METHOD FOR SHAPING A SHAPE MEMORY WORKPIECE AND SHAPING TOOL FOR SHAPING A SHAPE MEMORY WORKPIECE

Abstract

A method for shaping a shape memory workpiece includes: providing a shape memory workpiece having a first diameter and a predetermined shaping temperature; arranging the shape memory workpiece on a shaping tool; heating the shape memory workpiece to the shaping temperature; first expansion of the shape memory workpiece to a second diameter that is larger than the first diameter; first changing of the temperature of the shape memory workpiece to an intermediate temperature below or above the shaping temperature; bringing the shape memory workpiece to the shaping temperature again; second expansion of the shape memory workpiece to a third diameter that is larger than the second diameter; ejecting the shape memory workpiece from the shaping tool; and final cooling of the shape memory workpiece to a cooling temperature below the intermediate temperature.

A shaping tool is also provided.

Claims

1. A method for shaping a shape memory workpiece, comprising: providing a shape memory workpiece having a first diameter and a predetermined shaping temperature; arranging the shape memory workpiece on a shaping tool; heating the shape memory workpiece to the shaping temperature; first expansion of the shape memory workpiece to a second diameter that is larger than the first diameter; first changing of the temperature of the shape memory workpiece to an intermediate temperature below or above the shaping temperature; bringing the shape memory workpiece to the shaping temperature again; second expansion of the shape memory workpiece to a third diameter that is larger than the second diameter; ejecting the shape memory workpiece from the shaping tool; and final cooling of the shape memory workpiece to a cooling temperature below the intermediate temperature.

2. The method for shaping a shape memory workpiece according to claim 1, wherein the first changing of the temperature of the shape memory workpiece to an intermediate temperature comprises a first cooling of the shape memory workpiece to the intermediate temperature below the shaping temperature, or a first further heating of the shape memory workpiece to the intermediate temperature above the shaping temperature.

3. The method for shaping a shape memory workpiece according to claim 2, wherein the first changing of the temperature of the shape memory workpiece comprises changing the temperature of the shape memory workpiece by at least about 25° C.

4. The method for shaping a shape memory workpiece according to claim 2, wherein the first changing of the temperature of the shape memory workpiece comprises changing the temperature of the shape memory workpiece by at least about 40° C.

5. The method for shaping a shape memory workpiece according to claim 1, wherein the second diameter is about 1.5 times to about 1.9 times the first diameter; and/or the third diameter is about 1.5 times to about 1.9 times the second diameter.

6. The method for shaping a shape memory workpiece according to claim 1, wherein the second diameter is about 1.85 times the first diameter.

7. The method for shaping a shape memory workpiece according to claim 1, wherein the third diameter is about 1.85 times the second diameter.

8. The method for shaping a shape memory workpiece according to claim 1, wherein the first expansion and the second expansion comprise an expansion of the shape memory workpiece in the radial direction, in particular while maintaining the axial extension of the shape memory workpiece.

9. The method for shaping a shape memory workpiece according to claim 1, wherein the shape memory workpiece is held in a frictional manner during at least one of the first and second expansions.

10. The method for shaping a shape memory workpiece according to claim 1, wherein the shape memory workpiece: has a nickel-titanium alloy; and/or has a round shape; and/or has a stent pattern.

11. A shaping tool for shaping a shape memory workpiece, having: a guide element, and a traversing tube, which is movably arranged on the guide element, wherein disks are arranged on the traversing tube at predetermined axial distances, expansion wires or expansion elements are stretched between the disks, and wherein the expansion wires or expansion elements stretched between the disks form diameters in order to arrange a shape memory workpiece circumferentially thereon.

12. The shaping tool for shaping a shape memory workpiece according to claim 11, wherein the shaping tool has a receiving area for arranging thereon a shape memory workpiece having a first diameter, and wherein - the traversing tube is configured to be moved relative to the receiving area by means of an actuator, so that the shape memory workpiece can be passed by the disks in the receiving area.

13. The shaping tool for shaping a shape memory workpiece according to claim 11, wherein the disks are shaped such that the shaping tool is configured to expand the shape memory workpiece by moving the traversing tube along the guide element.

