EP3999311A1 - Verfahren zur herstellung eines biegeteils und biegemaschine zur durchführung des verfahrens - Google Patents
Verfahren zur herstellung eines biegeteils und biegemaschine zur durchführung des verfahrensInfo
- Publication number
- EP3999311A1 EP3999311A1 EP20737127.9A EP20737127A EP3999311A1 EP 3999311 A1 EP3999311 A1 EP 3999311A1 EP 20737127 A EP20737127 A EP 20737127A EP 3999311 A1 EP3999311 A1 EP 3999311A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- bending
- section
- workpiece
- twisted
- bend
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000005452 bending Methods 0.000 title claims abstract description 184
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 10
- 239000000835 fiber Substances 0.000 claims abstract description 60
- 239000002131 composite material Substances 0.000 claims abstract description 37
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 30
- 239000004416 thermosoftening plastic Substances 0.000 claims abstract description 29
- 238000010438 heat treatment Methods 0.000 claims abstract description 27
- 239000011159 matrix material Substances 0.000 claims abstract description 18
- 238000001816 cooling Methods 0.000 claims abstract description 17
- 239000007787 solid Substances 0.000 claims abstract description 13
- 239000012783 reinforcing fiber Substances 0.000 claims description 40
- 230000002093 peripheral effect Effects 0.000 claims description 6
- 239000000463 material Substances 0.000 abstract description 7
- 230000003014 reinforcing effect Effects 0.000 abstract description 3
- 230000007704 transition Effects 0.000 abstract 1
- 230000008569 process Effects 0.000 description 14
- 230000002787 reinforcement Effects 0.000 description 11
- 230000007935 neutral effect Effects 0.000 description 6
- 239000004033 plastic Substances 0.000 description 6
- 229920003023 plastic Polymers 0.000 description 6
- 239000012815 thermoplastic material Substances 0.000 description 6
- 229920000049 Carbon (fiber) Polymers 0.000 description 5
- 239000004917 carbon fiber Substances 0.000 description 5
- 239000003365 glass fiber Substances 0.000 description 5
- 239000011265 semifinished product Substances 0.000 description 5
- 230000001976 improved effect Effects 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000004918 carbon fiber reinforced polymer Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 238000001746 injection moulding Methods 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229920006231 aramid fiber Polymers 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 210000000080 chela (arthropods) Anatomy 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000011151 fibre-reinforced plastic Substances 0.000 description 1
- 230000009969 flowable effect Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000004413 injection moulding compound Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
- B29C53/14—Twisting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
- B29C53/02—Bending or folding
- B29C53/08—Bending or folding of tubes or other profiled members
- B29C53/083—Bending or folding of tubes or other profiled members bending longitudinally, i.e. modifying the curvature of the tube axis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
- B29C53/80—Component parts, details or accessories; Auxiliary operations
- B29C53/84—Heating or cooling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2101/00—Use of unspecified macromolecular compounds as moulding material
- B29K2101/12—Thermoplastic materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/08—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of continuous length, e.g. cords, rovings, mats, fabrics, strands or yarns
- B29K2105/10—Cords, strands or rovings, e.g. oriented cords, strands or rovings
- B29K2105/101—Oriented
- B29K2105/105—Oriented uni directionally
- B29K2105/106—Oriented uni directionally longitudinally
Definitions
- the invention relates to a method for producing a bent part from an elongated workpiece made of a fiber composite material, and to a bending machine for carrying out the method.
- Fiber composite materials belong to the material class of composite materials.
- a fiber composite material is a fiber-plastic composite that combines suitable reinforcing fibers (e.g. glass fibers or carbon fibers) and a plastic matrix that envelops the reinforcing fibers and enables force to be transmitted between the composite partners by means of adhesive or cohesive interaction. Since most plastics are not readily suitable for structural applications due to their plastic-specific material properties, reinforcement with reinforcing fibers is often an economical option for the production of structural materials. Due to the variability of reinforcing fibers and matrix materials, the properties of the composites can be varied within a wide range set in a targeted manner, which enabled applications in the lightweight construction sector for the aircraft and automotive industries, for example.
