【正文】 ake the workers to operate the spindle achieve the desired numerical accuracy. Third, the depth of the tool feed control Required different processing screw diameter spiral groove depth is also different from the depth of the spiral groove mm from dozens to more than 100 millimeters range around the tool into the institutions required to feed the thousands of ring rotation in order to achieve a screw machining . Feed because of the tool in the tool rotating at the same time achieve motion feed, so on a number of general machine tools used in mechanical, electrical control method of depth of cut does not apply to singlescrew machine. Single screw machine tools give agencies into the following different methods can be feed to control the depth of purpose. The first is: friction clutch and electrical switches to control the depth of the tool feed Its principle is to control depth of cut increases the tool cutter feed mechanism increases the load torque so that the tool feeding mechanism of the friction transmission chain slipping clutch, a mechanical linkage concurrent silent trigger electrical switches, optical signal prompted operator, when manual operator to disconnect the tool into the power sector. The advantages of this control method are: the control method is simple and spare parts processing and operational power from the impact of a sudden. Disadvantage are: processing of different diameter screw to adjust the clutch friction discs pressed the preload spring. Material because of the density of each screw, and the hardness of the existence of subtle differences in the degree of cutting tools sharp differences exist, thus the accuracy of this control method was not too accurate, may lead to screw spiral groove depth tolerance is too large. The second: use of an electromagnetic clutch, encoder control tool into the mix to the depth of Tool feed system, equipped with electromagnetic clutch and a tool for detecting the number of rotating ring gear and a gun encoder. It is a tool of control principle hand screw surface encoder to start counting switch, then start counting counting device, when the rotary tool to preset number of laps when the cutting depth is reached, the electromagnetic clutch automatic off open to the power tool into the concurrent silent, optical signal parts prompted the operator has finished processing. The detection device through the digital display shows the number of feed circles or feed. Torn off and the electromagnetic clutch, the tool does not only into the rotation with the vertical shaft to the sport. The advantages of this control method are: the depth of the spiral groove screw tolerance control more accurate, because of several significant table shows the depth of processing, or want a few laps and the depth of processing or circle the number of operations is also very intuitive and userfriendly. Disadvantage are: electrical control of machine tools at the same time more plex parts of this control method at the processing plant, if a sudden power failure, the prior data set will be lost. If you add in the electrical control of the battery to power at the earlydimensional detection devices to maintain the job, the problem can be resolved. Four, the control gear drive space Single screw machine screw in the processing, due to the spiral groove in the rotary tool and the workpiece rotation to plete the synthesis process. Just cut into the workpiece when the tool in the tangential direction of rotation has been going on a greater resistance knife, cutting tool at the workpiece to be cut when the role of the spiral groove, the tool in the tangential direction of rotation has been going up against a smaller knife and even by the spiral groove thrust workpiece. Because there is a boxhole processing machine tool, gear and other processing error, the tool axis of rotation of the drive space is too large, large amount of socalled open. Detect drive way too much space is a fixed power and output shaft rotation shaking, in the case of the transmission structure of conventional design and manufacture of machine tools, the transmission output shaft angle space at more than ten degrees to the dozens of degrees. Transmission gap caused by too large spiral screw groove surface then there is obvious marks, thus affecting the machining accuracy of the screw. Upon pletion of the assembly machine tool axis of rotation of the drive space is too large, in fact are subject to various errors gear, creating a backlash of the gear is too large. Machine tools in the mechanical transmission gear are used regardless of the accuracy of a few of the class, the designers take into account the gear manufacturing error, processing error box center distance, temperature, lubricating oil film thickness, the assembly error and other factors, machine design must ensure that transmission gear A certain amount of backlash, backlash decide the size of the gear tooth thickness tolerance size. Singlescrew machine has the Main Drive from other machine tool structure specificity. In order to reduce transmission or reasonable gap singlescrew machine tools currently used by the following two ways. The first is: the installation at the output shaft brake Tool at the output shaft rotating the location of cylindrical symmetry with radial brake, brake stand up to the tool frontend of the cylindrical rotary output shaft, brake for spring preload. The working principle of the brake is generated by the friction brake to increase the output shaft damping, reducing the sensitivity of the rotation axis. Are: brake and easy does not change the structure of the original machine tool structure, the method of indirect reduction to achieve the purpose of drive space, in practical applications there is a certain effect. One disadvantage: the prespring brake tool because of the cylindrical output shaft to exert a greater radial force, in fact increases the l