14. The shaping tool for shaping a shape memory workpiece according to claim 11, wherein the disks have sliding grooves along their circumference, wherein an expansion wire is slidably guided by the respective disk along each sliding groove, and wherein each expansion wire is preferably arranged in the respective sliding groove such that it projects radially outward with respect to the disk in the sliding groove of which the expansion wire is guided.

15. The shaping tool for shaping a shape memory workpiece according to claim 11, having: a heating device, preferably a heatable salt bath; and/or a cooling device, preferably a water bath.

16. The shaping tool for shaping a shape memory workpiece according to claim 15, wherein the heating device is a heatable salt bath.

17. The shaping tool for shaping a shape memory workpiece according to claim 15, wherein the cooling device is a water bath.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0136] Embodiments of the invention will be described in more detail below with reference to the accompanying figures. It goes without saying that the present invention is not limited to these embodiments and that individual features of the embodiments can be combined to form further embodiments within the scope of the appended claims.

[0137] The figures show:

[0138] FIG. 1 a flowchart for the method for shaping a shape memory workpiece;

[0139] FIG. 2 a sketch of a portion of a shaping tool;

[0140] FIG. 3 a sketch of a portion of a disk of a shaping tool;

[0141] FIG. 4a a sectional representation of a shaping tool in a first state;

[0142] FIG. 4b a sectional view of a shaping tool in a second state;

[0143] FIG. 4c a sectional representation of a shaping tool in a third state; and

[0144] FIG. 5 a sketched temperature-time profile according to an example of the present method.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0145] FIG. 1 shows a flowchart of an exemplary method, comprising the steps of: [0146] S10: providing a shape memory workpiece 100 having a first diameter and a predetermined shaping temperature FGT; [0147] S20: arranging the shape memory workpiece 100 on a shaping tool 10; [0148] S30: heating the shape memory workpiece 100 to the shaping temperature FGT; [0149] S40: first expansion of the shape memory workpiece 100 to a second diameter that is larger than the first diameter; [0150] S50: first cooling of the shape memory workpiece 100 to an intermediate temperature ZT below the shaping temperature FGT or further heating of the shape memory workpiece 100 to an intermediate temperature ZT above the shaping temperature FGT; [0151] S60: bringing the shape memory workpiece 100 to the shaping temperature FGT again; [0152] S70: second expansion of the shape memory workpiece 100 to a third diameter that is larger than the second diameter; [0153] S80: ejecting the shape memory workpiece 100 from the shaping tool 10; and [0154] S90: final cooling of the shape memory workpiece 100 to a cooling temperature below the intermediate temperature ZT.

[0155] The method of FIG. 1 depicts an exemplary method for shaping a shape memory workpiece 100. Due to the multiple steps of expansion S40 and S70, wherein the shape memory workpiece 100 is expanded at a shaping temperature FGT of the shape memory workpiece 100, and the intermediate step of cooling or further heating to a temperature below or above the shaping temperature FGT, the overall deformation of the shape memory workpiece 100 for substantially obtaining a target shape or a target diameter is advantageously divided. By dividing the deformation into several steps of expansion, even large changes in diameter, starting from a first or initial diameter to a target diameter or a final diameter, can advantageously be implemented, with damage to the shape memory workpiece 100 advantageously being reduced or prevented.

[0156] At the same time, ejecting the shape memory workpiece 100 in step S80, after expanding to the target diameter or the third diameter in the sense of step S70, enables the final cooling in step S90 to be directed specifically at the shape memory workpiece 100, whereby an energetically time-consuming cooling and possibly reheating of the shaping tool 10 can be prevented. Furthermore, thermal stresses on the shaping tool 10 are advantageously reduced as a result.

[0157] In addition, the steps S30 and S60 of heating or bringing the shape memory workpiece 100 to the shaping temperature FGT can in particular comprise heating or bringing the shape memory workpiece 100 to the shaping temperature FGT and heating or bringing the shaping tool 10 to the shaping temperature FGT. Furthermore, in exemplary embodiments, either the shaping tool 10 or the shape memory workpiece 100 can be indirectly heated or cooled by heating or cooling the respective other one of the shaping tool 10 and the shape memory workpiece 100.

