System and method for manufacturing 3D printed medical devices

Abstract

This invention provides a system and method for manufacturing 3D-printed medical devices. The method includes feeding a first filament and a second filament into the internal cavity of a heated barrel and onto a molten substrate. The heated barrel is then moved linearly and rotationally relative to the substrate to form a sheath comprising material from each of the first and second filaments. Furthermore, rotating the substrate provides a homogeneous mixture and creates support rings between the filament materials within the structure of the sheath.

Description

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 059,890, filed on July 31, 2020, which is incorporated herein by reference in its entirety.

[0002] This disclosure relates in general to medical devices, and more specifically to additive manufacturing or 3D printing of medical devices such as catheters and implantable stimulation leads.

[0003] Medical catheters and leads are commonly used to access blood vessels and other locations within the body and perform various functions at these locations. For example, delivery catheters can be used to deliver medical devices such as implantable medical leads. Many such medical devices are designed to navigate through tortuous paths in the body, such as through a patient's vascular system. Medical catheters and leads can be designed to be flexible enough to move through bends or curves in the vascular system, but rigid or resilient enough to be pushed through it. In many cases, such as those involving the cardiovascular system, the path to the treatment or deployment site may be tortuous, and there may be conflicting design considerations that require trade-offs between size, flexibility, material selection, and operational control. These contrasting properties present challenges in the design and manufacture of catheters. Existing manufacturing processes, such as conventional extrusion, may also limit the options available for designing and manufacturing catheters. Summary of the Invention

[0004] The technology disclosed herein relates generally to additive manufacturing of medical devices such as catheters and leads, which allows for the use of a wider range of filament or granular materials to produce a broad range of resulting catheter or lead properties. For example, a wider range of stiffness levels can be achieved compared to prior art techniques for manufacturing catheters, catheter components, or implantable devices. Specifically, this technology allows for the feeding of soft filaments at high feed forces during additive manufacturing or three-dimensional (3D) printing. Furthermore, this technology can facilitate the development of novel catheters and implantable devices.

[0005] Details of one or more aspects of this disclosure are set forth in the following drawings and description. Other features, objectives, and advantages of the technology described in this disclosure will be apparent from the specification, drawings, and claims. Attached Figure Description

[0006] Figure 1 This is a conceptual diagram of an exemplary additive manufacturing system based on this disclosure.

[0007] Figure 2 It is used for, for example Figure 1 A conceptual diagram of an exemplary additive manufacturing equipment for an additive manufacturing system.

[0008] Figure 3 Is with, for example Figure 1 A conceptual diagram of an exemplary heated barrel used in additive manufacturing systems.

[0009] Figure 4 It can be used before removing the substrate. Figure 1 A conceptual diagram of an exemplary conduit manufactured using an additive manufacturing system.

[0010] Figure 5 It is mainly formed from the first filament. Figure 4 A schematic diagram of a portion of an exemplary catheter.

[0011] Figure 6 It is mainly formed from the second filament. Figure 4 A schematic diagram of a portion of an exemplary catheter.

[0012] Figure 7 It is formed from a mixture of the first filament and the second filament. Figure 4 A schematic diagram of a portion of an exemplary catheter.

[0013] Figure 8 It is shown that, for example, Figure 1 A flowchart of an example of a method used in conjunction with an additive manufacturing system. Detailed Implementation

[0014] The present disclosure provides additive manufacturing systems and methods for medical devices such as catheters and leads, which allow for the use of a wider range of filament or granular materials to produce a broad range of resulting catheter or lead properties. For example, a wider range of stiffness levels can be achieved compared to prior art for producing catheters, catheter components, or implantable devices. Additive manufacturing can also be described as three-dimensional (3D) printing. The additive manufacturing system of this disclosure allows for feeding soft filaments at high feed forces, which can facilitate a wider range of operating conditions suitable for prototyping or manufacturing. Furthermore, a wider range of filament materials and operating conditions can be beneficial for new catheters and implantable devices. Specifically, two or more materials with different properties can be combined to form new composite materials with a unique set of properties.

[0015] The systems and methods described herein allow for the 3D printing of medical devices, which can facilitate the construction of structures with unique combinations of properties that enable novel treatments. Unique catheter handling properties can be achieved by combining materials in ways not traditionally combined in catheter manufacturing, and can include materials that are novel to the catheter construction. Furthermore, other catheter properties (e.g., electrical, thermal, fluorescent, or echogenic opacity) can also be achieved by combining materials as described herein. In addition, 3D printing allows for the inclusion of other accessories, such as maneuverability via drawstrings, in a space-efficient manner.

[0016] In some implementations, the systems and methods described herein can facilitate the simultaneous deposition of multiple standard geometries of 3D-printed resin filaments with varying stiffness at varying blending ratios to produce varying flexural moduli and deposited material colors. For example, two identical polymers of different stiffnesses can be combined into different types of layers by applying material while the medical device is spinning. Centrifugal force allows the medical device to uniformly distribute (e.g., along the layers) two materials (e.g., filament material or dopant) within a sheath formed by the system. Furthermore, the rheological properties of the filament material can also lead to a uniform layer distribution (e.g., due to the rotational motion described herein). In addition to the varying properties formed by multiple filaments, the processes described herein can form electrode rings and patterns from biocompatible conductive materials that are different from those currently feasible using conventional methods. Furthermore, the methods described herein are applicable to energy transfer (e.g., similar to vortex ring guns), electromagnetic applications (e.g., using ferrite beads), marking strips with sizes and patterns different from those currently feasible using conventional methods, etc.

[0017] As used herein, the term "or" is an inclusive definition, such as meaning "and / or," unless the context clearly specifies otherwise. The term "and / or" means one or all of the listed elements or a combination of at least two of the listed elements.

[0018] As used herein, the phrases “at least one of” and “one or more of” following the list of elements refer to one or more of any of the listed elements or any combination of one or more of the listed elements.

[0019] As used herein, the term "connection" or "link" refers to at least two elements being directly or indirectly attached to each other. An indirect connection may include one or more other elements between the at least two attached elements. Both terms may be modified by the interchangeable terms "operationally" and "operably" to describe a connection or link configured to allow components to interact to perform the stated or otherwise known function. For example, a controller may be operably connected to a resistance heating element to allow the controller to supply current to the heating element.

[0020] As used herein, any terms relating to position or orientation, such as “proximal,” “distal,” “end,” “outer,” “inner,” etc., refer to relative positions and do not limit the absolute orientation of the implementation, unless the context otherwise clearly specifies.

[0021] Unless otherwise stated, all scientific and technical terms used herein have the meanings commonly used in the art. The definitions provided herein are intended to facilitate understanding of certain terms frequently used herein and are not intended to limit the scope of this disclosure.

[0022] Reference will now be made to the accompanying drawings, which depict one or more aspects described in this disclosure. However, it should be understood that other aspects not depicted in the drawings fall within the scope of this disclosure. The same numbers used in the drawings refer to the same parts, steps, etc. However, it should be understood that the use of reference characters to designate elements in a given drawing is not intended to limit elements in another drawing labeled with the same reference characters. Furthermore, the use of different reference characters to designate elements in different drawings is not intended to indicate that elements referenced differently cannot be the same or similar.

