The problem of escape corner

87 ° -- want cutting tool way only along linear. Surfware company (Wei Si Telai overcomes a village, california) Glenn Coleman of vise general manager does not agree with products plan ministry this kind of view. He thinks, a chance that increases mill to grind efficiency ever by oversight, the fundamental respect of CAM software is main limitation element. He says, of this kind of circumstance best and paradigmatic the engine of computation of method of new-style cutting tool that is this company development " the limitative element that material cutting leads is not any other hardware components in cutting tool of machine tool, cutting or treatment process, " Coleman says, "Limitting a factor is the input of the machine tool, namely drive their cutting tool method. The order that the machine tool receives according to them only carries out the job, cutting tool method issues a statement. " typical cutting tool method often drive cutting cutting tool enters corner office, here, treatment load increases, programmer of requirement NC numerical control uses reduced treatment parameter. This is meant reduce speed of main shaft rotate speed, feed or cutting deepness, reduce cutting step pitch or some kind of combination of these circumstances, so that protect cutting cutting tool. To breach this kind of set back, the developer of Surfware company people slam the door the basic idea that method of existing cutting tool builds, rebuilt to be based on treatment kinetic (they say from numerical control technology at the beginning of it by oversight) cutting tool method. Horn of clench the teeth occupies Introduction Coleman, actually strategy of method of all and existing cutting tool is based on a kind of such thoughts, maintain cutting namely between constant cutting step pitch, be in at least a ministry. This is the idea that shakes from the hand the reservation when brace times and numerical control initial stage comes down -- the immediate goal in those days is to make the hand uses treatment method automation. As a result reservation is affected up to now. "This is improper, because maintain constant cutting step pitch,make inevitable generation blame constant on cutting cutting tool load. The blame on cutting cutting tool is constant load is to cause the cause that is forced to use reduced treatment parameter. " he says. When cutting cutting tool enters corner, the much of cutting tool is surrounded by workpiece material or with workpiece material clench the teeth. The part of this clench the teeth of cutting tool can come with one angle magnanimity and express, namely horn of cutting tool clench the teeth (TEA) . A few basic maths knowledge explained why this angle is very important. Cutting has geometrical concern between step pitch value and TEA. For example, 50% what be like cutting step pitch to be diameter of cutting cutting tool, criterion 90 degrees of cutting tool periphery with material clench the teeth. For example, 10% cutting step pitch is equivalent to TEA for 36.

87 ° (if pursue,show) 1 times. Given to random value of cutting step pitch, have a TEA that answers relatively to it only. But, should use constant radial cutting deepness only and along when linear cutting, this ability holds water. When cutting tool turns, the function that TEA increases the angle that is this corner or radius (if pursue,show) 2 times. Of TEA this kind increases is the cause that causes cutting tool load to increase. Graph 2: When cutting cutting tool arrives at corner, horn of clench the teeth increases quickly, when although be in,value of cutting step pitch keeps identical. Below this kind of circumstance, the value of cutting step pitch of 10% created the character of clench the teeth that is more than 128 ° . Graph 3: The chart of horn of cutting tool clench the teeth showed the result between method of left Truemill cutting tool and method of right tradition cutting tool is comparative. "So, as a result of it historic, build strategy of cutting tool method in maintain cutting between constant cutting step pitch appears to did not follow best logic on this one thought. " Mr Coleman summary says. The problem is the change of cutting tool load, it makes cutting cutting tool is immersed in adverse circumstance to fall. Unless operator perhaps controls equipment to adjust treatment parameter,plant in order to reduce this circumstance, have the service life that caustic has at the knife otherwise. Exterior precision and other work feature also can get bad influence. But, when undertaking adjustment, periodic time may increase. Although TEA cannot keep strictly constant, but the company thinks to be able to control it to reach very favorable situation stoutly. Be based on this kind of understanding, software project team begins to ponder over CAM software afresh, the product that includes their Surfware him company, and how is the cutting tool way that mill grinds generated. The course grooms, machinist and programmer of NC numerical control people consider this one issue, how can be the control of mutual to cutting tool and workpiece material clench the teeth used in cutting tool algorithm. These algorithm must apply at the algorithm in CAM software to differ normally with those. The formula that must develop place of method of computational cutting tool to need has code to its. "Design strategy of method of a cutting tool to realize this one purpose to be not bagatelle, executive solution is more difficult, but these had been finished. " Mr Coleman says. The height that the design the concept promotes economic product needs