| By finishing machining technology, it can be significantly improved the part’s surface roughness, decorative effect, and the surface quality, which directly affects the product performance, working precision, and the part’s service life. There are many kinds of finishing methods; any of them is not suit for all kinds of parts. Therefore, much attention has been paid in engineering to study the finishing technology for various parts in different case. This accelerates the finishing machining technology continuously innovation and improvement.Both the pressure roller in high speed winding equipment and the grooved roller in carbon fiber equipment are the most important parts in the high-tech fiber equipment for modern textile machinery industry. Now, these parts are mainly imported from overseas. The comprehensive profit level of the whole machine products is largely reduced due to the long delivering term and the expensive price. The rollers are difficult to be produced domestically for some reasons, including the complex structure, difficulties in manufacturing techniques, the high accuracy requirement, especially the high surface qualities requirement. The roller surface requires being hard chrome plated, and achieving super-mirror appearance requirements. In this work, surface finishing technologies have been investigated for theses rollers in order to solve the problems in the manufacturing process. The success will consequently bring benefits to the domestic economic construction and technology progress in the textile machinery.Based on the analysis of performance and machining techniques of the two key parts under the industrial working condition, investigations were conducted from the prospects of both substrate surface quality and surface coating technology. A series of experiments were carried out in order to combine the essences in finishing machining technique and surface coating method. Through continuous improvement and optimization, the overall quality of the two parts has been improved greatly. The requirement in products design can be fulfilled with these techniques. The main experiments and conclusions in this dissertation were given as follow:1. The optimization of the dry polishing technologies was completed through reforming the polishing equipment, selecting the grinding wheel, optimizing the machining parameters during the polishing process by trial-and-error method. Results demonstrated that the surface roughness of polished surface could reach to Ra0.04μm, appeared as a mirror. Since polished with a shaped grinder from abroad, the surface roughness of the grooves on the grooved roller could be decreased to Ra0.025μm, which exhibited a super mirror visual experience. These fulfill the surface quality requirements on the design drawings.2. By dry polishing, there is still a slight of scratches existed on chromium plating surfaces of the two parts. Moreover, the machining precision of raw products is easy to be decreased. This may affect the parts’comprehensive performance. Therefore, the wet polishing technologies were researched and validated on the production process. This research was completed through ultra-precision mirror finishing equipments market investigating, polishing belt selecting, and super mirror machining experiments and technologies’improvements. By this technology, the surface roughness of the pressure wire roller could be reduced to Ra0.001μm, showing a super mirror appearance, while no loss of its original machining accuracy. This has ensured the assembly use and its excellent performance.3. In order to further decreasing surface roughness of pear surface segments on the pressure wire roller, and ensure the whole surface stay at the same horizontal level, the sand blasting procedure techniques of pressure wire roller was improved. The minimum surface roughness of inferior smooth of pear chromium surface may reach Ra0.2μm. The surface was smooth, felt as a silk, and did not hook any fibers. The boundary between mirror surface section and pear segment stood clearly and accordingly. The angle between the radial and axial boundary line of the roller was90°. Moreover, by improved sand blasting procedure, the operation was simply, and the large amount of cost for protect tooling was saved, thus increasing the profits and performance of products.4. A new additive for the chrome plating solution was investigated and applied. It is validated that the performance of the traditional standard chrome plating solution has been great improved. The maximum current efficiency of the new plating solution was25%, which was1.8times than that of the present chrome plating solution. The uniform normal deposition under the low current density area was achieved in chrome plating for the grooved types of part with complex structure. The coating stayed a higher wear and corrosion resistance, gave a crystal brightness and silky feelings.5. An improved design on the Pb-Sn anode rod was used in the present experiments. Results revealed that the redesigned anode could promote the homogeneous of microstructures, increase the density and flexural strength, and thus upgrade the service life of rod with2times of extends. This new anode rod exhibited good electro conductibility, which can save electrical power about5%. During the plating process, the power line of plating was evenly distributed, which improved the dispersion ability of plating solutions, decreased the pollution from anode sludge. For this reason, the performance and quality of the plated layer was significantly improved.6. The original plating procedure on parts surface was reorganized and innovated. Secondary bright chrome plating technique was used instead of the traditional once bright chrome plating. Results revealed that the pear chromium surface quality and brightness of plated surface were significantly improved. Some defects, such as pitting, pinhole, chromium tumor, airflow marks, could not be found on the plated surface using the twice bright chrome plating. The procedure sequence was adjusted for grooved roller. The plating procedure was moved before the oxidation procedure instead of oxidation former than chrome plating. By this method, the problem was solved for the original oxide layer inside the cavity plane easily corroded by chromate solution. Meanwhile, plating fixture was simplified, and the repair possibility of products was reduced by70%. For this overcame the most difficult problem, which seriously has affected the product quality for long time, mass production of key pieces of grooved rollers has achieved.Overall, the experimental results in this work have been applied into the industrial production of parts. Being ensured the high precision of parts, the super mirror performance of parts surface has been achieved. Testing results and practical applications demonstrated that the techniques raised from the present dissertation took a leading level among the relevant industries in China. The products brought higher profits and had a great potential using in various businesses. With the present techniques, the quality and performance can be improved for parts and the whole equipment. This will enhance the core competitiveness of China’s textile machinery, and agreed with the direction of manufacturing development in our country at current stage. |
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