The precision adjustment of the mechanical press includes the adjustment of the level of the base working table during the installation of the press, the parallelism between the slider and the working surface during the test run of the press, the verticality of the slide stroke and the working surface, and the clearance between the slide and the guide rail. The accuracy adjustment of each item is not independent, and they are interrelated and mutually restrictive. A poor adjustment of one of the items will affect its associated accuracy. If the adjustment of the level of the base is not good, it will affect the level of the working table, and even affect the verticality of the slider stroke and the working surface; the poor adjustment of the parallelism between the slider and the working surface will also affect the stroke of the slider and the working surface. The verticality, while the gap between the slider and the column guide is not well adjusted, will in turn affect the parallelism between the slider and the working surface and the perpendicularity of the slider stroke and the working surface.
The leveling of the mechanical press base and working table is done during the installation of the equipment. According to the requirements of the mechanical press installation regulation, when the length of the press base and the working table is ≤1.5 m, and it is inspected at the center of the table; the length of the working table is 1.53 m, and the inspection is conducted at two sides and the center of working table. The horizontal accuracy of press base and the working table is adjusted by the foot pad. So if the adjustment of the level is expected to be good, the grinding of the foot pad is very important. That is, according to the technical requirements, the contact surface between foot pad and the base of the press should be more than 75%, and then the level of the base and the working table should be adjusted. According to the standard, the leveling of the base and the working table should not be greater than 0.2mm/m.
Generally, the technical specifications of the press in the operation manual should not exceed 0.1mm/m. This requires that the level adjustment work should be meticulous and lay a good foundation for future precision adjustment work. When the level adjustment of the base and the working table meets the technical requirements, the anchor bolts can be tightened, and the level of the working table can be checked again. After the technical requirements of the equipment are met, the foot pads are spot welded, and the level of the working table is checked to confirm that the requirements are met. Then the installation of the next process can be performed.
The parallelism adjustment between the slider and the work surface is performed after the press is basically qualified for the idle operation. Before the test running, the parallelism of the slider can be coarsely adjusted, and the parallelism is adjusted by rotating the worm gear coupling on the slider to achieve leveling. According to the requirements of the mechanical press installation regulation, the parallelism measurement should be performed at the four side points of the slider.
The tools required for parallel measurement of the slider and the work surface are: standard rocker, dial indicator, and benchmark chuck. As mentioned above, if the parallel adjustment of the slider does not meet the requirements that will affect the verticality between the stroke of the slider and the work surface. Therefore, the work must be careful, and the measurement should be measured—adjusted—re-measured, and the qualification can be approved after the value is stable. According to the regulation of the press, the deviation of the parallelism is allowed to be in the range of 0.02+0.2L1/1000mm. The factors affecting the parallelism of the slider are: the air pressure of balancer, the hydraulic protector air pressure, the gap between the slider and the column guide, the gap between the worm gear and the worm, and the gap between the four eccentric bearing bushings.
When adjusting the parallelism of the slider, the slider is generally stopped at the bottom dead center, because the position of the slider is 1~2° before and after the bottom dead center when the press is working. Adjust the gas pressure of the slider balance cylinder to the working pressure of the slider during normal operation, adjust the pressure of the slider hydraulic protector to its pre-pressure, and relax the gap between the slider and the column guide rail without contacting (or being squeezed) with the column rail. It is necessary to synchronize the four worm gears when rotating (ie, rotate in the same direction, not one down, one up, this is especially important), keep the slider in free gravity state when it stops, that is, the slider does not squeeze or contact with the surrounding. The four eccentric bearing bushes are equal in position, so that the slider can always maintain a parallel state with the work surface when moving, and indirectly keep the verticality of the slider stable. When these factors are all processed, the parallelism of the slider and the work surface is adjusted with half the effort, and the parallelism of the press is relatively stable when used.
Once the parallelism of the slider is adjusted and become stable after several measurements, the gap between the slider and the column guide can be adjusted. When adjusting, the slider should be in the self-weight state when it is at the top and bottom dead point, that is, the slider and the column have no squeeze or close contact. Use a wrench or feeler gauge as the adjustment tool, and by adjusting the bolt to adjust the gap of the guide rail to make the sum of the bilateral gaps between 0.12~0.24mm,then tighten the bolts in place to prevent the rail from loosening and affect the rail clearance. After the slider is tested for a period of time, check the lubrication of the guide rail to see if the oil film on the guide rail is formed, and whether the guide rail has heat. If above phenomenon occurs, adjust it again until the slider runs smoothly and the guide rail is in good condition.
When the parallelism of the slider and the gap of the guide rail are adjusted well, the measurement of the perpendicularity between the work surface and the slider stroke can be performed. The verticality of the slider stroke to the work surface is measured in two perpendicular directions, the deviation is ≤0.05+0.02s/100mm (s is the length of the slider stroke). The slider vertical measuring tools are: standard block, 500x1000mm angle square, magnetic gauge, dial indicator, standard rocker and so on.
Normally, the verticality measurement of the slider is generally the dimension for checking the parallelism and the clearance of the guide rail. If the verticality of the slider exceeds the allowable range, the parallelism of the slider and the clearance of the guide rail need to be re-examined. If the deviation is serious, repeat the adjustment until the verticality of the slider to the work surface is within the allowable deviation. In return, it can be proved that the parallelism of the slider and the clearance of the guide rail is within the allowable deviation if the deviation is within the range. Therefore, the relationship between the three is mutually unified and interconnected. Which one has problems will affect the other two. Only when all three meet the requirements of the relevant acceptance specifications and equipment technical documents, can the press be approved. The installation meets the technical performance requirements of each item, and the press installation inspection is considered qualified.