to use mathematical tool and process designing principle, the company thinks these never are used at CAM software development before. The final result of effort is engine of computation of method of TrueMill cutting tool, it has been gone to by union in the SurfCAM Velocity product of the company. This software makes the way that suits TEA suppose linear cutting, the diameter of the cutting step pitch that considers user definition and cutting cutting tool will decide corresponding TEA. Make cutting tool way then, horn of cutting tool clench the teeth never passes big. "Because cutting tool method is not to be based on constant cutting step pitch will decide, so their motion and those are based on constant the cutting tool motion of cutting step pitch is completely different. " Mr Coleman says, " because such, for the person that sees them first to great majority, they look some unfamiliar, strange even. " however, the method that adds cutting tool way very quickly looks is not very important; How to make it became serious problem more satisfactorily. Through maintaining TEA under a foregone threshold value, cutting tool load also is maintained under a foregone threshold value. This makes programmer people can use commendatory feed rate and rotate speed to serve as the smallest parameter, they can increase according to the function of uses machine tool and cutting cutting tool. Below existing technology, major programmer uses commendatory feed rate and rotate speed to serve as the threshold value that cannot be transcended, the limitation that offers according to cutting tool method will reduce them. But, this kind of eclectic practice sacrificed material cutting rate. Design engine of computation of method of new cutting tool to prevent this kind of eclectic practice. When cutting cutting tool moves along material, it changed the material form of next cutting. To control the clench the teeth between cutting tool and material, the data that must dominate this kind of dynamic change is attrib border. Say according to the company, motion of all cutting tool passes computation, because this can be accurate,know next cutting making material border. The computation that this means cutting tool method is the need that is based on material cutting, is not a basis appearance of spare parts geometry. "This method still facilitated the strange exterior of cutting tool method; They are not by the appearance place drive that machines area, " Mr Coleman says, "Of course, this appearance is built finally, but when be being passed finally till cutting tool, it just can become apparent. " hear in the machine tool (or did not hear) what got controlling because of the clench the teeth of cutting tool and material, compare the stress that the place of cutting tool method that makes at other method produces so, the stress on machine tool and cutting cutting tool is gotten less much. Corner is in the noise that did not chirp, because these cutting tool method do not have corner almost. Mr Coleman says, normally, the sound that gives out from main shaft electromotor or cooling pump greatly prep above by the sound of cutting metal. If there is acute angle corner in cutting tool method, cannot control TEA effectively, so software does not generate them. Graph of attrib border geometry may include acute angle corner, and it may be aleatoric appearance, but all shift of cutting tool method keep flowing and tangent. But, it is to see it go up quickly from the machine tool to the true magnanimity of any cutting tool method purify material. Surfware claims the user is being experienced " produce efficiency all-timely to grow up to now " . For example, a client that processes aluminous model plug-in unit to be aviation spare parts only reports, machine this spare parts to want to spend a hour many a little bit before, but use TrueMill to machine a spare parts to want to be less than 8 minutes only now. "The result just becomes fast not just a few percent, compare the cutting tool method once upon a time, the time that machines a spare parts has a few original only. " Mr Coleman says. Graph 4: The cutting tool way that green of screen upper part represents expresses to be in how can much outside work control cutting tool clench the teeth in cutting in groovy rough machining. Screen lower part shows increase cutting tool method to choose corner in order to facilitate, the cutting tool previously is too big so that cannot reach these places. Method of new cutting tool still controls cutting tool clench the teeth. The software that controls TEA is proved apparent particularly effective to harder data. Introduce according to Mr Coleman, because in the cutting tool in harder data overweighted adverse consequence compares weak data,this is in more serious. A lot of newest cutting cutting tool can endure the case that gets overload in the weaker data such as such as aluminium, at least now and then and short-term inside, he says. "But when should processing tool steel for example, the circumstance differred. In such material, had been in below rapid feed rate, although appear only circumstance of cutting tool overload, can bring about cutting tool damage badly. " the overload that because controlled TEA to avoid cutting tool,goes up, this one cause that causes trouble so is a problem no longer. It is 1/2 with the diameter inch 4 chamfer carry integral hard metal milling cutter, main shaft rotate speed is 12000rpm, but rate of process designing feed is 1000ipm. This does not use light cutting to finish. The axial deepness of cutting is 1/2 inch, TEA is 64 degrees, it is equivalent to 0.

