The hole diameter of reaming is generally less than Φ80mm, usually less than Φ40mm. For stepped holes and blind holes, the manufacturability of reaming is poor. IV. Boring and turning Boring is the further machining of a drilled, cast, or forged hole with a boring cutter. Can be performed on a lathe, boring machine, or milling machine. Boring is one of the commonly used hole processing methods, which can be divided into rough boring, semi-fine boring and fine boring. For rough boring, the dimensional tolerance grade is IT13 ~ IT12, and the surface roughness value is Ra12.5 ~ 6.3 μm; for semi-fine boring, the dimensional tolerance grade is IT10 ~ IT9, and the surface roughness value is Ra6.3 ~ 3.2 μm; for fine boring,mining dth bit, it is IT 8 ~ IT 7, and the surfaces roughness value is Ra 1.6 ~ 0.8 μm. 1 Lathe hole Lathe holes are shown in Fig. 7-11. For holes without through holes or holes with right-angle steps (Fig. 7-11b), the turning tool can make longitudinal feed motion first, and then change to transverse feed motion when cutting to the end of the hole, and then process the inner end face. In this way, the inner end surface can be well connected with the hole wall. Turn the inner hole groove (Fig. 7-11d), insert the turning tool into the hole, first make the transverse feed, and then make the longitudinal feed after cutting to the required depth. The turning hole on the lathe is the rotation of the workpiece and the movement of the turning tool. The size of the hole diameter can be controlled by the cutting depth of the turning tool and the number of passes. The combination of these two motions makes the cutting tracks of the abrasive particles on the inner surface of the hole cross without repeating, as shown in Fig. 7-28b. The radial pressing motion is the feed motion of the oilstone, and the greater the applied pressure, the greater the feed amount.Therefore, it is necessary to define a smaller surface roughness parameter value for the surface with matching requirements. Rolling auxiliary processing technology is a new processing technology which is gradually developed with the development of mechanical processing. Surface rolling is an auxiliary surface modification method, which has the advantages of small elastic pressure, small friction force, further reduction of surface roughness Ra value, significant improvement of surface hardness and increase of surface wear resistance, so it has attracted more and more technical personnel's attention and favor. For a new processing technology, technicians pay more attention to the excellent properties of materials obtained by this technology, but seldom involve the selection of process parameters and their impact on the processing quality. In surface rolling technology, the final surface condition is directly determined by the processing parameters such as spindle speed,dth rock bit, axial feed, processing times, static pressure and lubrication. Return to Sohu to see more Responsible Editor:. wt-dthtools.com