FR2871080A1 - Micromechanical or nanomechanical unit, e.g. dial, manufacture for watch, involves introducing data in movement control computing unit, adjusting ultrashort pulsed laser, starting machining program and machining transmission by laser - Google Patents

Abstract

The method involves transferring data on three dimensional machining software. Angle of incidence of beam is defined and part to be machined is positioned with respect to beam, based on material and machining depth. Data is introduced in a movement control computing unit (17). An ultrashort pulsed laser (14) is adjusted. Machining program is started and synchronous/asynchronous transmission (10) is machined by the laser. An independent claim is also included for a micromechanical or nanomechanical unit.

Description

METHOD FOR MANUFACTURING MICROMECHANICAL ORGANS AND

  The present invention relates to a method for manufacturing micromechanical and nanomechanical members using a short-pulse laser of the femto type as well as to micro-mechanical and nanomechanical devices. organs thus manufactured.

  In the field of bodies with micrometric or even nanometric dimensions, the notion of mechanical transmission is still in its infancy as dimensions, materials, or the manufacturing conditions impose severe constraints. In the case of small dimensions (organ width less than 2 mm or no teeth less than 2 mm) there is no procedural reference allowing the control of all mechanical parameters. In this case, very many problems constrain the use of transmission elements or small components in general for which the notion of geometry and accuracy is paramount and in particular, without being exhaustive: o the difficulty of machining and / or to control, o the complex control of the behavior of the materials (physicochemical properties), o the absence of tensile reinforcements or low-friction envelope in the case of the belts, o the difficulty of using stratified materials or composites, o the definition of functional forms, such as for example the teeth, o the modeling, then the reproduction of complex surfaces, especially left-handed ones.

  In order to meet the needs of micro-techniques, the invention relates to a method for the design and manufacture of micro- and nano-mechanical components which is based on the following capabilities: o geometric description of the micro- or nano-mechanical components, o geometric description of the transmission elements, o manufacture in all materials without distinction, machinability on a dimensional scale ranging from millimeter (10--3 meter) to nanometer (10-9 meter).

  In the case of small dimensions falling within the scope of the present invention, conventional machining methods do not allow the manufacture of mechanical elements as a direct homothety of conventional systems. The ultrashort pulse laser makes it possible to overcome this lack, independently of the machined material, provided that it can be the operating element of a digital information chain for machining.

  The use of Diode, YAG or CO2 lasers is relatively conventional in the machining of materials such as metals or excimer for polymers. These methods are limited when working in small dimensions on materials that do not withstand shocks or thermal stresses.

  Today, lasers that emit ultrashort pulses (less than five hundred femto seconds) are compact, versatile and reliable. The intensity and diversity of these lasers are constantly increasing: the beams obtained today cover the entire electromagnetic spectrum, from X-ray to T-ray (terahertz radiation, located beyond the infrared), and the powers peaks reach several petawatts (several billion megawatts). These devices apply in particular in physics, chemistry, biology, medicine, optics.

  Because of the extremely short duration of their pulses, they make possible the study of ultrafast phenomena occurring at the microscopic or atomic scale. In addition, very high powers can be produced during the short duration of the pulse, creating extreme conditions comparable to those found in fusion reactors.

  The use of the ultra-short pulse laser for the machining of micro-organs has the following advantages:> more precise optical machining means,> ablation of material under substantially athermic conditions,> there is at the beam-waist focal point, the beam can, in the case of transparent materials, go through thicknesses to work at a point in the mass without altering the surface or the material on the path traveled,> the beam is manipulated remotely and at all angles,> there is no restriction on the machined materials, - a finer resolution than the width of the laser beam is obtained by adjusting the laser so that only the intensity of the the central part, where the greatest power is concentrated, is greater than the ablation threshold of the material (control of the energy density in the focal plane),> absence of machining forces at the plane 30 ablation.

  The use of femto laser for the ablation of materials is known from the articles Kautek et al., "Femtosecond pulse laser ablation of metallic, semiconducting, ceramic, and biological materials," SPIE vol. 2207, pp. 600-611, Apr. 1994. * and Liu, X. et al., "Laser Ablation and Micromachining with Ultrashort Laser Pulses", Oct. 1997, IEEE Journal of Quantum Electronics, vol. 33, No. 10, pp. 1706-1716. US Patent USRE37585 discloses a method of destruction with the aid of a pulsed laser beam of a material characterized by a ratio of fluence rupture threshold (Fth) / laser beam width (T) having a steep, fast inflection, and net or at least a clearly detectable and sharp inflection of the slope for a predetermined value of the width of the laser beam. The method comprises producing a pulsed beam in which each of the pulses has a width less than or equal to the predetermined value of the width of the laser pulse. The beam, which is focused at or near a point on the surface of the object to be destroyed, can be associated with a mask placed on its path, the beam and the mask being able to be displaced along the X axes. , Y and Z to achieve the desired effect. This technique produces smaller impacts than the beam spot and the Rayleigh distance due to the increased precision of the damage threshold in short pulse mode. In order to solve the problem of the design and the manufacture of micromechanical components in particular, the invention relates to a method comprising, in its most general sense, a step of ablation by a pulse laser with a duration of less than 5.10-13 seconds and a higher power at 1012 watts of a part supported by a micromanipulator ensuring the positioning and orientation of the surface to be treated with respect to the orientation of the laser beam.

  Preferably, the workpiece is supported by a multiaxial system controlled by a micrometric or nanometric robot machining program with compensation or play catch.

  Advantageously, the method further comprises the steps of: o description of the shapes to be machined from the geometry defined using a 3D CAD representation, o transfer of data from the CAD to a three-dimensional machining software includes interpolations of the left surfaces, o definition of the steps according to the material and the machining depth so that the conditions of ablation are optimized, o introduction of the data in the control computer / driver displacements (17), o positioning, in the Y direction, of the focal zone D by illumination with the aid of the optical head (15), equipped or not with a diffraction device, o positioning on the plane E of the component with machining (10), o clamping of the component to be machined (10) by means of clamping means (12), o setting of the ultra-short pulse laser, o starting of the machining program and machining of the component (10) by ultra-pulsed laser at least said femto.

  According to an advantageous variant, the process according to the invention is carried out under a controlled atmosphere in order to avoid the appearance of nonlinear phenomena generated at the light / material interface, such as, for example, the breakdown of air or at the modification of the physicochemical properties of the medium.

