1、 Bio Applications and Systems Eng, Tokyo Univ of A griculture and Technology, Tokyo 18428858, Japan. Abstract: This paper uses HexaM made by ToyodaMachine Works Co.as an analyticalmodel of parallel mechanism type machine tools. Much collision may be generated for its complicated structure and workin
2、g space, when a workpiece is mach inedusing this machine. For example, those collisions are generated.between the moving components of the parallel mechanism ,between the moving components and a workpiece and between themoving components and the tool storage for autom atic changing.In th is paper,an
3、 algorithm for detecting and avoiding those collision swasproposed. The method for avoiding the collisions was conducted by readjusting the location of the workpiece without am ending the toolpath.It is confirmed through experim ent that the proposed algorithm is useful for detecting the collisions
4、and determining the location of the workp ieceprior to the actual machining.Keywords: parallel machine tools;ollision check; avoidance; toolpath; in stallation site In recent years, the PMT development and application of the growing, but because of its structure and working space is very complicated
5、, use it for processing the workpiece, it is very possible the machine components themselves interfere with the workpiece and the machine interference. Also, if like PMT HexaM 1, work on stage in the installation of automatic tool change devices and other peripheral equipment, the installation of th
6、e workpiece. It may limit the installation of the workpiece location, that is, peripheral equipment and workpiece interference that may arise when processing machines and peripheral equipment to interfere. PMT on their way to check interference and machine work space has been much research 2 5. Amon
7、g them, This writer and other Japanese companies Toyota Machine Works of PMT HexaM 1 as a model. Discussion of PMTs their interference in the inspection, the work space approximate expression 5. the other hand, 5-axis NC machining, cutting tool （knife, Chuck and Spindle） and the workpiece （workpiece
8、 and fixture） interference methods also have many. Among them, Takeuchi, etc. 6 tool system from the surface for a number of points as interference checking, and the workpiece surface are relatively simple function, when interference check point at the internal functions, be able to judge for the ma
9、chine and workpiece occurred interference; The author, etc. 7 and the method proposed here just the opposite. that is, from the workpiece surface, system selection interference checking, whether the system access tool for interference checking. As CNC machine peripheral devices are not generally pla
10、ced in the work tops , So, in these two methods, they did not consider processing machines and peripheral equipment to interfere in the issue. These studies are discussed in detail PMT their interference in the machine tool and workpiece and the interference checking and evasive methods, However, th
11、e use of PMT ago, but there are several problems : working platform for peripheral devices such as a barrier Machine 1 should consider the machines and peripheral equipment possible interference; the inspection machine and the interference of the workpiece. Consideration should also be given spindle
12、 plywood, plywood hinge link with the workpiece and the possibility of interference, However, the existing CAM software does not include such interference detection; machine when there is interference with the workpiece. General Tool always postural adjustments to avoid interference. In fact, PMT, i
13、n addition to postural adjustment tool, You can also adjust the location of the workpiece to avoid all interference. Moreover, This approach avoided the biggest advantage is not to change the existing CAM software. Based on common CAM software tool path of the output-based, shorten the time to inter
14、fere in the inspection checkpoints document composition, By adjusting the location of the installation of the workpiece to avoid the possibility of all kinds of interference, of the workpiece can test for processing at the workpiece and machinability best installation location calculation. 1.Interfe
15、rence checking and avoid interference Using the PMT HexaM, peripheral equipment （the knife） and the workpiece installation diagram shown in Figure 1. Therefore, For the machine, during processing and installation of the workpiece at the possibility of interference with his interference, machine tool
16、 and workpiece interference machines and the peripheral equipment, and interference with the surrounding devices workpiece interference. If you are using a parallel machine table without peripheral devices or devices placed around the far more, will not affect the location of the workpiece machining
17、 process or there will not be machines and peripheral equipment interference, can be omitted from the workpiece and the machine and equipment around the interference checking. F ig. 1Schemat ic of the parallelmechanism HexaM1.1 Their interference 1.1.1 The composition checkpoints During processing,
18、All tools can be applied to position literature 5 described method to check whether their intervention will happen. if there is interference, can be used in the adjustment of the workpiece location to avoid interference. Parts of the installation location changes, Processing Tool position will natur
19、ally be changed. Therefore, the need to conduct another inspection, not occur until the date their interference. As an installation at each location to location of all the tools for inspection computing time will be very long. To shorten the time of calculation, this is not the right tool for all lo
20、cations and to extract only a small number of knives location （hereinafter referred to as check points） interference checking. Therefore, point out checks must be done : at checkpoints if no interference in its own. in the other cutter location would not interfere in their occurrence. setting up che
21、ck-points advantage of a significant reduction in the frequency of inspections. From the z-axis cutter farther, the higher the position, the greater the degree of tilt, the more prone they interfere in 5. Therefore, wait for the processing of the workpiece, the tool path from the outside to share th
22、e measurement point, the higher the cutter location, tool tilt angle larger point as to determine whether they interfere in the check points. 1.1.2 Interfere with the inspection methods Tool position and posture straight at the moon and the space rotary disk space, it would be interference in its ow
23、n 5. Therefore, they interfere with the inspection methods : read all checkpoints, obtained a checkpoint each corresponding to the straight and rotating space Yuan Yuan space 5. cutter position and posture in response The straight round space and space Rotary Circle, convicted of the checkpoint will
24、 not interfere in their occurrence; In all the check points are not interfered, were judged to be installed in the position not to interfere in their occurrence. If a check point in the location or position of the straight excess space Yuan Yuan, or rotating space, can be used in the literature 5 me
25、ntioned in the inspection methods to interfere in the review. As space than the average round of inspections interference 5 calculation to be much smaller, so this kind of method can shorten each inspection, the computation time. 1.1.3 Avoid interference method As in the same horizontal plane, the c
26、utter in the z-axis location at the least prone to his interference. Therefore, If a checkpoint in a self-interference then we check points and the z-axis direction connectivity as evasive. Then, Parts of the installation location along the direction of movement of evading 10 mm. If two consecutive
27、evade direction of the angle is greater than 150 . that could have been avoided reversed direction in the horizontal plane does not exist in the location to install, so The workpiece can be installed to enhance upward position. In this paper, each increase by 10 mm. If they interfere with the main m
28、otor is a rotary screw lower interference Note workpiece is too high or the location of the workpiece too high, not with the machine tool. 1.2 Machine interfere with the workpiece 1.2.1 The composition checkpoints As shown in figure 2, machine and workpiece possible interference between parts of a k
29、nife, chuck, spindle head, spindle splint, Hinges and plywood link. workpiece can be seen from the surface and surface composition. Among them, Surface processing from the point with machine might happen to the non-interference by non-machined surface processing point is, here, processing and point
30、and non-point processing collectively referred inquiries to the point. F ig. 2Check method of the collision betw een the parallelmechanism and wo rkp iece Inquiries point with knives, and Chuck, The first spindle axis and the splint interference known as a category interference. Such interference on
31、ly with knives, the posture, and workpiece position unrelated to the installation. Therefore, if the screening of such interference, and only postural adjustment tool for evasive, This requires changes CAM software, beyond the scope of this discussion. Inquiries point splint hinge connecting rod or interfere in the resolution as interference in two categories. Such interference can be adjusted through the installation of the workpiece - Purchase avoided. Below these two types of intervention on the check points formed.