[0158] The method of shaping a shape memory workpiece 100 is not limited to the steps shown in FIG. 1. Instead, to achieve a specific target diameter or final diameter, one or more further steps of cooling or further heating to an intermediate temperature ZT below or above the shaping temperature FGT, bringing the shape memory workpiece 100 to the shaping temperature FGT again, and expanding the shape memory workpiece 100 to a diameter that is increased compared to the previous expanding step can be carried out, based on the respective steps S50, S60 and S70 according to FIG. 1. Preferably such that a target shape or a target diameter of the shape memory workpiece 100 is reached with the last step of expanding the shape memory workpiece 100, and so that steps S80 and S90 can follow next. The target diameter of the shape memory workpiece 100 can be a diameter that is larger than a predetermined diameter the shape memory workpiece 100 is configured to assume in use, for example after being inserted into a human body, in order to compensate for a possible springback of the shape memory workpiece 100 when it cools down after being ejected from the shaping tool 10.

[0159] In alternative embodiments, the method can be limited to steps S10, S20, S30, S40, S80 and S90, so that the shape memory workpiece 100 is expanded by means of a single step starting from a first or initial diameter to a target diameter or final diameter. Such a method provides a particularly fast and energy-efficient method for shaping a shape memory workpiece 100, which at the same time enables the product properties of the shape memory workpiece, such as in particular geometry and austenite finish temperature, to be set precisely by means of a precisely definable cooling rate.

[0160] FIG. 2 shows a sketch of a portion of a shaping tool 10. Also shown in FIG. 2 is a coordinate system which in particular has the axial direction a, the radial direction r and the circumferential direction u. In the representation of FIG. 2, the axial direction a extends substantially from right to left, the radial direction r substantially extends radially outward from the axial direction a, shown exemplarily from bottom to top, and the circumferential direction u extends along a circumference of a preferably circular element of the shaping tool 10, shown exemplarily as pointing into the drawing plane.

[0161] The shaping tool 10, as shown in FIG. 2, in particular has a guide element 20 and a traversing tube 30, which is traversably arranged on the guide element 20. The traversing tube 30 can be supported at least partially in a sliding manner on the guide element 20. As shown in FIG. 2, the guide element 20 can extend substantially in the axial direction a and can be formed by a rod or hollow cylinder, for example.

[0162] The traversing tube 30 preferably extends at least in parts parallel to the guide element 20. In other words, the traversing tube 30 can extend at least in parts along the axial direction a. The traversing tube 30 can in particular be hollow, preferably hollow-cylindrical, and accommodate the guide element 20 at least in parts.

[0163] As further shown in FIG. 2, several disks 40 are arranged on the traversing tube 30, and expansion wires or (e.g., web-like, flexible) expansion elements 50 are arranged or attached such that they are stretched between the disks 40 or extend between the disks 40. As further illustrated in FIG. 3, the expansion wires or elements 50 preferably run along an outer circumference of the disks 40 or through sliding grooves 42 of the disks 40.

[0164] The disks 40 are preferably arranged along the traversing tube 30 at predetermined axial distances from one another, i.e., distances substantially along the axial direction a. The disks 40 can be arranged substantially equidistant from one another or have a varying distance from one another. The shaping tool 10 can have any number of disks 40 or any number of disks 40 can be arranged on the traversing tube 30.

[0165] The number of disks 40 arranged on the traversing tube 30 can correspond at least to the number of different diameters that a shape memory workpiece 100 to be shaped gradually assumes in the method for shaping a shape memory workpiece 100.

[0166] In addition, in a transition area 14 between two discrete diameter areas 12, 16, each of which is formed by a plurality of disks 40 with the same diameter, no disk 40 or any number of disks 40 can be arranged on the traversing tube 30 to support the transition area 14 and to ensure a defined expansion angle 60, also during the formation of a shape memory workpiece 100.

[0167] The expansion angle 60 occurs as an angle in the transition area 14 of the shaping tool 10, in particular as an angle following the expansion wire 50 in relation to the axial direction a. The expansion angle 60 is determined by the diameter of two consecutive disks 40 and the axial distance between the two consecutive disks 40 in question. The expansion angle 60 thus describes, in combination with a traversing speed of the traversing tube 30, the deformation per time or the change in diameter per time, and thus the force applied to the shape memory alloy 100.

