CN1831685A - Method for processing shoe tree - Google Patents

Abstract

A method for preparing shoe tree includes scanning mother shoe tree for obtaining its surface data, carrying out calculation according to obtained data to convert calculated result to be control parameters for operating motion path of milling cutter on shoe tree machine, manufacturing semi finished product of shoe tree according to said control parameters for obtaining shoe tree as the same as the mother shoe tree.

Description

A kind of method of processing shoe tree

Technical field

The present invention relates to a kind of method of processing shoe tree, especially a kind of method based on the processing shoe tree of data-switching between female shoe last or hat block digital model and the process tool.

Background technology

The mould that basic styling is provided that uses when shoe tree is shoemaking.It is the free form surface closed shape of being made up of irregular curve and curved surface of a complexity, and its profile can not be made of elementary curved surface.The shoe tree appearance profile face that obtains by 3-D scanning is made of the series of discrete point, and they satisfy the certain precision requirement.Traditional shoe tree job operation is that the contact scanning device by machinery scans female shoe last or hat block, and this mother's shoe last or hat block is the shoe tree sample that designs, and obtains the feed data of digital controlled block cutting machine by scanning, then directly with this data input digital controlled block cutting machine work shoe tree.The method of common processing shoe tree is: by 3-D scanning equipment, behind the shape face data scanning with female shoe last or hat block, the treatment conversion of process software becomes the feed data of digital controlled block cutting machine, input digital controlled block cutting machine work shoe tree.Digital controlled block cutting machine control be the position at milling cutter body center, be the position of shoe tree surface profile and 3-D scanning obtains, the relation between two kinds of data is not simple plus-minus relation.In general, actual add man-hour the milling cutter enveloping surface and the shoe tree surface have only a contact point, promptly two faces are tangent.Know easily by geometric knowledge,, can on the normal direction of this point, add the diameter of milling cutter otch, thereby obtain milling cutter the rim of a bowl center O in order to obtain the cutter location (being the cutterhead center) of lip-deep certain point of processing shoe tree ₁The position.Because milling cutter body center O ₀Point and O ₁Relative position between the point is constant, therefore is easy to from an O ₁Position calculation go out the milling cutter body center O ₀The position of point.Because the shoe tree surface is irregular curved surface, its normal direction almost changes everywhere, so the contact point on the enveloping surface of milling cutter and shoe tree surface also changes thereupon.Calculate cutter location in this way if make, just need calculate the normal direction of shoe tree surface each point, calculated amount will be very big, cause production efficiency low.

Summary of the invention

The objective of the invention is at the deficiencies in the prior art, data transfer device between a kind of shoe tree digital model and the process tool is provided, this method utilizes discretize and minimum distance method to simplify complex mathematical calculating, utilize look-up table greatly to improve computing velocity, from angle based on the curved surface discrete point, solved the problem that calculates cutter track in the digital controlled block cutting by last surface face discrete point, guaranteed the machining precision of shoe tree, enhanced productivity.

To achieve these goals, the invention provides a kind of method of processing shoe tree, this method may further comprise the steps:

Steps A: female shoe last or hat block surface is scanned, obtained its surface data;

Step B: the surface data that obtains according to scanning carries out computing, converts thereof into the controlled variable of the cutter location movement locus of control shoe-last machine tool milling cutter;

Step C: according to the movement locus of the control of the controlled variable described in step B milling cutter, the blank shoe last or hat block is processed, obtained the shoe tree identical with female shoe last or hat block along described cutter location.