  The invention also relates to a micro-or nanomechanical member, characterized in that it is produced by laser ablation using a pulse laser with a duration of less than 5.10-13 seconds and a power greater than 1012 watts and in that it has at least one curvilinear line often irregular, formed in a perpendicular plane, at least a radius greater than 10-9m and less than 2mm. An example can be given by observing the edges that mark the intersection of two surfaces produced by any machining. At the macroscopic level (scale of a few millimeters 10-3m) these edges can be assumed rectilinear or circular and formed by salient or obtuse angles. However, at the microscopic level these same lines are characterized, in the plane perpendicular to the edge line, by a geometry, more or less regular, having at least one radius, often called connection fillet, of a few tenths of millimeters at the most .

  According to a variant, it has at least one irregular or left surface characterized, inter alia, by at least one radius located in the plane of curvature whose value is greater than 10-9m and less than 10-3m.

  The invention also relates to an organ characterized in that it: o has teeth spaced at a pitch less than two millimeters and in that it is produced by laser ablation using a pulse laser of a less than 5.10-13 seconds and with a power greater than 1012 watts, o is formed by a belt having a thickness or width of less than two millimeters and in that it is made by laser ablation with the aid of a pulse laser with a duration of less than 5.10-13 seconds and a power greater than 1012 watts, o has teeth whose depth is less than two millimeters and in that it is produced by laser ablation at a distance of using a pulse laser with a duration of less than 5.10-13 seconds and a power greater than 1012 watts.

  The member according to the invention may consist of - an element of an exhaust system of a watch, - an element of a regulation system of a watch, the body of a watch, and in particular the platinum comprising holes and holes serving as a support frame, - bridges of straight or left shapes for holding in place or guiding the rotation or displacement of the various components of a micro mechanism, - the material connections between solids, and in particular: recess, slideway, single or sliding pivot, translation and rotation, helical, plane support, single or finger ball joint, linear annular, linear rectilinear, punctual ..., - the so-called energy accumulator organs such as in particular the springs , whatever their shape, and the components of barrels, - micro-or nano-transmission devices by right or left gears, pulleys, friction wheels, homokinetic rigid or flexible links, hydrostatic and hydrodynamic elements ..., - pivot or slide links, - mechanical memory devices, in particular cams, - components related to the exhaust function and in particular those used for the distribution of energy, whatever their type and, without being exhaustive, mention may be made of expansion systems, cylinder, English anchor, pin, encounter wheel ..., which may include the following: ^ escape wheel, ^ tooth d ' exhaust, serge, arm, hub, anchor, wand, pallet or lift for entry or exit, fork, horn for entry or exit, dart, starter pin or exit, ^ large and small plateau, pendulum, the oscillating organs, said of regulation, that they are of the family of pendulums or spiral-balances, and, more generally, all the vibrating systems following depreciated or non-linear modes, whether linear or not, with or without mechanical or viscomechanical damping devices. We consider here, without being exhaustive, the adjacent elements and in particular: ^ cock, ^ pendulum, ferrule, piton, piton door, racket, flat spiral, helicoid spiral falling complex left or right, - elements related to rotating control systems and in particular without restricting vortices or carousels, - oscillating masses whether they are of revolution, linear or pivoting, - the indicating members as per for example, the dials, the inscriptions, the hands, the display symbols such as the date indicators, whether simple or perpetual, date setting, moon phase, etc.

  - the ringing organs, - the covering elements, for example: mirror, bezel, case, crown, correctors, dial, needles, case ring, bottom, barrettes, bracelets and their components, pushers, display cell, boxes, whether made in one or more rooms, with or without elements such as: winding, crown, pushers ...

  Advantageously, at least one of the dimensions of the member according to the invention is less than two millimeters and advantageously less than 0.5 millimeters. According to one variant, the process of obtaining is constituted by a mold.

  It is preferably constituted by an isotropic material, polymorphic (for example laminated ...) or hard composite.

  According to a particular embodiment of the invention, it relates to the field of components of micro and nano transmissions (gears or not, chains, pulleys, toothed or non-toothed belts, left or right gears, other constant velocity transmission elements. ..

  It is known that synchronous / asynchronous movement / power transmissions, particularly by means of belts, cover an extremely wide field of application in all sectors of the industry, including that of watchmaking.

  Many solutions exist to transmit the movements / powers such as, for example, those involving gear transmission as proposed by most traditional watch movements.

  These solutions are limited in the general case where the spacings are distant and where the motors and receivers are not parallel and in cases where at least one dimension of one of the components is less than 2 mm A toothed belt transmission is constituted in particular by a belt / pulley assembly. It is asynchronous when the belt used is smooth (rubbing strips) and synchronous when the belt used is toothed. We consider here that the micro or nano mechanical chain as a particular form of the toothed belt since it itself has notches meshing with teeth.

  It should be noted that the asynchronism comes from the possibility of sliding belts on the pulleys under the action of too much torque. In order to overcome this drawback, at least partially, it is necessary to add a tensioning device and / or guide called roller, which is not always the case especially with regard to synchronous transmission kinematic chains.

  The pulleys, toothed wheels and tension rollers are produced by traditional methods such as turning and / or milling, spark erosion, ultrasonic machining. The traditional belts are made in particular by molding, the molds being made by electroerosion, ultrasound or by the LIGA process (Lithography, Galvanisierung, Abformung).

  These methods are particularly useful for the production of micro molds whose dimensions go beyond 2 mm and directs the manufacturer to use injectable plastics which, for as little as the operation is possible according to the temperature constraints or dynamic viscosity, is limiting in particular for the use of materials such as metals, composites or heterogeneous multilayers The object of the present invention is in particular to provide a method of manufacturing motion / power transmissions, or any another micro-mechanical element, by means of micro-belts, in order to meet the quality constraints, required in particular in the field of watchmaking, and allowing the use of complex materials without limitation of dimensioning as well as the realization of the structures of sandwich type or composites.

  This object is achieved by a method of manufacturing a belt transmission characterized in that it describes shapes to be machined from the geometry defined on a 3D CAD plane, transfers the data on a three-dimensional machining software holding In particular, it counts interpolations of the surfaces, defines steps according to the material and the machining depth so that the ablation conditions are optimized, introduces data into the computer control / driver displacements, positions, in the direction Y, the focal zone C by illumination with the aid of the optical head A, equipped or not with a diffraction device, positions the component to be machined on the plane B, clamps the component to be machined using conventional systems such as flanges, adhesive, etc., adjusts the femto ultra-short pulsed laser to less than 500 fs (5.10-13 seconds), starts the machining program and manufactures the component with a femto laser.