[0023] Figure 1 An example of an additive manufacturing system 100 according to this disclosure is shown. System 100 can be configured and used to produce conduits, conduit components, leads, or subassemblies. System 100 can use or include consumable filament materials or resins in granular form having various hardness levels. System 100 can be configured to operate a wide variety of process conditions to produce conduits, conduit components, leads, or subassemblies using resins in filament or granular form with various hardness levels. Generally, system 100 defines a distal region 128 or distal end and a proximal region 130 or proximal end. System 100 may include a platform 124 comprising a rigid frame to support one or more components of the system.

[0024] As illustrated in the example embodiment, system 100 may include one or more components, such as a heating cylinder 102, a heating element 104, a filament processing system 106, an optional wire processing system 107, a substrate processing system 108, a controller 110, and a user interface 112. The filament processing system 106 may be operatively coupled to the heating cylinder 102. The filament processing system 106 may supply one or more filaments 114 to the heating cylinder 102. The optional wire processing system 107 may be used to supply one or more wires 115 to the heating cylinder 102. The heating element 104 may be operatively or thermally coupled to the heating cylinder 102. The heating element 104 may provide heat from one or more filaments 114 supplied by the filament processing system 106 to melt the filament material in the heating cylinder 102. The optional wires 115 may not be melted by the heating cylinder 102. The substrate processing system 108 may be operatively coupled to the heating cylinder 102. The substrate processing system 108 provides a substrate 116 extending through a heated barrel. Molten filament material located in the heated barrel 102 can be applied to the substrate 116. The substrate 116 or the heated barrel 102 can be translated or rotated relative to each other via the substrate processing system 108. The substrate processing system 108 can be used to move the substrate 116 or the heated barrel 102 relative to each other to cover the substrate 116 with molten filament material, thereby forming a sheath 118. Optional wire 115 can be incorporated into the sheath 118 (e.g., molded into the sheath, laminated within the sheath, etc.).

[0025] The substrate 116 may also be described as a mandrel or rod. A sheath 118 may be formed or deposited around the substrate 116. In some embodiments, the sheath 118 may be formed concentrically around the substrate 116. In one example, the sheath 118 is formed concentrically and centered around the substrate 116.

[0026] When system 100 is used to manufacture catheters or catheter components, sheath 118 may be described as a catheter sheath. Some or all of the substrate 116 may be removed or detached from sheath 118, and the remaining structure attached to the sheath may form a catheter or catheter component, such as a sheath. Figure 4 An example of a catheter that can be formed by system 100 is shown.

[0027] The substrate 116 may be formed of any suitable material capable of allowing molten filament material to be formed thereon. In some embodiments, the substrate 116 is formed of a material that melts at a higher temperature than any of the filaments 114. An example of a material that can be used to form the substrate 116 includes stainless steel.

[0028] Controller 110 may be operatively coupled to one or more of the heating element 104, filament processing system 106, substrate processing system 108, and user interface 112. Controller 110 may activate, start, or otherwise “turn on” the heating element 104 to provide heat to the heating barrel 102 to melt the filament material therein. Furthermore, controller 110 may control or command one or more motors or actuators of various parts of system 100. Additionally, controller 110 may control one or more motors or actuators of the filament processing system 106 to provide one or more filaments 114. Furthermore, controller 110 may control one or more motors or actuators of the substrate processing system 108 to move one or both of the heating barrel 102 or substrate 116 relative to each other. Furthermore, controller 110 may send or receive data to user interface 112, for example, to display information or receive user commands. Control of components operatively coupled to controller 110 may be determined based on user commands received by user interface 112. In some implementations, user commands may be provided in the form of machine-readable code or a coded language.

[0029] The substrate handling system 108 can be provided using any suitable specific implementation. In some embodiments, the substrate handling system 108 may include one or more head frames 120, optional tail frames 122, and one or more motors coupled to or included in the head frames or tail frames. One or both of the head frames 120 and tail frames 122 may be coupled to the platform 124. A frame can be defined as a structure that holds or secures the substrate 116 during the formation of the sheath 118. The head frame 120 is defined as the frame closest to the end of the substrate 116, where the formation of the sheath 118 begins during the formation process. In the illustrated embodiment, the sheath 118 is shown proximal to the head frame 120 and distal to the heated barrel 102.

[0030] When substrate 116 is secured by one or both of holders 120, 122, the substrate is typically positioned through a substrate channel defined by heated cylinder 102. One or both of holders 120, 122 may include clamps or other securing mechanisms to selectively hold substrate 116. Such clamps may be operatively coupled to a substrate motor. In some embodiments, the substrate motor may be used to control the opening and closing of the clamps. In some embodiments, the substrate motor may be used to rotate substrate 116 about longitudinal axis 126 in a clockwise or counterclockwise direction. A translation motor is operatively coupled between holders 120, 122 and platform 124. In some embodiments, the translation motor may be used to translate holders 120, 122 in a longitudinal direction along longitudinal axis 126. In some embodiments, the translation motor may also be used to translate holders 120, 122 in a transverse direction other than longitudinal axis 126. The transverse direction may be oriented substantially orthogonal to or perpendicular to longitudinal axis 126.

[0031] In some embodiments, the substrate processing system 108 may be configured to move the headstock 120 relative to the platform 124 at least in the longitudinal direction (e.g., parallel to the longitudinal axis 126). This movement of the headstock 120 relative to the platform 124 allows the substrate 116 to be fed through the substrate channel of the heated barrel 102. The distal portion of the substrate 116 may be clamped in the headstock 120. At the start of the sheathing process, the headstock 120 may be positioned close to the heated barrel 102. The headstock 120 may move distally away from the heated barrel 102, for example, in a direction parallel to the longitudinal axis 126. In other words, the headstock 120 may move toward the distal region 128 of the system 100 while pulling the fixed substrate 116 through the heated barrel 102. As the substrate 116 passes through the heated barrel 102, molten filament material from the filament 114 may be formed or deposited on the substrate 116 to form the sheath 118. The heating cylinder 102 can be stationary relative to the platform 124. In some embodiments, the tailstock 122 can be omitted.

[0032] In some embodiments, the substrate processing system 108 may be configured to move the heating cylinder 102 relative to the platform 124 at least in the longitudinal direction (along the longitudinal axis 126). Substrate 116 may be fed through the substrate channel of the heating cylinder 102. The distal portion of the substrate 116 may be clamped in the headstock 120. The proximal portion of the substrate 116 may be clamped in the tailstock 122. In one example, at the start of the sheathing process, the heating cylinder 102 may be positioned close to the headstock 120. The heating cylinder 102 may move proximally away from the headstock 120. The heating cylinder 102 may move toward the proximal region 130 of the system 100. As the heating cylinder 102 passes the substrate 116, molten filament material may be deposited onto the substrate 116 to form a sheath. The headstock 120 and tailstock 122 may be stationary relative to the platform 124. In another example, the heating cylinder 102 may begin near the tailstock 122 and move toward the distal region 128.