The described computing of step B comprises:

In three coordinate systems, with cutterhead enveloping surface discretize and calculate the movement locus of cutter location; Wherein,

The first coordinate system true origin is positioned on the shoe tree, and (x, y z) describe the space at shoe tree place, and the Z axle is consistent with the length direction of shoe tree with rectangular coordinate for it;

The second coordinate system true origin is positioned on the shoe tree, and (r, α z) describe the space at shoe tree place, and the initial point of second coordinate system is identical with the initial point of first coordinate system, and the Z axle of second coordinate system overlaps with the Z axle of first coordinate system with cylindrical coordinates for it;

The three-coordinate true origin is fixed on the milling cutter body, and is the milling cutter body central point, and (x, y z) describe the space at milling cutter body place, and the Z axle of the axis of milling cutter body and first coordinate system has an inclination angle [theta] with rectangular coordinate for it;

When the inclination angle [theta] of cutterhead=0, the Z axle of three-coordinate and the Z axle of first coordinate system in the same way, the X-axis of three-coordinate is pointed to the Z axle of first coordinate system and perpendicular;

When inclination angle [theta] ≠ 0 of cutterhead, coordinate system is constant, still is XYZ, and just cutterhead integral body is that the axle center has rotated angle θ with the Y-axis;

Wherein, the computing method of described cutter location movement locus specifically comprise:

Set the initial position at cutterhead center, concrete steps comprise, in second coordinate system, and the cutterhead center O ₀Move to next reference locus point (r _{O0, i}, α _{O0, i}, z _{O0, i}), the coordinate (r of its coordinate and a last tracing point _{O0, i-1}, α _{O0, i-1}, z _{O0, i-1}) the pass be:

$z_{O_0,i}=z_{O_0,i-1}+{\mathrm{\Δz}}_0;$ ${\mathrm{\α}}_{O_0,i}={\mathrm{\α}}_{O_0,i-1}+{\mathrm{\Δ\α}}_0;$ $r_{O_0,i}=R_0,$

Wherein, Δ z ₀With Δ α ₀Be cutterhead increment on vertically z and angle [alpha] direction when for the helical movement in second coordinate system;

In second coordinate system, obtain the view field D of cutterhead on the blank shoe last or hat block _LInterior shoe tree discrete point, the D of view field _LThe set of the shoe tree discrete point that to be cutter can be worked in current location;

Coordinate transform is with the D of view field _LIn point coordinate become coordinate in the three-coordinate by the first coordinate system coordinate;

In three-coordinate, calculate the horizontal range d of each subpoint to the cutterhead enveloping surface _{X, 1}, the minor increment that described horizontal range is a subpoint along the X-axis of three-coordinate to the cutterhead enveloping surface calculates minor increment d in these horizontal ranges _Min, in view field, determine processing stand;

In second coordinate system, the centre coordinate of cutterhead when calculating the processing shoe tree:

r _nc，l＝R ₀-d _min；

α _nc，i＝α _o，i；

z _nc，i＝z _o，i；

Wherein, r _{Nc, i}=R ₀-d _MinThe feed distance of milling cutter when just carving shoe last or hat block.

In three-coordinate in the calculated level distance, for a bit (x on the shoe tree, y, z), do not need each point in it and the look-up table is compared, but can calculate its corresponding index rapidly by y and z, find the y with this point, the discrete point of the immediate cutterhead enveloping surface of z coordinate.If there are not corresponding point, then explanation does not have this point and cutterhead enveloping surface not to have the projection intersection point; If the coordinate figure of the enveloping surface corresponding point that find is 999, then explanation does not have intersection point yet, separates to imaginary number and separates, and is set to 999 at this in order to handle convenient void is separated, found after the immediate cutterhead discrete point of this point correspondence, the method for employing interpolation calculates the distance of cutterhead enveloping surface;

In sum, the present invention has solved the problem that is calculated cutter track in the digital controlled block cutting by last surface face discrete point from the angle based on the curved surface discrete point.The present invention utilizes discretize and minimum distance method to simplify complex mathematical calculating, utilizes look-up table greatly to improve computing velocity.

Below in conjunction with the drawings and specific embodiments technical scheme of the present invention is described in detail.