  Synchronous and asynchronous movements / power transmissions are thus obtained by means of belts which meet the quality constraints, required in particular in the field of watchmaking, namely:> the choice of materials (mechanical properties and manufacturing processes), > the difficulty of using loaded structures (reinforcements reinforced with fibers, etc.), - the definition of tooth profiles,> the difficulty of machining.

  The ultrashort pulse laser does not diffuse heat outside the irradiated volume regardless of the material being machined.

  The machining process is based on the ablation process that implements complex phenomena. The athermal nature of the process is due to the shortness of the conjugated pulses at a very high intensity of the order of 1019 Watt / cm2 at the focal plane of the beam. The current trend directs the tools to 100 fs pulses (1.0 x 10-13 seconds) for an energy of the order of MJ / pulse.

  Physically, the electrons undergo a heating by phenomenon of the type Bremsstrahlung inverse. The ejected electrons transmit their energy to the other electrons of the network of atoms by shock and provoke an ionizing avalanche which causes an expulsion of matter.

  The energy transfer of the electrons to the atomic network of the machined material takes place in a period of time approximately 1000 times slower than the duration of a pulse. Ablation of material takes place even before there is thermal diffusion outside the irradiated zone.

  This procedure uses the light-material interface to cause local ablation of the material. Beyond the marked thermal incidence, the ablation accuracy is significantly improved compared to conventional pico second or excimer lasers.

  The fluences required in the case of machining vary from 0.25 to a few tens of J / cm 2 depending on the desired speed and quality of machining, typically at least 0.5 to 0.25 pin / pulse.

  In one embodiment, the machining is done in the open air or in a controlled atmosphere (neutral gas). The advantage of machining in a controlled environment is to avoid nonlinear phenomena produced within the light-material interface, such as the breakdown of air at the focal plane and the corollary appearance of instability altering. very partially the quality of machining. Moreover and in order to improve the energy efficiency of the ablation it is possible to add on the laser, in the case of industrial series, qualitative optics such as for example a diffractive set.

  It should be noted that the use of an ultra-short pulsed laser allows:> in plastic materials (thermoplastics, polymers ...), cutting without thermal damage of the size zone,> in composite materials, the size direct without delamination of the multilayer material, - machining of all metals without formation of sagging or burrs or even flaring at the incident surface.

  In general, machining operates without difficulty on the scale of about ten pm. By using this tool, we confirm the size of micro-belts whose tooth height (belts or wheels) is of the order of 0.5mm. The limits of machining precision are those related to the beam offset.

  The present invention allows the use of complex materials without limitation of dimensioning as well as the realization of sandwich or composite type structures and meets the quality requirements of the motion / power transmissions when the motor-receiver axes are in particular parallel and of geometric constructions such as: simple cases called parallel strands, - simple cases said cross-strands.

  The motion / power transmissions performed according to the invention are of the asynchronous and / or synchronous type.

  In one embodiment, the belt-driven motions / power transmissions are asynchronous and consist of at least one wheel, a belt and have at least one tension and / or guide roller which is located at inside or outside the micro-belt.

  In addition, the asynchronous micro-belt transmissions are mounted on pivot or slide links, which enables:> to increase the winding angle on the pulleys,> to provide clutch / disengagement functions.

  Synchronous belt micro-transmissions consist of at least two toothed wheels and a toothed belt of the same module, which has the effect of allowing the transmission of mechanical power between a motor element and a slip-free receiving element, thus correcting the problem posed by the functional or accidental sliding of asynchronous transmissions, especially in case of overload.

  Asynchronous micro-belt transmissions comprise smooth wheels, tension and / or guide rollers and flat or trapezoidal or striated belts.

  Synchronous belt synchronous movements / power transmissions comprise in particular: a carrier geometry with controlled deformation (elasticity range of the material), a curvilinear or polygonal profile toothing, an ortho-radial, straight, inclined or curvilinear toothing on the buoyant plan.

  The components of a movement / power transmission made according to the present invention are made of material having sufficient mechanical characteristics to ensure the transmission function which is the case in particular for plastics and polymers, metals, and composites.

  The present invention also relates to micro-molds characterized by the fields of complex materials used, the dimensions of realization and the possibilities they offer for the realization of sandwich-type or composite structures.

  Other features of the invention are set forth in the dependent claims.

  The invention will be better understood from the following detailed description with reference to the accompanying diagrammatic drawings, in which: FIG. 1 represents, by way of example, a device for manufacturing synchronous / asynchronous movements / power transmissions, FIG. 2 shows a synchronous / asynchronous transmission of motions / power relative to a simple case with parallel strands; FIG. 3 represents a curvilinear tooth profile; FIG. 4 represents two examples of asynchronous transmission with secondary pulleys arranged. FIG. 5 is a sectional view of a laminated belt in the interior and exterior of the transmission.

  FIG. 1 illustrates a device 20 for manufacturing a synchronous / asynchronous movement / power transmission (10) comprising: a working plane (11) having in particular 6 axes (A, B, C, X, Y, Z); ) programmable and clamping means (12), - a computer (13) including a three-dimensional modeling software such as 3D CAD, - a femtype ultra-short pulse laser (14) comprising a head optical system (15) for the emission of a beam (16) concentrated on a focal zone (D), - a computer control / driver displacements (17), A method of manufacturing a synchronous / asynchronous transmission by micro-belt comprises in particular the following steps:> description of the shapes to be machined from the geometry defined on a 3D CAD plane,> data transfer on a three-dimensional machining software taking into account in particular interpolations of the left surfaces,> step definition in function of the material and the machining depth so that the ablation conditions are optimized, - data entry into the control computer / driver displacements (17),> positioning, in the Y direction, of the focal zone D by illumination with the aid of the optical head (15), equipped or not with a diffraction device,> positioning on the plane E of the component to be machined> fixing the component to be machined (10) to by means of 25 positioning and holding means (12),> adjustment of the ultra-short pulse laser femto less than in particular 500 fs (5.10-13 seconds),> start of the machining program and machining of the component (10) by femto laser.

