Undertake accurate adjustment to the parameter of the machine tool

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  • source:TRIANA CNC Machining
Oscillatory analysis is to detect a very important facet of machining center function, but also be to be short of a respect that lose at present. If had not undertaken this kind of analysis on high speed machine tool, so machine tool production manufacturer perhaps won't know what the machine tool can do after all. In undertaking milling is machined, because take knife case bad and when giving out shrill offensive voice, experienced machinist and NC process designing member can react somewhat. Insufficient ideal causes the cutting parameter that chooses as a result of its this, face this one situation, they can reduce certain parameter. That is to say, they will move parameter of low certain technology. The certain and specific parameter that they reduce may be cutting deepness, also may be speed and the assorted parameter that feed leads, it is the cantilever length of cutting tool even. No matter be what parameter, "Reduce " it is a when acquire better treatment property flexible strategy. The treatment personnel with relatively rich experience, adjusting these parameter respects are special adroitness, they can lower these parameter necessary rate, in order to make its reach acceptable cutting level. In most job shops, the method that uses this kind to reduce treatment parameter -- this kind of eclectic plan -- a kind of when be regarded to be operation personnel proper response. However, in high speed treatment, using this kind of method that reduces treatment parameter is not correct answer measure. In fact, people discovers those who run in the opposite direction to this one practice is the essence that machines with high speed even. Parameter itself is very important, if rotate speed of cutting deepness, main shaft and cutting tool length are met,affect the performance of treatment. However, the machine tool that machines when a high speed gives out brace up quavery, the processability that mirrors a machine tool can be behaved not when beautiful, "Reduce " parameter may be just the opposite to what one wished. Have a lot of workshops that use high speed machining center, with respect to the because of this actual productivity that wasted them for nothing, cannot reach goal of production finally. In domain of application of high speed treatment, to obtain more stable cutting treatment, a lot of manufacturer still perhaps need to use parameter " reduce " means, but have a kind of more effective method, use parameter namely " on tone " means. If involve main shaft rotate speed and cutting tool length at the same time these two parameter, so deal with brace up quivering better answer will be to raise among them certain parameter. Although this looks a little strange, but practical experience makes clear, higher main shaft rotate speed and inferior and rigid cutting tool, perhaps occupy only firstly, can allow machine tool processing to have invasive cutting depth more, because these change make oscillatory tendency of the system more harmonious. Always realise this job shops, can understand the true essence that high speed machines, work inside limits of main shaft rotate speed namely, by intuition or experience cannot decide, different situation falls to have different ideal cutting requirement. There is an opportunity now job shops understands this very, this workshop is located in a branch of the Warner Robins air base of Georgia namely. The workshop that the milling treatment in war industry course of study can undertake this reacting quickly is air force a branch of military unit corresponding to a company of maintenance of the 402nd the 573rd product in safeguarding a group. The task of this job shops includes battleplan and transport to change the treatment of spare parts, the whole world always flies to the refill-unit of all planes of this base, be in charge of machining by its. The maintenance here is very frequent, because these planes need apace to return action status, accordingly this workshop often needs to ask according to limited delivery time, small lot is produced a few complex the component with the key. Process designing member Mr David Devore and Mr Mike Estes say, begin to use high speed machining center when this one job shops at first when, they are right this utterly ignorant, the use efficiency of this machine tool is very so low at that time. When using these machine tools to undertake machining, cutting tool often is broken off, include 3/4in among them (1in=25.