Description of drawings

Fig. 1 is the shoe tree schematic surface of discretize;

Fig. 2 is the milling cutter cut-open view;

Fig. 3 is a cutterhead syndeton synoptic diagram;

Fig. 4 is the milling cutter body enveloping surface;

Fig. 5 is the digital controlled block cutting machine structural representation;

Fig. 6 is that the position of milling cutter body enveloping surface and shoe tree concerns synoptic diagram;

Fig. 7 is the position view that is provided with of three coordinate systems of the present invention;

Fig. 8 processes the processing step process flow diagram of shoe tree for the present invention;

Fig. 9 converts the processing step process flow diagram of controlled variable of the cutter location movement locus of control shoe-last machine tool milling cutter after with the scan-data computing to for the present invention.

Embodiment

As shown in Figure 1, be the shoe tree schematic surface of discretize.As can be known from Fig. 1, shoe tree surface 1 is the free form surface closed shape of being made up of irregular curve and curved surface of a complexity, and its profile can not be made of elementary curved surface.The shoe tree appearance profile face that obtains by 3-D scanning is made of the series of discrete point, and they satisfy the certain precision requirement.

Usually in processing during shoe tree, employing be digital controlled block cutting machine.As Fig. 2, shown in Figure 3, be respectively milling cutter cut-open view and cutterhead syndeton synoptic diagram.As shown in Figure 2, milling cutter 2 is designed to bowl-shape, and the diameter of otch is about 30mm.As shown in Figure 3,3 identical milling cutters 2 are fixed on the milling cutter body 3.A milling cutter 2 is laid for 120 ° in every interval.Add man-hour, milling cutter body 3 forms a circular enveloping surface A, as shown in Figure 4 with the rotating speed high speed rotating of 7000-8000r/min.Because rotating speed is very high, some intersects with this circular enveloping surface so need only processing object, and this part will be cut.

Adopt the processing mode of two coordinate linkages during the host work of digital controlled block cutting machine, as shown in Figure 5.Blank shoe last or hat block 1 ' to be processed longitudinally is fixed on the C axle, and is center rotation with the C axle under the driving of C shaft step motor.Simultaneously, digital controlled block cutting machine drives Z axle sliding table by synchromesh gear, odontoid belt and screw mandrel, along Z direction move left and right.By X-axis stepper motor and screw mandrel, the X-axis sliding table that is positioned at above the Z axle sliding table can be along translation before and after the directions X.The high speed fire proof motor that is fixed on the X-axis sliding table drives the milling cutter body high speed rotating by flat belt.Therefore, under the help of X-axis and two sliding tables of Z axle, the crushing wheel of high speed rotating can free movement on the X-Z plane, distance by control milling cutter body 3 centers and C axle center can be processed each cross section outline of blank shoe last or hat block according to measuring the shoetree contour data that obtain, and cuts away unnecessary material and can obtain required shoe tree.

Because the high speed rotating of milling cutter body, we can regard whole cutter as an enveloping surface, and it is actually the annulus enveloping surface face that is formed by a circle (the milling cutter edge of a knife) rotation, as long as rapidoprint contacts and will be cut with this enveloping surface.As shown in Figure 4, set up a space coordinates O ₀XYZ.Wherein, radius is circle formation enveloping surface after Y ' axle rotates a circle of a, center of circle O ₁With the cutterhead center O ₀Distance be b.Actually add man-hour, cutterhead has an inclination angle [theta], and promptly cutterhead integral body is that the center has been rotated counterclockwise angle θ with Y ' axle.The surface equation of enveloping surface is

${(\±\sqrt{{(x\cos \mathrm{\θ}-z\sin )}^2+y^2}-b)}^2+{(x\sin \mathrm{\θ}+z\cos \mathrm{\θ})}^2=a^2...(*)$

Digital controlled block cutting machine control be the position at milling cutter body center, be the position of shoe tree surface profile and 3-D scanning obtains, the relation between two kinds of data is not simple plus-minus relation.In general, actual add man-hour the milling cutter enveloping surface and the shoe tree surface have only a contact point, promptly two faces are tangent.

