Patent Publication Number: US-2021177490-A1

Title: Catheter tips and related methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. provisional patent application No. 62/949,332 filed Dec. 17, 2019, the contents of which are incorporated herein by reference in their entirety as if set forth verbatim. 
    
    
     FIELD 
     The present disclosure relates generally to producing tips for use in ablation catheters, and particularly to methods for mass production of tips for use in ablation catheters. 
     BACKGROUND 
     Cardiac arrhythmias, such as atrial fibrillation, occur when regions of cardiac tissue abnormally conduct electric signals to adjacent tissue, thereby disrupting the normal cardiac cycle and causing asynchronous rhythm. 
     Procedures for treating arrhythmia include surgically disrupting the origin of the signals causing the arrhythmia, as well as disrupting the conducting pathway for such signals. By selectively ablating cardiac tissue by application of energy via a catheter, it is sometimes possible to block or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions. 
     Currently, radiofrequency (RF) ablation catheter tips each have to be individually machined to create irrigation holes and/or to create the shell. This is both time and labor intensive, which increases overall costs but also reduces repeatable and scalable manufacturing. 
     The solution of this disclosure resolves these and other problems of the art. 
     SUMMARY 
     Accordingly, the inventors of this disclosure have recognized that there is a need for manufacturing multiple catheter tips at once with one or more removable inserts or molds that can be electroplated to create a catheter tip including a dome. Many inserts could be processed at once depending on the size. 
     In some examples, a method of manufacturing a catheter tip is disclosed. The method includes electroplating a conductive material over an insert including a negative to a domelike shape thereby forming a shape of the catheter tip including a dome with the domelike shape, selectively positioning a plurality of irrigation holes between outer and inner surfaces of the catheter tip, removing the insert thereby leaving the catheter tip and the plurality of irrigation holes and electropolishing the catheter tip. 
     In some examples, the catheter tip being generally tubular with a dome-like cover. 
     In some examples, the insert is generally tubular with an inner lumen. 
     In some examples, the insert includes a plastic. 
     In some examples, the plastic includes Acrylonitrile Butadiene Styrene (ABS). 
     In some examples, the plastic includes Polycarbonate. 
     In some examples, the conductive material includes gold. 
     In some examples, the conductive material includes palladium. 
     In some examples, the conductive material includes platinum. 
     In some examples, the method includes forming the insert by molding a plastic material from a mold of a size and shape of the catheter tip. 
     In some examples, the step of selectively positioning the plurality of irrigation holes includes the steps of selecting an irrigation hole diameter, selecting a catheter tip wall thickness, determining a lateral and a vertical growth rate of the material, and determining a size of an insert irrigation hole negative based on the irrigation hole diameter, the wall thickness, and the lateral and the vertical growth rate of the material. 
     In some examples, the lateral and the vertical growth rate of the material is 1:1, and the step of determining a size of an insert irrigation hole negative includes adding the irrigation hole diameter with the catheter tip wall thickness. 
     In some examples, the step of selectively positioning the plurality of irrigation holes is done simultaneously. 
     In some examples, the step of electroplating the conductive material over the insert includes axially aligning a pin with a longitudinal axis of the insert, and holding, by the pin, the insert during electroplating. 
     In some examples, the step of selectively positioning the plurality of irrigation holes includes forming an irrigation hole pattern on the catheter tip out of a secondary non-plateable material. 
     In some examples, the secondary non-plateable material is nylon. 
     In some examples, the secondary non-plateable material is polypropylene. 
     In some examples, the secondary non-plateable material is polyester. 
     In some examples, the method includes setting an outer diameter of the insert to an inner diameter of the catheter tip. 
     In some examples, the method includes thickening a lower edge of the catheter tip with the secondary non-plateable material thereby preventing formation of a rounded edge adjacent a base of the catheter tip. 
     In some examples, the method includes positioning a step of the secondary non-plateable material at a lower edge adjacent a base of the catheter tip. 
     In some examples, the step includes a height of approximately 0.002″ thereby thickening the lower edge and preventing formation of a rounded edge. 
     In some examples, the method includes offsetting a hole diameter of one or more holes in the hole pattern by a wall thickness. 
     In some examples, the step of selectively positioning the plurality of irrigation holes includes oversizing an operational catheter tip diameter by a wall thickness of the catheter tip. 
     In some examples, the step of selectively positioning the plurality of irrigation holes includes sizing a manufacture diameter of the irrigation holes by an operational catheter tip diameter plus a wall thickness of the catheter tip. 
