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2009 2

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A novel approach to minimizing material loss for computer numerical control flank-regrinding of worn

《机械工程前沿（英文）》 2023年第18卷第3期 doi: 10.1007/s11465-023-0757-z

摘要： Flanks of end mills are prone to wear in a long machining process. Regrinding is widely used in workshops to restore the flank to an original-like state. However, the traditional method involves material waste by trial and error and dramatically decreases the potential regrinding. Moreover, over-cut would happen to the flutes of worn cutters in the regrinding processes because of improper wheel path. This study presented a new approach to planning the wheel path for regrinding worn end mills to minimize material loss and recover the over-cut. In planning, a scaling method was developed to determine the maximum size of the new cutter according to the similarity of cutter shapes before and after regrinding. Then, the wheel path is first generated by envelope theory to regrind the worn area with a four-axis computer numerical control grinder according to the new size of cutters. Moreover, a second regrinding strategy is applied to recover the flute shape over-cut in the first grinding. Finally, the proposed method is verified by an experiment. Results showed that the proposed approach could save 25% of cutter material compared with the traditional method and ensure at least three regrinding times. This work effectively provides a general regrinding solution for the worn flank with maximum material-saving and regrinding period.

关键词： flank-regrinding worn end mill wheel position and orientation material loss over-cut

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study of the efficacy and complication of thoracoabdominal incision for nephrectomy: a comparison with flank

Minggen YANG, Xiaokun ZHAO

《医学前沿（英文）》 2009年第3卷第2期页码 191-196 doi: 10.1007/s11684-009-0026-5

摘要： This retrospective study was performed to compare the outcome of thoracoabdominal incision flank incision for radical nephrectomy in the patients with large renal tumors. A questionnaire assessing postoperative pain, administration of pain medications and the return to activities and work was sent to the patients who undergoing radical nephrectomy through the 11th rib (group 1: underwent flank incision, including 96 patients) or the 9th to 10th rib (group 2: undergoing thoracoabdominal incision, including 98 patients) from 2003 to 2007 in our hospital. A case retrospective analysis assessing operation time, perioperative hemorrhage volume, size of tumor, success in the treatment of tumor thrombus in renal vein or vena cava, time length of presence of drainage tube, postoperative analgesia usage and length of stay was conducted in patients whose questionnaires were returned. A total of 56 patients (58%) in group 1 and 60 (61%) in group 2 responded to the questionnaire. Time lengths of operation and presence of abdominal drainage tube were shorter in group 2 than those in group 1. Perioperative hemorrhage volume in group 2 was obviously less than that in group 1. The mean size of tumors in group 1 was significantly smaller than that in group 2 ( < 0.0005). The success rate of treating thrombus in renal vein or vena cava in group 2 was significantly higher than that in group 1 ( <0.05). Lengths of off-bed time and stay were the same in both groups. There were no differences between groups in terms of pain severity on postoperative day 1, on day of discharge and 1 month postoperatively ( >0.05). There were no significant differences between groups in the time following surgery when pain completely disappeared, when pain medications were discontinued, and when the patient returned to daily activities and work ( >0.05). The thoracoabdominal incision provides excellent exposure and allows for early vascular control. Efficacy and complication was comparable for thoracoabdominal and flank incisions in terms of incisional pain, analgesic requirements after discharge and return to normal activities.

关键词： surgery renal tumors nephrectomy

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Five-axis rough machining for impellers

Ruolong QI, Weijun LIU, Hongyou BIAN, Lun LI

《机械工程前沿（英文）》 2009年第4卷第1期页码 71-76 doi: 10.1007/s11465-009-0010-4

摘要： The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that is difficult to machine because of its twisted blades. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. An integrated rough machining course with detailed algorithms is presented in this paper. An algorithm for determining the minimum distance between two surfaces is applied to estimate the tool size. The space between two blades that will be cleared from the roughcast is divided to generate CC points. The tool axis vector is confirmed based on flank milling using a simple method that could eliminate global interference between the tool and the blades. The result proves that the machining methodology presented in this paper is useful and successful.

关键词： five-axis impeller tool-path planning flank milling ruled surface