Know easily by geometric knowledge,, can on the normal direction of this point, add the diameter of milling cutter otch, thereby obtain milling cutter the rim of a bowl center O in order to obtain the corresponding cutterhead center (cutter location) of processing lip-deep certain point of shoe tree (radius is r in second coordinate system) ₁The position.Because milling cutter body center O ₀Point and O ₁Relative position between the point is constant, therefore is easy to from an O ₁Position calculation go out the milling cutter body center O ₀The position of point.Because the shoe tree surface is irregular curved surface, its normal direction almost changes everywhere, so the contact point on the enveloping surface of milling cutter and shoe tree surface also changes thereupon.Make and calculate cutter location in this way, just need calculate the normal direction of shoe tree surface each point, calculated amount will be very big.

The present invention has adopted minimum distance method to avoid normal direction calculating, thereby has simplified the calculating of cutter location.Add man-hour actual, when shoe tree is in a certain position, have only a contact point between the shoe tree surface of cutterhead enveloping surface and current correspondence, that is to say, when the milling cutter of rotation when the X axis shoe tree moves, contact is exactly this point at first.This contact point has the characteristic of minor increment, promptly, in the time of cutterhead and the surperficial certain distance D apart of shoe tree (this distance only needs the assurance cutterhead not contact with shoe tree), may touch in the zone (being called view field) of shoe last or hat block surface at the milling cutter enveloping surface, this projects to along the X-axis machining direction, and distance on the enveloping surface is the shortest (to be designated as d _Min).If cutterhead is along the feed of X axis shoe tree, distance is d _Min, just can process this point.Obtain the cutter location of the point that shoe tree surface institute might be worked into, just can carve shoe tree.

Ensuing problem is exactly to calculate the distance of certain point and cutterhead enveloping surface on the shoe tree.For each shoe tree point, y ₁=y _{S, i, j}, z ₁=z _{S, i, j}, equation is converted into about x ₁Unary biquadratic equation:

${\mathrm{Ax}}_1^4+{\mathrm{Bx}}_1^3+{\mathrm{Cx}}_1^2+{\mathrm{Dx}}_1+E=0...(**)$

Wherein, A, B, C, D and E are the coefficients that equation (*) produces when being transformed to equation (* *).

Can adopt algebraic method directly to separate this equation obtains apart from x ₁But speed is very slow, and the calculating of finishing whole shoe tree cutter location needs tens hours.Main bottleneck is that the double counting amount is big: cutter location of every calculating, (supposing has N just to need all shoe tree points in the compared projections zone _iIndividual point) with the distance of cutterhead enveloping surface, just separates N _iEquation of n th order n; When calculating next cutter location again, (supposing has N still to need all shoe tree points in the compared projections zone _I+1Individual point) with the distance of cutterhead enveloping surface, separates N again _I+1Individual equation.Separate unary biquadratic equation itself with regard to more complicated, and number of times has more increased total computing time too much.

The present invention has adopted the method for look-up table and discretize, will bring up to 3 to 5 minutes computing time.Set up coordinate system dexterously and the discretize let us only need be separated linear function; Introducing look-up table then needs to solve an equation hardly, has improved computing velocity greatly.

In order to calculate cutter location, at first to do two preliminary works.

The first, set up 3 coordinate systems, as shown in Figure 7,

1) the first coordinate system XYZ: be fixed on the rectangular coordinate system on the shoe tree, true origin is O.

2) the second coordinate system R α Z: be fixed on the cylindrical coordinate on the shoe tree, true origin also is O.

3) three-coordinate XYZ is fixed on the rectangular coordinate system on the milling cutter body: true origin is the cutterhead center O ₀, when the inclination angle [theta] of cutterhead=0, the Z axle of three-coordinate and the Z axle of first coordinate system in the same way, the X-axis of three-coordinate is pointed to the Z axle of first coordinate system and perpendicular forever.When θ was not 0, coordinate system was constant, and just cutterhead integral body is that the axle center has rotated angle θ with the Y-axis.Because three-coordinate is fixed on the milling cutter body, so the equation of cutterhead enveloping surface is constant forever in this coordinate system.

