The research of technology of CNC Machining of cam of wide chamfer cylinder

The working face of columnar cam chamfer namely two lateral laws are sectional line must strict parallel; 2.

Columnar cam chamfer is working paragraph must wait wide. This is the requirement that assures roller to move smoothly in columnar cam chamfer. When columnar cam chamfer when width is not big, can find corresponding diameter establish line of center of antrum of chamfer of milling cutter edge to undertake machining, easier treatment gives the columnar cam slot that accords with afore-mentioned requirements. According to having data introduction, at present the milling treatment of columnar cam is to use this kind of method to come true. Because this kind of method has too much limitation, to actual milling treatment brings a lot of difficulty. When once search,be less than the standard cutting tool with as broad as groove equal measure for example, must undertake changing making to cutting tool. The columnar cam chamfer with broad to groove larger measure, find diameter and chamfer very hard wide equal standard cutting tool. Although have corresponding cutting tool, consider machine tool main shaft to output the limitation of power and main shaft and stiffness of tool clamping apparatus even, especially the limitation of structure of machine tool main shaft to cutting tool. Example exactly the number accuses head of machine tool main shaft to be 7 ∶ 40 inner cone of 24, deserve to use the tool system of JT40, can use φ 20mm only greatly most establish milling cutter (no matter straight handle or awl handle) . This is wide to groove the columnar cam that is 38mm (it is the treatment cam that article place narrates) for cannot machine, must explore new treatment method. The basis carries out experience and analytic research below, the introduction is less than cam chamfer one kind to establish milling cutter widely to have the method of CNC Machining to columnar cam chamfer with the diameter, the is cam of wide chamfer cylinder CNC Machining that say. One, chamfer of cam of treatment craft cylinder is surround to go up in columnar face wait for wide chamfer, the along circumferential surface milling limits when its are machined often is more than 360 ° , comfortable undertake machining at using the vertical CNC Milling that contains table of numerical control circumgyrate. According to the actual structure of columnar cam, the radial when choosing the arbor that takes key to make cam machine and Zhou Xiangding fiducial, make axial with the stage shoulder of arbor fixed position is standard, the whorl that uses arbor front department passes cam of nut impaction cylinder. The axial of columnar cam and radial size are average bigger, the arbor that causes to overcome place of force of the cutting when be being machined as a result of cantilever is out of shape and arise in treatment process brace up quiver, use a bearing to go up at tailstock, as coaxial as the rotor line of numerical control revolving stage tip withstands arbor center Kong Zunfu aids bearing. The bottom of columnar cam chamfer is in each sectional going up is to wait normally deep, choose flat bottom cylinder to establish milling cutter treatment commonly. Columnar cam is the cylinder of a sincere normally before milling treatment, want to pass the working procedure such as groove, rough machining, semifinishing machining, finish machining; Because groovy antrum width is bigger, accordingly, the one part knife that eliminates groovy working procedure and rough machining process orbit is OK the central line of edge chamfer antrum is generated besides, the others knife course, mark must be towards the left of line of center of edge chamfer antrum, right both sides by corresponding distance equidistant slant buy is generated, if pursue,1 is shown. Graph the 2 dimension of chamfer of 1 columnar cam develop a plan 2, the model that seek solution is in the CNC Machining of columnar cam chamfer, how to beg the knife that two side surface machines in giving every working procedure orbit is among them crucial. To cylinder apparently cam chamfer, it is normally develop columnar range first, the knife that begs this working procedure to machine two side surface inside XOS plane of orbit spread out curvilinear XS; Pass coordinate changeover next, the knife that will spread out curvilinear XS changeover to go up for 4 coordinate machine tool orbit. The method seeking solution of curvilinear XS develops in either discussing to machine working procedure below, and generate final knife the coordinate of orbit changes a method. 1.

Those who spread out curvilinear XS if the graph is shown 2 times,seek solution, among them the central line that Lo is columnar cam chamfer, to working procedure of I line, what Lli and Lri are the groovy antrum that this working procedure will machine respectively is left, right two side surface spreads out a curve, this chamfer is wide for Bi, radius of treatment cutting tool is Bi) of ≤ of R(apparent 2r, machine this chamfer antrum left, right lateral knife orbit spreads out a curve to be CLli and CLri, set Po is nodded for on-line of groovy antrum center, no nods the law arrow of place in Po for line of groovy antrum center, so left, right knife the computational method that orbit develops the correspondence on the curve to nod Pli and Pri is: Graph the 2 dimension of chamfer of 2 columnar cam spread out graph <DIV Align=left> to nod Po move along line of groovy antrum center, can beg a knife of this working procedure namely orbit inside XOS plane spread out curvilinear XS; According to treatment working procedure, ordinal change the groovy width Bi in every working procedure, can beg a treatment place to need groovy pitch all knives of orbit spread out a curve. </DIV><DIV Align=left>2.