  Comparative experiments indicate that going from 100 to 10 fs significantly improves machining accuracy. The fluences used in micro-machining typically vary from 0.2 to 50 J / cm 2 depending on the desired quality and machining speed. The ablation rates represent a few minutes / pulses depending on the materials machined.

  It should be noted that the combination of rotations and translations along the six axes (A, B, C, X, Y, Z) of the space allows machining any component (10), even complex.

  In order to avoid the appearance of non-linear phenomena resulting from the light / material interface, it will be possible to machine under vacuum or under projection of neutral gas (helium, argon, etc.). Controlled atmosphere machining also significantly improves the quality of machining. In the case of specific applications, it will be possible to improve the optical precision by adopting a diffraction or optical servocontrol system mounted in addition to the focusing device.

  The shapes to be machined are described from the geometry defined on a 3D CAD plane. The data is transferred to three-dimensional machining software taking into account interpolations of the left surfaces. A time step is defined according to the material and the machining depth so that the ablation conditions are optimized. Then the program is introduced into a control computer that controls the movements.

  The most common displacements are: a) the rapid positioning, which forces the moving parts to reach the programmed point by making a linear trajectory, at the maximum speed allowed by the machine, b) the linear interpolation, which makes it possible to reach the point programmed by traversing a linear path at the speed specified by the programmer, and c) circular interpolation, whose function is to describe complete circles or arcs from certain characteristic geometrical elements that define them. , such as the coordinates of the center and those of the extreme points, for example, d) the helical interpolation, which combines a circular motion in a plane with a translation movement perpendicular to this plane, e) the conical interpolation in the plane, where each parabolic segment is geometrically defined by a group of 3 points, the last point of a segment to be the first segment of the segment ivant, f) polynomial interpolation, which allows the definition of trajectories from polynomials and which is used for the smoothing of spline curves.

  Most of the shapes machined on the elements involved in carrying out the micro-transmissions can be machined in one plane. To do this, we use machining techniques in 2D or 2D1 / 2. Among these functions are: a) contouring (mode in which the tool remains positioned at a constant depth while describing, in the plane, a series of straight lines and curves), b) drilling and its operations (c) the machining of negative volumes.

  In the case of more complex surface machining such as toothing or left-hand surfaces, the laser beam is shifted along 3 axes simultaneously or even more with a rotating plate and a rotatable optical head. The most successful variation is the pivoting of the optical head on two axes (twist head) in addition to pivoting plate for a combination of both.

  Conventionally, the geometric representation of the complex surfaces generated by the material ablation process by means of an ultra-short pulse laser makes use of the definition of special curves called poles with poles. The most common representation method is one that uses Bezier curves. There is also an evolution known as B-spline curves.

  For more complex shapes and especially for those that fall into the definition of curvilinear profiles for which the conics are necessary (arcs of circles, ellipses, parabolas, etc.) we use the rational curves where the representation of the conics is generated by a quotient of polynomials and not by an integral polynomial parametric equation. We use the most common rational curves, namely the rational Bezier curves defined by polynomials where a surface is decomposed into simple elements called meshes themselves defined by points called poles. In the same way we use the Splines and NURBS (Non-Uniform Rational BSpline) curves which are defined by sets of points forming surface tiles in a network.

  These families of curves can be explained in more precise terms: ^ Bézier curves: defined as parametric curves calling in particular on the following notions: Bernstein polynomials, De Casteljau evaluation algorithm, subdivision, degree elevation, derivation, properties geometric (affine invariance, convex hull, decrease in variation), ^ B-spline functions defined as base of 5 P (k, t, r), node multiplicities, CAk class join, local and minimal supports, ^ B curves -spline in the form of parametric B-splines using notions of control polygon, evaluation algorithm of De Boor, and having particular geometric properties such as: affine invariance, local control, the envelope convex, the multiple nodes at the edge, the insertion of knots, geometrical curves which correspond to the notion of geometric continuity, geometric invariants, that known forms Frenet frame, nusplines, tau-splines.

  Through the use of this mode of description and representation, the indexing of the displacement of an ultra-short pulse laser makes it possible to manufacture all the forms that go into the production of micro- and nanomechanisms.

  In general, the relative displacement between the laser beam and the workpiece is based on the spatial manipulation of the workpiece support. It should be noted in the method of the invention that for particular cases, the beam may, independently of the displacements of the part to be ablated, at the output of the optical head, be deflected by means of different optical systems: mirrors, scanner, telescope...

  As a whole, the material ablation machining process using an ultrashort pulse laser 35 is based on a compromise that incorporates the following factors: time, accuracy, surface state.

  The kinematic combination mechanism that drives the motion of the part (motion with multiple robotic axes) uses a control computer (otherwise called a numerical control restrictive form) which from a data algorithm addresses commands to the attention a power servo consisting of drives and electric actuators that generate the movements with the required precision.

  The field of machining by ablation of material by means of an ultra-short pulse laser is very vast. To define it, two aspects must be taken into account: ^ the dimensional accuracy of the ablation resulting from the beam size in the beam waist, which is called the irradiation zone, the mathematical definition of the curves or surfaces to be machined.

  The invention is distinguished in the first place by the fact that the allowable geometries are not limited to segments of straight lines (simple interpolation) or circles. Moreover, it is common, especially in watchmaking techniques, to encounter bodies or connections determined more or less vaguely or even implicitly (geometry resulting from the intersection of two surfaces imposed by the shape of the tools). Obviously, these methods are not suitable for the machining of complex shapes, including left, and more broadly for all operations where a precise control of the intersections of surfaces (fillets) is required.

  To enable machining by ablation of material, in all possible cases, we define the shapes or surfaces to be treated by means of mathematical principles using geometry and algorithmics (graphs, algorithmic geometry, probabilistic algorithms). .).

