RU2208502C2 - Method for working shaped concave surfaces with variable profile - Google Patents

Abstract

FIELD: machine engineering, manufacture of die sets and press-molds. SUBSTANCE: method comprises steps of using tool in the form of body of revolution with tore- like working surface; simultaneously imparting to tool two translatory non-linearly matched motions for shaping and rotating feed motion; performing rotation feed motion in plane normal relative to plane of said translatory motions realized normally and in parallel relative to basic plane and non-linearly matching them with rotation feed motion for periodically touching worked surface with tool simultaneously in two points on mutually opposite sides of profile; reversing rotation feed motion at time moment of touching worked surface and tool; making tore like working surface with curvature radius less than minimum curvature radius and using tool with diameter exceeding width of worked profile. EFFECT: enlarged manufacturing possibilities, enhanced quality of worked surface. 7 dwg

Description

 The invention relates to mechanical engineering and can be used for processing complex-shaped parts with a concave shape with a profile that varies in cross section, for example, working surfaces of dies and molds.

 A known method of software processing multi-coordinate shaping of sculpted surfaces of parts [1] p.153 ... 157. However, this method can be used only for processing open complex parts that do not have intersecting surface sections with small radiuses of mates. In addition, problems arise in the accuracy of the profile shape (main cutting edge) in the manufacture of such tools with varying curvature along the profile of the producing surface.

 The closest analogue is a method of processing complex curved surfaces with a tool, a body of revolution, with a curved producing surface and with four nonlinearly coordinated formative movements [2], one of which is rotational and is located in the plane of the generatrix of the tool. Processing is carried out with a tool with two conical and torus radial surfaces. Each convex or rectilinear side of the profile is treated with the same side of the profile of the tool, and the concave mating portion of the profile of the part with the radius torus, processing is carried out with three simultaneous nonlinearly coordinated formative movements lying in one profiling plane, and one of them, rotational, is carried out in such a way so that the rectilinear generatrix of the tool is successively tangent to each point of the processed convex section of the profile, and the other two determined the conditions of the run-in.

 However, this method does not allow high-quality processing of surfaces whose curvilinear profile is formed by concave sections.

 A method for processing shaped concave surfaces with a varying section profile by a tool, a body of revolution, with a torus producing surface, which is informed by two simultaneous nonlinearly coordinated forming movements and a rotational feed motion, characterized in that the rotational feed motion is carried out in a plane perpendicular to the translational motion plane, and translational movements normal to and parallel to the basal plane nonlinearly agree with the rotational movement in such a way o the tool periodically and simultaneously touches the surface to be machined at two points located on opposite sides of the profile, and at the moments of touching the opposite sides of the profile, the rotational movement of the tool feed is reversed, while the radius of curvature of the torus producing surface is smaller than the minimum radius of curvature and the diameter of the tool is larger than the width of the workpiece profile.

 The proposed method allows to expand the technological capabilities of processing elements of complex parts such as grooves, grooves of dies and molds with a universal tool with a torus producing surface on CNC machines, as well as to improve the quality of the machined surface by reducing the actual front and rear angles during oblique cutting.

 FIGS. 1, 2, 3 show sequential surface treatment circuits; FIG. 4 is a plan view of a portion of a finished surface; FIG. 5 is an algebraological representation of the tool, FIG. 6 is a section BB in FIG. 2 for calculating the tool path.

Surface treatment 1 (Fig. 1) is carried out by a tool 2 with a body of revolution with a torus producing surface, the radius of curvature of which r is smaller than the minimum radius r _p , and the diameter of the tool D is larger than the maximum width B of the cross section of a complex profile groove (stream).

 Processing is carried out on 4-coordinate CNC machines, milling or grinding, with continuously carried out rotational movement of the table, for example, IR500PMF4.

The tool is informed of the main movement ω _ZИ , and it is _brought to touch with the workpiece in t. A, equidistant from the opposite sides of the profile (t. M and M '). After that, the tool is given two simultaneous feed movements: translational along the axis of rotation of the table OY S _YИ and rotational movement around the axis OY ω _YИ . In this case, the width of the cut-off layer is determined by the movement ω _YИ , the thickness - S _YИ . As a result, a lens-shaped allowance is produced until the tool touches the opposite sides of the profile at points M and M '(Fig. 1 a, b).

Next, the tool is informed of additional movement along the axis 0Z S _ZИ , and it is coordinated with the movements ω _ZИ and S _YИ so that the instrument periodically touches simultaneously two opposite sides of the profile, and at the moment of contact the rotational feed movement is reversed (figure 2). Thus, the tool, making a reciprocating motion of the feed around the OY axis from one to the other side of the profile and constantly descending to the bottom of the groove, moves along the OY axis by δY, and along the OZ axis by δZ. Screw reverse-rotational movements are performed until the tool drops to the bottom of the groove (figure 3). The geometric location of the points of contact with the tool of the workpiece for one pass to the bottom of the groove in the plan is a figure in the form of a figure eight (figure 4).