[0033] One or more motors of the substrate handling system 108 may be used to rotate one or both of the substrate 116 and the heating cylinder 102 (e.g., the inlet die) relative to each other. In some embodiments, only the substrate 116 may rotate about the longitudinal axis 126. In some embodiments, only a portion of the heating cylinder 102 (e.g., the inlet die) may rotate about the longitudinal axis 126. In some embodiments, both the substrate 116 and the heating cylinder 102 may rotate about the longitudinal axis 126.

[0034] The heating cylinder 102 may be part of a subassembly 132. The subassembly 132 may be coupled to a platform 124. In some embodiments, one or more motors of the substrate processing system 108 may be coupled between the subassembly 132 and the platform 124 to translate or rotate the subassembly 132, including the heating cylinder 102, relative to the platform 124 or the substrate 116. In some embodiments, one or more motors of the substrate processing system 108 may be coupled between the frame of the subassembly 132 and the heating cylinder 102 to translate or rotate the heating cylinder relative to the platform 124.

[0035] In some embodiments, the substrate 116 may be rotated relative to the heated barrel 102 about a longitudinal axis 126 to facilitate the formation of certain structures of the sheath. In one example, one or both of the headstock 120 and tailstock 122 of the substrate processing system 108 may rotate the substrate 116. In another example, the substrate processing system 108 may rotate the heated barrel 102 or the subassembly 132.

[0036] Rotation of the heating cylinder 102 (e.g., specifically the inlet die) relative to the substrate 116 helps maintain the concentricity of the sheath 118. In other words, by rotating about the longitudinal axis 126 while forming the sheath, the molten filament can be formed into a more concentric circle and helps reduce the eccentricity of the filament material (e.g., due to the rheological properties of the filament material). Specifically, the rheological properties of the filament material can help provide a uniform layered distribution (e.g., due to the rotational motion described herein).

[0037] In addition, system 100 may include one or more concentricity guides 134. The concentricity guides 134 can facilitate adjusting the concentricity of the sheath around the substrate 116 before or after the substrate passes through the heating cylinder 102. The concentricity guides 134 may be longitudinally spaced from the heating cylinder 102. In some embodiments, the spacing may be greater than or equal to 1 cm, 2 cm, 3 cm, 4 cm, or 5 cm. The spacing may be sufficient to allow the sheath 118 to cool and no longer be deformable. In some embodiments, one or more concentricity guides 134 may be positioned distal to the heating cylinder 102 and engage the sheath 118. In some embodiments, one or more concentricity guides 134 may be positioned proximal to the heating cylinder 102 to engage the substrate 116. The concentricity guides 134 can reduce sagging of the substrate 116 and are less susceptible to eccentricity when aligning the frames 120, 122 and the heating cylinder 102.

[0038] The filament processing system 106 can be provided using any suitable specific implementation. One or more filaments 114 can be loaded into the filament processing system 106. For example, the filaments 114 can be provided in the form of wound coils. The filaments 114 can be fed to the heated barrel 102 through the filament processing system 106. In some embodiments, the filament processing system 106 may include one, two or more clamping rollers to engage one or more filaments 114. In some embodiments, the filament processing system 106 may include one or more motors. One or more motors may be coupled to one or more clamping rollers to control the rotation of these clamping rollers. The force applied by the motors to the clamping rollers and thus to one or more filaments 114 can be controlled by a controller 110.

[0039] In some embodiments, the filament processing system 106 may be configured to feed filaments 114 comprising at least a first filament and a second filament. A sheath 118 may be formed of one or both of the materials of the filaments 114. The filament processing system 106 is capable of selectively feeding the first and second filaments. For example, one motor may feed the first filament and another motor may feed the second filament. Each motor may be independently controlled by a controller 110. Selective or independent control of the feeding may allow the same or different feed forces to be applied to each filament of the filaments 114.

[0040] Filament 114 can be made from any suitable material, such as polyethylene, PEBAX elastomer (commercially available from Arkema SA (Colombes, France)), nylon 12, polyurethane, polyester, liquid silicone rubber (LSR) or PTFE.

[0041] The filament 114 may have any suitable Shore hardness. In some embodiments, the filament 114 may have or be defined with a Shore hardness suitable for the catheter. In some embodiments, the filament 114 has a Shore hardness of at least 25A and up to 90A. In some embodiments, the filament 114 has a Shore hardness of at least 25D and up to 80D.

[0042] In some embodiments, the filament processing system 106 may provide soft filaments as one of the filaments 114. In some embodiments, the soft filaments may have a Shore A hardness of less than or equal to 90A, 80A, 70A, 80D, 72D, 70D, 60D, 50D, 40D, or 35D.

[0043] In some embodiments, the filament processing system 106 can provide hard filaments and soft filaments with a Shore hardness lower than that of the soft filaments. In some embodiments, the soft filaments have a Shore hardness that is 10D, 20D, 30D, 35D, or 40D lower than that of the hard filaments.

[0044] System 100 can be configured to provide a sheath 118 with a Shore hardness between that of hard filaments and soft filaments. In some embodiments, the filament processing system 106 can provide hard filaments with a Shore hardness of 72D or higher and soft filaments with a Shore hardness of 35D or higher. System 100 is capable of providing a sheath 118 with a Shore hardness of 35D or higher and less than or equal to 72D.

[0045] System 100 can be configured to provide a sheath 118 having or defining a plurality of segments with different Shore hardness. In some embodiments, system 100 is capable of providing a sheath 118 having one or more of 35D, 40D, 55D and 72D segments.

[0046] The filament 114 may have any suitable width or diameter. In some embodiments, the filament 114 has a width or diameter of 1.75 mm. In some embodiments, the filament 114 has a width or diameter less than or equal to 1.75 mm, 1.5 mm, 1.25 mm, 1 mm, 0.75 mm, or 0.5 mm.

[0047] In some embodiments, the sheath 118 may include a continuous transition between at least two different Shore hardness scales, such as... Figure 4As shown. Controller 110 can be configured to vary the feed force applied to one or more filaments 114 to change the ratio of material in the sheath over the longitudinal distance. By varying the feed force, system 100 can provide different Shore A hardness segments in sheath 118. In one example, a sharp transition between uniform segments can be provided by stopping or slowing longitudinal movement while continuously or discretely varying the feed force of one filament of substrate 116 relative to another filament relative to the heated barrel 102 in large steps. In another example, a gradual transition between segments can be provided by continuously or discretely varying the feed force of one filament relative to another filament in small steps while moving substrate 116 longitudinally relative to the heated barrel 102.

[0048] By rotating the heated barrel 102 (e.g., the inlet die) relative to the substrate 116 in the rotational direction, various materials of two or more filaments can be more uniformly mixed and intentionally delaminated. In this way, the materials can be blended and delaminated more uniformly than materials achieved using typical co-extrusion. For example, the first filament material can be offset to the outer surface of the sheath 118, while the second filament material can be offset inward within the sheath 118 to form a uniform and intentional delamination, which can, for example, create reliable properties and characteristics. Furthermore, these processes can provide discrete rings (e.g., tuned pulse vortex rings) and patterns within the structure of the sheath 118 (e.g., formed by mixing filament materials). Discrete rings and patterns can, for example, enhance the circumferential strength of the sheath 118. The volume and spacing of the discrete rings can vary depending on the total fluid volume.