  The process of machining by ablation of material by means of an ultra-short pulse laser differs from other machining processes in that it uses indiscriminately, depending on the accuracy or complexity of machining required, relational data algorithms, without this list being exhaustive, on the following mathematical principles: ^ curvature, torsion, Frenet reference, Jordan's theorem, isoperimetric inequality, envelopes or focal curves, ^ surfaces and hypersurfaces as the two fundamental forms of a surface and in particular the curvatures, Gauss-Bonnet formula, intrinsic geometry, parallel transport, geodesics, Morse theory making it possible to connect the type of homotopy of a variety to the critical points of a generic function having certain good properties , including in the demonstration of the Gauss-Bonnet formula, but also the Hessian, the critical points and the Morse lemma, defined functions on a surface such as height and distance functions, vector fields and Morse diagram, especially the techniques used in reconstruction theories, combinatorial and algebraic topology elements and in particular: triangulations, simplicial complexes, Euler-Poincaré characteristic , manifolds, classification theorem of surfaces, ^ elements of differential geometry: Geometry of surfaces in R3: Gaussian application, curvatures and principal directions, classification of points (elliptic, hyperbolic, parabolic, plane), focal surfaces, geodesic, ^ quadric Euclidean and smooth-surface osculator quadrics, skeletons in the form of flat curves, evolves, skeletonization, as well as their geometric criteria (distance to the skeleton, differentiability of the functions distances, ridges and ravines) and their topological properties (homotopies and retractions), references to the Voronoi diagram, triangula Delaunay in 2D, and skeleton approximation, reconstruction and meshing of surfaces, taking into account the restricted Delaunay triangulation, the nerve theorem of homotopies and homeomorphisms, but also criteria for sampling curves and surfaces, algorithms surface refinement, algorithmic geometry and in particular the intersections of segments, the computation of convex envelopes in 2 and nD, property of duality, linear programming, geometric data structures, complex or not, using deterministic and probabilistic algorithms, use of interpolation and smoothing algorithms as well as cross-validation on the choice of smoothing parameters and in particular without this list being exhaustive: least-squares smoothing (taking into account weights and constraints), interpolation by polynomial splines: spline spaces, minimization of an energy, calculation algorithm interpolation spline, spline bases (B-spline), spline smoothing smoothing splines, calculation algorithms, cross-validation methods for choosing the smoothing parameter.

  The ablation method described in the present invention makes extensive use of algorithms using the Non Uniform Rational Basic Splines (NURBS) technique.

  We define these NURBS as a set of techniques for interpolation and approximation of curves and surfaces. These techniques are very present in the systems of formal and numerical computation and taken up by the main geometrical modeling softwares like for example CAD or CAD / CAM tools.

  These functions are defined from real values called nodes that correspond to the uniform case. They have a given degree which is for the classical forms that we machine 2 or 3 and rarely more. Their value is between 0 and 1 but not zero only over an interval.

  The function described is all the smoother because its degree is high: degree 1 = continuous function, degree 2 = differentiable function (no angular points), degree 3 = differentiable function twice (no break in curvature), When one modifies a node the function is deformed continuously.

  When 2 nodes coincide (the node becomes double) one has a loss of continuity with, either a discontinuity, a point angular, or a rupture of curvature.

  The order of continuity at a node is equal to the degree minus the multiplicity of the node, for example: B-spline of degree 2, single knot -4diviability, B-spline of degree 2, double knot -4 angular point, ^ B- spline of degree 2, triple-knot -4 discontinuity In the case of curves defined by control points (for example tooth profile), plane points (called control points) and a set of values (referred to as vector) are given. some knots). We can cite fundamental properties: 1. The curve is entirely contained in the convex envelope (because the coefficients of the combination of are between 0 and 1 with a sum equal to 1).

  2. This definition does not depend on the dimension, so it can be used both in the plane and in the 3-dimensional space, and even beyond.

  3. The curve depends only on the relative position of the nodes; if we make a translation or a homothety the curve is unchanged; the nodes (0, 0,1,2,4,4,4) will give the same curve as (-1, -1,1,3,7,7,7).

  4. When a basic function is 1, the others are zero and the curve goes through the control point associated with it; in particular, when the first (respectively last) node is of multiplicity, the first (respectively the last) base function y is 1 and the curve passes through the first (respectively last) point: we have a so-called end curve floats whose Bezier curves are a special case.

  Finally, it is interesting to define the role of homogeneous coordinates forming rational curves.

  Finally, note that the mathematical method described above is the only one that can guarantee the homothetic factors useful for the proper use of the theory of mechanisms applied to micro- and nano-mechanisms (respect of conditions of sliding, friction, meshing -).

  The method of ablation by means of an ultra-short pulse laser finds its application for the following general case: at least one of the dimensions of the part to be ablated is less than or equal to 2 millimeters. The dimensions being counted overall and defined as the measurement of the segment which connects the two points of the same part the most distant in the same direction, - and more generally all the micro- and nano-mechanical elements whose definition of the radii berthing (intersection of two surfaces) imposes precise millimetric dimensional conditions.

  FIG. 2 illustrates a synchronous / asynchronous belt transmission / power transmission (10) comprising in particular a main pulley (23), a belt (20), a secondary pulley (22) and a tensioning roller (21). The pulley (23) is flat and provided on its periphery equidistant radial teeth comparable to a flat gear wheel. The pulley (23) is provided with a flange (not shown) to guide the belt (20).

  It should be noted that the belts (20) notably have curvilinear tooth profiles (30), as shown in FIG. (3).

  When producing a synchronous transmission, the flanges (not shown) are arranged on a single pulley (23) and preferably that having the smallest diameter.

  It should be noted that, in the case of embodiments of pulleys (23) or small micrometric or nanometric members with / without curvilinear profiles (30), no rule is imposed we will speak of customized profiles. Furthermore, for each type of tooth profile there are teeth with straight flanks or involutes (not shown).

  The invention also relates to the manufacture of millimeter or nanometer gearing, a gear being considered here as the element used in the composition of a synchronous transmission ensuring the connection between two shafts and transmitting a mechanical power of a driving shaft (motor ) to a driven shaft (receiver) maintaining a constant ratio of angular velocities.

  More precisely, different shapes are to be considered: The elementary shape is said to be external parallel and is characterized, apart from the absence of relative sliding of the two intermeshing wheels, by a ratio of the angular velocities equal to the inverse ratio of the number of teeth or diameters and by a relative rotation of the wheels in the opposite direction. A variant exists in a form called inner parallel where the two wheels rotate in the same direction. This described form, parallel, external, or internal, with straight teeth is also characterized by a step, a module and a transmission ratio. The geometry of the toothing is symmetrically described in the meshing plane according to a curvilinear profile.

  A more elaborate form meets the criteria of helical toothing defined by a regulated surface generated by an infinity of tangents to the basic helix. It can also be defined as the surface generated by an involute moving along the helix.

  The particular form called rack and pinion is characterized in that the rack is a particular wheel whose primitive line is a straight line, it can from a geometric point of view be seen as a wheel of infinite diameter.

