Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D3/00—Cutting work characterised by the nature of the cut made; Apparatus therefor
  • B26D3/006—Cutting work characterised by the nature of the cut made; Apparatus therefor specially adapted for cutting blocs of plastic material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D1/00—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor
  • B26D1/01—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work
  • B26D1/46—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work having an endless band-knife or the like
  • B26D1/48—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work having an endless band-knife or the like with tensioning means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D5/00—Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D7/00—Details of apparatus for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
  • B26D7/26—Means for mounting or adjusting the cutting member; Means for adjusting the stroke of the cutting member
  • B26D7/2614—Means for mounting the cutting member
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
  • B26F1/00—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor
  • B26F1/38—Cutting-out; Stamping-out
  • B26F1/3806—Cutting-out; Stamping-out wherein relative movements of tool head and work during cutting have a component tangential to the work surface
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
  • B26F3/00—Severing by means other than cutting; Apparatus therefor
  • B26F3/06—Severing by using heat
  • B26F3/08—Severing by using heat with heated members
  • B26F3/12—Severing by using heat with heated members with heated wires

Definitions

• the invention relates to a device for cutting pieces of any shape from a block of hot-melt material by means of a deformable resistive profile which is heated, preferably electrically, and held in tension in an appropriate initial position, the cutting being carried out by relative movement of the workpiece and the profile.
• the cutting is carried out by relative displacement of the block of material to be cut and of the profile. It is always noted, due to the frictional forces exerted on the profile during the displacement of the block and / or the profile, that the profile takes a deflection, that is to say deforms, which harms the surface condition of the cut made. There is in particular the appearance of wavelets on the surface of the cut material. Conversely, too low a speed causes rapid deterioration of the surface of the cutting line by thickening of this cutting line. As a result, in the case of too high a speed, the deformation of the wire tends to modify the cut to be made while, in the case of a too low speed, the cutting line becomes particularly important.
• the object of the present invention is therefore to propose a device for cutting pieces of any shape from a block of hot-melt material, this device making it possible to obtain optimum cutting quality by means of a very thin profile whose small cross-section makes it possible to offer a high-quality surface finish and a fine cut line while working at a temperature which can be constant and which can be adjusted to a high pre-calibrated threshold.
• Another object of the present invention is to produce a cutting device making it possible to obtain parts of complex shape, directly from cutting, without adjustment retouching and without surface state rectification operation.
• Another object of the present invention is to propose a fully automated cutting device in which the mission of an operator is facilitated, no adjustment being necessary including in the case where the material to be cut is changed.
• Another object of the invention is to propose a cutting device in which the cutting time can be reduced by maintaining the relative speed of movement of the block of material and of the profile at the maximum speed corresponding to a speed at which one does not observe neither excessive deformation of the profile nor thickening of the cutting line.
• the subject of the invention is a device for cutting pieces of any shape from a block of hot-melt material of any shape by means of a deformable resistive profile, such as a wire, electrically heated and kept in tension.
• a deformable resistive profile such as a wire, electrically heated and kept in tension.
• block of material and profile being animated by a relative displacement during which the block opposes to the profile a resistance tending to modify the deformation of the profile compared to its initial deformation
• the installation comprises means for controlling the relative speed of movement of the profile and of the block of material to be cut at the instantaneous position of at least a portion of the profile to give the profile at each instant an optimal deformation corresponding to the previously chosen cutting position .
• the profile can be kept fully automatic at all times in an optimal cutting position corresponding to a deformation value or to a range of pre-selected deformation values while thus generating very good cutting precision. and a perfect surface condition of the cut piece.
• the control means include means for real-time and continuous detection of the position of at least a portion of the profile, for example a point on the profile, to produce signals representative of the deformation of the profile, means of processing in real time and continuously said signals to generate at least one control signal as output, control means for moving the block of material and / or the profile, these control means being sensitive to said control signal to increase or reduce the relative speed of movement of the block and the profile.
• control signal can be produced for a value or a range of values of the deformation signals of the profile chosen by the operator according to the cut to be made. It thus becomes possible to voluntarily cause an arrow of the profile to allow the cutting of a block y in particular at the level of a cusp. or else to modify the acceleration or deceleration printed on the part and / or on the profile as a function of the value of said profile deformation signals with respect to the chosen reference deformation value. Such an installation therefore makes it possible to obtain a configurable deflection of the profile.
