Change nicety of pitch guide screw machines research

Keywords:vOverview of CNC1 of 　 of Cutting Principle of 　 of Screw of Ariable Pitch 　 increases of the function ceaselessly as contemporary machinery, change pitch guide screw already was become firstly crucial part, does wide application install machine Q in fill? Aviation transmits machine and feed machine to go up. But, how accurate treatment goes out change pitch guide screw fails to be solved well all the time however. Long-term since it is the method that uses manual treatment on milling machine is finished, precision is low, labor strength is great, and often faulty part. Current, numerical control lathe has the function such as circular arc interpolation only, to changing the revolving on pitch guide screw is out of shape helicoid cannot be machined, the function that gives numerical control machine tool without sufficient play [1] . This research is aimed at change the treatment of pitch guide screw, pass numerical control system to transform, increased special treatment to change the function of pitch guide screw, with CNC Turning method treatment goes out change pitch guide screw, improved efficiency and treatment quality. 2 change the treatment principle of pitch guide screw changes surface of the chamfer inside pitch guide screw is a helicoid, a bit more aleatoric contrail on blade of cutting of lathe tool of the figuration when treatment is a corkscrewed yarn, spread out along circumferential direction for all the time line [2] , see a picture 1. Graph 1 in the abscissa is round circumference, ordinate is pitch, because be to change pitch corkscrewed yarn, photograph adjacent is circumferential the slope of straight line segment is different, the increment promoting role of each straight line segment is △ α , its numerical value is: T of △ α =arctg{(△ .

Random of ─ of the Tm in S)/[S2+Tm(Tm+ △ T)]} (1) type a paragraph of pitch, mm; A bit more aleatoric circumgyrate circumference on blade of cutting of S ─ cutting tool, mm; △ T ─ changes pitch increment, mm. According to type (1) can reach change of △ α and pitch increment, pitch and guide screw external diameter change the relation between, see a picture 2 to the graph 4. When △ when α is bigger, transfer to make sure space of two-phase adjacent helix is flowing, accept circular arc or linear connection, see a picture 1. Accordingly, whole change pitch guide screw is comprised by two cento line. Main corkscrewed yarn equation is: Graph the corkscrewed yarn after 1 circumferential way develops pursues the relation nicety of increment of 2 litres of horn and pitch increment machines a graph the relation of increment of 3 litres of horn and pitch change pursues the relation of increment of 4 litres of horn and external diameter (the T1 in 2) type, t2, ... , t, the 1st, 2, ... Q? The axial of I group corkscrewed yarn is apart from, t1 of 　 of Mm; 　 　 , t2, ... , t, the 1st, 2, ... Q? The axial with I group bit more initiative corkscrewed yarn is apart from, α of 　 of Mm; 　 　 1, α 2, ... α I, the 1st, 2, ... , litre of horn of I group corkscrewed yarn, s of 　 of Rad; 　 　 , a bit more aleatoric Zhou Xiang dimension on corkscrewed yarn, mm. T1, t2, ... Ti and α 1, α 2, ... α I, size is respectively: (　 of 3) (4) type (3) and type (4) generation enters type (2) gets: ＋ of Ti ＝ Ti-2 (Ti-2 - S of ＋ of T of Ti-3) ＋ △ .

(Ti - Ti-1)/S (5) 　 by type (5) can look, to aleatoric and specific treatment, t of Ti, △ and S are constant. Accordingly, change a bit more aleatoric axial distance on pitch guide screw and the linear function relation that its are existing to decide between dimension of corresponding Zhou Xiang, can realize its function impact through the linkage between two reference axis, namely the interpolation of axial and circumferential direction concerns, circumferential direction is the whirl of workpiece, axial is the fore-and-aft shift of lathe tool. According to type (5) , control workpiece every rotate an equivalent angle, fore-and-aft shift is apart from lathe tool accordingly, can machine those who give place to need to change pitch guide screw. Change to promoting role greatly pitch guide screw, still must be in transfer place amend. Compose became the hardware of system of 3 numerical control to be able to machine methodological treatment to go out with turning change pitch guide screw, the interpolation motion concern that must secure between implementation workpiece Zhou Xiang and axial and a few auxiliary motion, if the graph is shown 5 times,systematic hardware is formed. Graph the main shaft that hardware of system of 5 numerical control comprises block diagram clip to hold work and join of one photoelectricity coder, the tool carrier that clip maintains lathe tool by X to drive to servo electric machinery with Z, can come true fore-and-aft with transverse linkage. Because the car runs,pitch guide screw should undertake for many times repetition cutting, need has good Z to locate with main shaft, accordingly, installed journey switch, those who serve as a machine tool is absolutely at 0 o'clock to. Basis of Z electric machinery the signal of main shaft coder, the feed of solid existing law moves, in order to form helicoid, when cutting the leftest end, to electric machinery through X control retreats a knife, return initiative fore-and-aft position, control X to electric machinery transverse feed, achieve cutting deepness of the regulation, undertake cutting the 2nd times, circulate so, till achieve,change eligibly pitch guide screw is sectional deepness. Signal of machine tool face plate is used at showing condition and setting condition. Numerical control system is the core of CNC lathe, use at inserting servo of complementary operation, control, tool carrier to move to wait. Software of 4 treatment system by type (2) comes type (5) is knowable, machining a process, t1, t2, ... , ti and α 1, α 2, ... , α I is constant, only S and Ti are variable, and S is to pass the corner signal of coder to control, namely: θ of S=2 л R (a bit more aleatoric circumgyrate radius on blade of cutting of ─ of the R in 6) type, mm; The corner of θ ─ coder, rad. Accordingly, want to output the signal of angle θ according to coder only, control lathe tool is fore-and-aft by type (the rule of 5) moves can. To achieve pilot real time sex, use iteration method. By type (2) knows: J of θ of π R of Tij ＝ Tj-1+2.

　 of Tg α I (7) has turned when corner θ when θ of △ of an equivalent horn, θ of △ of ＋ of θ of θ J+1 ＝ (2 π of ＋ of 8)tij+1 ＝ Tij R.

△ θ .

Type of 　 of Tg α I (9) (R of the 2 π in 9) .

△ θ .

Tg α I is a constant interpolation to every time, accordingly, in iteration can nod translate into of below a bit computation currently the addition with one fixed cost, calculative time reduces a figure greatly block diagram of 6 treatment software is little. Implementation changes the machine program block diagram of pitch guide screw sees a picture 6. Module of the initialization in the program finishs the computation that mathematical model constant is worth, so that operation amount reduces in interpolation process; Main shaft, Z locates to initiative dot module is used at bit more initiative fixed position, because change turning of pitch guide screw, there is strict immanent connection between the motion of motion of Z axis direction and main shaft; Interpolation machines module according to inside the mathematical model of buy realizes different pitch paragraph treatment; Feed control module is used at be being finished for many times to take a knife and do not cause chaos to buckle. Graph experiment of 5 last words makes clear block diagram of 6 treatment software, with CNC Turning method treatment changes intensity of labor of pitch guide screw is low, quality is stable, hardware composition and lathe of ordinary numerical control are identical, just join in original system change the systematic software that pitch machines, method of this kind of treatment can be used at machining small size to change only pitch guide screw, accordingly, still have a few limitation. CNC Milling CNC Machining