[0049] The heating cylinder 102 (e.g., the inlet die) and the substrate 116 can move relative to each other in the rotational direction at a rate of about 80 RPM and / or less than or equal to 5000 RPM. Specifically, the rotational rate between the heating cylinder 102 and the substrate 116 can be between about 200 RPM and / or less than or equal to 300 RPM. More specifically, the rotational rate between the heating cylinder 102 and the substrate 116 can be between about 260 RPM and more than or equal to.

[0050] It should be noted that the substrate 116 moves relative to the heating cylinder 102 (e.g., the input die) along the longitudinal axis 126 while rotating about the longitudinal axis 126. For example, in one or more embodiments, the ratio of movement in the longitudinal direction to movement in the rotational direction may be approximately 44 revolutions per inch.

[0051] This combination of axial and rotational movement can result in a specific pitch of the filament material forming the sheath. Furthermore, the resulting structure of the filament material can produce unique internal annular reinforcing structural patterns. Specifically, this structure can be generated via tuned rheological polarimetric and annular flow modes within a variety of semi-immiscible fluids with unique hardness. These patterns can be formed at various volume ratios of annular material to encapsulating material.

[0052] The uniformity and properties of the resulting sheath can be adjusted based on the rotational and longitudinal speeds. Furthermore, the optimal speeds (e.g., longitudinal and rotational) can depend on the material properties of the filaments forming the sheath.

[0053] Figures 5 to 7 The diagram illustrates a uniform transition between two separate filament materials. For example, as shown... Figure 5 As shown, the catheter may be primarily formed of a first filament material, and as... Figure 6 As shown, the catheter can be primarily formed from a second filament material. The ratio of the filament material can be adjusted by regulating the feed force on each filament. Figure 7 This illustrates a combination of a first filament material and a second filament material, which is spun to obtain a homogeneous and layered blend or mixture. The pitch of the filament materials (e.g., due to a combination of axial and rotational movement) can... Figure 7 The structure shown (e.g., a ring) is illustrated. Additionally, as... Figures 5 to 7 The illustrated conduit may include discrete loops (e.g., tuned pulse vortex rings) formed by each of the different filament materials due to the rotational force applied to the sheath. In other words, each of the filament materials may form discrete loops that interact and combine at the intersections of the different filament materials (e.g., as...). Figure 7 (As shown). Furthermore, the volume and spacing of the discrete rings can be defined by the total fluid volume used to form the sheath. As previously mentioned, these discrete rings enhance the circumferential strength of the sheath and provide properties based on the composition of the discrete rings.

[0054] In one or more embodiments, particulate material (e.g., fluorescent labeling material) may be added to the sheath and the particulate material may be uniformly dispersed (e.g., distributed across the outer surface, etc.) due to the rotational force applied to the sheath.

[0055] Furthermore, due to the rotational force applied to the filament materials, two or more filament materials may delaminate. For example, the heavier material may be biased towards the outer surface of the resulting sheath, while the lighter material may be biased towards the interior of the resulting sheath.

[0056] A specific example of blending two filament materials into a medical device can occur with the bonding of materials involving balloon catheters. If the two filament materials do not bond well together, an adhesive or bonding layer may be required to provide bonding between them. By using the rotational method described herein, the filament materials can be uniformly bonded. Therefore, the number of material combinations can be increased, as materials previously marked as poorly bonded can be uniformly blended using the rotational force of this method. In other words, these materials can be optimized in ways previously unavailable.

[0057] System 100 can also be configured to provide sheaths 118 of varying thicknesses. In some embodiments, controller 110 may be configured to change one or more parameters, such as at least one of the following: the longitudinal velocity of the substrate 116 relative to the heated barrel 102, the feed force applied to one or more filaments 114, and the heat provided by the heating element 104. Changing one or more of these parameters during the formation of sheath 118 can be used to change the thickness of the sheath in the longitudinal direction. In some embodiments, controller 110 may be configured to use a specific heated barrel to change one or more of these parameters.

[0058] One or more wires 115 provided by the wire handling system 107 can be introduced in any suitable manner. In some embodiments, the wire 115 may be attached to a substrate 116 and pulled by movement of the substrate. An example of a wire is a traction wire that can be used to manipulate a conduit manufactured by system 100. In some embodiments, a specially shaped heated cylinder may be used to hold one or more wires 115.

[0059] Any suitable type of heating element 104 can be used. In some embodiments, the heating element 104 may be a resistance heating element that provides heat in response to an electric current. Other types of heating elements that can be used for the heating element 104 include radio frequency (RF) or ultrasonic heating elements. The heating element 104 is capable of providing enough heat to melt the filament 114. In some embodiments, the heating element 104 can heat the filament 114 to a temperature greater than or equal to 235°C, 240°C, 250°C, or 260°C. Generally, one or more heating elements 104 can be used to heat the filament 114 to any suitable melting temperature known to those skilled in the art who benefit from this disclosure.

[0060] The controller 110 can be communicated using any suitable user interface 112. Non-limiting examples of the user interface 112 include one or more of a fixed or portable computer, monitor or other display, touchscreen, keyboard, mouse, tablet computer, mobile phone, knob, switch, button, etc. In some embodiments, the user interface 112 may allow the user to input direct commands or input codes to the programming operations of the controller 110.

[0061] As used herein, the term "flow rate" refers to the filament feed rate in any suitable unit of measurement. In some embodiments, material 1 may be 35D PEBAX, while material 2 may be 72D PEBAX. Generally, the total feed rate (F###) may decrease as the mixing ratio shifts to softer materials. Reducing the feed rate can decrease the tendency for softer materials to clog. Certain techniques described herein can reduce the need to reduce the total feed rate. The flow rate command (E###) can directly affect the wall thickness of the printed catheter sheath.

[0062] Figure 2 An example of the additive manufacturing equipment 200 of the additive manufacturing system 100 is shown in an end view along the longitudinal axis 126, which is shown as a circle and a cross. More details of some components of the additive manufacturing system 100 are shown, such as the heated barrel 102 and the filament handling system 106.

[0063] The heating cylinder 102 may include a heating block 202 that at least partially defines an internal volume 204. The internal volume 204 may be heated by a heating element 104. The heating element 104 may be thermally coupled to the heating block 202 to melt the filament material within the internal volume 204. Generally, the system 100 may be configured to melt any portion of the filament 114 within the internal volume 204. The heating element 104 may be disposed within an exposed volume or an external volume 502 defined in the heating block 202. The heating element 104 may be positioned near or adjacent to the internal volume 204. In some embodiments, one, two, three, or more heating elements 104 may be thermally coupled to the heating block 202.

[0064] The heating block 202 allows a substrate 116, which may be an elongated substrate or component, to pass through the heating block. The substrate 116 can extend or pass through the internal volume 204. A substrate channel 206 defined by the heating cylinder 102 can extend through the internal volume 204. The substrate channel 206 can extend in the same or similar direction as the substrate 116. The substrate channel 206 can extend along the longitudinal axis 126.