- Fiber composite materials are available in various forms as semi-finished products intended for further processing, e.g. as plates or as elongated workpieces in the form of tubes or rods.
- DE 10 2018 003 235 A1 describes a method and a device for producing a hollow structural component formed from a fiber-reinforced plastic for a vehicle.
- a tube formed from the fiber composite plastic, from which the hollow structural component is produced is held at points spaced apart from one another along the tube by means of respective robots, while the tube is heated in at least one partial area by means of a heating device.
- the robots each have several robotic arms that are articulated and movable relative to one another.
- the pipe is bent into a two-dimensional or three-dimensional course at least in the heated sub-area by the pipe, which is held by the robot during the bending, being bent around a bending head in the sub-area by at least one of the robots.
- the illustration shows a prototype of a car sun visor frame made of glass fiber reinforced polyamide of type PA6 with several curved sections
- the steel wire of the series component was replaced by a glass fiber strand.
- the process should have a high application potential if the inserts can be produced economically.
- the bent parts should be improved in terms of shape retention and rigidity.
- a bending machine suitable for carrying out the method is provided.
- a further object is to provide a two-dimensional or three-dimensional bent part which can be produced from an elongated thermoplastic fiber composite material workpiece by means of bending and which, compared to conventional bent parts, has improved component properties, e.g. in terms of shape retention and rigidity.
- the invention provides a method with the features of claim 1 and a bending machine with the features of claim 7. Furthermore, a bent part having the features of claim 10 is provided.
- an elongated workpiece which consists of a fiber composite material.
- the fiber composite material has a thermoplastic matrix consisting of a thermoplastic material, in which in the longitudinal direction of the Reinforcing fibers running through the workpiece are embedded.
- a section of the workpiece to be provided with a bend is heated to a first temperature at which the thermoplastic matrix is in a thermoplastic state, so that this section is plastically deformable.
- the section to be provided with the bend hereinafter also referred to as the “bending zone”, is created between a mechanically stronger front section and a stronger rear section.
- the term “solid” takes into account the fact that thermoplastics (thermoplastics) are solid before they are heated and after they have cooled down, but this is not synonymous with stiff.
- thermoplastics are flexible even in the solid state and some can also be processed and changed in shape in the solid state. This should not be ruled out in the present case.
- the thermoplastic state on the other hand, the thermoplastic material is soft and no longer dimensionally stable, so it may not be able to be returned to its original shape after deformation.
- the method further comprises the step of twisting the heated section by relatively twisting the rear section and the front section by an angle of rotation such that the reinforcing fibers in the heated section are brought into a twisted configuration and a heated twisted section is produced from the heated section .
- a twisting of the reinforcing fibers is created in the area of the heated section.
- the relative rotation can be achieved in that the front section is held firmly and only the rear section is rotated about its longitudinal axis.
- a reverse variant holding the rear section while rotating the front section
- the method further comprises the step of producing a bend in the heated, twisted section by bending at least part of the twisted section around a bending shape.
- the shape of the bend or its inner radius can be specified.
- the bend then lies between the front and the rear section, which in each case remain unbent and include a bending angle after the bending process.
- the step of twisting the heated section can occur temporally before the step of producing the bend or partially overlap with this step, that is to say can be carried out in phases at the same time as the bending.
- the soft matrix material is partially displaced during a pure bending process (without additional torsion) and all reinforcing fibers try to position themselves near the neutral fiber. This results in the inserted reinforcing fiber bundle fanning out in the area of the bend. After this simple bending without additional torsion, the result in many cases is an incorrect cross-section of the bending point and thus usually a significantly reduced rigidity of the manufactured component. If, on the other hand, the fiber composite material is twisted before and / or during the creation of the bend, more material is introduced into the area of the bend.
