MIKRON is high-powered machining center of 5 axes linkage in aviation engine titanium alloy impeller processes the application that go up

The whole that machines difficulty to analyse article place to consider is centrifugal type impeller, exterior surface roughness is worth a requirement to be Ra=1.

6 μ M. Blade curved surface is free curved surface and curvature change is big, outline precision asks to achieve 0.

05mm less than. From the analysis on the structure of impeller, because flow path is narrow, produce treatment extremely easily cutting tool and draw near blade collision interference, need machine tool swings the axis is had bigger swing limits, let interference with be helpful for cutting tool avoiding in limited space. Span of blade root ministry is made an appointment with 1.

2mm, root ministry round role asks to be less than R2mm, and blade length exceeds 40mm again, how to achieve fast purify surplus, need union considers the tigidity of design of characteristic of titanium alloy material, cutting tool and machine tool main shaft. Blade ply is thinner, the weakest position is 0.

5mm, the largest position also only 3mm (see a picture 1) . How is vibration overcome in machining a process, realize better appearance to machine quality? Besides high speed main shaft and the choice that can realize high speed to machine cutting tool of titanium alloy material, also ask the machine tool machines stability of process trends performance in linkage. From the analysis on impeller material, titanium alloy is regarded as the material of impeller widely with its good mechanical performance, but titanium alloy belongs to difficult treatment material in machining, its machine difficult and main show to be in the following: (1) cutting temperature is high because the coefficient of thermal conductivity of titanium alloy is very small (the 1/5 that is iron only, aluminous 1/14) , the heat in metal cutting of the generation when cutting comes out not easily, inside the lesser limits that is centered around cutting area and cutting blade, cutting temperature is very high, cause workpiece burn, cause what bate of cutting tool material accelerates cutting tool to wear away, this is a when titanium alloy machines marked characteristic. (2) the chemical active of titanium falls in high temperature greatly easy wait with the oxygen in atmosphere, nitrogen, hydrogen produce intense and chemical reaction, build the hard fragile layer such as TiO2, TiN, TiH, cause already cutting area and not the hardness of cutting area is inhomogenous, cutting tool gets power not all, of aggravate cutting tool wear away. (3) flexibility restores model of flexibility of big titanium alloy to measure for 107.

8GPa, it is the 1/2 of steel about, below cutting strength effect, the cutting with meeting large generation is out of shape and big flexibility restores. The place on put together is narrated, the treatment efficiency that how improves this kind of impeller (shorten from the handling time of 30h the handling time of 18h) with blade figuration quality, need considers each element make choice of integratedly the technology program with appropriate equipment and proper design. 2.

Treatment program 　 (1) the machine tool chooses to shorten handling time, rough machining need goes efficiently surplus. Be in low rotate speed, big in cutting late treatment position, concussion load bears in the biggest torsion of main shaft the treatment stability that cutting tool will be helpful for inside limits. If pursue,2 are shown. While the machine tool chooses, should consider to machine the fabricating characteristics of material. Blade is titanium alloy (Ti6Al4V) material, appropriate of treatment cutting speed is low, cutting temperature should avoid when treatment exorbitant, make titanium alloy from all round oxygen and hydrogen are absorbed in atmosphere, generation organizes change to make machine exterior aggrandizement thereby. Process data considering this kind, cutting deepness but bigger, make point of a knife is under sclerotic layer cutting, be helpful for improving cutting tool life. (2) the join effect that tool of tool clamping apparatus is having workpiece and workbench not just, more important is to be able to be in treatment firm workpiece, prevent vibration. If use special have suck brace up functional special fixture, to improving workpiece appearance quality can have profit greatly. What need an attention at the same time is, the axis should swing to have in treatment process bigger swing horn (more than 90 ° ) , need considers workpiece to be apart from the least space of workbench face, avert the collision interference of main shaft and workbench, if pursue,3b place is shown. Graph 3a is suit sheet, the tool fixture that small lot produces. Produce the business of the type to large quantities of quantities, the proposal adopts appropriative tray to if graph 3c place is shown,exchange location system. (3) craft of cutting cutting tool, treatment and cutting parameter the optimization to achieve efficiency, we choose appropriative titanium alloy to machine cutting tool. The bovine bazoo knife of 8mm of diameter of choice of rough machining cutting tool (φ 8R 1mm) , in order to suit low rotate speed, deep treatment, big go the craft feature that bits measures. Ministry of cutting tool blade appears dentate, the formation that can prevent big grain to cut bits and be helpful for those who cut bits breaking away from. On setting of rough machining craft, cut deep (Ap) amount to 8mm, cutting tool can get when full knife cutting retrorse active force, because use clip of knife handle of common bedspring chuck to hold cutting tool to be pulled easily, choose knife handle of locking of side firm style so. Rough machining cutter track 1: It is among two lamina area, cutting of full knife of mode of 5 axes linkage, monolayer cuts deep 8mm; Later again to two side deflection, feed of the biggest side direction (Ae) value 6mm; The biggest place horn to achieve (A axis) - 102.

6 ° . Use program of this kind of technology to shorten greatly flow path opens rough handling time, if specific technology parameter expresses 1 to show. According to circle of blade root ministry horn sets (R ≈ 1.

5mm) with the graph 4 in the reason outside blade is the least be apart from (9.

9mm) , the 2nd times the cutting tool of rough machining and finish machining uses special cone-shaped ball knife: Top is R1.

The ball of 5mm, handle diameter diameter is 8mm, with 6 ° taper horn joins among. In the meantime, to can cool adequately deep narrow the treatment cutting tool inside the space and in be helpful for cutting bits eduction flow path, should consider to use contain the heat of cold passageway inside the center to go up type knife handle (see a picture 5) . Cutter track of Nextpage 　 rough machining 2: To area of stricture of ministry of flow path root, we try program of two kinds of feasible technology. The first kind of plan uses cycloidal treatment means is progressively by surplus of the purify inside extroversion, monolayer machines deepness 12mm, divide a layer in all, and control of side direction feed is 0.

13mm, implementation cuts deep treatment greatly and can rise go bit amount. But use cycloidal treatment, in enter cutter track of interior of flow path space to be able to have choppy tip dot, cause blade of cutting tool collapse easily. If craft parameter is expressed 2, the watch is shown 3 times, cutter track contrail is shown 6 times like the graph. In program of the 2nd kind of treatment, manage treatment entity to avoid cutting tool to be nodded in choppy needle. Use open mode to machine cutter track first two lamina intermediate area surplus is excised, monolayer cuts deep 2mm, in all 12. Machine means with cycloid in flow path bottom next, use blade of cutting of cone-shaped cutting tool enough long (32mm) characteristic, with side edge progressively treatment reachs the designated position. Cutter track contrail is shown 7 times like the graph. Finish thick go after surplus, finish machining lamina and flow path place get limitative factor, be compared and speech is less. 3.

Epilogue union machines hardware data character and product structure characteristic, how to increase efficiency and the focal point that make sure workpiece quality is research of project technology personnel effectively. CNC Milling CNC Machining