[0168] The expansion angle 60 thus influences the process time and also very significantly the geometry of the shaping tool 10, since the larger the expansion angle 60, the shorter the shaping tool 10 can be realized, which in turn contributes to reducing the use of material for the shaping tool 10, which reduces its thermal capacity and increases the energy efficiency of the process. Furthermore, a shorter shaping tool 10 with a correspondingly comparatively low thermal capacity allows a heating device to be of compact design, and as a result in turn has a comparatively low power loss, which in turn finally increases the energy efficiency in the process and also the energy efficiency of the shaping tool 10. On the other hand, a large expansion angle 60 causes the shape memory workpiece 100 to slip off the shaping tool 10 comparatively more easily, since the static friction between the shape memory workpiece 100 and the expansion wires or elements 50 decreases during the expansion as the expansion angle 60 increases.

[0169] As outlined in FIG. 2 by means of the braces, substantially three different characteristic portions can be formed on the shaping tool 10. Here, a receiving area 12 can form in particular on an axial first portion of the shaping tool 10, on which disks 40 in cooperation with expansion wires or elements 50 arranged or tensioned thereon form a first discrete diameter that is suitable for shape memory workpieces 100 having a first or initial diameter to be arranged on it, in particular to be arranged under prestress on it. The first or initial diameter of the shape memory workpiece 100, and thus the first discrete diameter formed by the disks 40 with the expansion wires 50 arranged thereon in the receiving area 12, can be, for example for stents, in a range from about 3 mm to about 15 mm, preferably in a range from about 6 mm to about 12 mm. However, neither stents nor other exemplary shape memory workpieces, such as heart valves, are limited to the aforementioned diameters. Adjoining the receiving area 12 and following in the opposite direction of the axial direction a, a transition area 14 can e.g., extend on the shaping tool 10, which forms a transition between the first and a second discrete diameter. A disk 40 does not necessarily have to be arranged in the transition area 14. However, one or more disks 40 arranged in the transition area 14 can support the expansion of a shape memory workpiece 100 with a targeted expansion angle 60, whereby a particularly reliable method for shaping a shape memory workpiece 100 can be provided. Adjoining the transition area 14 and following in the opposite direction of the axial direction a, a discrete diameter area 16 can extend, for example, within which at least two disks 40 in particular having the same diameter can be arranged.

[0170] The opposite direction of the axial direction a referred to above is a direction that is substantially parallel and opposite to the axial direction a.

[0171] The disks 40 in the discrete diameter area 16 can in particular have a larger diameter with respect to the disks 40 in the receiving area 12. The disks 40 arranged in the discrete diameter area 16 can form a second discrete diameter with the expansion wires 50 arranged or tensioned on them, in order to expand a shape memory workpiece 100 to a corresponding diameter.

[0172] The ratio of the average diameter of the transition area 14 to the diameter of the disks in the receiving area 12 can preferably be in the range from about 1.5 to about 1.9, particularly preferably about 1.85. Furthermore, the ratio of the diameter of the disks 40 in the discrete diameter area 16 to the mean diameter of the transition area 14 can preferably be in the range from about 1.5 to about 1.9, particularly preferably about 1.85.

[0173] In alternative embodiments, the ratio of the diameter of the disks in the discrete diameter area 16 to the diameter of the disks in the receiving area 12 can preferably be in the range from about 1.5 to about 1.9, more preferably about 1.85.

[0174] An actuator 32 is only outlined in FIG. 2 and is configured in particular to displace or move the disks 40 in and opposite to the substantially axial direction a or parallel to the traversing tube 30. To this end, on the one hand, the disks 40 can be arranged movably or traversably on the traversing tube 30 and can be moved directly by the actuator 32.

[0175] On the other hand, the disks 40 can be fixed or fixedly arranged on the traversing tube 30 and can be configured to be moved or displaced indirectly by the actuator 32, for example via the traversing tube 30. The movement or displacement by the actuator 32 is preferably configured as a movement or displacement substantially along the axial direction a or parallel to the traversing tube 30.

[0176] In further exemplary embodiments, a disk 40 can be provided with a shape in order to bring about a specific reshaping when the shape memory workpiece 100 passes, such as the formation of a hook on the shape memory workpiece 100.