- the twisted additional material can now be compressed in the area of the inner radius and stretched in the area of the outer radius without resulting in a clearly unfavorable change in cross section.
- bending parts can be produced which, after the forming process, also have an at least largely round cross section in the area of the bends.
- a workpiece produced with the aid of a pultrusion process which has a round cross section and reinforcing fibers that run exclusively in the longitudinal direction (ie unidirectional).
- the pultrusion process enables the continuous production of elongated workpieces with a constant cross section in an economical manner.
- the workpieces that can be used as semi-finished products for further processing can, for example, have the shape of round bars or, more generally, have a continuously round cross-section of almost any length.
- the endless workpieces produced by this special extrusion process have a high tensile strength.
- the workpieces preferably used have reinforcing fibers that run exclusively in the longitudinal direction, that is to say no additional fibers that run at a significant angle at an angle to the longitudinal direction and / or that are in the form of mats or braids.
- Pultruding can achieve a high fiber volume with a very low air void content.
- the fiber volume fraction in the fiber composite is in the range from 30% to 70%, possibly also above or below.
- the reinforcing fibers can be, for example, glass fibers, carbon fibers or aramid fibers or combinations of two or more types of fibers.
- Pultruded CFRP round bars are preferably used, i.e. round bars with carbon fibers as reinforcing fibers.
- the extent of the mutual twisting between the front and rear sections can vary from workpiece type to workpiece type and can be adapted to the requirements (e.g. bending radius, length of the section to be bent). In many cases, good results have been achieved by choosing the angle of rotation such that the reinforcing fibers in the twisted section have a fiber layer angle in the range from 5 ° to 85 °, in particular from 10 ° to 35 °.
- the fiber layer angle FLW is defined analogously to the shear angle in the classic consideration of mechanical torsional loads.
- parameter L is the length of the heated section that is converted into a twisted section.
- Parameter DW is the angle of rotation or twist angle by which the front and rear sections are rotated relative to one another.
- Parameter R is the radial distance of a reinforcing fiber under consideration from the neutral fiber, i.e. from the center of the workpiece section.
- the parameter R corresponds to the radius (radius) of the workpiece in the area of the heated section.
- FLW (DW * R) / L.
- the section of the workpiece to be provided with a bend is preferably heated in a contactless manner, so that there is no mechanical contact between elements of the heating device and the initially colder and then heated section.
- hot air is used to warm up. This results in a particularly gentle Heating with thorough warming of the entire cross-section of the workpiece to such an extent that the core temperature of the workpiece (in the area of the longitudinal center axis) is sufficient to deform the fiber composite material thermoplastically.
- heating by means of infrared radiation or induction or high-frequency heating (dielectric heating and inductive heating) can be provided.
- the process can be carried out completely manually if required, for example in the case of small series or individual parts. However, a partially or fully automated implementation using a bending machine is usually provided.
- the method is carried out automatically with the aid of a bending machine which has a bending head with a bending mold and with a bending arm that can be rotated about the bending mold, which has a clamping device for clamping a front section of the workpiece against a circumferential section of the bending mold and is rotatable about a bending axis .
- a step (a) the workpiece is brought into a starting position in the bending machine.
- a gripper device with a single-axis or multi-axis movable gripper is brought into engagement with the front section of the workpiece.
- a counterholder device rotatable about an axis of rotation is brought into engagement with a rear section of the workpiece, a section to be provided with a bend being located between the front section and the rear section.
- Steps (b) and (c) can be carried out simultaneously or offset in time in any order.
- the section to be provided with the bend is then heated by means of a heating device of the bending machine. Because the front section and the rear section are held in position by means of the bending machine, the heated section cannot or hardly deform by itself at first, even if the thermoplastic material changes to a thermoplastic state.
- a step (e) the front section is then brought into an engagement area of the bending head by a coordinated movement of the gripper of the gripper device and the counter-holder device.
- the clamping device will clamp the front section against a circumferential section of the bending mold.
