The problem of numerical control process designing that high speed machines and skill are discussed

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  • source:LAMOND CNC Machining
High speed treatment serves as one of efficient process instrumentation, wide application received in current manufacturing industry. High speed is machined from on century end is entered practical after changing level, got response instantly in domestic manufacturing industry, our project technology personnel is opposite initiative phase to machine equipment and process designing method at this kind very unfamiliar, because this encountered a lot of problems in applying actually. End at present, this kind of process instrumentation has not been been familiar with by personnel of large-scale project technology far and master, this report from inside the forum on current media and net can see. A few problems in be being machined with respect to high speed here and skill undertake a few discuss, the hope can be brought to everybody a few inspire and help. High speed treatment included two implications, it is revolution of tall main shaft, usually main shaft revolution is in at least 12000 turn / cent, current and highest can amount to 60000 turn / cent (Mikron can supply this kind of equipment) . 2 it is high speed feed, feed speed divides rice in every commonly even a few meters, because the regular job status of cutting tool of machine tool equipment, cutting and common treatment have very big difference, when because this is in,writing CNC Machining program and technological process cannot again the train of thought of the same old stuff of continue to use. In process of high speed treatment, because feed rate is very old, machine tool main shaft (or the athletic component such as workbench) inertial become cannot an element of oversight, choose in what the machine tool is designed and control a system in matching a course, should give adequately consideration. Face the successful product of the market as, this kinds of equipment was designing production process cogency to be made in this respect surely of a lot of improve. Must not think nevertheless, inertial problem was solved thoroughly at this point. In use process, hour of the person that use should consider this factor, use otherwise undeserved, can shorten not only the service life of facilities of existing high speed treatment, the product quality that still can produce to you produces an effect. We do not discuss the design of the machine tool and the issue that how production process improves here, what pay close attention to here is the note in use process. Machine the influence with the inertial machine tool in the process to avoid high speed, theoretic it is OK to want us to decrease to change feed way in machining a process as far as possible in cutting process only, but come true really impossibly actually, change feed direction often is used inevitably, at this moment when we are taking a knife for nothing as far as possible inverting, do not be in cutting position in cutting tool when haul; Or feed rate is lowered before changing feed way; This wrote machine program to raise a difficult problem to us, can choose appropriate CAM software to complete process designing work at this moment. Pursue for example 2 medium example, we choose the means of corkscrewed yarn to undertake mill is cut, its effect should compare a figure many what 1 medium traditional mill cuts means effect to be close friends. Feed way is changed when choosing cutting tool to not was in cutting position as far as possible. For example below two example: Graph 3: Use circular arc to derive (guide) the cutting tool when making cutting direction changes is in blame cutting position: Graph 4: When cutting direction is being changed to wait for special appearance in treatment antrum when cutting tool derives completely, because cutting tool derives without method, when process designing, corner part uses circular arc to transfer as far as possible, so that make change direction,change as far as possible smooth, if can be in corner when lower feed rate appropriately, so the effect will be better. In high speed treatment, notice the control of cutting deepness even, here has two levels to need to notice, one is the axial cutting deepness of cutting tool, one is the cutting deepness of cutting tool radial. The control of cutting deepness to whether the action that machined a beautiful spare parts and a service life that prolong cutting tool to have special key. The person that at present great majority is used is used to be in finish machining when treatment of use high speed, actually rough machining when cutting of use high speed is OK faster eliminate mental allowance, also should popularize use; Usually, in rough machining process, use axial is small cut deep, for many times statified cutting get rid of gives mental allowance is the most commonly used treatment method; In finish machining process, cutting of small surplus high speed can get very good surface machines quality, this basically is a needle the finish machining in mould production process, cannot copy absolutely, grow a reason in finish machining for example when, we should consider treatment metabolic is affected, if choose the finish machining way of small surplus right now, can increase a reason metabolic influence. Right now we use large surplus commonly statified the method of cutting will reduce an edge intermediate metabolic influence. A few surplus are withheld more when rough machining that is to say, the reservation that is not customarily is less surplus has precision work; (this kind of long and thin predestined relationship is machined on convention when, usually width achieves with deepness comparing 1: 5 when, machine a predestined relationship intermediate part predestined relationship changeless form already very not easy, if use high speed treatment, achieve 1: 10 very relaxed however) following graphs: Graph large surplus is statified in treatment of 5 high speed cutting finish machining predestined relationship the choice of the cutting tool in treatment of high speed of give typical examples is very important, current tool supplier can provide the cutting tool that suits high speed treatment almost, choice cutting tool basically has the following two respects regard, one is high speed rotates the dynamic balancing condition of next cutting tool, another effective cutting time that is cutting tool (namely cutting tool life) . To make sure high speed rotates the cutting tool below condition can circle axes stability to rotate, use two kinds of method at present, it is to use the cutting tool that contains dynamic balancing device, machinery was installed to delimit inside broach shell piece or use design of fluid dynamic balancing; Plant even if use integral cutting tool additionally, broach shell and cutter hub close for an organic whole, actually the purpose assures to installation gap is reduced in cutter hub and process of broach shell installation namely, integral cutting tool this respect is optimal, but the broach shell as a result of cutting tool and cutter hub are an organic whole, once cutter hub discards as useless, broach shell also discarded as useless together, cost is accordingly higher. Use heat to bilge cold the method outfit that shrink places cutting tool, also can get very good result, be about to after broach shell heats through adding shrinkage fitting buy, reload enters the method of cutter hub, cutting tool can intensify after waiting for refrigeration. In process of high speed treatment, of cutting tool wear away should compare low speed position a lot of bigger, because the life of this cutting tool also is an account that treatment of influence high speed uses extensively, when use high speed is machined, should find to reduce the system with cost and the equilibrium point true ability that improve efficiency to reveal the value that high speed machines according to the actual condition of factory oneself. Whether to choose high speed treatment, cannot blind follows suit, do not see so that all industries suit to use this kind of process instrumentation actually, high speed treatment can improve treatment efficiency admittedly, but the cost as a result of equipment, cutting tool is corresponding also rise, because this is found,one increases efficiency and the equilibrium point that drop cost especially important. High speed treatment can improve treatment efficiency not only, still can overcome the difficult problem of a few craft that encounters in low speed treatment. For example, the spare parts is machining the existence in the process to be out of shape, a very headachy problem is in project application, use common treatment method, often cannot get ideal result, the measure that can consider to use high speed to machine right now will solve. Above all, the heat in metal cutting that arises in process of high speed cutting has 90% to be cut bits is taken away, is not in conducting work, so OK greatly because heat in metal cutting passes into workpiece,reduce, make workpiece produces heat to be out of shape. Next, can see in above example, the reason grows in treatment in the process, if use small cut deep statified the method of treatment, can reduce the influence of radial cutting power to workpiece, reduce workpiece to be out of shape thereby. Additional, high speed treatment still has an accepted profit, the exterior quality after be being machined namely is very good. When if be,using high speed to machine, cost factor appears so not important. Anyhow, whether to use high speed treatment, the scale that uses high speed treatment wants to decide according to the oneself circumstance of the factory. Efficient process instrumentation is machined besides high speed at present besides, cutting deep puissant cutting greatly also is a kind of significant step actually. In high speed treatment is done not have practical before changing, people had been made in this respect a lot of research and discuss, high speed is at present little cut deep treatment to compare popularity, but cut deep puissant cutting to also was not forgotten greatly. Still perhaps can be paid close attention to by people afresh one day, the industry characteristic that the reason differs namely and treatment content are having different pursuit cause. CNC Milling CNC Machining