4mm) end panel milling cutter. From the point of the reaction circumstance of this one workshop, can be rein in only the cutting speed of certain treatment project (graph 1) . The job shops of company of graph 1 Warner Robins, purchasing its after the high speed machine tool of top rotate speed, the milling that begins survey to use resonance frequency machines a circumstance but, be introduced from Makino company when this workshop and install its highest when machining center of the MAG 3 that amounts to 30000r/min high speed, they undertook to this machine tool " knock experiments " . That is to say, this workshop uses an acute hammer, resemble making the cutting tool that Zhong Na installs in appearance stroke main shaft, in order to test the oscillatory character of the machine tool (graph 2) . Graph the machining center of 2 specific to a kind combination, knife handle and milling cutter, use " knock experiments " can finding the end that makes metallic cutting speed achieves top main shaft rotate speed and cutting deepness Nextpage to use method of this kind of analysis is to find out each cutting tool that uses on specific machine tool or knife handle the stable cut speed after debug. Be in Robins company, once found these stable parameter, they use their go up at new machine tool, improved the treatment quality of this workshop spare parts, productivity and cutting tool service life thereby, and the level that when overall index exceeded milling of its high speed to machine, reachs. Because difference is such big, because this this workshop decision is on its existing high speed machine tool,also undertake same assaying. On these machine tools, this workshop discovers, when move with quite high rate when its and exceeding the rate that place runs all the time before this workshop, the work of a lot of cutting tool is more steady, richer effect is more safe. After switching on the mobile phone, make its speed agrees with these optimal parameter, the workshop begins instantly more work quietly move, cutting quantity increases, the treatment quality of the spare parts rises, and the phenomenon that cutting tool did not appear to be broken off. Air base of graph 3 Warner Robins Air Force Base provides a service for freight plane and battleplan. Job shops backs this machine the execution of this one mission now, this workshop begins to use the parameter that obtains from inside oscillatory analysis to run high speed machine tool. When exceeding fixed rate, this workshop realises, this kind of analysis achieves overall beneficial result to the machine tool actually crucial. This among them reason and resonance frequency are concerned. The avery kind of of machine tool, knife handle and cutting tool is special combination, have specific stable rate value, allow a machine tool to be able to reach the biggest cutting deepness and metallic cutting capacity thereby. Back-to-back move still has more explanations, but now, its enough shows an issue, but cannot conclude these come from the rate value at experience. To Robins company, also do not have practical method, will find stable parameter through trying cutting, because this workshop often uses a lot of cutting tool. Accordingly, this workshop and outside assist cooperative unit signed a contract, it can help this workshop measure the vibration of all machine tools quickly, the assorted circumstance of each cutting tool that uses daily according to the machine tool next or knife handle, decide its first-rate speed and cutting deepness. Graph 4 the member that can see technical personnel installing the part of a new treatment process designing of dashboard of cutting tool of the Nextpage on the wing of the plane from here says, present cutting function can keep basically identical. Especially the environment of the workshop produced very big change, as a result of brace up quiver decrease, the treatment environment inside the workshop is very quiet. And, can have depth with higher rate as a result of high speed machine tool puissant cutting, and do not produce cutting tool to rupture phenomenon, because this machine tool has taller manufacturing efficiency. Besides, can provide the information that concerns optimal treatment parameter again now, because of this process designing member the manufacturing efficiency of itself also rises further. Offer them now among them a resource is " cutting tool dashboard " , the member that it can let these process designing forecasts the character that for some specific milling takes any cutting parameter of knife place make choice of and setting and productivity accurately. Now, when among them after the cutting tool that place of machining center of a high speed uses and knife handle make choice of, can choose its according to their circumstance optimal parameter. In fact, analyse obtains parameter according to vibration, will be inputted automatically in Catia. When these cutting conditions need to adjust a setting, if cutting deepness may not accord with cutting to ask, concerned parameter can undertake drill accusing through cutting tool dashboard, in order to find out another group of effective cutting conditions, in order to eliminate the source of generation flutter. Even if feed speed, also can undertake modulatory through this kind of means, namely according to main shaft curve pitching moment to have a test to its (graph 5) . Graph 5 in cutting tool dashboard " rotate speed " on the watch, green area represents the stable cutting district of this one specific cutting tool. Dashboard of this cutting tool can make process designing member hold easily charge deepness of speed, cutting and cutting load, can change according to the trends of the machine tool circumstance, company and BlueSwarf company signed the influence Warner Robins that forecasts these change to coop goes " knock experiment is analysed " and offer include cutting tool dashboard inside agreement. BlueSwarf company is a business that pursues assaying of machine tool vibration technically. This company is sold to a few job shops " Metalmax " analyzer, use at the internal analysis of the workshop, but this company also will analyse