     In some examples, the method includes maintaining, following the step of selectively positioning the plurality of irrigation holes and the step of removing the insert, a 1:1 ratio of lateral and vertical growth of the conductive material. 
     In some examples, the method includes overmolding the secondary non-plateable material onto the insert. 
     In some examples, holes of the hole pattern are configured for being filled by the secondary material. 
     In some examples, the step of removing the insert includes melting the insert thereby leaving leave behind the catheter tip. 
     In some examples, the step of removing the insert includes dissolving the insert in acid thereby leaving leave behind the catheter tip. 
     In some examples, the step of electropolishing the dome includes removing surface roughness and/or burrs. 
     In some examples, a method of manufacturing a plurality of catheter tips is disclosed. The method includes simultaneously performing a method of any preceding claim to manufacture the plurality of catheter tips. 
     In some examples, a catheter tip made by any method of this disclosure. 
     In some examples, a method of manufacturing a plurality of catheter tips is disclosed. The method includes electroplating a conductive material over a plurality of inserts including a negative to a domelike shape thereby forming a plurality of domes including the domelike shape, selectively positioning a plurality of irrigation holes between outer and inner surfaces of each respective dome, removing each respective insert thereby leaving a respective dome, and electropolishing domes of the plurality of catheter tips. 
     In some examples, the insert being generally tubular with an inner lumen. 
     In some examples, each respective insert includes a plastic. 
     In some examples, the plastic includes Acrylonitrile Butadiene Styrene (ABS). 
     In some examples, the plastic includes Polycarbonate. 
     In some examples, the conductive material includes gold. 
     In some examples, the conductive material includes palladium. 
     In some examples, the conductive material includes platinum. 
     In some examples, the method includes forming each respective insert by molding a plastic material from a mold of a size and shape of each respective catheter tip. 
     In some examples, the step of selectively positioning the plurality of irrigation holes includes the steps of selecting an irrigation hole diameter, selecting a catheter tip wall thickness, determining a lateral and a vertical growth rate of the material, and determining a size of an insert irrigation hole negative based on the irrigation hole diameter, the wall thickness, and the lateral and the vertical growth rate of the material. 
     In some examples, the lateral and the vertical growth rate of the material is 1:1, and the step of determining a size of an insert irrigation hole negative includes adding the irrigation hole diameter with the catheter tip wall thickness. 
     In some examples, the step of selectively positioning the plurality of irrigation holes is done simultaneously. 
     In some examples, the step of electroplating the conductive material over the plurality of inserts includes axially aligning a pin with a longitudinal axis of each respective insert, and holding, by the respective pin, the respective insert during electroplating. 
     In some examples, the step of selectively positioning the plurality of irrigation holes includes forming an irrigation hole pattern on each respective catheter tip out of a secondary non-plateable material. 
     In some examples, the secondary non-plateable material is nylon. 
     In some examples, the secondary non-plateable material is polypropylene. 
     In some examples, the secondary non-plateable material is polyester. 
     In some examples, the method includes setting an outer diameter of each respective insert to an inner diameter of the respective catheter tip. 
     In some examples, the method includes thickening a lower edge of each respective catheter tip with the secondary non-plateable material thereby preventing formation of a rounded edge adjacent a base of the respective catheter tip. 
     In some examples, the method includes positioning a step of the secondary non-plateable material at a lower edge adjacent a base of the respective catheter tip. 
     In some examples, the step includes a height of approximately 0.002″ thereby thickening the lower edge and preventing formation of a rounded edge. 
     In some examples, the method includes offsetting a hole diameter of one or more holes in the hole pattern by a wall thickness. 
     In some examples, the step of selectively positioning the plurality of irrigation holes includes oversizing an operational catheter tip diameter by a wall thickness of each respective catheter tip. 
     In some examples, the step of selectively positioning the plurality of irrigation holes includes sizing a manufacture diameter of the irrigation holes by an operational catheter tip diameter plus a wall thickness of each respective catheter tip. 
     In some examples, the method includes maintaining, following the step of selectively positioning the plurality of irrigation holes and the step of removing the insert, a 1:1 ratio of lateral and vertical growth of the conductive material of each respective catheter tip. 
     In some examples, the method includes overmolding the secondary non-plateable material onto each respective insert. 
     In some examples, the holes of the hole pattern are configured for being filled by the secondary material. 
     In some examples, the step of removing each respective electroplated insert includes melting the respective insert thereby leaving leave behind the respective catheter tip. 