[0065] The width or diameter of the internal volume 204 is greater than the width or diameter of the substrate 116. The width or diameter of the internal volume 204 or the substrate 116 is defined in a transverse direction orthogonal to the longitudinal axis 126. In one example, the transverse direction may be defined along the transverse axis 210. In some embodiments, the gap between the substrate 116 and the internal volume 204 is relatively small to facilitate the formation of a sheath 118 around the substrate 116. Figure 1 The composition of the filament material was changed.

[0066] The portion of the internal volume 204 surrounding the substrate 116 can receive a flow of molten filament material from the filament 114. When more than one filament material is supplied to the internal volume 204, the filament materials can flow around the substrate 116 and be blended or mixed.

[0067] In the illustrated embodiment, filament 114 includes a first filament 212 and a second filament 214. The first filament 212 is provided into the internal volume 204 through a first filament port 216, which is at least partially defined by the heating block 202. The second filament 214 is provided into the internal volume 204 through a second filament port 218, which is at least partially defined by the heating block 202. Each filament port 216, 218 is in fluid communication with the internal volume 204.

[0068] The filament 114 may be delivered to the internal volume 204 in the same or different manner. In the illustrated embodiment, the first filament 212 is delivered to the internal volume 204 in a different manner than the second filament 214.

[0069] The filament processing system 106 may include a first processing subassembly 220. The first processing subassembly 220 delivers a first filament 212 into an internal volume 204. The first processing subassembly 220 may include one or more pressure rollers 222. Each of the one or more pressure rollers 222 may be operatively coupled to a motor. Any suitable number of pressure rollers 222 may be used. As shown, the first processing subassembly 220 may include two sets of pressure rollers 222. The pressure rollers 222 may be used to apply a prime mover to the first filament 212 to move the first filament, for example, toward the internal volume 204.

[0070] The heating cylinder 102 may include a first guide sheath 224. The first guide sheath 224 may extend between the filament processing system 106 and the internal volume 204. The first guide sheath 224 may be coupled to the heating block 202. The first guide sheath 224 may extend from the outside of the heating block 202 into the first filament port 216. The first guide sheath 224 may define a lumen in fluid communication with the internal volume 204. The internal width or diameter of the lumen may be defined to be greater than the width or diameter of the first filament 212. The first filament 212 may extend from the pressure roller 222 of the first processing subassembly 220 through the first guide sheath 224 to the first filament port 216 and extend distally through the first guide sheath 224 into the internal volume 204.

[0071] As used here with respect to filament 114, the term "far side" refers to the direction closer to the internal volume 204, while the term "proximal side" refers to the direction closer to the filament processing system 106.

[0072] In some embodiments, the proximal end of the first guide sheath 224 may terminate near one of the pressure rollers 222. The distal end of the first guide sheath 224 may terminate at a shoulder 226 defined by the first filament port 216. The distal portion or distal end of the first guide sheath 224 may be positioned close to or adjacent to the internal volume 204.

[0073] The internal width or diameter of the lumen of the first guide sheath 224 can be defined to be substantially the same as or equal to the internal width or diameter of the first filament port 216 (such as the minimum internal width or diameter of the first filament port). In other words, the inner surface of the first guide sheath 224 can be flush with the inner surface of the first filament port 216.

[0074] In some embodiments, the heating cylinder 102 may include a support element 228. The support element 228 may be coupled to a first guide sheath 224. The first guide sheath 224 may extend through a lumen defined by the support element 228. The support element 228 may be adjacent to the heating block 202. In an illustrated embodiment, the support element 228 is coupled to the heating block 202. The support element 228 may include a coupling protrusion configured to be mechanically coupled to a coupling receiver 230 defined by a first filament port 216. In some embodiments, the coupling receiver 230 may define threads, and the coupling protrusion of the support element 228 may define complementary threads.

[0075] The coupling receiver 230 may terminate at the shoulder 226 of the first filament port 216. The coupling protrusion of the support element 228 may be designed to terminate at the shoulder 226. In some embodiments, the distal end of the support element 228 and the distal end of the first guide sheath 224 may engage the shoulder 226. In other embodiments, the distal end of the support element 228 may engage the shoulder 226, and the distal end of the first guide sheath 224 may engage a second shoulder (not shown) defined by the first filament port 216 located distal to the shoulder 226.

[0076] When the first filament port 216 defines a shoulder, the first filament port 216 may define at least two different internal widths or diameters. The larger internal width or diameter may be set to pass through the support element 228, and the smaller internal width or diameter may be set to match the internal width or diameter of the first guide sheath 224.

[0077] When the second filament port 218 defines two shoulders, the first filament port 216 may define at least three different internal widths or diameters. The largest internal width or diameter may be sized to pass through the support element 228. The intermediate internal width or diameter may be sized to accommodate the distal portion of the first guide sheath 224. The smallest internal width or diameter may be sized to match the internal width or diameter of the first guide sheath 224.

[0078] The filament processing system 106 may include a second processing subassembly 232. The second processing subassembly 232 delivers the second filament 214 into the internal volume 204. The second processing subassembly 232 may include one or more pressure rollers 222. Each of the one or more pressure rollers 222 may be operatively coupled to a motor. Any suitable number of pressure rollers 222 may be used. As shown, the second processing subassembly 232 may include a set of pressure rollers 222. The pressure rollers 222 can be used to apply a driving force to the second filament 214.

[0079] The heating cylinder 102 may include one or more of a second guide sheath 234, a heat sink 236, and a heat interruption section 238. The second guide sheath 234 may extend at least between the second processing subassembly 232 and the heat sink 236. The second guide sheath 234 may be coupled to the heat sink. The second guide sheath 234 may be coupled to the second processing subassembly 232. The heat sink 236 may be coupled to the heat interruption section 238. The heat interruption section 238 may be coupled to the heating block 202. The heat interruption section 238 may extend from the outside of the heating block 202 into the second filament port 218.

[0080] The second guide sheath 234 may define a lumen in fluid communication with the internal volume 204. A second filament 214 extends through the second guide sheath 234 from the second processing subassembly 232 to the radiator 236, through the radiator 236, through a thermal interruption, and then through the second filament port 218. In some embodiments, the second guide sheath 234 may extend to the pressure roller 22 in the second processing subassembly 232. In some embodiments, the second guide sheath 234 may extend at least partially into the radiator 236.

[0081] A thermal interruption portion 238 may be located adjacent to the heating block 202. The thermal interruption portion 238 may be positioned between the heat sink 236 and the heating block 202. The thermal interruption portion 238 may include a coupling protrusion configured to mechanically engage with a coupling receiver 240 defined by a second filament port 218. In some embodiments, the coupling receiver 240 may define threads, and the coupling protrusion of the thermal interruption portion 238 may define complementary threads. The second filament port 218 may include one or more shoulders, such as those described with respect to the first filament port 216, except that the second filament port 218 may not be configured to receive the second guide sheath 234. The internal width or diameter of the support element 228 may be larger than the internal width or diameter of the thermal interruption portion 238, for example, to accommodate the external width or diameter of the first guide sheath 224. In other embodiments, the second filament port 218 may be configured to receive the second guide sheath 234 in a manner similar to that of the first filament port 216, which receives the first guide sheath 224.

