WO2009097448A1

WO2009097448A1 - Spraying technology

Info

Publication number: WO2009097448A1
Application number: PCT/US2009/032461
Authority: WO
Inventors: Michael Hicks; Seth Crozier
Original assignee: Machine Solutions Inc
Current assignee: Machine Solutions Inc
Priority date: 2008-01-30
Filing date: 2009-01-29
Publication date: 2009-08-06
Anticipated expiration: 2010-07-30

Abstract

A spray coating system and apparatus which has a housing, a sprayer for spraying a liquid on an article or device such as a medical stent, and an assembly for loading, holding, handling and moving the stent relative to the sprayer to provide a particular coating profile thereto. A mandrel based holder may be used with the stent. The system may be substantially automated. In use, an article or device such as a stent is manually or otherwise preloaded on a mandrel, the mandrel is placed in a loader, which transfers the preloaded mandrel to a handler. The handler linearly and rotatably moves the stent under a spray from the sprayer in a predetermined motion or motion profile. The handler then transfers the sprayed product and mandrel to an unloader for removal. The spray system, apparatus and method are particularly useful for spray coating drug or other compositions on medical stents.

Description

SPRAYING TECHNOLOGY

CROSS-REFERENCE TO RELATED APPLICATIONS, IF ANY

This application claims the benefit under 35 U. S. C. §119(e) of co-pending

US Provisional Patent Application Serial No. 61/062,900, filed 1/30/08, which is

hereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX, IF ANY

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention. The present invention relates, generally, to spraying or coating systems, apparatus and methods. Particularly, the invention relates to medical device manufacturing spray coating systems, apparatus and methods. Most particularly, the invention relates to a system, apparatus and methods for spray coating drug eluting stents. The systems, apparatus and methods may be useful in other applications and fields as well.

2. Background Information.

Various medical procedures exist which involve inserting devices into the vasculature of a patient. These include endoscopy, biopsy, angiography, angioplasty, atherectomy, and the like. Percutaneous transluminal coronary angioplasty (PTCA) is a form of angioplasty which is performed to reduce or eliminate blockages in coronary arteries and restore or improve blood to flow heart tissue. Arteries are accessed by advancing a catheter through a percutaneous needle puncture made in the groin to the femoral artery, or arm to the brachial artery. A balloon disposed on the catheter is placed to opening a blockage caused by plaque in a coronary artery and inflated to open the blockage. A stent is a tubular structure which is implanted at the blockage site via a catheter after angioplasty to keep the artery open and prevent regrowth of plaque or restenosis. Modern stents may contain one or more drugs or other bioactive agents to reduce or prevent restenosis. These stents are sometimes referred to as drug eluting stents. The drugs or agents are typically applied to the stent via spraying.

Existing spraying and coating technology in this field is believed to have significant limitations and shortcomings. For this and other reasons, a need exists for the present invention.

All US patents and patent applications, and all other published documents mentioned anywhere in this application are incorporated by reference in their entirety.

BRIEF SUMMARY OF THE INVENTION

The invention provides a spray coating system, apparatus and method which is practical, reliable, accurate, efficient, and safe, and which is believed to fulfill the need and to constitute an improvement over the background technology.

The system, apparatus and method a suitable for processing and manufacturing medical devices, and best suited for spray coating stents and related medical devices. The spray coating system provides an integrated solution for precision coating of stents and other medical devices. The system delivers consistent coating uniformity by minimizing variability due to tooling and motion control. A single step coating process eliminates stent flipping and related defects. The system accommodates air-assist, ultrasonic and needle dispensing technology to deliver any drug/polymer chemistry. The scalable machine base is configurable to suit manual, R&D use as well as higher volume automated production. The system includes easy-to-use software with intuitive touch screen controls requiring minimal user training. The system is constructed with pharmaceutical grade components and precision motion systems to facilitate equipment and process validation. Optional enclosure configurations include sealed spray chamber, exhaust system with filtration, and glove box with pass through. The system can be used in production coating, coating process development engineering and research and development coating.

In a basic aspect, the invention provides a system or apparatus for spray coating articles such as stents which includes a base, a sprayer for spraying a liquid on an element or product, and a holder for supporting and moving the element relative to the sprayer for full and uniform coverage.