The second, with cutterhead enveloping surface discretize.Discrete density degree is determined by processing request.The all coordinate of discrete point in three-coordinate are deposited in the ff table.Each line data of look-up table is represented o'clock (x, y, z) coordinate in three-coordinate.Because the y coordinate in the look-up table and the fixed interval of z coordinate, be exactly the index of putting so in fact y coordinate in the look-up table and z coordinate represent.

Then we just can begin to calculate cutter location.

The track of cutterhead is made up of cutter location, is a helix.A systemic circulation in the corresponding program of the calculating of the cutter location of whole shoe tree, milling cutter is machined to the shoe tree head from the shoe tree afterbody.

Cutter location of every calculating need be done following work:

1. set initial " reference position " at cutterhead center.In second coordinate system, the cutterhead center O ₀Move to next reference locus point (r _{O0, i}, α _{O0, i}, z _{O0, i}), the coordinate (r of its coordinate and a last reference locus point _{O0, i-1}, α _{O0, i-1}, z _{O0, i-1}) the pass be:

$z_{O_{0,}i}=z_{O_0,i-1}+{\mathrm{\Δz}}_0,{\mathrm{\α}}_{O_0,i}={\mathrm{\α}}_{O_0,i-1}+{\mathrm{\Δ\α}}_0,r_{O_0,i}=R_0,$

Δ z wherein ₀With Δ α ₀Be cutterhead increment on vertically z and angle [alpha] direction when for the helical movement in second coordinate system.Described " reference position " is meant, cutterhead center O when this value is not the processing shoe tree ₀Orbital radius.Given " reference position " passed through, three-coordinate can determine that the shoe tree point can show, thereby calculates minor increment in this coordinate system.But minor increment is irrelevant with the setting value of " reference position ".

2. in second coordinate system, pick out the view field D of milling cutter enveloping surface A on shoe tree 1 _LIn the shoe tree discrete point, as shown in Figure 6.

3. coordinate transform is with the D of view field _LIn point coordinate become coordinate in the three-coordinate by the first coordinate system coordinate.

4. in three-coordinate, calculate the horizontal range d of each subpoint to the cutterhead enveloping surface _{X, 1}, by relatively drawing minor increment d _Min

1) calculates the D of view field _LIn each puts the horizontal range of enveloping surface

In three-coordinate, for a bit (x, y on the shoe tree, z), do not need each point in it and the look-up table is compared, but can calculate its corresponding index rapidly by y and z, find the y with this point, the discrete point of the immediate cutterhead enveloping surface of z coordinate.If there are not corresponding point, then explanation does not have this point and cutterhead enveloping surface not to have the projection intersection point; If the coordinate figure of the enveloping surface corresponding point that find is 999, then explanation does not have intersection point yet, separates to imaginary number and separates, and is set to 999 at this in order to handle convenient void is separated.Found after the immediate cutterhead discrete point of this point correspondence, the method for employing interpolation calculates the distance of cutterhead enveloping surface.

2) in these distances, calculate minor increment d _MinThereby, in view field, determine processing stand.

5. in second coordinate system, calculate cutterhead centre coordinate when processing shoe tree

r _nc，j＝R ₀-d _min，α _nc，i＝α _0，i，z _nc，i＝z _o，i；

Wherein, r _{Nc, i}=R ₀-d _MinThe feed of milling cutter is apart from x when just carving shoe last or hat block.

The technological process of the controlled variable of the cutter location movement locus of controlling the shoe-last machine tool milling cutter will be converted to, as shown in Figure 9 after the scan-data computing.

In sum, the integrated artistic step that the present invention processes shoe tree comprises as shown in Figure 8:

Step 101: female shoe last or hat block surface is scanned, obtained its surface data, this surface data is as the background mathematics model that carries out computing in the subsequent step;

Step 102: the surface data that scanning obtains according to step 101 carries out computing, converts thereof into the controlled variable of the cutter location movement locus of control shoe-last machine tool milling cutter;

Step 103:, along described cutter location the blank shoe last or hat block is processed according to the control of the controlled variable described in the step 102 milling cutter, obtained the shoe tree identical with female shoe last or hat block.