To perform line feed at the end of the passage, the tool is informed of two movements along the axes OZ and OX - δZ ₁ and δX _1, respectively (Fig. 1 b). As a result, the origin of the tool coordinate system moves to point B _{1 of the} beginning of the next pass.

 Such a processing method with a screw reciprocating feed motion allows the maximum use of the peripheral portion of the torus surface of the tool with maximum angles when cutting. The lateral portions of the torus producing surface with small rear angles work for a small part of the processing time. Processing of the lateral sections of the producing surface is carried out at the very bottom of the groove. In addition, with a dominant rotational feed, the actual front and rear angles are reduced due to oblique cutting. All of the above increases the quality of processing and tool life and extends the technological capabilities of using a universal tool with a torus producing surface for processing concave complex sections.

The calculation of the tool path is as follows:
1. An algebraological formula of the machined surface f _{d is} compiled using the Rvachev functions [3].

где

- уравнение торовой производящей поверхности, где r - радиус кривизны торовой производящей поверхности, R - радиус прямолинейных участков профиля инструмента,
f_П1 = z-z₁, f_П2 = z-z₂ - уравнения прямолинейных участков профиля инструмента;
операция

определяется по формуле R-дизъюнкции:

операция

определяется по формуле R-конъюнкции:

3. Определяются координаты всех точек инструментальной поверхности в области оперативного пространства, которое определяется областью, ограниченной шестью взаимно перпендикулярными плоскостями, параллельными осям 0X_И, 0Y_И, 0Z_И.2. An algebraological formula is compiled for the tool producing surface. For a tool with a torus producing surface, it has the form (Fig. 5):

Where

- the equation of the torus producing surface, where r is the radius of curvature of the torus producing surface, R is the radius of the straight sections of the tool profile,
f _П1 = zz ₁ , f _П2 = zz ₂ - equations of straight sections of the tool profile;
operation

determined by the formula of R-disjunction:

operation

determined by the formula of R-conjunction:

3. The coordinates of all points of the instrumental surface in the area of the operating space are determined, which is determined by the area bounded by six mutually perpendicular planes parallel to the axes 0X _AND , 0Y _AND , 0Z _AND .

5. Определяются координаты точек инструмента (х_И", y_И", z_И") после перемещения его по оси OZ_И на величину δZ и поворота на угол δφ′ в направлении, противоположном предыдущему повороту, с использованием аффинных преобразований до выполнения условия касания его с обрабатываемой поверхностью в двух точках, лежащих на противоположных сторонах M₁ и M₁' (фиг.2), то есть до выполнения условий:

Точки касания двух сторон профиля определяются методом фильтрации, то есть определения их принадлежности разным множествам по их относительному расположению в системе координат детали.4. The new coordinates of the tool points (x _AND ', y _AND ', z _AND ') are determined, after turning through the angle δφ and moving along the OY axis by the value δY using affine transformations until the condition for touching one side of the profile is fulfilled (Fig. .6):

5. The instrument determines the coordinates of the points (x _AND ", y _AND", z _I ") after moving it to the OZ axis _and the amount δZ and rotation through an angle δφ 'in a direction opposite to the previous rotation, using affine transformation before performing tangency conditions it with the surface to be treated at two points lying on opposite sides of M ₁ and M ₁ '(figure 2), that is, until conditions are met:

The points of contact of two sides of the profile are determined by the filtration method, that is, determining their belonging to different sets by their relative location in the part coordinate system.

The touch points M ₁ and M ₁ 'define the boundary points at which the tool is reversed.

Sources of information
1. Forming of complex surfaces on CNC machines./ Radzevich S.P. - K .: Vyshka shkola, 1991. - 192 p.

 2. Patent 2167746. A method of processing curved surfaces. / Ambrosimov S. K., Petrukhin A.A; Lipetsk. tech. un T. Publ. 05/27/2001. Bull. fifteen.

 3. Rvachev V.L. The theory of R-functions and some of its applications. - Kiev: Science. Dumka. 1982.- 551 p.

Claims (1)

 A method of treating concave surfaces with a varying cross-sectional profile with a tool in the form of a body of revolution with a torus producing surface, to which two simultaneous translational nonlinearly coordinated shaping movements and a rotational feed motion are reported, characterized in that the rotational feed motion is carried out in a plane perpendicular to the plane of translational motions normal and parallel to the basal plane and nonlinearly coordinate with the rotational feed movement for the tool touching the machined surface simultaneously at two points on opposite sides of the profile, and at the moments of touching the opposite sides of the profile, the rotational feed movement is reversed, while the torus producing surface is made with a radius of curvature less than the minimum radius of curvature, and the diameter of the tool is larger than the width of the processed profile.

Images