- a bend is produced between the front section and the rear section in a bending operation by rotating the bending arm about the bending axis.
- the counterholder device is rotated before and / or during the rotation of the bending arm about the bending axis in order to introduce a torsional moment about an axis of rotation running parallel to the longitudinal direction of the rear section in such a way that the twisted portion is produced in the area between the counter-holder device and the bending form, in which the reinforcing fibers are present in a twisted configuration.
- steps (a) to (d) it is also possible to carry out steps (a) to (d) as described above and then to introduce the torsion before the workpiece is introduced into the bending mold.
- the heated section can be held in place by means of the gripper device in step (e '), while the counter-holder device is rotated about an axis of rotation parallel to the longitudinal direction of the rear section in order to introduce a torsional moment such that the twisted one in the area between the counter-holder device and the gripper device Section is generated in which the reinforcing fibers are in a twisted configuration.
- the front section can be brought into an engagement area of the bending head and clamped there by means of the clamping device.
- the bend is then created by turning the bending head.
- the bending machine can be equipped with a cooling device for active cooling of the twisted section. This can work with compressed air, for example. If more time is available, passive cooling is also possible, that is, automatic cooling of the curved and twisted section to the second temperature at which the curved and twisted section is sufficiently firm and dimensionally stable. Then the bent part can be removed from the bending mold.
- a gripper device with a single-axis or multi-axis movable gripper in addition to the bending head is usually advantageous, particularly when a workpiece is to be provided with more than one bend in the same bending plane or in different bending planes. This additional possibility of manipulation is therefore preferably provided.
- an alternative procedure is also possible in which work is carried out without an additional gripper device.
- the gripper of a gripper device is brought into engagement with the front section of the workpiece
- the front section is brought into engagement directly with the bending head and there by means of the clamping device by clamping the front section held in position.
- the counter holder device is moved accordingly so that the section to be heated is already close to the bending head.
- step (e) can then be omitted since the front section is already clamped on the bending head.
- the invention also relates to a bending machine for producing a bent part from an elongated workpiece made of a fiber composite material.
- the bending machine comprises a control device and a bending head, which has a bending form and a bending arm which can be rotated about the bending form and which has a clamping device for clamping a front section of the workpiece against a peripheral section of the bending form, the bending arm being rotated around a bending drive controlled by the control device Bending axis is rotatable.
- the bending machine further comprises a counterholder device controllable by the control device, which is configured to be brought into engagement with a rear section of the workpiece in order to stabilize an alignment of the rear section during a bending operation.
- the counterholder device can be rotated about an axis of rotation by means of a rotary drive controlled by the control device in order to rotate the workpiece about its longitudinal axis or longitudinal direction.
- a heating device is provided which is designed to heat a section of the workpiece to be provided with a bend to a first temperature at which the thermoplastic matrix is in a thermoplastic state, the section to be heated between the front section and the rear section lies.
- the control device is configured or configurable to rotate the counterholder device before and / or during a rotation of the bending arm about its bending axis about the axis of rotation such that a twisted section can be generated in an area between the counterholder device and the bending form.
- the heating device is preferably a non-contact heating device that can work with hot air or infrared radiation or induction, for example.
- a gripper device with a gripper movable in one or more axes is also provided, which can optionally be moved into an area between the bending head and the counter-holder device and can be moved parallel to the axis of rotation of the counter-holder device.
- the gripper device can be equipped, for example, with guides running orthogonally to one another in order to be able to move the gripper in two or three dimensions.
- a robot unit can also be used as a gripper device.
- a cooling device assigned to the bending head is preferably provided for cooling the twisted section provided with the bend to the second temperature, at which the twisted section changes to a thermoplastic or solid state.
- the cooling device can work with compressed air, for example.
- the invention also relates to a bent part made of an elongated workpiece made of a fiber composite material which has a thermoplastic matrix in which reinforcing fibers extending in the longitudinal direction of the workpiece are embedded.