Step pitch of 140 inches process designing cutting. Some mill mill of Germany grinds Rockwell hardness to be the material of 64C, feed rate is 300ipm, use a diameter to be the cutting tool of 8mm, it contains radius to be the pushbutton type razor blade of 2mm. Occupy a report for consistency, use be based on constant one of defect of the cutting tool method of cutting step pitch are cutting tool function abhorrent. The result that the metabolic place of cutting tool condition creates is forecasted hard, must monitor them closely so. Mr Coleman says, but, produce the consistency of cutting tool method of higher rate to the control of TEA, this character had gotten an user people the most positive assessment. "Because cutting tool load does not have peak value, if the method of new process designing is beginning,work inside a few seconds so good, so it works extremely likely from beginning to end good. Operator can go away from the machine tool and need not worry about accident circumstance to happen, need not control to the adjustment of feed feel hesitant. " he says. Graph 5: Do not follow constant the cutting tool method of cutting step pitch looks irregular, abhorrent, but the condition of cutting cutting tool keeps constant and have the law, avoid to produce stress, it can make cutting tool ruptures to perhaps shorten the service life of cutting tool. Leave constant cutting step pitch means the certain and sealed field that enters treatment, mr Coleman complement says: "Because this is a new field, have a few sealed cases so. " can prove, the biggest question in these sealed circumstances is to lack relevant treatment data. Existing data too too conservative, he says. He predicts need understands through the experiment a lot of. Surfware proposal runs simple linear experiment cutting in the brim of a preform, such users can find ideal treatment parameter, they offer the optimal combination of material cutting rate and service life of cutting cutting tool. The company thinks the user can feel quite open-eyed, open-eyed can be at them below so ideal treatment condition such apace cutting. Thenceforth rises, no matter the appearance of the spare parts how, those parameter can be used at identical cutting tool and same material. Likewise important fact still has cutting cutting tool to become apparent more durable, although machine parameter,increase. Graph the 3 identical groove that showed the process designing of method of SurfCAM cutting tool that uses method of TrueMill cutting tool and level respectively. Because method of the first cutting tool offers controlled cutting tool load and automatic ground to clear, can be worth with bigger than standard way cutting step pitch so to it surely process designing, if this experiment place is shown. On the common site that selects from inside cutting tool method, method of the first cutting tool never exceeds its target TEA, and standard way nearly always its target is worth prep above. Standard way includes cutting tool the area of complete clench the teeth. This explains, although be below bigger treatment parameter, the stress that compares the way that makes with existing technology to arise on cutting cutting tool with new way is less. The developer of this software people 2005 autumn release SurfCAM Velocity, begin user of its consign terminal. In this version, mill of axis of 2 1/2 of Technical Board be confined to. The company plans to be in 2006 extend this one concept first quarter to complex much surface thick mill function. Graph the 4 results that previewed this kind to extend. CNC Milling CNC Machining