• Figure 1 shows a schematic perspective view of an overall device for cutting parts of any shape according to one invention
• FIGS. 2A and 2B respectively represent diagrammatically in cross section of a sensor and of the profile as well as the signals representative of the position of the profile produced by said sensor in a first position of the profile and in a second position of the profile;
• FIG. 3 represents a schematic view in vertical section of a box mounted on the support element shown in FIGS. 1 and 4 and
• Figure 4 shows a front view of another architecture of a device for cutting parts according to the invention.
• the devices for cutting parts from a block 11 of hot-melt material of any shape by means of a deformable resistive profile 4 have various and varied architectures.
• the resistive profile 4 is a wire or a blade, possibly pre-bent, the latter is connected, at each of its ends or in the vicinity of the latter, to members 5, 6 ensuring the maintenance in tension of said wire, these members 5, 6 for maintaining tension being carried by at least one support element 3 constituting at least one of the structural elements of the device.
• the support element 3 depends on the rest of the structure defined by the general reference 1 of said device. Two embodiments of the support element 3 are provided below.
• the support element 3 is an armature, preferably in the form of an arc, this armature being mechanically coupled to the arm 8 of a manipulator robot 9 by means of an articulated connection. 19 as shown in FIG. 1.
• This robot 9 rests on a plate-like structure 20 bearing on the ground.
• This structure also supports a plate 10, possibly rotatable, on which is placed the block 11 of material to be cut, of any shape.
• the control members of the turntable 10 or of the arm 8 of the robot 9 can, in a manner known per se, be constituted by motors controlled in operation by an appropriate control signal.
• the use of a handling robot 9 makes it possible to obtain a large number of movements of the support element 3. This is in particular shown in FIG. 1 by the arrows indicating the different possibilities of movement of the handling robot. This results in a possibility of cutting pieces of any shape.
• the speed of movement of the profile 4 thus obtained by the combination of these different movements can be regulated, as will be described below, due to the presence of means for controlling the speed of movement of the profile 4 at the position d 'at least a portion of the profile 4. It is the same with the speed of rotation of the rotary plate 10 supporting the block 11 of material to be cut to obtain one or more pieces of any shape.
• the support element 3 is formed by two parallel vertical rails constituting the frame of the device and along which the tension maintenance members 5, 6 (FIG. 3) move. of the profile.
• These tension-maintaining members 5, 6 can be housed inside a box 2 shown in FIG. 3 and which will be described below, this box 2 moving to slide along the constituent rails of the element support 3.
• the boxes 2, arranged on either side of the ends of the profile 4 move together along the vertical rails.
• the displacement of the profile 4 along these two vertical rails ensures cutting in Y.
• These vertical rails are themselves mobile along one or more horizontal rails. The displacement of these rails along the horizontal rails ensures the X cut of the block 11 of material.
• the block 11 is in turn arranged on a plate 10, rotary or not, carried by a table. and disposed between the vertical rails carrying the members 5, 6 for maintaining the profile 4 in tension.
• the members 5, 6 for maintaining the tension of the profile 4 are, for example, constituted by two jacks 5 arranged at each end of the profile 4, these jacks 5 being housed in guide bearings 7 arranged either inside a casing 2 removably mounted on said support element 3, as shown in FIG. 3, or directly in said support element 3, for example at the ends of the arms of the arch, in the case of a support element 3 constituted by an arc-shaped armature of the type shown in FIG. 1.
• These jacks 5 can be mounted either with free movement in translation and with a stationary position which can be adjusted in translation inside said guide bearings 7, or respectively with free movement in translation and with a single stationary position inside said guide bearings 7.
• the vee rin 5 is a cylinder with free movement in translation also called an automatic displacement cylinder.
• This jack 5 cooperates with a return member 6 exerting an adjustable continuous permanent tension, so that the elongation of the cutting wire forming a profile 4 is compensated by the continuous movements of said jack 5 with automatic movement between two extreme positions.
• it is further arranged, near the end of the jack 5 receiving the cutting wire 4, at least one pulley 13, preferably two pulleys 13, 14, acting as rollers tensioners. These pulleys 13, 14 fulfill several functions.
• these pulleys 13, 14 are shaped to recognize the diameter of the wire so that, as soon as a change of wire occurs, this information is transmitted to processing means 18 which will be described below so as to take into account the new configuration of the wire, in particular when choosing the wire deformation value (s) corresponding to an optimal cut.