In another basic aspect, the invention provides a method of spray coating articles such as stents which includes the steps of manually or otherwise preloading the stent on a mandrel, placing the mandrel on a loader, which transfers the preloaded mandrel to the holder. The holder linearly and rotatably moves the product under a spray from the sprayer in a predetermined motion. And, the holder then transfers the sprayed product and mandrel to an unloader for removal.

The aspects, features, advantages, benefits and objects of the invention will become clear to those skilled in the art by reference to the following description, claims and drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

Figure 1 is a perspective view of an embodiment of the spray coating system of the present invention.

Figure 2 is another perspective view of the system.

Figure 3 is a front, elevation view of the spray coating system.

Figure 4 is a top, plan view of the spray coating system.

Figure 5 is a left end or side view of the spray coating system. Figure 6 is a right end view of the system.

Figure 7 is a front, elevation view of an embodiment an element handling and spraying section of the present invention used with the system of the present invention.

Figure 8 is a left end view of element handling and spraying section, partially in section along line 8-8 of Figure 7.

Figure 9 is a detailed view of a portion of the element and spraying section taken at area 9 of Figure 8.

Figure 10 is a right end or side view of the element handling and spraying section.

Figure 11 is a front view, partially in section along line 11-11 of Figure 10, of the element handling and spraying section.

Figure 12 is a detailed view of a portion of the element handling and spraying section shown at area 12 of Figure 11.

Figure 13 shows an embodiment of an operator control interface of the system of the invention. DETAILED DESCRIPTION

Figures 1-6 show a preferred embodiment of a spray coating system 10 of the present invention. The system 10 is useful for spraying liquid and semi- liquid compositions on devices, articles, structures or elements. The system 10 is particularly useful for coating medical mechanical elements, articles or devices such as stents and the like. Compositions which may be utilized and sprayed by the system 10 include one or more drugs, pharmaceuticals, or bioactive agents that provide a therapeutic pharmaceutical function to the stent. Compositions may also include primers, sealers and the like, either alone or in combination with each other or with bioactive agents. The system 10 may be used to spray a plurality of compositions on the stent in a step wise process or in certain cases simultaneously.

The system 10 comprises a housing 20, an element handling and spraying assembly 30 including loading , handling, moving, spraying and unloading means, , and various power and control means. In use, a product, element or article such as a stent 15 is preloaded, manually or otherwise on a mandrel , which is preferably a thin, elongated rod of a predetermined diameter and length, the mandrel with pre-loaded stent is loaded, moved, sprayed, and then unloaded. The process is preferably automated, but may include one or more manual and override steps.

One embodiment of the housing 20 has a base 21 set of legs 22a-d, a work top 23, an electronics cabinet 24 disposed below the work top, and a shield cabinet 25 enclosing a predetermined area of the work top 23. The shield 25 preferably has a clear front panel 26 that is closeable to cover a predetermined portion of the front of the shield 25. The cabinet 25 protects the spray process from the external environment, as well as protecting the external environment, and user, from the spraying process.

Referring also to Figure 13, an adjustable electronic control and monitor panel is also preferably adjustably disposed on the base 21. The control/monitor panel 27 is communicatively connected to electronic power and control systems disposed in cabinet 24. The panel 27 is used by an operator/user to monitor and control use of the system 10.

Referring to Figures 1-3 and 7, a preferred embodiment of the element handling and spraying assembly 30 of the spray coating system 10 is shown. The assembly 30 receives the article to be sprayed, moves it in a predetermined pattern in cooperation with spraying whereby the article is coated, and deposits the sprayed article for removal and/or other processing. Referring also to Figures 8 and 10, in addition to the mandrel 40 for holding the article 45 to be sprayed, the assembly 30 basically comprises a loading assembly 50 for loading and unloading the mandrel/article combination 40/45, a handling assembly 60 for moving the mandrel/article 40/45 in a predetermined pattern or profile, and a spraying assembly 80 for spraying the article 45 in cooperation with the handling assembly 60.

Referring also to Figure 12, the mandrel 40 serves as a primary support vehicle for the article 45 which is processed by the system 10. In a preferred embodiment, it has an end element 41 which has a predetermined configuration for cooperative engagement with the handling assembly 60, and a wire element 42 which is connected to the end element 41 and extends therefrom. The end element 41 is preferably constructed of a metal whereby it may be magnetically engaged by the handling system 60 as described in details below. The wire element 42 is preferably constructed of Nitinol and has a predetermined length and diameter. In a preferred use method, the article 45, for example a stent, is slid over the wire element 41 , manually, by a user/operator.