- the single or multiple bent bent part has at least one section with a bend which is formed between an adjacent front section and an adjacent rear section, the reinforcing fibers in the front section and rear section running essentially in the longitudinal direction of the sections and in the area of the Be in a twisted configuration.
- bent parts made in accordance with the claimed invention.
- a bent part can be used alone or in combination with other bent parts as reinforcement for an injection-molded part, in that the at least one bent part is overmolded with a suitable plastic after its production.
- Bending parts can also be cast in concrete in the construction industry as a replacement for or in addition to steel reinforcement bars and serve as reinforcement or reinforcement of concrete structures.
- 1 shows a schematic side view of the bending machine 100 according to an embodiment
- 2A to 2D show different phases of a forming operation for the production of a fiber composite material bent part with a twisted section
- 3A and 3B show different phases of a forming operation in another embodiment
- FIGS. 4A and 4B schematically show two exemplary embodiments for bent parts which can be produced with the aid of the method or the bending machine;
- FIG. 5 shows a schematic illustration to illustrate the fiber layer angle of reinforcing fibers in a twisted section.
- a computer-numerically controlled bending machine 100 which is set up for bending elongated workpieces made from a fiber composite material.
- 1 shows a schematic side view of the bending machine 100 according to one embodiment.
- the bending machine is suitable and provided for providing an elongated workpiece 110 made of a fiber composite material with one or more bends.
- the workpiece 110 is a round rod made of a fiber composite material produced using a pultrusion process, in which carbon fibers 115 running parallel to the longitudinal center axis 112 of the workpiece are embedded in a matrix 111 made of a thermoplastic material (see enlarged detail I).
- the volume fraction of the fibers is between 30% and 40% in the example, but can also be higher or lower in other examples.
- the reinforcing fibers run unidirectionally, so there are no reinforcing fibers and no fiber braids in the workpiece that are clearly inclined to the longitudinal center axis.
- the diameter of the round rod can, for example, be in the range from 1 mm to 40 mm, in particular in the range from 2 mm to 10 mm.
- a bent part with one or more bends is to be formed from the workpiece, which is to be used later as an insert in order to reinforce an injection-molded component in critical areas.
- the finished bent part is later coated with an injection molding compound in an injection molding process.
- the workpiece 110 is in the form of a rod-shaped semi-finished product with a finite length (for example between 1 m and 2 m) and can be inserted into the bending machine manually, semi-automatically or fully automatically by an operator.
- a longer workpiece supply (coil) is used and the sections to be bent are gradually withdrawn from the workpiece supply.
- the bending machine 100 has a right-angled machine coordinate system MK marked with lowercase letters x, y and z, with a vertical z-axis and horizontal x- and y-axes.
- the x-axis runs parallel to the workpiece axis 112 of the still unbent workpiece.
- the machine axes and their drives are controlled via a central control unit of the bending machine.
- the bending machine 100 comprises a bending head 120 with a bending form 122 and a bending arm 124 which can be rotated about the bending form and which has a clamping device 130 which is intended to clamp a front section of the workpiece, which will be explained later, against a peripheral section of the bending form.
- the bending arm 124 and the bending form 122 are each rotatable about a common vertical bending axis 125.
- the machine axis belonging to the bending arm is referred to here as the Y-axis and is driven by a bending drive in the form of an electric servo motor.
- the clamping jaw of the clamping device is actuated via the P-axis.
- the bending head as a whole can be moved vertically (parallel to the z-direction of the machine coordinate system) using the Z-axis.
- a counterholder device 150 of the bending machine is arranged at a distance from the bending head.
- the counterholder device 150 can be moved as a whole by means of a machine axis (C axis) parallel to the x axis of the machine coordinate system and can be rotated about the direction of movement, which in the example is horizontal, by means of an A axis of the bending machine.
- the counterholder device comprises a tubular body 152 which, in its end area facing the bending head, has a pliers-like clamping device 155 with radially adjustable clamping jaws, which are intended to be brought into engagement with the rear section 118 of the workpiece and to clamp it in such a way that it cannot slip without damaging the workpiece.