• These pulleys can also allow the supply of a current for heating the wire.
• the cooling means 12 are in this case constituted by a turbine arranged substantially in the axis of the wire inside said housing 2 as shown in FIG. 3.
• a mechanical cylinder with adjustable stationary positions At the other end of the wire (not shown in FIG. 3) , it may for example be arranged a mechanical cylinder with adjustable stationary positions.
• This cylinder is in this case constituted by a threaded axis carried by a thermally insulating and non-conductive bearing formed for example in a housing similar to that shown in FIG.
• this axis comprising in the vicinity of its ends a shoulder and possibly a stop limit switch as well as a nut for adjusting the axial position.
• said members for maintaining the profile in tension can be envisaged. Thanks to these members for maintaining the profile in tension, the deformation of the profile is produced, which occurs during the cutting of the part to be produced. This deformation of the profile results in a bending of the profile during the part / profile contact, this bending generating an elongation of the profile during cutting. This ensures, thanks to these tension holding members, an almost constant tension of the profile.
• Profile 4 generally consists of a wire or a blade, possibly pre-curved, deformable.
• the wires used are metallic wires, stainless steel or nickel / chrome alloy with a very small section, preferably between 40 and 200 microns. The nature and dimensions of the wire are chosen according to the heating temperature and the material to be cut.
• the wire is heated by suitable heating means. Generally, this wire is heated by the passage of a current supplied by a dimmer, this dimmer delivering for example a voltage of 220 Volts at 50 Hertz. As shown in Figure 3, these heating means can also be integrated in a housing 2 removably mounted on said support member 3 of the structure of the installation.
• the wire heating temperature depending on the melting temperature of the material to be cut, is generally in the range [200 - 600 ° C]. This temperature can be kept constant due to the presence in the installation of means for controlling the relative speed of movement of the profile and of the block 11 of material to be cut to the instantaneous position of at least a portion of the profile.
• control means include means for real-time and continuous detection of the position of a portion.
• profile 4 to produce signals representative of the deformation of profile 4, time processing means real and continuous of said signals to generate at output at least one control signal, means for controlling movement of the block 11 of material and / or of the profile, these control means being sensitive to said control signal to increase or reduce the speed relative movement of the block 11 and the section 4.
• the detection means can affect a large number of forms.
• the simplest detection means can consist of an all-or-nothing sensor, such as an electrically conductive eyelet forming a contactor, arranged around the profile, preferably at one end of the latter.
• an all-or-nothing sensor such as an electrically conductive eyelet forming a contactor, arranged around the profile, preferably at one end of the latter.
• the contacting eyelet comes into contact with a conductive element also circular incorporated in the frame of said installation thus generating a signal capable of being processed for generate an appropriate control signal to which the movement control means of the block 11 and / or of the section 4 described above are sensitive.
• this type of detection means although applicable in the present invention, lacks precision.
• a preferred solution therefore consists in using means of real-time and continuous detection of the position of at least a portion of the profile 4 which are made up of a transmitter-receiver assembly.
• the transmitter consists at least of the section 4 traversed by an electromagnetic wave while the receiver consists of at least one sensor 15, disposed in the vicinity of said section, the amplitude of the signal or signals supplied by said receiver being proportional to the transmitter-receiver distance.
• the output of the sensor 15 varies linearly with the displacement of the profile 4.
• FIGS. 2A and 2B An example of such a sensor is shown in FIGS. 2A and 2B. In FIG.
• the senor is formed of at least four plates 16A, 16B, 16C, 16D conductive opposite in pairs and arranged around said profile 4, preferably at least at one of the ends of the latter in the area Zl detection above.
• These conductive plates 16A, 16B, 16C, 16D such as copper plates, transmit signals via a wire, preferably shielded, to an electronic card 17 which, after amplification and filtration, transmits a signal to appropriate processing means 18, a signal corresponding linearly to the deviation of the profile.
• These signal processing means can be installed for example on a microcomputer, as shown in FIG. 1, controlling the machine or on the robot's control cabinet.
• These processing means 18 in turn generate a control signal to which the movement control means of the block 11 or of the section 4 are sensitive.
• the design of the detection means is based on the law of variation of the power of an electromagnetic wave propagating in a vacuum which varies in 1 / R 2, R being the transmitter / receiver distance.