  The transposition of the helical teeth to the rack and pinion kinematics is possible. It should be ensured that when the two primitive rolls of the gear rotate without sliding, the two conjugate primitive helices remain constantly tangent, which implies two conditions: the two propellers must be in opposite directions, namely left can only form a parallel gear with a pinion on the right; It is necessary to respect the geometrical conditions related to the gearing (conditions of meshing).

  The present invention also takes into account the case of the concurrent gears. In the first place it is necessary to consider the right form in which the primitive surfaces are two cones having same vertex which roll without sliding on one another. The teeth are straight or spiral. In the particular case of the concurrent gears the present invention lays down, without being exhaustive, the case of the continuity of meshing and interference by the so-called complementary gearing method. This approach makes it possible to study meshing in the concurrent gear, with a sufficient approximation, by simply considering a parallel gear. Thus all the questions relating to the continuity of meshing, the interferences, the relative sliding, are treated by considering the parallel gear according to its angular velocities, the numbers of teeth, the module and the angle of pressure.

  The present invention also incorporates the case of left gears, such as the wheel and worm. The worm meshes with its wheel conjugate at a given distance. It is important to note that usually the wheel is cut with a tool corresponding exactly to the worm with which it must mesh (method of envelopes). The use of an ultrashort pulse laser relieves this constraint to small dimensions which otherwise remained unachievable by conventional methods. In this type of gear, particular attention will be paid to the relative slip as well as to the notion of reversibility.

  The elaborate form dealing with left helical gears notably because of the point contact between toothing makes operation under low loads particularly effective for very small movements.

  The so-called complex shape of the hypoid gear will also be taken into account, particularly in that the ablation process allows a size to very small dimensions which is excluded by any other known method.

  Regardless of the shape and size of the gears, it is essential to observe the interference conditions during design, particularly those related to asymmetric shapes and machining conditions.

  The mathematical aspect, which includes the descriptive methods related to the generation of curves and left surfaces, provides a control of geometric interference. In addition, the technique of laser ablation using ultra-short pulses makes it possible to control the interferences of machining. The two aspects being conjugated, the present invention is the only relevant answer to the definition, manufacture and control of interference for micro and nano transmission, regardless of the tooth shapes or materials used.

  FIG. (4) illustrates two examples of asynchronous transmission (10) with secondary pulleys (22) inside / outside and where the asynchronous pulley (23) is flat and provided with flanges (not shown) on either side of said pulley (23) to guide the belt (20) to said transmission (10).

  The belts (20) are in particular of flat section, trapezoidal or striated.

  The method of the present invention allows the use of any materials suitable for the components of the transmission (10) namely: plastics, metals, minerals, composites.

  PLASTIC MATERIALS Plastic material means any material containing a high polymer as an essential ingredient, as defined in ISO 472 and ISO 472 (January 2002) Plastics. By high polymer or more generally polymer, is meant a product consisting of molecules characterized by a large number of repetitions of one or more species of atoms or groups of atoms (constitutional units), connected in sufficient quantity to lead to a set of properties that practically do not change with the addition or elimination of one or a small number of constitutional units (ISO 472). It is also a product made up of high molecular weight polymer molecules (ISO 472).

  The following polyolefins: o polyethylene PE o polypropylene PP o polyisobutylene P-IB o polymethylpentene P-MP o polyvinyl chlorides and their derivatives (PVC) according to standards ISO 1043-1 / 458-2 / 4575/1264 1060-15 2 / 2898-1, 6401, and in particular: polychlorides of vinyl chlorinated PVCC polyvinylidene chloride PVDC o copolymer vinyl chloride and propylene VC / P o mixture of vinyl chloride and chlorinated polyethylene PVC / E o mixture of vinyl chloride and acrylobutadiene styrene PVC / ABS o copolymer grafted vinyl chloride and acrylate PVC / A.

  vinyl polyvinyl acetate / vinyl acetate copolymer PVC / AC Vinyl polyacetates and their PVAC derivatives and in particular: polyvinyl acetate PVAC vinyl polyvinyl alcohol PVAL vinyl polybutyral PVB polyformal vinyl PVFM Styrenics according to ISO 1043 standards 1 / 2580-35 1 / 2897-1 / 4894-1 / 6402-1: o polystyrene shock SB o polystyrene acrylonitrile SAN o acrylobutadiene styrene ABS o acrylonitrile styrene acrylate ASA o polystyrene-anhydride maleic modified elastomer mSMA o mixture based PS and in particular PC / ABS, ABS / PA, PS / Polyphenylene ether PPE, PS / PP and PS / PE.