- the workpiece 110 is cut to a specific length as a pre-assembled workpiece, some of which is located inside the tube 112 and can be supported there.
- the workpiece is withdrawn from a longer workpiece supply (coil).
- a feed device for this purpose provided with which the workpiece can be advanced in the x-direction of the machine coordinate system over the C-axis.
- a clamping device is provided for clamping the workpiece.
- the workpiece can be fed and rotated using a roller feeder instead of a pincer feeder.
- a special feature of the bending machine 100 is that, in addition to the bending head and the counterholder device, a gripper device 140 is also provided, which can be controlled by the control of the bending machine via additional machine axes and is provided with the aid of a gripper 145 attached to it in certain phases of workpiece processing to grip the front section 117 of the workpiece and hold it in a predefined position.
- the gripper unit can, for example, be configured as a robot unit or it can be constructed with the aid of orthogonal slides.
- the gripper 145 can be moved parallel to the x-axis of the machine coordinate system (that is, in the longitudinal direction of the workpiece) and perpendicular to it (e.g. parallel to the z-direction of the machine coordinate system).
- a possibility of movement in the y-direction is also provided.
- the bending machine further comprises a heating device 160 which is configured to heat a portion 119 of the workpiece to be bent, which lies between the front portion 117 and the rear portion 118, to a first temperature before the start of a bending operation the matrix material of the fiber composite material becomes thermoplastic, so that the workpiece in the heated section can be bent non-destructively with a permanent change in shape.
- the heating device 160 comprises a hot air blower 162 which generates hot air which is then passed via a hose or a pipe in the direction of an outlet nozzle 165 which can be moved in the immediate vicinity of the section to be heated.
- the outlet nozzle 165 comprises a concave-cylindrical channel on the side facing the workpiece, so that the outlet nozzle can partially encompass the workpiece in the area to be heated in order to achieve contactless heating of the section from several sides. This ensures a sufficiently uniform heating of the section 119 to be heated up to the core area at the longitudinal center axis 112 in relatively short times, without the temperature in the area of the outer surface rising so far that the thermoplastic material changes to the flowable state.
- the heating device can be numerically controlled via its own machine axis or moved manually by an operator into the heating position shown and removed from it.
- Cooling device 170 is also provided in order to achieve rapid active cooling of the twisted and heated section. The cooling device works with compressed air, which can be directed through a nozzle 172, which is adjustable in its spatial position, onto the heated twisted section that is still in contact with the bending form.
- FIGS. 2A to 2D A possible procedure for the production of a bent part from such a fiber composite material with longitudinally extending reinforcing fibers is explained below with reference to FIGS. 2A to 2D.
- 2A shows a situation in which the workpiece 110 has been brought into a starting position in the bending machine 100 by an operator or by machine.
- the displaceable gripper device 140 grips the front section 117, which lies at the free end of the workpiece.
- the clamping device 155 of the counterholder device 150 grips the rear section 118.
- the front and rear sections are still coaxial and all reinforcing fibers 115 run unidirectionally parallel to the longitudinal center axis in the workpiece.
- the section 119 to be bent is then heated with the aid of the heating device 160 to such an extent that the thermoplastic material in the section to be bent is plastically deformable.
- the core temperature can be in the middle range, e.g. in the range from 250 ° C to 300 ° C. This situation is shown in Figure 2A.
- the heating device 160 is then moved back.
- the workpiece with the now pliable, heated section 119 is held in the coaxial configuration at the front section 117 by the gripper device and at the rear section 118 by the counterholder device.
- the gripper device or its gripper 145 and the counter-holder device 150 now move in a coordinated, synchronized manner parallel to the x-direction via the control unit, so that the relatively cooler and solid, i.e. not thermoplastically deformable, front section 117 comes into the engagement area of the clamping device 130 and is clamped by it is in that the clamping device clamps the front portion against a peripheral portion of the contoured bending form (see. Fig. 2B).