The coordinate that machines along line of cam chamfer center changes above of 　 of methodological </DIV><DIV Align=left> to calculate is in columnar face spread out what undertake inside plane, the knife that gives speech of chamfer of treatment cylinder cam to beg orbit, must will planar inside spread out a curve to be changed to columnar face. Hypothesis axis of rotation is the A axis that circles X axis, pi is a knife a knife on orbit dot, the coordinate that it spreads out a curve to go up in 2 dimension plane is (X, s) , the coordinate on 4 coordinate machine tool is (X, y, z, a) . Because antrum of columnar cam chamfer is normally,wait deep, accordingly, after the deepness that Z coordinate needs to machine for place in the setting is worth, in be being machined, be changeless; To the others 3 coordinate, construction gives the following coordinate to change formula: In </DIV> type, r is the radius of columnar camshaft. Type is the coordinate changeover formula that uses generally at present on, columnar to using milling of line of center of chamfer of cam of edge of standard cutting tool to machine cam is correct. 3.

To going up type is in the analysis that wide chamfer cylinder produces a problem in cam treatment is become will go up when the CNC Machining that type promotion applies cam of cylinder of Yu Kuan chamfer, change calculative knife through coordinate orbit produced a few problems however in be machined actually. After treatment of columnar cam chamfer ends, whether to accord with a requirement to examine, the check that is equal to columnar cam roller with the diameter is provided undertake examining, the groovy size that discovers a treatment however differs, the appearance that has jamming of cartridge or shell case. Careful observation, the law that machines the groovy antrum that come out so is sectional always do not wait for wide rectangular chamfer up and down, is to go up sometimes wide next narrow horn chamfer. To clear up among them reason, to formula (method of denotive coordinate changeover had 2) place thorough analysis and research. If the graph is shown 3 times, by formula (1) is knowable, treatment chamfer antrum the knife of two side surface the Pl on trochoid and Pr dot are by on-line of groovy antrum center Po is equidistant slant buy and, press formula (after 2) is changed, pl and Pr nod corresponding corner and not be equal to the corner that Po nods, also namely Pl and the VlVl of cutter shaft vector with corresponding Pr and the VoVo of cutter shaft vector with Po corresponding dot are not parallel, accordingly, nature became the groovy antrum that treatment comes out to go up wide below narrow horn chamfer, the wide rectangular chamfer such as the fluctuation that is not a need. Set sectional it is θ with the included angle of axes, the radius of columnar camshaft is R, the angle error of VlVl of cutter shaft vector and VoVo is: Δ A ＝ (B/2 - R)sin θ / R 　 　 (3) pursues <DIV Align=left> of sketch map of treatment of chamfer of 3 columnar cam by formula (3) is knowable, when θ ＝ 0 ° , also namely when line of cam chamfer center and columnar axis are vertical, angle error is 0, namely groovy antrum is the wide rectangular mouth such as fluctuation; When θ ＝ 90 ° , also namely when line of cam chamfer center and columnar axes parallel, angle error is achieved the biggest, the horn mouth phenomenon of groovy antrum is the right now most serious; When ＜ of 0 ＜ θ when 90 ° , as the accretion of θ , angle error is bigger, horn mouth phenomenon is more serious also. The phenomenon that effective treatment appears agrees completely with afore-mentioned analysises, this specification is formulary (the analysis of 3) is completely correct. 4.

The coordinate of CNC Machining of cam of wide chamfer cylinder changes a method by the analysis above knowable, formulary (2) causes cam trough to go up wide below narrow the main reason of horn mouth is, pl and the corner with Pr corresponding dot are the Sl of arc length value that nods his according to these two and Sr come calculative, and Sl and Sr are to not be equal to groovy antrum center the arc length of Po is worth So. Accordingly, if Pl and Pr nod corresponding corner all according to groovy antrum center the So of arc length value of Po is calculated, can eliminate appearance of chamfer of this kind of horn. According to this kind of train of thought, new and tectonic coordinate changes formula. Plane spreads out to go up in the 2 dimension of columnar face, line of center of the antrum that set groove spreads out music on-line the dot is Po(xo, so) , machine two side apparently corresponding knife the site that the dot is developing a curve to go up is Pl(xl, sl) and Pr(xr, sr) , so, coordinate changes formula to be: </DIV>(4) application is formulary (the knife that 4) generates when orbit machines columnar cam chamfer, the result accords with afore-mentioned tentative idea completely, groove had done not have the columnar cam that treatment comes out to go up wide next narrow horn chamfer phenomena, however the wide rectangular chamfer such as true fluctuation. CNC Milling CNC Machining