  polyacrylics (PMMA) according to ISO 7823-1 / 10 7823-2 / 8257-1 o polyacrylonitrile PAN o copolymer A / MMA acrylonitrile / methyl methacrylate o copolymer acrylonitrile / butadiene o copolymer styrene / acrylonitrile SAN o copolymer acrylonitrile / butadiene / styrene ABS o copolymer methyl methacrylate / acrylonitrile. butadiene / styrene MBS PMMA / ABS mixtures or alloys Saturated polyesters PET and PBT polyalkylene terephthalates according to ISO 1043-1 / 1628-5 / 7792-1, Polyamides (PA) according to ISO 1043-1 / 1874- 1/599/34514 / 7628-1 / 7628-2 / 7375-1 / 7375-2, where PA 6.6 o PA 6.10 o PA 6.12 o PA 4.6 o PA 6 o PA 11 o PA 12 o the following polyoxymethylenes (POM) ISO 1043-1 o fluoropolymers according to ISO 1043-1 o polytetrafluoroethylene PRFE o polyvinylidene fluoride PVDF o poly (ethylene-propylene) perfluorinated FEP o ethylene copolymer PTFE ETFE o cellulosics according to ISO 1043- 1 o cellulose nitrate or nitrocellulose CN o ethylcellulose EC and methyl cellulose HC o cellulose acetate CA and cellulose triacetate CTA Polymers with aromatic skeleton according to ISO 1043-1: o polycarbonate PC according to ISO1043-1 / 1628- 4 / 7391-1 / 7391-2 o phenylene polysulfidePPS o polyphenylenes ether PPE o poly2-6 dimethyl phenylene oxide o polyphenylene ether polyethylene ether ketone PEEK o polyaryletherketoneetherketone PAEK o polyetheretherketone PEK o polyetherketone o aromatic polysulfone PSU oployethersulfone PESU o polyphenylsulfone PPSU o aromatic polyamide o olyarylamides PAA o polyphthalamides PPA o o amorphous semi-aromatic polyamides PA 6-3T o polyamide-imides PAI o bisphenol A polyterephthalate (polyacrylate) o polyetherimide PEI o cellulose propinate CP and cellulose acetate proprionate CAP o cellulose acetate butyrate CAB o liquid crystal polymers (vectra, Sumika and Zenite) LCP o thermoplastic elastomers according to ISO 1043-1 o block copolymers of the type Hytrel or Pebax o ionomers of the type Surlyn o ulbrablend S (BASF) PBT + ASA o cycoloy (GE Plastics, Lastilac (Lati) PC + ABS o xenoy (GE plastics) PC + PET o orgalloy RS6000 (ATO) PA6 / PP o stapron N (DSM) ABS / PA 6 o lastiflex AR-VO (Lati) o PVC + terpolymers The polyurethanes according to ISO 1043-1 in particular to obtain: cast elastomers, or thermoplastic or polyurethane-polyurea (thermosetting) or cellular polyurethanes, microcellular elastomers from the following compounds: polyurethane PUR o isocyanate + hydrogen donor o isocyanate o polyisocyanates and especially toluene diisocyanate TDI o polyols (polyesters and polyethers) o amines MDA and MOCA o silicones SI according to ISO 1043-1 o polysiloxane silicone Si o phenoplasts PF and in particular PF2E1, PF2E1, PF2C1, PF2C3, PF2A1-2A2, PF1A-1A2, PF2D1, PF2D4 o aminoplasts (MF , UF) according to ISO 4614 and 1043-1 melamine formaldehyde MF o ureadealdehyde UF thermosetting unsaturated polyesters In general, it should be noted that, where possible and desirable, these materials can receive reinforcements and these include: o aromatic polyamide (Dupont Kevlar 35 Nemours) o glass in all its forms, including silico-sodic forms; o high modulus carbon o high strength carbon o boron o steels o mica o wollastonite o calcium carbonate o talc o polytetrafluoroethylene (PTFE), eg Teflon (trade name).

  Furthermore, the treated plastic products may or may not be covered with mineral, synthetic, or metal films without this in any way affecting the scope of this patent.

METAL

  This is mainly and without this being an exhaustive list of all pure metals and their alloys.

  In particular, solid metal alloys can be mentioned: Steels and cast iron o copper or aluminum o nickel or chrome o molybdenum tungsten or manganese o gold, platinum or silver o titanium or cobalt or boron or niobium or tantalum, as well as pure metals.

MINERALS Quartz

COMPOSITE AND CERAMIC MATERIALS

  É'É Composites This is, from a general point of view, materials matrix / binder organic or metallic and including, but not limited to: Phenolics Polyesters Epoxides Polyimides Reinforced fibers / reinforcements additives, mainly: Celluloses Glass E, C, S, R ... Bore

  Whiskeys AleO3, SiO2, ZrO2, MgO, TiO2, BeO, SIC, ...

  Aramid low modulus Aramid high modulus High carbon toughness Carbon high modulus Boron Steel Aluminum And loaded with mineral materials, in particular: Chalk, silica Kaolin Titanium oxide Glass ball These composites may contain additives, especially catalysts or accelerators, and under the solid form can be found in the following forms: o Single-layer o Laminate o Sandwich We cite more particularly the following composites without this being exhaustive: o Aluminum / Copper - Metal matrix composite A177.9 / SiC17.8 / Cu 3, 3 / Mgl, 2 / Mn 0.4 o Aluminum / Lithium - Metal Matrix Composite A181 / SiC15 / Li 2 / Cu 1.2 / Mg 0.8 o Carbon / Vinyl Ester - Carbon Fiber - Ester Matrix Vinyl o Carbon / Polyaramid - Carbon fiber Polyaramide fiber o Carbon / Carbon composite - Carbon fiber 10 Carbon matrix o Carbon / Epoxy composite - Carbon fiber Epoxy matrix o Carbon / Polyetheretherketone composite - Carbo fiber ne - PEEK matrix o Polyamide composite / Vinyl ester Polyaramid fiber - Vinyl ester matrix o Polyethylene / Polyethylene composite - Polyethylene fiber - Polyethylene matrix o E-glass / Epoxy - Borosilicate glass / Epoxy o Polyaramide / Polyphenylene Sulfide - Polyaramid fiber - PPS matrix.

  Ceramics They consist of polycrystalline or polyphase natural raw materials or synthetic sintered alumina, silica, silico-aluminous or silico-magnesian compounds (cordierite, mullite, steatite) and more widely oxynitride, sialon, carbide ... Preferred materials are, irrespective of their mode of implementation, such as dry pressing, thermoplastic injection, strip casting, etc.: Monocrystalline short fibers dispersed inside an organic, metallic matrix or ceramic. As well as metal carbide wiskers, organometallic precursors such as SiC or Si3N4.

  The main ceramics are given without being exhaustive: Alumina Al2O3 Alumina / Silica Al2O3 80 / SiO2 20 Alumina / Silica Al2O3 96 / SiO2 4 - Saffil O Alumina / Silica / Boron Oxide Al2O3 70 / S102 28 / B2O3 2 o Alumina / Silica / Boron oxide Al2O3 62 / SiO2 24 / B2O3 14 o Potassium aluminosilicate Muscovite Mica o Boron carbide B4C o Silicon carbide SiC o Silicon carbide - bonded by SiC reaction 15 o Silicon carbide - pressed hot SiC o Tungsten carbide / Cobalt WC 94 / Co 6 o Machinable glass ceramics SiO2 46 / Al2O3 16 / MgO 17 / K2O 10 / B2O3 7 o Permeable ceramics SiO2 50 / ZrSiO4 40 / Al2O3 10 20 o Titanium diboride TiB2 Titanium dioxide TiO2 99.6% o Magnesium oxide MgO o Aluminum nitride A1N o Aluminum nitride - Machinable Shapal-M o Boron nitride BN o Silicon nitrile Si3N4 o Silicon nitride - bound by reaction Si3N4 o Nitride Silicon - Hot Pressed Si3N4 o Silicon Nitride / Aluminum Nitride / Alumina Sialon o Zinc Oxide / Alu mine ZnO 98 / Al2O3 2 o Yttrium oxide Y2O3 o Beryllium oxide BeO 99.5 o Quartz - Melted SiO2 o Ruby Al2O3 / Cr2O3 / Si2O3 o Sapphire Al2O3 99.9 o Alumina silicate SiO2 53 / Al2O3 47 o Silica SiO2 96 o Glass - Alumino-silicate SiO257 / Al2O3 36 / CaO / MgO / BaO 5 o Zirconia - unstabilized ZrO2 99 o Zirconia - stabilized with Yttria ZrO2 / Y2O3 o Zirconia - stabilized with Magnesia ZrO2 / MgO Most machined shapes on the elements involved in the realization of transmissions (10) or any other micro- or nano-component can be machined in a plane. To do this, we use machining techniques in 2D or 2D1 / 2.