     In some examples, the step of removing each respective electroplated insert includes dissolving the respective insert in acid thereby leaving leave behind the respective catheter tip. 
     In some examples, the step of electropolishing the plurality of catheter tips includes removing surface roughness and/or burrs. 
     In some examples, a catheter tip is disclosed that is made by a process including the steps of electroplating a conductive material over an insert having a negative to a domelike shape thereby forming a catheter tip comprising a dome, selectively positioning a plurality of irrigation holes between outer and inner surfaces of the dome, removing the insert thereby leaving the catheter tip, and electropolishing the catheter tip. 
     In some examples, a plurality of catheter tips is disclosed that is made by a process including the steps of electroplating a conductive material over a plurality of inserts comprising a negative to a domelike shape thereby forming a plurality of catheter tips each having a dome, selectively positioning a plurality of irrigation holes between outer and inner surfaces of each respective catheter tip, removing each respective insert thereby leaving a respective catheter tip, and electropolishing each catheter tip of the plurality of catheter tips. 
     The present disclosure will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and further aspects of this disclosure are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the disclosure. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation. 
         FIG. 1  is a schematic illustration of a system for ablating tissue of a subject, in accordance with some embodiments of the present disclosure. 
         FIG. 2  is a schematic illustration of one step in a method of this disclosure to manufacture an example catheter tip. 
         FIG. 3  is a schematic illustration of one step in a method of this disclosure to manufacture an example catheter tip. 
         FIG. 4  is an illustration of a flow diagram illustrating an example method according to aspects of the present disclosure. 
         FIG. 5  is an illustration of a flow diagram illustrating an example method according to aspects of the present disclosure. 
         FIG. 6  is an illustration of a flow diagram illustrating an example method according to aspects of the present disclosure. 
         FIG. 7  is an illustration of a flow diagram illustrating an example method according to aspects of the present disclosure. 
         FIG. 8  is an illustration of a flow diagram illustrating an example method according to aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The term “electroplating” in this disclosure is intended to mean the act of coating an object by electrolytic deposition with a metal, such as chromium, silver, gold, platinum, palladium, and the like. 
     As used herein, the term “non-plateable material” can mean any material that does not easily, or is incapable of, being electroplated. Such materials can include one or combination of nylon, polypropylene, polyester, non-blended plastics, the material marketed under Valox® which are thermoplastic polymer resins, and the like. 
     As used herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, “about” or “approximately” may refer to the range of values±20% of the recited value, e.g. “about 90%” may refer to the range of values from 71% to 99%. 
     Medical devices such as some types of catheters include electrodes that are used, for example, for conducting electrical signals to or from patient tissue. Embodiments of the present disclosure that are described hereinbelow provide methods for producing a catheter tip for use with electrodes having low impedance at low frequencies. In principle, it is possible to produce such electrodes by coating (e.g., soldering or gluing) discrete locations of a catheter with conductive (e.g., metal) layers. These metal layers reduce the impedance of the electrode at low frequencies, but such coating processes are inefficient for high volume manufacturing (HVM). The disclosed techniques enable producing the catheter tips using very large-scale integration (VLSI) processes that enable high productivity in HVM. The disclosed techniques help to increase the functionality of catheter tips by producing them at HVM without compromising production costs. Furthermore, using VLSI processes on catheter tips reduce the production cost of the distal end. 
       FIG. 1  is a schematic, pictorial illustration of a catheterization system  20 , in accordance with an embodiment of the present disclosure. System  20  includes a probe, in the present example a cardiac catheter  22 , and a control console  24 . Catheter  22  may be used for any suitable therapeutic and/or diagnostic purposes, such as sensing signals from a heart (not shown) of a patient  28 . 
     Console  24  can include a processor  34 , typically a general-purpose computer, with suitable front end and interface circuits for receiving signals from catheter  22  and for controlling the other components of system  20  described herein. Console  24  can include a driver circuit  42 , which drives magnetic field generators  36  placed at known positions external to patient  28  lying on table  29 , e.g., below the patient&#39;s torso. 
     In some embodiments, console  24  includes a memory  50  and a display  46 , configured to display data, such as an image  44  of at least part of the heart of patient  28 . In some embodiments, image  44  may be acquired using a computerized tomography (CT) system, by a magnetic resonance imaging (MRI) scanner, or using any other suitable anatomical imaging system. A physician  30  (such as an interventional cardiologist) inserts catheter  22  through the vascular system of patient  28  lying on a table  29 . Catheter  22  includes a distal-end assembly  40 , shown in an inset  26 . Physician  30  moves assembly  40  in the vicinity of the target region in the heart by manipulating catheter  22  with a manipulator  32  near the proximal end of catheter  22 . The proximal end of catheter  22  is connected to interface circuitry in processor  34 . 