[0082] The guide sheaths 224 and 234 can be made of any suitable material. In some embodiments, one or both of the guide sheaths 224 and 234 may comprise a synthetic fluoropolymer. One or both of the guide sheaths 224 and 234 may comprise polytetrafluoroethylene (PTFE). Another suitable material may comprise ultra-high molecular weight polyethylene (UHMWPE).

[0083] Any suitable material can be used to manufacture the support element 228. In some embodiments, the support element 228 may be a thermal insulator. The support element 228 may comprise a thermoplastic. The support element 228 may be made of polyamide-imide, such as TORLON polyamide-imide (commercially available from McMaster-Carr Supply Co. (Elmhurst, Illinois)). Other suitable materials may include liquid crystal polymers, polyaryletherketones (PAEK), polyphenylene sulfide, and polysulfone.

[0084] Support element 228 provides mechanical support for the first guide sheath 224. Support element 228 may comprise a substantially rigid material. In some embodiments, support element 228 comprises a material having a higher hardness than the material used to manufacture the first guide sheath 224.

[0085] Heat sink 236 can be made from any suitable material. Heat sink 236 may include a material with high thermal conductivity. In some embodiments, heat sink 236 includes aluminum.

[0086] The thermal interruption portion 238 can be made of any suitable material. The thermal interruption portion 238 may include a material with low thermal conductivity. In some embodiments, the thermal interruption portion 238 includes titanium. The thermal interruption portion 238 may include a necking portion to reduce the amount of material between the proximal and distal portions of the thermal interruption portion. The necking portion may help reduce the thermal conductivity between the proximal and distal portions of the thermal interruption portion 238.

[0087] Generally, the use of device 200 can be advantageous for using softer filaments at high feed forces and pressures, which tend to compress soft filaments and may cause blockages. Using higher feed forces and pressures allows for a wider range of process conditions and provides a consistent sheath around the substrate. Specifically, the use of a first guide sheath 224 that extends at least partially into the first filament port 216 can be advantageous for using softer filaments and greater “pushing power.” Additionally or alternatively, the use of support element 228 can also be advantageous for using softer filaments and greater “pushing power.”

[0088] Figure 3A partial cross-sectional side view of an example of a heating cylinder 102 is shown. The heating cylinder 102 or heating block 202 may extend from a proximal side 410 to a distal side 412. In some embodiments, the heating cylinder 102 may include one or more of the following: a heating block 202, an inlet die 402 coupled to the proximal side 410 of the heating block, an outlet die 404 coupled to the distal side 412 of the heating block, a proximal retaining plate 406 that facilitates holding the inlet die close to the heating block, and a distal retaining plate 408 that facilitates holding the outlet die close to the heating block.

[0089] The inlet die 402 and the outlet die 404 can be held in any suitable manner. In an exemplary embodiment, the outlet die 404 can be held by the distal shoulder of the distal retaining plate 408. In some embodiments, the inlet die 402 can be held by the proximal retaining plate 406 between the distal shoulder of the proximal retaining plate 406 and a fastener 500 (such as a nut having a lumen extending through it), the fastener being threaded onto the retaining plate to engage the proximal surface of the inlet die. The retaining plates 406, 408 can be fastened to the heating block 202 in any suitable manner.

[0090] The inlet die 402 may at least partially define the substrate inlet port 414. The outlet die 404 may at least partially define the substrate outlet port 416.

[0091] The inlet die 402 may at least partially define the internal volume 204. The outlet die 404 may at least partially define the internal volume 204. In some embodiments, the outer surface of the inlet die 402, the inner surface of the outlet die 404, and the inner surface of the heating block 202 may together define the internal volume 204.

[0092] The substrate channel 206 can be described as extending from the proximal side 410 to the distal side 412 of the heating cylinder 102, or vice versa. The substrate channel 206 may extend through the internal volume 204. As shown, the substrate channel 206 may extend through one or more of the proximal retaining plate 406, the inlet die 402, the heating block 202, the outlet die 404, and the distal retaining plate 408.

[0093] Figure 4 An example of a conduit 600 that can be manufactured using system 100 is shown before the removal of substrate 116. Substrate 116 may include a lubricating coating on its outer surface to facilitate removal. The lubricating coating may extend around the circumference of substrate 116. An example of a lubricating coating is a PTFE coating.

[0094] The substrate 116 may be covered with a gasket 602, such as a PTFE layer. The gasket 602 may be placed above the lubricating coating. The gasket 602 may extend around the circumference of the substrate 116.

[0095] The gasket 602 may be covered with a braid 604, such as a stainless steel braided layer. The braid 604 may be placed on top of the gasket 602. The braid 604 may extend around the circumference of the gasket 602. The braid 604 may be porous.

[0096] The sheath 118 can be applied to the woven fabric 604. When the sheath 118 is formed, the padding 602 can be adhered to the sheath 118 through the holes in the woven fabric 604.

[0097] In the illustrated embodiment, the conduit 600 includes a first segment 606, a second segment 608, and a third segment 610. Each segment 606, 608, and 610 may have a different hardness. In some embodiments, the first segment 606 may have a high hardness, the third segment 610 may have a low hardness, and the second segment 608 may have a hardness that varies continuously in the longitudinal direction between the hardness of the first and third segments. For example, the first segment 606 may have a Shore hardness of 72D, the third segment 610 may have a Shore hardness of 35D, and the second segment 608 may have a Shore hardness that gradually changes from 72D to 35D along its length.

[0098] Figure 8 The use of system 100 is shown. Figure 1 This is an example of an additive manufacturing method 800. Method 800 can be used to manufacture implantable medical catheters.

[0099] Method 800 may include, for example, feeding substrate 802 through a substrate channel in a heated barrel. The substrate channel may be in fluid communication with an internal cavity of the heated barrel.

[0100] Method 800 may include feeding a first filament 804 into an internal cavity through a filament port of a heated barrel, and feeding a second filament 806 into the internal cavity through another filament port.

[0101] Method 800 may include, for example, melting one or more filaments 808 in an internal cavity. Any portion of the filaments housed in the internal cavity may be melted. For example, melting a first filament and a second filament in the internal cavity.

[0102] Method 800 may include, for example, moving a heated barrel relative to a substrate 810 in a longitudinal direction to form a conduit sheath comprising material from at least a first filament and a second filament.

[0103] In addition, method 800 may include moving a heated barrel (e.g., an inlet die) relative to substrate 812 in a rotational direction about a longitudinal axis, such that the first filament and the second filament produce discrete loops when forming a guide tube sheath.

[0104] In some embodiments, method 800 may further include adjusting the ratio of the first filament to the second filament in the longitudinal direction to change the Shore hardness of the catheter sheath in the longitudinal direction. In one or more embodiments, the change in the ratio of the material in the sheath in the longitudinal direction may be continuous.