[0177] Also indicated in FIG. 2 is a point that is marked as a magnification V. This point of the magnification V represents an exemplary portion of a disk 40 in more detail. The magnification V will be further explained in FIG. 3.

[0178] FIG. 3 shows a sketch of a portion of a disk 40 of an exemplary shaping tool 10. The sketch in FIG. 3 is reproduced as a partial sectional view of a disk 40, with several expansion wires or elements 50 also being shown in section in addition to the disk 40 for illustration purposes are. Also shown in FIG. 3 are the axial direction a pointing out of the drawing sheet, the radial direction r pointing radially outward starting from the axial direction a, and the circumferential direction u running in the circumferential direction u of the disk 40, which is circular at least in parts.

[0179] As shown in FIG. 3, each of the expanding wires or elements 50 can be arranged in at least one sliding groove 42, the sliding groove 42 preferably being arranged at a position along an outer circumference or along an outer circumferential side of the disk 40. The sliding groove 42 or the sliding grooves 42 can in particular have an opening that is open outward in the radial direction r, so that an expansion wire or element 50 arranged in the sliding groove 42 protrudes in the radial direction r with respect to the disk 40, in particular with respect to an outer circumference of the disk 40 or an outer circumferential side of the disk 40.

[0180] The protrusion of the expansion wire or element 50 with respect to the disk 40 can be made clear in particular by means of the overhang 46. In the sectional view according to FIG. 3, the overhang 46 describes a distance between the outermost point, in the radial direction r, of the expansion wire or element 50 with respect to an outermost point, in the radial direction r, of the disk 40, which adjoins the sliding groove 42. In exemplary embodiments, the overhang 46 can be about 5% to about 60%, preferably about 8% to about 40%, particularly preferably about 10% to about 20% with respect to the diameter or cross-section of the expansion wire or element 50. Advantageously, a sliding groove 42 designed such that it forms the overhang 46 with the expansion wire or element 50 arranged therein, which is less than 50% with respect to the diameter of the expansion wire 50, allows the expansion wire or element 50 to be radially secured or radially fixed in the sliding groove 42.

[0181] In exemplary embodiments, the sliding groove 42 of the disk 40 can be designed such that an expansion wire or element 50 arranged therein at least in parts can be guided in a sliding manner. In other words, the sliding groove 42 of the disk 40 can be formed such that the disk 40 can be displaced relative to the expansion wire 50. For this purpose, in exemplary embodiments, a sliding groove 42 can be formed in the axial direction a, in particular as a bore, which has a diameter or cross section that corresponds at least to the diameter or cross section of the expansion wire or element 50 arranged therein at least in parts. This advantageously enables a shape memory workpiece 100 to be arranged on a shaping tool 10 such that the shape memory workpiece 100 is held by the expansion wires or elements 50 and at the same time can be passed through by the disks 40, for example in the axial direction a or in a direction parallel to the traversing tube 30.

[0182] In preferred embodiments, the number of sliding grooves 42 corresponds at least to the number of expansion wires or elements 50 to be arranged on the disks 40, so that each expansion wire or element 50 can be arranged in a separate sliding groove 42.

[0183] In further preferred embodiments, the sliding grooves 42 are arranged substantially equidistantly on the outer circumference of the disk 40 or on an outer circumferential side of the disk 40, so that the shaping tool 10 enables a particularly uniform expansion of, in particular, round or substantially round workpieces. In alternative embodiments, the arrangement of the sliding grooves 42 can also deviate from an equidistant arrangement on the disk 40. Furthermore, in alternative embodiments, the sliding grooves 42 can be arranged on an inside of a disk, i.e., not on the outer circumference of the disk 40.

[0184] As further shown in FIG. 3, the disk 40 may have a concave portion 44 or a radially inwardly directed recess along its outer circumference or along its outer circumferential side and between two adjacent sliding grooves 42.

[0185] The concave portion 44 or the radially inwardly directed recess between two adjacent sliding grooves 42 advantageously ensures that in the case of a relative movement of the disks 40 in the axial direction a relative to the expansion wires 50, contacting of a shape memory workpiece 100 arranged on the expansion wires 50 and of the disks 40 can be prevented. This further allows the axial extension of the shape memory workpiece 100 to be advantageously maintained during expansion, in addition to preventing contamination from contact between the shape memory workpiece 100 and the disks 40 at high temperatures.