  In the case of the machining of more complex surfaces such as complex teeth (not shown), the beam (16) of the laser is moved along three axes simultaneously or even four axes with a rotating plane (11) and an optical head ( 15) pivoting.

  Ultrashort pulse laser machining responds to the fabrication of all the shapes that go into making micro transmissions as defined in the present invention.

  The subject of the present invention is also the micro molds obtained characterized by the fields of the complex materials used, the dimensions of realization and the possibilities which they offer for the realization in particular of laminated belts (50) with several layers (51), such as shown in Figure (5).

  In general, all the molds machined by the method described in the invention, and whatever their type, are composed or use a number of functional subassemblies:> the molding elements: imprint (punch and matrix),> the functional elements carcass, feed, mechanisms for release and demolding of the injected parts, mold temperature control devices,> the auxiliary elements: fixation and manipulation device, centering systems, robots for setting up prisoners and extraction of molded parts, safety devices and demolding control.

  The process of machining an ultra-short pulse laser mold will focus on making a cavity of the cavity in which the three-dimensional negative representation of the object (including any dimensional corrections) is limited by the two parts that are the punch and the matrix.

  This method allows the production of any micro or nano molded part since the art of molding is preserved and the viscosities of the materials used allow it (very small dimensions).

  Note that the aforementioned process is applicable to all mouldable materials without exception and that the results obtained on the surface conditions are excellent, which is important especially for the friction parts.

Claims (4)

  1 Method for manufacturing a micro- or nanomechanical member by ablation, by a pulse laser, of a workpiece supported by a micromanipulator ensuring the positioning and orientation of the surface to be treated with respect to the orientation of the laser beam , said laser being a pulsed laser having a duration of less than 5.10-13 seconds and a power greater than 1012 watts on the surface of interaction interaction, characterized in that it comprises the following steps: o description of the shapes to be machined,   o transfer of the data to a three-dimensional machining software taking into account in particular interpolations 15 of the left surfaces, o definition of the angles of incidence of the beam and the positioning of the workpiece relative to the laser beam, depending on the material and of the machining depth so that the ablation conditions are optimized, o introduction of the data in the control computer / driver of the displacements (17), o setting of an ultra-short pulse laser of a duration less than 5.10-13 seconds and a power greater than 1012 watts on the beam / material interaction surface, o start of the machining program and machining of the component (10) by pulsed laser.   Method for manufacturing a micro- or nanomechanical member, characterized in that the energy gradient of the laser beam is determined so that only the intensity of a central zone whose cross-section is less than 50% of the section total beam is greater than the ablation threshold of the material.   3 A method of manufacturing a micro- or nanomechanical member according to claim 1 or 2, characterized in that the workpiece is supported by a multiaxial system controlled micrometric robot machining program catch-up or play compensation.   A method of manufacturing a micro- or nanomechanical member according to claim 1, characterized in that it further comprises the steps of: describing the shapes to be machined from the geometry defined on a 3D CAD plane, o transfer of the data to a three-dimensional machining software taking into account inter alia interpolations 15 of the left surfaces, o definition of the steps according to the material and the machining depth so that the ablation conditions are optimized, o introduction of the data in the control computer / driver of displacements (17), o positioning, in the Y direction, of the focal zone D by illumination with the aid of the optical head (15), equipped or not with a diffraction device, o positioning on the plane E of the component to be machined 25 (10), o fixing the component to be machined (10) by means of fastening means (12), o adjustment of the ultrashort pulse laser , o start of the program machining and machining of the component (10) by ultra-short pulse laser of the femto type at most.     A method of manufacturing a micro- or nanomechanical member according to claim 1, characterized in that it is carried out under a controlled atmosphere in order to avoid the appearance of non-linear phenomena which result from the light-material interface such as the breakdown of the air or alteration of the material.   6 - Micro or nanomechanical organ, characterized in that it is produced by laser ablation using a pulse laser with a duration of less than 5.10-13 seconds and a power greater than 1012 watts, and in that at least one of these dimensions is less than or equal to 2 millimeters, these dimensions being counted overall and defined as the measurement of the segment which connects the two points of the same part the most distant in the same direction.   7 - micro or nanomechanical body according to claim 6, characterized in that it has at least one often irregular curvilinear line, formed in a perpendicular plane, at least a radius greater than 109m and less than 2 mm.   8 - micro or nanomechanical organ, characterized in that it has at least spaced teeth in a pitch less than two millimeters and in that it is produced by laser ablation using a pulse laser of a duration less than 5.10-13 seconds and a power greater than 1012 watts.   9 - micro-or nanomechanical organ, characterized in that it is formed by a belt having a thickness or a width less than two millimeters, and in that it is made by laser ablation with the aid of a pulse laser with a duration of less than 5.10-13 seconds and a power greater than 1012 watts.   Micro or nanomechanical organ, characterized in that it has teeth whose depth is less than two millimeters and in that it is produced by laser ablation using a pulsed laser of a duration less than 5.10-13 seconds and greater than 1012 watts.   11 - micro or nanomechanical member according to claim 5 or 6, characterized in that it is constituted by an element of a watch exhaust system.   12 - micro or nanomechanical member according to claim 5 or 6, characterized in that it consists of an element of a clock control system.   13 - micro or nanomechanical organ according to claim 11 or 12, characterized in that the largest dimension is less than one millimeter, 14 - micro-or nanomechanical organ according to claim 5 or 6, characterized in that it is constituted 20 by a mold.   - micro or nanomechanical organ according to any one of claims 5 to 13, characterized in that it consists of a hard isotropic material.