[0105] In one or more embodiments, moving the heating cylinder relative to the substrate in the rotational direction may include movement at a rate of about 200 RPM and / or less than or equal to 300 RPM. Specifically, the rotational rate may be about 260 RPM, and the axial or linear rate may be about 2 inches per minute. In one or more embodiments, moving the heating cylinder relative to the substrate may include movement at a ratio of rotational direction to longitudinal direction of about 25 rpm, 35 rpm, 44 rpm, etc., and / or less than or equal to 150 rpm, 100 rpm, 50 rpm, etc. Specifically, the ratio of rotational direction to longitudinal direction may be about 44 rpm (e.g., 44 discrete material rings per inch). It should be noted that, in addition to the rotational-to-linear ratio, rheological properties may also be affected by pressure, material viscosity, encapsulation flow geometry, etc.

[0106] In one or more embodiments, the method may further include adding particles to the conduit sheath before moving the heating cylinder relative to the substrate.

[0107] Explanatory Implementation Plan

[0108] While this disclosure is not limited thereto, an understanding of various aspects of this disclosure will be gained through discussion of the specific examples and illustrative embodiments provided below. Various modifications to the examples and illustrative embodiments, as well as other embodiments of this disclosure, will become apparent herein.

[0109] A1. An additive manufacturing system, comprising:

[0110] A heating cylinder extending from a proximal side to a distal side and including a substrate inlet port located on the proximal side and a substrate outlet port located on the distal side, the heating cylinder defining an internal volume and a substrate channel extending from the proximal side through the internal volume to the distal side, wherein the heating cylinder defines a first filament port in fluid communication with the internal volume to receive a first filament and a second filament port in fluid communication with the internal volume to receive a second filament.

[0111] A heating element thermally connected to a heating cylinder to heat the internal volume;

[0112] A filament processing system comprising one or more motors for feeding at least a first filament through a first filament port and a second filament through a second filament port into an internal volume;

[0113] Substrate processing system, the substrate processing system comprising:

[0114] Headframe, the headframe including a distal clamp for securing a distal portion of an elongated substrate, wherein the substrate is positioned to pass through a substrate channel in a longitudinal direction when the headframe is secured; and

[0115] One or more motors that cause one or both of the substrate fixed to the headstock and the heating cylinder to translate or rotate relative to each other; and

[0116] A controller, operably connected to a heating element, one or more motors of the filament handling system, and one or more motors of the substrate handling system, is configured to:

[0117] One or more motors of the filament processing system are controlled to selectively control the feeding of the first and second filaments into the internal volume.

[0118] Activate the heating element to melt any portion of the first or second filament within the internal volume; and

[0119] One or more motors of a substrate processing system are controlled to move one or both of a substrate and a heating cylinder relative to each other in a longitudinal direction to form an elongated conduit sheath around the substrate, wherein the conduit sheath comprises material from at least a first filament and a second filament; and

[0120] One or more motors of the substrate processing system are controlled to move one or both of the substrate and the heating cylinder relative to each other in a rotational direction about a longitudinal axis, such that the first filament and the second filament form discrete loops.

[0121] A2. The system according to embodiment A1, wherein the substrate and the heating cylinder move relative to each other in the rotational direction at a rate of approximately 260 RPM.

[0122] A3. The system according to any of the preceding embodiments A, wherein the substrate and the heating cylinder move relative to each other in the longitudinal and rotational directions at a rate of approximately 44 revolutions per inch.

[0123] A4. The system according to any of the preceding embodiments A, wherein the elongated catheter sheath includes particles near the outer surface of the catheter sheath.

[0124] A5. The system according to any of the preceding embodiments A, wherein the first filament has a Shore hardness of less than or equal to 90A, 80A, 70A, 80D, 72D, 70D, 60D, 50D, 40D or 35D.

[0125] A6. The system according to any of the preceding embodiments A, wherein the first filament has a Shore hardness that is 10D, 20D, 30D, 35D or 40D lower than the Shore hardness of the second filament.

[0126] A7. The system according to any of the preceding embodiments A, wherein the heating barrel includes an inlet die, a heating block and an outlet die, wherein the heating block defines a first filament port and a second filament port.

[0127] A8. The system according to any of the preceding embodiments A, wherein the controller is configured to change the feed force applied to at least one of the first filament and the second filament to change the ratio of material in the catheter sheath over the longitudinal distance.

[0128] A9. The system according to implementation scheme A8, wherein the change in the ratio of material in the catheter sheath over the longitudinal distance is continuous.

[0129] A10. The system according to any of the preceding embodiments A, further comprising a substrate, wherein the substrate includes a lubricating coating, a liner, and a braid, and a catheter sheath is formed around the braid. B1. A method of additive manufacturing for an implantable medical device, the method comprising:

[0130] The substrate is fed along the longitudinal axis through the substrate channel in the heating cylinder, and the substrate channel is in fluid communication with the internal cavity of the heating cylinder;

[0131] The first filament is fed into the internal cavity through the filament port;

[0132] The second filament is fed into the internal cavity through another filament port;

[0133] Melt the first and second filaments in the internal cavity;

[0134] The heated barrel is moved relative to the substrate at least in the longitudinal direction to form a conduit sheath comprising material from at least a first filament and a second filament; and

[0135] The heating cylinder is moved relative to the substrate in a rotational direction about the longitudinal axis, causing the first and second filaments to form discrete loops when forming the conduit sheath.

[0136] B2. The method according to embodiment B1 further includes adjusting the ratio of the first filament to the second filament in the longitudinal distance to change the Shore hardness of the catheter sheath in the longitudinal distance.

[0137] B3. The method according to implementation scheme B2, wherein the change in the ratio of the material in the catheter sheath over the longitudinal distance is continuous.

[0138] B4. The method according to any of the preceding embodiments B, wherein moving the heating cylinder relative to the substrate in the rotational direction comprises moving it at a rate of 260 RPM.

[0139] B5. The method according to any of the preceding embodiments B, wherein moving the heating barrel relative to the substrate comprises moving it at a ratio of approximately 44 revolutions per inch in the rotational direction to the longitudinal direction.

[0140] B6. The method according to any of the preceding embodiments B, wherein the first filament has a Shore hardness of less than or equal to 90A, 80A, 70A, 80D, 72D, 70D, 60D, 50D, 40D or 35D.

[0141] B7. The method according to any of the preceding embodiments B, wherein the first filament has a Shore hardness that is 10D, 20D, 30D, 35D or 40D lower than the Shore hardness of the second filament.

[0142] B8. The method according to any of the preceding embodiments B further includes adding particles to the conduit sheath before moving the heating barrel relative to the substrate in the rotational direction.

[0143] Therefore, various embodiments described herein are disclosed. It should be understood that the aspects disclosed herein can be combined in combinations different from those specifically given in the specification and drawings. It should also be understood that, depending on the example, certain actions or events of any process or method described herein may be performed in a different order, and may be completely added, combined, or omitted (e.g., performing the described technique may not require all the described actions or events). Furthermore, although for clarity some aspects of this disclosure are described as being performed by a single module or unit, it should be understood that the techniques of this disclosure can be performed by combinations of units or modules associated with, for example, a medical device.