Referring also to Figure 11, the loading assembly 50 preferably comprises first and second loader/holder platforms 51 a and b, and a drive mechanism 55. The loader/holder platforms 51 are substantially identical and disposed a predetermined distance apart on the work top 23. Each loader/holder 51 includes a base 52, a cradle 53 disposed on top of the base 52, and an actuator arm 54 which extends downwardly from the base 52 through an aperture in the work top 23. The actuator arm 54 is connected to an actuator/drive mechanism 55 which is disposed below the work top 23. The cradle 53 has a pair of upwardly extending arms 56 which has a predetermined profile at its top end for supporting the mandrel 40. In a preferred use, the mandrel 40 is placed on the first loader/holder platform 51a manually at the start of a coating procedure, when the first platform

5 Ia is in a normal, down position. The system 30 transfers the mandrel 40 (and article 45) to the second loader/holder platform 51b during processing as will be described further below, and the mandrel 40 is manually removed therefrom at the end of processing. This involves, generally, the first platform 5 Ia moving upward to transfer the mandrel 40 to the handling assembly 60 and then moving downward after transfer to be clear of the handling assembly 60. Subsequently, the second platform 5 Ib moves from its normally down position to an up position under the handling assembly 60, whereupon the handling assembly 60 disengages the mandrel 40 and the mandrel 40 rest in the second cradle of the second platform 5 Ib. Finally, the second platform 5 Ib moves back to its down position.

The handling assembly 60 comprises a pair of arm assemblies 61a and b, and an actuator/drive mechanism 71 for imparting linear (horizontal motion from the perspective of Figure 7) and rotational motion thereto. The arm assemblies 61 a and b extend through a horizontal slot 13 in vertical plate 14. Each arm assembly 61 preferably comprises an elongated first member 62 that extends through the slot 13 and a shorter second member 63 that is disposed at and oriented at a right angle to the outward end of the first member 62. As is best shown in Figure 12, each second member 63 has a collet 64 disposed at its distal end, the collet 64 including a collet holder 65, a collet nut 66 and a collet knob 67. First arm 61a (at the Left in Figures 11 and 12) has a magnetic holding function with respect to the mandrel 40 connection, by way of a holder 68 and a disc magnet 69. Second arm 61b at the Right (again with respect to Figures 11 and

12) has a guiding function for connection to the mandrel 40. The collet 64b ha a guide 70 that engages the terminal end of the wire element 42 of the mandrel 40.

Referring to Figures 8-10, each arm assembly 61 is shown to be belt driven by a servo motor 32. This allows the collet 16 to rotate synchronously or asynchronously depending on process requirements. The arms 61 are moved linearly and horizontally together to receive a preloaded mandrel 40 from the vertically moveable mandrel loader 51 a, and move the mandrel 40 under the spraying assembly 80 in a predetermined sequence of at least one pass, continuous or otherwise, and at a predetermined speed. After the spraying process, the handling assembly arms 61a and b move, in tandem, the mandrel 40 to unloader platform 5 Ib, which is also preferably vertically movable.

Referring again to Figure 12, a preferred embodiment of the mandrel engagement handling and rotating features of the handling assembly 60 . The magnetic mandrel holder end of second arm assembly 61a has a through hole 22 with a conical shaped "lead in" configuration. The magnetic mandrel holder of first arm 61a has a counter bore 26 feature allowing magnet 69 to be pressed in. The magnetic end element41 of mandrel 40 is preferably made of magnetic 17-4 stainless steel which allows it to be pulled into the conical lead of the magnetic mandrel holder 61b and permits an automated loading process. The Nitinol wire element 41 of mandrel 40 is a press fit into the magnetic mandrel end 42. The right side arm 61b is configured substantially similar to the left 61a, except that the magnetic mandrel holder is replaced with the wire guide 70. The wire guide 70 has a conical lead in like the magnetic mandrel holder 64a, but has a smaller through hole and doesn't have a magnet pressed in. The purpose of the wire guide 30 is to support the right hand side of the mandrel assembly 40 to prevent run out. Radial run out typically causes the stent to shift position under the spray pattern and can limit the length of the product 45 being coated.