• the profile forming a transmitter or more particularly a transmitting antenna, is connected to electronics which supplies a carrier wave, such as a sinusoidal signal of frequency 100 kHz, on said wire.
• a carrier wave such as a sinusoidal signal of frequency 100 kHz
• the profile, thus traversed by this electromagnetic wave, preferably sinusoidal makes it possible to induce, thanks to the concentric magnetic field produced, in the sensor 15, signals whose values are directly proportional to the 4-plate profile distance 16A or 16B or 16C or 16D.
• Figures 2A and 2B One such example is shown in Figures 2A and 2B.
• FIG. 2A there are shown signals obtained from four plates when the section 4 is in the rest position, that is to say a position in which the wire is for example arranged substantially in the center of the four plates.
• FIG. 2B on the contrary, making a cut has generated a deformation of the wire, resulting in a displacement of a portion of the profile in the direction of bringing the wire closer to two plates. This results in a variation of the signals representative of the deformation of the profile produced by each of the plates as shown in the associated signal diagrams.
• the processing means 18 of said signals If, on the contrary, the value F of the deflection is less than the value FI of predetermined minimum deflection or greater than the value F2 of predetermined maximum deflection, the processing means 18 of said signals generate a control signal inducing at the level of the means of control, such as a stepping motor or others described above, an increase or a reduction in the relative speed of movement of the block 11 of material and of the profile 4, for example, in the second case, by reduction of the speed of displacement of the support element 3.
• the control signal produced by said processing means 18 is sent when the measured value and / or calculated signals representative of the deformation of the profile 4 is located outside a predetermined range of values.
• the calculation of reduction and / or increase in speed can be done in different ways. This calculation depends on the complexity of the rest of the installation. Thus, for example, in the case of a machine comprising a manipulator robot, the speed regulation means must take account of the other characteristics of said robot. To calculate the appropriate speed, these means preferentially use well-known methods in automation, such as correction with proportional integral and derivative action (PID) or simpler but nevertheless effective methods such as that described below.
• PID proportional integral and derivative action
• This ⁇ is added to the instantaneous speed V to obtain a speed VI .
• the value VI then constitutes the new relative speed of movement of the block 11 and of the profile 4.
• a control signal is therefore sent to the movement control means of the block 11 and / or of the profile 4 in order to modify the speed. The speed can thus be changed periodically with each new cycle of the control loop.
• This periodicity is of the order of 200 milliseconds. It can be seen that, in such a detection system, the portion of the profile 4, the position of which is detected, is reduced to one point.
• the sensor 15 shown diagrammatically in FIGS. 2A and 2B is shown housed inside the housing 2 in FIG. 3.
• the removable housing 2 therefore integrates, in this case, both the means for heating the profile, the means cooling the profile 12, the members 5 and 6 for maintaining the profile in tension as well as part of the means for controlling the relative speed of movement of the profile and of the block of material to be cut to the instantaneous position of at least a portion of the profile, in particular the sensor 15 and the electronic card 17. Maintenance thus becomes particularly easy. It suffices, in the event of a problem, to remove said housing 2 from the support element 3 and to replace it with a new housing. The machine is thus not immobilized during the repair of said elements.
• the air flow required for cooling the profile is between 110 and 180 liters / minute.
• the initial thread tension is generally chosen between 300 and 700 g.
• the minimum and maximum limits of authorized wire deformation can be fixed by way of example at respectively 0.3 mm deviation at 30 cm from the center of the sensor for the lower terminal and 0.5 mm deviation at 30 cm from the center of the sensor for the upper bound. Obviously, these limits can be modified, possibly by reprogramming, with each new cutting. It is thus possible to cut out parts with a very large permissible deflection of the profile, in particular when it is necessary to cut out cusps.

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• Life Sciences & Earth Sciences (AREA)
• Forests & Forestry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

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• 1996
  • 1996-10-03 FR FR9612051A patent/FR2754208B1/fr not_active Expired - Fee Related
• 1997
  • 1997-10-03 AU AU45597/97A patent/AU4559797A/en not_active Abandoned
  • 1997-10-03 EP EP97943936A patent/EP0929385B1/de not_active Expired - Lifetime
  • 1997-10-03 WO PCT/FR1997/001755 patent/WO1998014311A1/fr active IP Right Grant
  • 1997-10-03 DE DE69729642T patent/DE69729642D1/de not_active Expired - Lifetime

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