     Reference is now made to insert  26  with distal-end assembly  40 , which can include a flexible printed circuit board (PCB) sheet  60  disposed around an internal member  69 . In some embodiments, assembly  40  further includes a dome  66 . Sheet  60  and/or dome  66  may be perforated so as to form one or more irrigation holes  64 , which are configured to allow irrigation fluid to flow out from the insertion tube when irrigating the tissue of the heart, for example during an ablation procedure. 
     Assembly  40  once finished can include one or more electrodes  62  and/or one or more ring electrodes  63 , which are configured to conduct electrical signals to or from the tissue of the heart. During a medical procedure, such as a cardiac mapping, electrodes  62  and/or ring electrodes  63  are brought into contact with the tissue of the heart, so as to sense electrical signals originated therefrom. Assembly  40  can be used for ablating tissue of the heart. 
     In some embodiments, processor  34  typically includes a general-purpose processor, which is programmed in software to carry out the functions described herein. The software may be downloaded to the computer in electronic form, over a network, for example, or it may, alternatively or additionally, be provided and/or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory. 
     The configuration of assembly  40  shown in  FIG. 1  is an example configuration, which is chosen purely for the sake of conceptual clarity. In alternative embodiments, any other suitable configuration can also be used. For example, the size and shape of assembly  40 , and the number and locations of electrodes  62  and/or ring electrodes  63  may be implemented using any suitable components and layout appropriate for conducting a suitable medical procedure on tissue of any organ of patient  28 . 
     Turning to  FIG. 2 , a schematic illustration of one step in an example method of this disclosure to manufacture an example catheter tip is shown, such as the manufacture of some or all of assembly  40 . In some examples, the solution of this disclosure uses electroplating to metallize components, including plastics such as polycarbonate and ABS. The system and methods of this disclosure use a removable insert and/or mold that can be electroplated to create a catheter tip including a dome. Once electroplated, the insert can be removed (e.g., by melting the insert, by dissolving the insert in acid, etc.) to leave behind the electroplated shell which now has formed the catheter tip. The electroplated catheter tip can then be electropolished to remove surface roughness and/or burrs. The solution of this disclosure includes using and/or manufacturing a plurality of inserts that can be processed simultaneously (e.g., see  100   s - 1000   s  of inserts being plated at the same time). 
     In particular,  FIG. 2  depicts an example mold  200  from which insert  100  can be created. For example, insert  100  can be formed by molding a plastic material from mold  200 , which as shown can be a size and shape of assembly  40 . Mold  200  can be substantially cylindrical with a mid-section  165  to correspond to an outer surface of mid-section  155  of insert  100 . Mold  200  can also include a dome region  176  to correspond to dome  166  of insert  100 , as well as a base section  168  to correspond to base  158  of insert  100 , and a plurality of irrigation hole regions  164  for corresponding holes  64  of assembly  40 . 
     In order to position hole regions  164  in some examples, an irrigation hole diameter can be selected as well as a desired catheter tip wall thickness. A lateral and a vertical growth rate of the material can also be determined along with determining a size of an insert irrigation hole negative based on the irrigation hole diameter, the wall thickness, and the lateral and the vertical growth rate of the material. For example, a size of hole regions  164  can be set to approximately 0.0065″ to offset lateral growth of electroplated material of approximately 0.0035″ thickness. 
     In determining a size of an insert irrigation hole negative, the irrigation hole diameter of hole regions  164  can be added with the catheter tip wall thickness. Moreover, lateral and the vertical growth rate of the material can be predetermined at a ratio of approximately 1:1, though other ratios larger and smaller are contemplated as needed or required. Hole regions  164  can also be positioned, size, or otherwise created simultaneously. Hole regions  164  can be positioned by forming an irrigation hole pattern on one or more regions of insert  100  (e.g., dome cover  166 ) out of a secondary non-plateable material. 