- the counter holder device 150 is rotated by a predeterminable angle of rotation by means of the A axis. Since the counterholder device holds the rear section 118 in a non-positive manner, it is rotated along with it, so that a torsional moment is exerted on the workpiece. This is transferred from the relatively firm rear section 118 to the relatively more flexible and plastically deformable heated section 119, which is located between the firmly clamped front section 117 and the rear section 118 which is rotated relative thereto and is still coaxial.
- the angle of rotation of the counterholder device is usually selected so that in the area of the twisted section maximum fiber layer angles in the range from approx. 5 ° to approx. 85 ° result (cf. FIG. 5 for the definition of the fiber layer angle).
- the process parameters are chosen so that the twisted section largely retains its cross-sectional dimensions, both in terms of shape and diameter.
- the counterholder device executes a controlled compensating movement in the longitudinal direction of the workpiece (by means of the C-axis) during the twisting, so that the distance between the bending form and the counterholder device becomes somewhat shorter during twisting, by a cross-section reduction in the twisted Section counteract.
- the complete torsion is introduced before the actual bending operation begins.
- Fig. 2D the complete torsion is introduced before the actual bending operation begins.
- the bending arm 124 with the clamping device 130 carried by it is rotated around the bending axis 125.
- the bending shape follows this rotation.
- the heated and twisted section is drawn around the bending mold and thereby bent, the concavely contoured outer contour of the bending mold 122 stabilizing the inside contour of the resulting bend and specifying its bending radius.
- the desired bending angle is present between the straight front section 117 and the straight rear section 118, which in the example is approximately 90 °.
- the cooling device 170 is fed and cold compressed air is blown onto the bent, still relatively warm twisted section until it has cooled down enough that the thermoplastic matrix changes back to a solid state, in which the bent section can be removed from the bending form without deformation. For this purpose, the tensioning device is then relieved.
- FIGS. 3A, 3B which manages without a gripper device.
- 3A shows the same situation in different perspectives in the left and right partial figures. The same applies to FIG. 3B, which shows a later situation in two perspectives.
- the front section 117 is already in front the heating of the section 119 to be bent is brought into the area of engagement of the bending head 120 between the bending mold 122 and the clamping device 130 on the bending arm and clamped on the bending mold by means of the clamping device 130.
- the heating device 160 is then advanced and heats the section 119 to be bent in the immediate vicinity of the bending head.
- the counterholder device 150 is rotated by the desired angle of rotation with respect to the bending head, so that the twisting of the reinforcing fibers in the heated section results in the manner described and a twisted section 119 is created.
- the bending arm with the clamping device 130 is rotated about the bending axis 125 so that the heated section is drawn around the bending mold 122 and is given the desired shape of the bend. It is then cooled as described.
- the bending part can be machined so that only a single bend is created. It is also possible to apply two or more bends in a common bending plane or in different bending planes. By rotating the counter-holder device before the section to be bent is heated, different bending planes can be implemented.
- the front section does not have to run continuously in a straight line, but can already have one or more bends.
- the bending angle (angle between the longitudinal axis of the first section and the second section after the bend has been created) can be between 1 ° and 360 °, for example. Large bending angles of significantly more than 180 ° can be achieved, for example, by using a bending form with a helical circumferential groove (helical tool).
- the extent of the rotation between the front and rear section when generating the twisted section depends on the one hand on the intended length of the section to be bent, usually in such a way that the longer the angle of rotation of the counterholder device relative to the gripper device or the bending head is greater the section to be twisted. The same applies to the bending radius. The larger the bending radius of the bend to be produced, the larger the angle of rotation will generally also be in order to achieve a sufficiently twisted state in the heated or twisted section.
- FIGS. 4A and 4B schematically show two exemplary embodiments for bent parts that can be produced with the aid of the method or the bending machine. They are each made from pultruded CFRP rods and can be used, for example, as fiber composite inserts for the local reinforcement of injection molded parts.