the job to contract for those in the spot outside assist the job shops of the unit undertakes analytic metrical. Real test is the cutting tool that simple knock runs in machining center only, use an acute hammer stroke cutting tool that is to say, the sensor that goes up through point of a knife next takes feedback news. Because differ,assorted cutting tool and knife handle need have a test respectively, because this is whole,assaying may need to cost a few hours or time of a few days. The detail of certain cutting tool, if there is what relation between round horn radius and test result, because this is not of each cutting tool,each real data must check. Nevertheless, the job shops of Warner Robins company still needs to check 45 ～ on machine tool of every high speed the setting value of 50 cutting tool. Specific rate so, why does machining center need so do? Why machining center in the rate with specific some or the cutting tool that use specific length can Where is better job? This answer and a fact concern: Each mechanical system contains some of a few groups of solid natural and oscillatory frequency, machining center, knife handle and cutting tool system are not exceptional also. This system has these natural frequency, in its cutting adds man-hour, on certain level, it can produce vibration according to these frequency. Can machining at the same time apparently occurrence microwave effect. These wave motion may produce slight effect to machining a knife. And, this also may affect feedback orgnaization, to cutting treatment is caused damage. This machine tool has encountered the situation with this kind of fluctuant surface when cutting is machined. This kind of fluctuant meeting causes the change of cutting deepness, the result makes the bear on cutting tool also produces wave motion. This kind of wave motion often is negligible, the reaction of the machine tool is very so little also. However, in puissant cutting process, oscillatory extent can become more apparent, actually fluctuant itself also can produce driving force. The deflexion of cutting tool can cause bigger ripple, this will increase the oscillatory rate in cutting deepness. Vibration of type of this kind of self-excitation is so called actually " brace up quiver " . The treatment quality of the service life of cutting tool and spare parts can be affected, the sound that gives out makes a person be borne hard more. Nextpage arranges the place of 10000r/min more than in main shaft rotate speed, installed a distinct possibility. When be in higher rate, the natural frequency of the some cutting speed when making edge and workpiece are contacted likely and this system is harmonious and consistent. When this kind of circumstance happening, the machine tool still is worn in vibration, but point of a knife basically moves as ripple. Right now, cutting bear is consistent and balanced, cutting is very smooth. To a lot of workshops, this kind of result is a kind of appearance that makes a person very strange, the main shaft rate with certain very high specific speed, taller cutting deepness is achieved when can allowing its to compare high rate or inferior rate. The graph is shown 6 times accountable this one problem. Inside the scope of rotate speed of whole main shaft that sees from here, the efficiency of higher production cutting that peak value indicates to this one specific machine tool and place of cutting tool setting can be achieved. The section that contains alternate shadow line expresses to produce the place of flutter. Accordingly, when rotate speed is 17792r/min, the stable cutting treatment that has depth of especially big cutting is likely, if the traversal speed of the machine tool summary prep above or be worth under this slightly, although did not achieve the puissant milling of same standard,also be likely so. Actually, always do not understand the job shops of this one magical speed, won't know its machining center can do some of what business after all. Graph legend of this 6 stability makes clear, inside whole speed limits, range is brought in the main shaft rotate speed of specific stricture inside, the depth that increases cutting is likely. The rate that the purpose that knock experiments stabilizes to find these namely in fact, job shops also may not know its cutting tool can do some of what business after all. The distinction of the function of magical and characteristic cutting tool of cutting tool, announced high speed machines a respect a more potential striking fact. When to Warner Robins when BlueSwarf company the company's oldest high speed machining center undertakes beating a trial, it discovered a scheme 7 in shows phenomenon. Generally speaking, shorter cutting tool can undertake milling is machined steadily, but be not always is such. On this one specific machine tool, when using two longer cutting tool, discover this system can have the job steadily actually, can achieve bigger cutting deepness, of its cutting tool if the graph is shown 7 times,debug a setting. On this one specific machine tool, the flexibility of cutting tool is taller, the rate of its metal cutting is higher also. Graph 7 in afore-mentioned photographs, the computer showed the test case of two cutting tool, this test has inside the workshop of Robins company at first, after experimenting through a few minutes merely, with respect to the different performance that can see two cutting tool. Gules peak value expresses to use the cutting deepness that place of shorter cutting tool may achieve, and the blue peak value of its backside expresses to use longer this workshop already used the bigger cutting deepness that cutting tool place allows to achieve this machine tool is old, the character of service of this machine tool is good, the information that concerns of course provided very great help. Come for years, the labour tabulation of this machine tool has been compared all the time now. Of the machine tool if do not have these valuable information,move, achieve the goal of such get twice the result with half the effort impossibly, perhaps say, the machine tool moves in potential yield and quality will drop somewhat. CNC Milling