     Hole regions  164  can also be created by being predetermined holes of insert  100 . In certain examples, the hole diameter of one or multiple hole regions  164  in the irrigation hole pattern can be offset by a wall thickness of insert  100 . Hole regions  164  in this example can be positioned by oversizing an operational catheter tip diameter by a wall thickness of finished assembly  40 . Hole regions  164  can also be positioned by sizing a manufacture diameter of holes  64  by an operational catheter tip diameter plus a wall thickness of finished assembly  40   
     Hole regions  164  of any hole pattern according to this disclosure can also be configured to be filled by the secondary non-plateable material. It is understood that hole regions  164  and/or holes  64  themselves associated with assembly  40  can also be created after the insert  100  has been electroplated and removed (e.g., by being drilled). The secondary non-plateable material in some examples can be overmolded onto insert  100 . 
     Once molded, insert  100  can be correspondingly shaped as a generally tubular feature with an inner lumen and can include at least one plastic, such as Acrylonitrile Butadiene Styrene (ABS) and Polycarbonate. The depicted shape of insert  100  is merely exemplary and other shapes and designs are contemplated as needed or required. Insert  100  can be formed in mold  200  from a variety of techniques, including injection molding, open molding, resin transfer molding (e.g., a castable resin), high-volume molding, compression molding, additive manufacturing, and the like. Insert  100  can be a negative to a domelike shape with dome section  166 . The outer diameter D of insert  100  can be set or otherwise be based on a desired diameter of finished assembly  40 . For example, diameter D can be 0.091″ to simulate the inner diameter of assembly  40 . 
     Once one or more inserts  100  are formed, as shown in  FIG. 3 , a conductive material can be electroplated along an inner surface of insert  100  thereby creating an electroplated shell used with assembly  40 , along with any corresponding selectively positioned holes  64 . In some examples, a plurality of shells for a corresponding plurality of assemblies  40  and holes  64  can be created simultaneously. Insert  100  in  FIG. 3  includes dome cover  166  with the dome-support  168 , each corresponding to similar features of assembly  40  once electroplated. Insert  100  also includes one or more hole regions  164  which have been selectively positioned between inner and outer surfaces of insert  100  by mold  200 , including on or about dome cover  166  and mid-section  155 . While not shown, hole regions  164  can also be positioned on or about base  158 , which can be located at the proximal end of insert  100 . It is understood that insert  100  can include an internal lumen for directing irrigation ultimately into the inside of cavity of assembly  40 . 
     In some examples, methods of electroplating the conductive material with the inner surface of insert  100  can include vapor deposition or some other chemical deposition process that deposits a thin layer of the conductive material over the inner surface of insert  100 . The conductive material can completely cover, or plate, the inner walls of insert  100  and one or more computing systems can control the entire process of electroplating and/or insert  100  removal. In some examples, the conductive material can also be electroplated over insert  100  by axially aligning a pin  78  with a longitudinal axis  125  of insert  100  and holding, by the pin  78 , the insert  100  during the electroplating. 
     In some examples, a lower edge on or adjacent base  158  of insert  100  can be thickened, as shown. The lower edge can be thickened with the secondary non-plateable material to prevent formation of a rounded edge thereabout. A step  153  can be used to thicken the lower edge, whereby the step  153  can have a height of approximately 0.002″ or any other height needed ore required. 
     After insert  100  has been electroplated with the conductive material, insert  100  can be removed thereby leaving the catheter tip of assembly  40 , and corresponding dome  66  and holes  64 . Insert  100  can be removed from the conductive, electroplated material by applying heat (e.g., melting) to the insert  100  thereby leaving behind dome cover  66 , midsection  55 , base  58  and other corresponding regions of assembly  40 . Insert  100  is also contemplated for removal by dissolving insert  100  in acid thereby leaving behind assembly  40 . Once insert  100  is removed, assembly  40  can be electropolished. In some examples, electropolishing assembly  40  can include removing surface roughness and/or burrs from the electroplated material formed previously with insert  100 . In some examples, assembly  40 , and any constituent parts thereto manufactured with one or more of the herein disclosed steps can be finished to include a fingerprint, such as a unique marking, identifier or the like. Such markings and/or identifiers can include but not be limited to surface roughness, unique edges to the part certain sharpness, and the like. 
       FIG. 4  is a flow diagram illustrating an example method  400  of manufacturing a catheter tip according to one example of this disclosure. Step  410  of method  400  can include electroplating a conductive material over an insert comprising a negative to a domelike shape thereby forming a shape of the catheter tip comprising a dome with the domelike shape. Step  420  of method  400  can include selectively positioning a plurality of irrigation holes between outer and inner surfaces of the catheter tip. Step  430  of method  400  can include removing the insert thereby leaving the catheter tip and the plurality of irrigation holes. Step  440  of method  400  can include electropolishing the catheter tip. 
