After the triangular surface of the drilling and milling machine is abraded, the repair method should be the stone scraper method. Generally speaking, the sliding bearing has a margin for adjustment and repair, which can be repaired manually according to the installation source program.
First remove the cover plate in front of the workbench base, then loosen the three fastening screws on the flange, but do not loosen them too much, let alone remove them. Turn the worm clockwise to drive the adjustable nut to rotate. When the tooth sides of the adjustable nut and the main nut are close to the two different sides of the lead screw respectively, the gap between the lead screw and the nut can be removed.
The spindle assembly determines the accuracy of the machine tool. The main reason is often caused by the improper adjustment of the clearance between the front and middle bearings of the spindle. When the radial circular runout exceeds the tolerance, it is generally necessary to appropriately reduce the clearance of the front bearing. During adjustment, a certain thickness of the front two semicircle adjusting washers shall be repaired to move the bearing inner ring to the large end of the front journal. Therefore, the movement of the inner ring can change the radial clearance of the front bearing. When the axial movement exceeds the tolerance, the clearance of the middle bearing generally needs to be adjusted. The thickness difference between the two inner and outer spacers can be corrected according to the preload method. If the assembly accuracy is out of tolerance after the above adjustment method is adopted, check whether the coaxiality of the front and middle body holes of the bed is out of tolerance, whether the spindle accuracy is qualified, and whether all adjusting parts and fasteners are assembled in place. The clearance of the main shaft bearing shall be adjusted appropriately. It is not allowed to be too tight or too loose. Therefore, the spindle assembly accuracy error shall be measured before adjustment.
Heat treatment of resin sand castings is a very important process link. Compared with other processing processes, heat treatment generally does not change the shape and overall chemical composition of the workpiece. Heat treatment can deform the rigidity of the drilling and milling machine, but by changing the microstructure inside the workpiece or the chemical composition of the cast iron platform and machine tool casting surface, Endow or improve the service performance of the workpiece. It is characterized by improving the internal quality of cast iron platform and drilling and milling machine bed castings. As a large-scale casting, the lathe bed casting of drilling and milling machine must undergo aging treatment in order to improve its service performance and improve the internal quality of lathe bed casting. There are four basic processes for the overall heat treatment of bed castings, bed columns, worktables and other castings: annealing, normalizing, quenching and tempering. The tempering process shall be strictly followed during tempering of bed castings. Support bars shall be added at the parts with dense ribs or prone to deformation to prevent deformation and fracture caused by tempering temperature. A specially assigned person shall take care of the tempering furnace thermometer and control the temperature in time to prevent the temperature from being too high or too low, which will have a great impact on the tempered workpiece. The milling operation of drilling and milling machine is to operate the cutter with one or more cutting edges and rotating around a fixed axis. During cutting, the cutter is fixed and the workpiece is fed and processed. The chip shape generated by cutting can further distinguish the difference between this cutting operation and other metal cutting operations. The chips generated by milling are generally short and discontinuous fragments, and the discontinuous chips generated during milling are caused by the geometric shape of the tool; Not like turning, discontinuous chips are produced by chip rupture. For most milling operations, the undeformed chip thickness changes from one end of the chip to the other. The chip thickness may occur at either end of the chip or near the center of the chip, but this depends entirely on the cutting process.
During milling, because the chips change regularly and discontinuously, the cutting force and cutting temperature also change periodically, rather than in an undisturbed state. When the tool cuts into the workpiece, the tool tip will be subjected to strong impact and sudden shock, and then the cutting load is changing all the time. When the tool cuts into the workpiece, the tool surface is cold, but it is gradually heated during chip formation. After chip formation, it begins to be cooled until the next cutting action is generated.