[0186] FIGS. 4a, 4b and 4c show a portion of an exemplary shaping tool 10 in a first state (FIG. 4a), a second state (FIG. 4b), and in a third state (FIG. 4c). Basically, FIGS. 4a, 4b and 4c show which positions the disks 40 and the plurality of expansion wires or elements 50 can assume in different steps of a method for shaping a shape memory workpiece 100. A schematically outlined shape memory workpiece 100 is shown arranged on the shaping tool 10 by way of example.

[0187] As indicated in FIGS. 4a, 4b and 4c, the expansion wires or elements 50 can be fixed in particular on a lower fixing portion of the shaping tool 10. In particular, the distal ends of the expansion wires or elements 50 can preferably be fixed to the lower fixing portion of the shaping tool 10. In exemplary embodiments, but not shown in the figures, the expanding wires or elements 50 can extend in particular between an upper fixing portion and a lower fixing portion of the shaping tool 10 and can preferably be stretched between the upper fixing portion and the lower fixing portion. The upper and lower fixing portions can be formed on the guide element 20, for example, but are not limited thereto.

[0188] In further exemplary embodiments, which are not shown in the figures, however, the expansion wires or elements 50 can in particular be guided back at a lower end of the guide element 20, in particular toward an upper fixing portion of the shaping tool 10.

[0189] In preferred embodiments, not shown in the figures though, a first end and a second end of the expansion wires or elements 50, in particular all or both ends of the expansion wires or elements 50, can be attached to an upper fixing portion or to an upper end of the shaping tool 10, with the expansion wires or elements 50 preferably being guided back at a lower end of the guide element 20. This advantageously makes it possible that no fixing, in particular no mechanical fixing, of the expansion wires or elements 50 is required at the lower end of the shaping tool 10. A further advantageous result of this is that the shaping tool 10 is also suitable for attaching particularly small shape memory workpieces 100, since the attachment of the shape memory workpiece 100, in particular to a lower portion of the shaping tool 10, in particular to the receiving area 12, is not affected by a fixation of the expansion wires or elements 50. Even more advantageously, this improves the durability and maintenance of the shaping tool 10 since the fixation of the expansion wires or elements 50 is not necessarily subject to direct heating by a heating device such as a salt bath.

[0190] FIG. 4a shows a first state of the shaping tool 10, which describes an example of a state of the shaping tool 10 when it is suitable for a shape memory workpiece 100 to be placed thereon. To this end, the shaping tool 10 can have a pronounced receiving area 12, which extends e.g., on a lower portion of the shaping tool 10 in the axial direction a, with the expansion wires or elements 50 forming a diameter that is suitable for arranging a shape memory workpiece 100 having a first or initial diameter thereon. In addition to the receiving area 12, the shaping tool 10 can further have a transition area 14 and a discrete diameter area 16, which adjoin or extend from the receiving area 12 in this order opposite to the axial direction a.

[0191] FIG. 4b shows a second state of the shaping tool 10 which, by way of example, describes a state of the shaping tool 10 when the shape memory workpiece 100 has been expanded to a second diameter. The expansion wires or elements 50 form a diameter in the transition area 14 which the shape memory workpiece 100 or portions of the shape memory workpiece 100 has or have after a first expansion, for example.

[0192] FIG. 4c shows a third state of the shaping tool 10, which, by way of example, describes a state of the shaping tool 10 when the shape memory workpiece 100 has been expanded to a third diameter. The expansion wires or elements 50 in the discrete diameter area 16 preferably form a diameter which the shape memory workpiece 100 has after a second expansion.

[0193] For the expansion itself, and as illustrated in a comparison between FIGS. 4a, 4b and 4c, at least the disks 40, which form the transition area 14 and the discrete diameter area 16, are preferably displaced or moved downward in the axial direction a, so that they preferably pass the shape memory workpiece 100 or pass the initial receiving area on which the shape memory workpiece 100 was originally arranged. The shape memory workpiece 100 can advantageously be expanded uniformly by passing of the disks 40. As is further illustrated by a comparison of FIGS. 4a, 4b and 4c, the shape memory workpiece 100 can be arranged or held at substantially the same position on the shaping tool 10 even after a step of expansion, and its axial extension can be maintained as highlighted in FIGS. 4a, 4b, and 4c by means of the dashed auxiliary lines HL.

