabolic, but irregular curved surfaces, the curved surfaces can be made by hand using sludge or plaster as the base embryo. Then use a three-coordinate measuring machine to measure the cross-sections, characteristic lines and parting lines on each section, and output them in a prescribed format. After the probe radius is compensated for modeling, the curve is smooth during the modeling process, thereby designing and manufacturing a brand-new mold.
With its high precision, high flexibility and excellent digitization capabilities, the coordinate measuring machine has become an important means of modern manufacturing, especially the design, development, manufacturing and quality assurance of the mold industry.
First, the measuring machine can provide quality assurance for the mold industry, and it is the best choice for mold manufacturing companies to measure and inspect. The flexibility of the measuring machine in handling different tasks and its own high precision make it an arbiter. While providing dimensional data for process control, the measuring machine can provide additional performance such as in-factory product inspection, machine tool verification, customer quality certification, gauge inspection, machining test, and optimization of machine tool settings. The highly flexible three-coordinate measuring machine can be configured in the workshop environment and directly participate in the various stages of mold processing, assembly, mold trial, and mold repair, providing necessary detection feedback, reducing the number of rework and shortening the mold development cycle, thereby ultimately reducing The manufacturing cost of the mold and control the production.
Second, the measuring machine has strong reverse engineering capabilities and is an ideal digital tool. Through the combination of different types of probes and different structure measuring machines, the three-dimensional data and geometric characteristics of the surface of the workpiece can be quickly and accurately obtained, 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 the PC-DMIS measurement software to complete the replication of complex workpiece CAD models with free-form surface shape features. Without any conversion, it can be directly recognized and programmed by various CAD software, thus greatly improving the efficiency of mold design.
Specifically, when using measuring machines to complete design and inspection tasks in mold manufacturing companies, pay close attention to the selection of measurement standards, the calibration and selection of probes, the planning of the number of measurement points and measurement locations, the establishment of coordinate systems, and the impact of the environment. , The influence of local geometric features, CNC control parameters and many other factors. Each of these factors is sufficient to affect the accuracy and efficiency of the measurement results.
The coordinate measuring machine is a measuring system that detects the three-dimensional coordinates of the surface point of the workpiece through the relative movement of the probe system and the workpiece. By placing the measured object in the measuring space of the three-coordinate measuring machine, the coordinate position of each measuring point on the measured object is obtained by the contact or non-contact detection system, and the software performs mathematical calculations according to the space coordinate values of these points. The geometric size, shape and location to be measured. Therefore, the coordinate measuring machine has the characteristics of high precision, high efficiency and omnipotence, and it is an ideal solution to complete the geometric measurement and quality control of various auto parts.
Auto parts have the characteristics of high quality requirements, large batches, and different shapes. According to the measurement types of different parts, it is mainly divided into three categories: box, complex shape and curved surface. The configuration of each relative measurement system is not the same. It is necessary to interact with each other from the measurement system host, detection system and software. The matching and selection.
The engine is composed of many parts of various shapes, and the manufacturing quality of these parts is directly related to the performance and life of the engine. Therefore, it is necessary to conduct very precise inspections in the production of these parts to ensure the accuracy and tolerances of the products. In modern manufacturing, more and more high-precision comprehensive measuring machines are used in the production process. The goal and key of product quality are gradually transformed from the final inspection to the control of the manufacturing process, and the parameters of the processing equipment are fed back through information. Make timely adjustments to ensure product quality, stabilize production processes, and improve production efficiency.
In the selection of traditional measurement methods, people mainly rely on two measurement methods to complete the measurement of box-like workpieces and workpieces with complex geometric shapes, namely: the detection of box-like workpieces by a three-coordinate measuring machine; Gear detectors, special cam detection equipment, etc. complete the measurement of workpieces with complex geometric shapes. Therefore, for companies engaged in the production of workpieces with complex geometric shapes, the quality control companies that complete the above products not only need to configure general measuring equipment, such as three coordinate measuring machines, general standard measuring tools, and measuring instruments, but also need to configure special testing equipment, such as various Various sizes and types of gear special testing equipment, cam testing equipment, etc. This often results in the measurement department of the enterprise needing to configure multiple types of measurement equipment and professional inspection personnel engaged in measurement operations. The utilization rate of measurement equipment is low, and at the same time the enterprise bears higher training costs for measurement personnel and measurement equipment use and maintenance costs; It is impossible to realize flexible and universal metrological detection. Therefore, reduce the measurement cost of the enterprise, the training cost of the measurement personnel, the use and maintenance cost of the measurement equipment, and achieve the purpose of improving the efficiency of measurement and detection, so that the enterprise has the real-time quality control ability of the production process, which will be related to the enterprise's market activities The adaptability of the company plays an important decisive role in helping companies establish and maintain a good market reputation.