Optimization of injection mold by Werth X-ray computed tomography



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The use of computed tomography technology can improve the measurement accuracy of the first piece and further complete the correction of the die Application of Werth X-ray computed tomography technology to optimize injection mold -- only one loop is required. Vemaggmbh produces plastic parts with high technical content. As the general manager of the company, Werner veser has to make several modifications to the mold before it is put into production. For example: LED headlamp lens. Veser, a measurement in the field of tool manufacturing, was advised to try computed tomography when he was exploring replacing traditional measurement methods. This technology is widely used in the medical field with excellent effect, but it is still rarely used in the industrial field. Fortunately, the recommended service provider is located in schonaich, Germany, 100 kilometers away from VEMA GmbH. 'This makes the initial communication and coordination very convenient, and good progress has been made in the first contact of innovation,' veser said. 'When we put forward our requirements, we obtained good measuring instruments and correction results, which is really unimaginable.' Mark waschitschek and Herbert layher, two smart people with innovative thinking, are the behind the scenes planners of purchasing tomoscope equipment from Werth company. The two managers devoted themselves to the injection mold industry and worked in different suppliers. Finally, they worked in this company. One of them is a technical manager and the other is quality management. Five years ago, they began to study methods to measure the disappearance of complex technologies. In the course of a transaction, they were exposed to computed tomography measurement technology and soon realized its great potential. One equipment can be used by many people. However, one such CT equipment can not function on small tools, mold plants or injection molds. Therefore, tomoscope equipment has been transformed into providing external services. Werth measurement technology company of Germany has improved CT equipment into coordinate measurement technology. Vera company applies this technology to the manufacturing of LED headlights in the automotive industry. Werner veser explained: 'We have rich practical experience. Many automotive lighting equipment manufacturers come to us to learn practical operation experience. Because we have been able to provide mold processing and injection mold at the same time, and we have rich experience in both fields. We are an ideal partner in mold development and original product production. However, manufacturing lenses and reflectors is not Simple things. The product is not only required to be as pure as glass, but also the surface quality is very demanding. They must share equally and meet the requirements from the angle of each other. A deviation of 2% mm means a loss of 30% of the amount of light. Therefore, the optical function plane of the final product must meet the high surface accuracy. Most of these requirements are realized through the mold, and it must have high reliability. Compared with mold manufacturing, injection mold process control is relatively easy. In order to achieve the required accuracy level, veser usually adopts the following methods: he introduces the customer's component CAD data into his system and obtains the possible reduction of components in CAD. Then, veser obtains the inner cavity contour of the die according to the part shape, and then designs the die. Generate NC program in cam part software through CAD file. Finally, the workshop grinds out the mold and is equipped with springs, sliders, etc. Using Werth X-ray computed tomography technology to optimize the injection mold -- only one loop is needed to optimize the mold to ensure the accuracy through simulation and simple operation on the injection mold. The tolerance of the realized dimension is maintained at 0.1mm. Then start fine-tuning, which requires high measurement accuracy of injection mold. If deviation from the target data is found, the die needs to be corrected. Pay particular attention to thick wall parts, including LED lenses, which shrink and change. Because the measurement data resolution of the contact measuring machine is relatively low, some correction circuits are needed. In addition to the limited number of measurement points, inaccessible positions cannot be measured using probes and other measurement methods. It is also difficult to measure the assembled parts by the usual measurement methods. This is important because the surface angle and relative position of the light source are critical. This means that an excellent choice is to obtain complete dimensional data through a variety of detection means, which requires additional work and will produce errors. The initial modeling and die correction are realized by tomography technology. There is an X-ray generator and detector in the computer tomography measurement equipment, and its working principle is similar to that of CCD camera. It converts the X-ray image into a two-dimensional image for subsequent processing. The unique feature of the tomoscope equipment of Werth company is the integration of coordinate measurement technology and computed tomography technology. In this way, the accuracy of the measured data can reach the micron level, and can show the detailed characteristics of the workpiece. These accurate data can be analyzed by a variety of means. According to the specification, to generate the point cloud map of STL grid distribution, it can be edited and optimized easily. For Herbert layher and mark waschitschek, this is an ideal method for measuring plastic parts, but Werth also has something in common: 'in terms of mold measurement, our goal is not to be a single supplier of measuring equipment. At VEMA, we have proved that CT technology is an ideal application for mold correction.' In actual production, the working process is as follows: without contact measurement, Werner veser directly places the injection molded parts on tomoscope. Irradiate the part with X-ray, and then generate STL file from three-dimensional point cloud image as initial CAD data. The deviation can be seen directly from the color distribution. 'If the error of the part is qualified, the data will be imported into the first piece measurement report, which is completed.' Mark waschitschek explained, 'if there are defects, we can clearly see which areas need to be modified on the mold. CAD and measurement expert Carlos Machado joined us.' Working with Werner veser, Carlos Machado is mainly responsible for processing STL data. He tells the engineer which areas need to be corrected, and then uses the CAD / CAM system to reconstruct the corrected mold and optimize the CAD file of Yuanshu mold. He used a case to illustrate the potential principle: 'if a round cup originally wanted to come out of the mold, then the spatial error will be transferred to the other side, and the next cup will come out as round.' Vena has put this theory into practice, but there is no such accuracy level. This is because for an optimized application, the probe of the measuring instrument can only collect 1% of the measuring points, and CT technology can better deal with this problem. Werner veser spoke highly of the role of werthtomoscope. Using Werth X-ray computed tomography technology to optimize injection mold - only one loop is needed to improve quality & save time. He especially explained how simple the operation process is. 'If the mold needs to be corrected, I can obtain a new CAD file through the cam system. Then I can remanufacture my mold. So far, all Abrasives have been optimized and no more correction circuits are required. We improve quality and save time.' Vena has been using Werth's computed tomography measurement technology for a year and a half. Veser also uses this technique to analyze plastic panels. 'The X-ray captures the contour of the whole cavity. This means that with appropriate software, we can determine the location of the shrinkage hole. This provides an important reference for the injection molding process. In case of a recall, we can prove the quality of the parts to the customer,' he explained Manufacturers who cannot afford such equipment but hope to measure and analyze their products through this technology. Herbet layher gave the following suggestions: 'buy a computer with offline winwerth software, which costs less for the whole system. Then we provide STL files for you to analyze.' Founded in 1982, VEMA GmbH specializes in processing and manufacturing plastic parts with high technical requirements. It is an excellent global R & D partner for complex products.