[0194] FIGS. 4a, 4b and 4c are only schematic representations which, for the sake of clarity, do not show the entire shaping tool 10. The shape memory workpiece 100 arranged on the shaping tool 10 is also shown only schematically and not true to scale, in particular with regard to the axial extension.

[0195] In further exemplary embodiments of the shaping tool 10 that are not shown, it can have one or more further transition areas 14 and one or more further discrete diameter areas 16, which extend from the discrete diameter area 16 shown opposite to the axial direction a.

[0196] FIG. 5 shows a sketched temperature-time profile according to an example of the present method. The temperature-time profile shown in FIG. 5 for a method for shaping a shape memory workpiece 100 is to be considered a merely qualitative sketch and overview of how a method for shaping a shape memory workpiece 100 can take place.

[0197] As shown in FIG. 5, the shape memory workpiece 100 is preferably first warmed or heated to a shaping temperature FGT or to a temperature that is in the range of the shaping temperature FGT for the shape memory workpiece 100. While the shape memory workpiece 100 is in the temperature range of the shaping temperature FGT, it can preferably be deformed or reshaped, in other words expanded (shown in FIG. 5 with “reshaping 1x”). The degree of reshaping can be defined as desired, but is preferably in a range below about 1.9, particularly preferably about 1.85.

[0198] As further illustrated in FIG. 5, the shape memory workpiece 100 is cooled or further heated following a first reshaping or expansion, preferably to a temperature below or above the shaping temperature FGT. This temperature below or above the shaping temperature FGT can be referred to as the intermediate temperature ZT and can be below 500° C., for example, in particular in the range from about 250° C. to about 500° C., or above 525° C., particularly in the range of about 525° C. to about 600° C.

[0199] Subsequently, the shape memory workpiece 100 is brought back to the shaping temperature FGT, i.e., heated or cooled, in order to then be deformed or reshaped again. If the shape memory workpiece 100 has the desired target diameter after the second reshaping (shown in FIG. 5 with “reshaping 2x”), which is to be impressed on the shape memory workpiece 100 as a shape memory, it can then be cooled or quenched (in FIG. 5 illustrated by the short “cooling time”), e.g., cooled or quenched to about room temperature.

[0200] From the combination of multiple deformation of the shape memory workpiece 100 at the shaping temperature FGT, together with the intermediate change to a temperature below or above the shaping temperature FGT, and the final cooling as soon as the shape memory workpiece 100 has been expanded or reshaped to its target shape or diameter, predetermined shape memory properties or superelastic properties, comprising a desired diameter assumed at a predetermined ambient temperature and a predetermined load state, are impressed on the shape memory workpiece 100.

[0201] Furthermore, two heating durations for heating the shape memory workpiece 100 to the shaping temperature FGT are shown in FIG. 5 by way of example. The “heating time 1” represents the period of time that is required when the shaping tool 10 is not preheated, i.e., the method for shaping by means of the shaping tool 10 is started at about room temperature. In contrast, the “heating time 2” represents a shorter period of time if the shaping tool 10 has already run a shaping cycle with a shape memory workpiece 100. The comparatively shortened “heating time 2” is made possible in particular by the fact that the shape memory workpiece 100 is ejected from the shaping tool 10 for final cooling, as a result of which the shaping tool 10 itself does not undergo any significant cooling, in contrast to the ejected shape memory workpiece 100.

TABLE-US-00001 List of Reference Numerals 10 shaping tool 12 receiving area 14 transition area 16 discrete diameter area 20 guide element 30 traversing tube 32 actuator 40 disk 42 sliding groove 44 concave portion 46 overhang 50 expansion wire 60 expansion angle 100 shape memory workpiece S10–S90 steps for a method for shaping a shape memory workpiece a axial direction r radial direction u circumferential direction FGT shaping temperature HL auxiliary line V magnification ZT intermediate temperature