     The method  400  can include additional steps as would be appreciated and understood by a person of ordinary skill in the art. For example, method  400  can include forming the insert by molding a plastic material from a mold of a size and shape of the catheter tip. The example method  400  can be performed by an example system, as disclosed herein, a variation thereof, or an alternative thereto as would be appreciated and understood by a person of ordinary skill in the art. 
       FIG. 5  is a flow diagram illustrating an example method  500  of manufacturing a plurality of catheter tips according to one example of this disclosure. Step  510  of method  500  can include electroplating a conductive material over a plurality of inserts comprising a negative to a domelike shape thereby forming a plurality of catheter tips comprising the domelike shape. Step  520  of method  500  can include selectively positioning a plurality of irrigation holes between outer and inner surfaces of each respective catheter tip. Step  530  of method  500  can include removing each respective insert thereby leaving a respective catheter tip comprising the dome-like shape. Step  540  of method  500  can include electropolishing each catheter tip of the plurality of catheter tips. 
     The method  500  can include additional steps as would be appreciated and understood by a person of ordinary skill in the art. For example, method  500  can include forming each respective insert by molding a plastic material from a mold of a size and shape of each respective catheter tip. The example method  500  can be performed by an example system, as disclosed herein, a variation thereof, or an alternative thereto as would be appreciated and understood by a person of ordinary skill in the art. 
       FIG. 6  is a flow diagram illustrating an example method  600  of manufacturing a catheter tip according to one example of this disclosure. Step  610  of method  600  can include electroplating a conductive material over an insert being a negative to a domelike shape and thereby forming a shape of the catheter tip to be a dome with the domelike shape. The step of electroplating causes the insert to be encapsulated with the conductive material thereby forming the catheter tip. Step  620  of method  600  can include selectively positioning a plurality of irrigation holes between outer and inner surfaces of the catheter tip. Step  630  of method  600  can include electropolishing the catheter tip. 
       FIG. 7  is a flow diagram illustrating an example method  700  of manufacturing a plurality of catheter tips according to one example of this disclosure. Step  710  of method  700  can include electroplating a conductive material over a plurality of inserts comprising a negative to a domelike shape thereby forming a plurality of catheter tips having the domelike shape. The step of electroplating causing the inserts to be encapsulated with the conductive material thereby forming the catheter tips. Step  720  of method  700  can include selectively positioning a plurality of irrigation holes between outer and inner surfaces of the catheter tip. Step  730  of method  700  can include electropolishing the catheter tip. 
       FIG. 8  is a flow diagram illustrating an example method  800  of manufacturing a plurality of catheter tips according to one example of this disclosure. Step  810  of method  800  can include simultaneously performing any method previously described to manufacture the plurality of catheter tips. 
     In some examples, the insert can be formed by applying a negative photoresistive formed mask coating to the negative molded part at the location of each irrigation hole that is sized to irrigation hole target and wall thicknesses to account for lateral growth. In some examples, a 0.003″ hole in a 0.005″ thick dome can include a photoresist dot of 0.013″. A masked area of this example could prohibit surface plating on the masked area and permit annular growth from the surrounding palatable surface. By controlling the thickness of the plate and/or maintaining approximately 1:1 plate height:width ratio, the resulting hole size can meet the target. In this respect, a negative photoresist process can work by coating the negative molded part in a layer of photocrosslinking (e.g., SU-8 epoxy-based polymer) or photopolymeric (e.g., methyl methacrylate) material then exposing the hole pattern locations to an appropriate curing treatment (e.g., e-beam or UV light). In some examples, a photoresist developing agent can then be applied to remove the none-developed layers leaving only the resist layer in the pattern and sizing desired. In some examples, the electrode material may not grow from this surface so the irrigation hole can remain open. This example is particularly advantageous as it can leave an inset shape (e.g., a circle) on the inside of the created electrode of the diameter and thickness of the photoresist deposit used to create the irrigation hole, which can be created as the electrode metal grows over the edge of the photoresist coating. 
     The descriptions contained herein are examples of embodiments of the disclosure and are not intended in any way to limit the scope of the disclosure. As described herein, the disclosure contemplates many variations and modifications, including any of the herein discussed methods, steps, catheter tips, and solutions to manufacture a plurality of catheter tips simultaneously. These modifications would be apparent to those having ordinary skill in the art to which this disclosure relates and are intended to be within the scope of the claims which follow.