[0144] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include non-transitory computer-readable media, which correspond to tangible media such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible by a computer).

[0145] The instructions can be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), or other equivalent integrated or discrete logic circuit systems. Therefore, the term "processor" as used herein can refer to any of the foregoing structures or any other physical structures suitable for implementing the described techniques. Furthermore, this technique can be fully implemented in one or more circuit or logic elements.

[0146] All references and publications cited herein are expressly incorporated in their entirety by way of citation for all purposes, unless in any way directly contradict this disclosure.

[0147] Unless otherwise specified, all numerical values ​​used in the specification and claims to represent characteristic dimensions, quantities, and physical properties are to be understood as being modified by the terms “precisely” or “about”. Therefore, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and appended claims are approximate values ​​that may vary within typical ranges of experimental error, depending on the desired properties sought by a person skilled in the art using the teachings disclosed herein.

[0148] As used herein, the term “configured as” may be used interchangeably with the terms “adapted as” or “structured as”, unless otherwise clearly stated in this disclosure.

[0149] Unless the context clearly specifies otherwise, the singular forms “a,” “an,” and “the” cover implementations with plural indicators.

[0150] As used in this article, "have," "having," "include," "including," "comprise," and "comprising" are used in their open-ended sense and usually mean "including but not limited to." It should be understood that phrases such as "basically composed of" or "composed of" are categorized under "comprising."

[0151] References to “an embodiment,” “an embodiment,” “certain embodiments,” or “some embodiments,” etc., mean that a particular feature, configuration, composition, or characteristic described in connection with that embodiment is included in at least one embodiment of this disclosure. Therefore, the appearance of such shortened terms throughout the document does not necessarily refer to the same embodiment of this disclosure. Furthermore, particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more embodiments.

[0152] The terms "preferred" and "ideally" refer to embodiments of this disclosure that may provide certain benefits in certain circumstances. However, other embodiments may also be preferred in the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are useless, nor is it intended to exclude other embodiments from the scope of this disclosure.

Claims

1. An additive manufacturing system, comprising: A heating cylinder extending from a proximal side to a distal side and including a substrate inlet port located on the proximal side and a substrate outlet port located on the distal side, the heating cylinder defining an internal volume and a substrate channel extending from the proximal side through the internal volume to the distal side, wherein the heating cylinder defines a first filament port in fluid communication with the internal volume to receive a first filament and a second filament port in fluid communication with the internal volume to receive a second filament, wherein the first filament port and the second filament port respectively enter the substrate channel; A heating element, thermally connected to the heating cylinder to heat the internal volume; A filament processing system comprising one or more motors for feeding at least a first filament through a first filament port and a second filament through a second filament port into the internal volume; Substrate processing system, the substrate processing system comprising: Headframe, the headframe including a distal clamp for securing a distal portion of an elongated substrate, wherein the elongated substrate is positioned to pass longitudinally through a substrate channel when secured by the headframe; and One or more motors, said one or more motors causing one or both of the elongated substrate fixed by the headstock and the heating cylinder to translate or rotate relative to each other; and A controller, operatively coupled to the heating element, the one or more motors of the filament processing system, and the one or more motors of the substrate processing system, is configured to: Control the one or more motors of the filament processing system to selectively control the feeding of the first filament and the second filament into the internal volume; Activate the heating element to melt any portion of the first or second filament within the internal volume; and The one or more motors of the substrate processing system are controlled to move one or both of the elongated substrate and the heating cylinder relative to each other in the longitudinal direction to form an elongated conduit sheath around the elongated substrate, wherein the conduit sheath comprises material from at least the first filament and the second filament; and The one or more motors of the substrate processing system are controlled to move one or both of the elongated substrate and the heating cylinder relative to each other in a rotational direction about the longitudinal axis, such that the first filament and the second filament form discrete loops.

2. The system of claim 1, wherein the elongated substrate and the heating cylinder move relative to each other in the rotational direction at a rate of 260 RPM.

3. The system of claim 1 or 2, wherein the elongated substrate and the heating cylinder move relative to each other at a ratio of 44 revolutions per inch in the longitudinal direction and the rotational direction.

4. The system according to any one of claims 1-2, wherein the elongated catheter sheath comprises particles near the outer surface of the catheter sheath.

5. The system according to any one of claims 1-2, wherein the first filament has a Shore hardness of less than or equal to 72D.

6. The system according to any one of claims 1-2, wherein the first filament has a Shore hardness that is 10D lower than that of the second filament.

7. The system according to any one of claims 1-2, wherein the heating cylinder comprises an inlet die, a heating block, and an outlet die, wherein the heating block defines the first filament port and the second filament port.

8. The system according to any one of claims 1-2, wherein the controller is configured to change the feed force applied to at least one of the first filament and the second filament to change the ratio of material in the catheter sheath over the longitudinal distance.

9. The system of claim 8, wherein the change in the ratio of the material in the catheter sheath over the longitudinal distance is continuous.

10. The system according to any one of claims 1-2, further comprising the elongated substrate, wherein the elongated substrate comprises a lubricating coating, a liner, and a braid, and the conduit sheath is formed around the braid.

11. A method for additive manufacturing of an implantable medical device, the method comprising: The substrate is fed along the longitudinal axis through a substrate channel in the heating cylinder, the substrate channel being in fluid communication with the internal cavity of the heating cylinder; The first filament is fed into the internal cavity through the filament port; The second filament is fed into the internal cavity through another filament port; Melt the first filament and the second filament in the internal cavity; The heating cylinder is moved relative to the substrate at least in the longitudinal direction to form a conduit sheath comprising material from at least the first filament and the second filament; as well as The heating cylinder is moved relative to the substrate in a rotational direction about the longitudinal axis, such that the first filament and the second filament form discrete loops when forming the conduit sheath. The heating cylinder defines a first filament port in fluid communication with the internal cavity to receive the first filament and a second filament port in fluid communication with the internal cavity to receive the second filament, wherein the first filament port and the second filament port respectively enter the substrate channel.

12. The method of claim 11, further comprising adjusting the ratio of the first filament to the second filament in the longitudinal distance to change the Shore hardness of the catheter sheath in the longitudinal distance.

13. The method of claim 12, wherein the change in the ratio of the material in the catheter sheath over the longitudinal distance is continuous.

14. The method according to any one of claims 11 to 13, wherein moving the heating cylinder relative to the substrate in the rotational direction comprises moving it at a rate of 260 RPM.

15. The method according to any one of claims 11 to 13, wherein moving the heating cylinder relative to the substrate comprises moving it at a ratio of 44 revolutions per inch in the rotational direction to the longitudinal direction.

16. The method according to any one of claims 11 to 13, wherein the first filament has a Shore hardness of less than or equal to 72D.

17. The method according to any one of claims 11 to 13, wherein the first filament has a Shore hardness that is 10D lower than that of the second filament.

18. The method according to any one of claims 11 to 13, further comprising adding particles to the conduit sheath before moving the heating cylinder relative to the substrate in the rotational direction.

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