Need to prove at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (2)

1, a kind of method of processing shoe tree is characterized in that, this method comprises:

Steps A: female shoe last or hat block surface is scanned, obtained its surface data;

Step B: the surface data that obtains according to scanning carries out computing, converts thereof into the controlled variable of the cutter location movement locus of control shoe-last machine tool milling cutter;

Step C:, along described cutter location the blank shoe last or hat block is processed according to the control of the controlled variable described in step B milling cutter, obtained the shoe tree identical with female shoe last or hat block.

2, the method for processing shoe tree according to claim 1 is characterized in that, the described computing of step B comprises:

In three coordinate systems, with cutterhead enveloping surface discretize and calculate the movement locus of cutter location; Wherein,

The first coordinate system true origin is positioned on the shoe tree, and (x, y z) describe the space at shoe tree place, and the z axle is consistent with the length direction of shoe tree with rectangular coordinate for it;

The second coordinate system true origin is positioned on the shoe tree, and (r, α z) describe the space at shoe tree place, and the initial point of second coordinate system is identical with the initial point of first coordinate system, and the Z axle of second coordinate system overlaps with the Z axle of first coordinate system with cylindrical coordinates for it;

The three-coordinate true origin is fixed on the milling cutter body, and is the milling cutter body central point, and (x, y z) describe the space at milling cutter body place, and the Z axle of the axis of milling cutter body and first coordinate system has an inclination angle [theta] with rectangular coordinate for it;

When the inclination angle [theta] of cutterhead=0, the Z axle of three-coordinate and the Z axle of first coordinate system in the same way, the X-axis of three-coordinate is pointed to the Z axle of first coordinate system and perpendicular;

When the inclination angle [theta] of cutterhead ≠ 0, coordinate system is constant, still is XYZ, and just cutterhead integral body is that the axle center has rotated angle θ with the Y-axis;

Wherein, the computing method of described cutter location movement locus specifically comprise:

Set the initial position at cutterhead center, concrete steps comprise, in second coordinate system, and the cutterhead center O ₀Move to next reference locus point (r _{O0, i}, α _{O0, i}, z _{O0, i}), the coordinate (r of its coordinate and a last tracing point _{O0, i-1}, α _{O0, i-1}, z _{O0, i-1}) the pass be:

$z_{O_0,i}=z_{O_0,i-1}+\mathrm{\Δ}{z}_0;{\mathrm{\α}}_{O_0,i}={\mathrm{\α}}_{O_0,i-1}+\mathrm{\Δ}{\mathrm{\α}}_0;r_{O_0,i}=R_0,$

Wherein, Δ z ₀With Δ α ₀Be cutterhead increment on vertically z and angle [alpha] direction when for the helical movement in second coordinate system;

In second coordinate system, obtain the view field D of cutterhead on the blank shoe last or hat block _LInterior shoe tree discrete point, the D of view field _LThe set of the shoe tree discrete point that to be cutter can be worked in current location;

Coordinate transform is with the D of view field _LIn point coordinate become coordinate in the three-coordinate by the first coordinate system coordinate;

In three-coordinate, calculate the horizontal range d of each subpoint to the cutterhead enveloping surface _{X, l}, the minor increment that described horizontal range is a subpoint along the X-axis of three-coordinate to the cutterhead enveloping surface calculates minor increment d in these horizontal ranges _Min, in view field, determine processing stand;

In second coordinate system, the centre coordinate of cutterhead when calculating the processing shoe tree:

r _nc，i＝R ₀-d _min；

αn _c，i＝α _o，i；

z _nc，i＝z _o，i；

Wherein, r _{Nc, i}=R ₀-d _MinThe feed distance of milling cutter when just carving shoe last or hat block.

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