- Each of the bent parts BT 1, BT2 is made from an elongated workpiece 110 made of a fiber composite material which has a thermoplastic matrix 111 into which unidirectional reinforcing fibers 115 are made Carbon are embedded.
- Each of the bending parts has two opposing sections 119, each with a bend which is formed between an adjacent front section 117 and an oppositely adjacent rear section 118.
- the bending radii can be, for example, between 3 mm and 10 mm, possibly also above or below.
- the bending angle for BT1 (FIG. 4A) is 180 °, and for the larger bends in BT2 (FIG. 4B) it is greater, for example at around 330 °.
- the reinforcing fibers 115 run essentially in the longitudinal direction of the sections. In the area of the bends, however, there is a twisted configuration of the reinforcing fibers.
- FIG. 5 shows a twisted section 119 of length L in a workpiece 110 with a radius (radius) R to illustrate a twist and the fiber layer angle generated thereby.
- the starting workpiece was produced in the pultrusion process and had reinforcing fibers running unidirectionally in the longitudinal direction before the deformation .
- the twisted section 119 lies between a front section 117 and a rear section 118. During the torsion operation, the sections 117 and 118 have been rotated relative to one another by an angle of rotation DW (also called a twist angle).
- the reinforcement fiber 115 shown with a solid line runs on the outer circumference of the twisted section at a radial distance R from the neutral fiber NF, which runs in the center of the workpiece 110.
- the reinforcement fiber 115 ran parallel to the neutral fiber NF before the torsion.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
- Moulding By Coating Moulds (AREA)
Abstract
Description
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DE102019210412.6A DE102019210412A1 (de) | 2019-07-15 | 2019-07-15 | Verfahren zur Herstellung eines Biegeteils und Biegemaschine zur Durchführung des Verfahrens |
PCT/EP2020/068768 WO2021008896A1 (de) | 2019-07-15 | 2020-07-03 | Verfahren zur herstellung eines biegeteils und biegemaschine zur durchführung des verfahrens |
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DE (1) | DE102019210412A1 (de) |
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CN113218106A (zh) * | 2021-04-28 | 2021-08-06 | 哈尔滨工程大学 | 基于TiNi基合金弹热效应新型固体制冷装置及其原型机的设计 |
FR3130809A1 (fr) | 2021-12-22 | 2023-06-23 | Arkema France | Composition (méth)acrylique pour composite, son procédé de préparation et son utilisation |
CN116373271B (zh) * | 2023-06-05 | 2023-10-03 | 成都飞机工业(集团)有限责任公司 | 一种增强复材卡箍随动成型装置及成型方法 |
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DE59003759D1 (de) * | 1989-06-05 | 1994-01-20 | Sulzer Innotec Ag | Profilstange aus kompaktem Verbundwerkstoff und Herstellungsverfahren. |
US5326524A (en) * | 1990-03-23 | 1994-07-05 | Phillips Petroleum Company | Method of making plastic rods |
US5234333A (en) * | 1990-03-23 | 1993-08-10 | Phillips Petroleum Company | Apparatus for making and postforming reinforced plastic rods |
JP5383245B2 (ja) * | 2009-02-20 | 2014-01-08 | 三菱重工業株式会社 | パイプ曲げ加工装置 |
DE102017120143A1 (de) * | 2017-09-01 | 2019-03-07 | Groz-Beckert Kg | Biegeverfahren und Biegevorrichtung zum Biegen eines Verbundwerkstoffstabes |
DE102018003235A1 (de) * | 2018-04-20 | 2018-09-27 | Daimler Ag | Verfahren und Vorrichtung zum Herstellen eines FVK-Hohlstrukturbauteils für ein Fahrzeug, insbesondere für ein Kraftfahrzeug |
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2019
- 2019-07-15 DE DE102019210412.6A patent/DE102019210412A1/de active Pending
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DE102019210412A1 (de) | 2021-01-21 |
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