The spraying assembly 80 comprises a nozzle 81, a nozzle arm 82, reservoir 83, delivery path 84, a drive mechanism 85, and an actuator 86. The nozzle arm 82 that holds the spray nozzle 81 or other dispensing mechanism uses the actuator 86, for example a vertical nozzle adjusting lead screw)that allows the spray nozzle 82 to extend through vertical slot 39 and over the product 45 being coated. This is beneficial because the spray pattern can be turned on and when it reaches a stable state it is extended over the product 45. The height of the nozzle 81 above the product 45 is adjustable.

Figures 7-9 best show preferred embodiments of drive and motion control features of the handling and spraying assembly 30. As mentioned before, each arm 61 has a rotary servo motor 73 which through belt drive connection 76 produces rotational motion of the product, for example a stent 45, being coated. This belt drive 76 keeps the motor 73 behind the vertical plate 14 and reduces the number of components exposed to the spray solution that need to be cleaned. The linear motion of the machine 30 is a result of the linear motor 74 and linear encoder 75. There are two forcers on a linear motor shaft, one forcer for each arm 61 allowing the arms 61 to move linearly in a synchronous or asynchronous manner.

Figure 13 shows an embodiment of an operator control interface 60 of the system 10 of the invention provided by monitor 27.

Returning to Figures 1 and 2, the system 10 preferably further includes venting means, particularly center 31, front 32 and rear 33 vents, which is preferably integrated with the top 23 of base 21. The system 10 may be combined with product input, product inspection, automation, and other known accessories.

A basic embodiment of the method of use of the system 10 comprises the steps of manually or otherwise preloaded a mandrel 40 by connecting an article 45 to the mandrel, and placing the mandrel 40 in a loader 50. Afterwards, the loader 50 transfers the preloaded mandrel 40 to a handler 60 . The handler 60 holds and linearly and rotatably moves the mandrel under a spray from a sprayer 80 in a predetermined motion. The handler 60 then transfers the sprayed product 45 and mandrel 45 to an unloader, for example a separate portion of loader 50, for removal and/or other processing.

In a preferred embodiment of the method of the invention, stent 45 is placed on wire element 42 of mandrel 40. The mandrel 40 is then placed on first platform 5 Ia of loading assembly 50, while the platform 5 Ia is in an initial down position. The wire element 41 is placed on cradle of the platform 51a, for example in a holding profile at the upward distal ends of arms 56a and b. An automated spray cycle is started by actuating "Start Auto Spray" on control panel 27. The platform 5 Ia raises to a predetermined level where the wire element 42 is aligned with the collets 64 of the arm assemblies 61 of handling assembly 60. The arms 61a and b move inwardly towards each other from their initial spread apart position, and the collet ends engage the mandrel 40. Magnetic end element 41 is drawn to and mates with collet 64 of left arm 61a. Distal end of wire element 42 is guided into and mates with collet 64 of right arm 61b. Platform 51a lowers to its initial position. Arm assembly 61 linearly and horizontally to the right (in Fig. 7 for example) to a point where the front or right-most end of the mandrel is directly below spray nozzle 81 of spray assembly 80. The collets of arms 61 are actuated to rotate the mandrel/stent 40/45. The spray arm 82 then may move to adjust the vertical position of the nozzle 81 a predetermined distance above the mandrel 40 and spraying of the rotating stent 45 begins at a predetermined flow rate of composition from the reservoir 83. Simultaneously, the arm assembly 61 resumes advancement linearly and horizontally to the right, at a predetermined speed, whereby spray is deposited along the length of the stent 45. The arm assembly 61 may reverse course one or more times to add one or more additional coats to the stent. After a the predetermined spray profile is completed, the nozzle arm 82 is raised (if it was previously lowered) so that the nozzle 81 is free and clear of the mandrel 40. The arm assembly 61 one then moves the mandrel 40 further to the right until is aligned over platform 51 b of the loading assembly 50. Platform 5 Ib is moved upwardly from its initially down position. The arms 61a and b spread apart as their collets release the mandrel 40, which rests on the cradle 53 of platform 51b. Platform 51b then lowers to its down position. The arm assembly 61 then returns to its initial position on the left side of the assembly 30. The mandrel 40 is then removed from the cradle 53 of platform 51b. The stent is then removed, manually for example, from the mandrel 40. Alternatively, the stent 45 may be further processed while still on the mandrel 40.

The system 10 provides several advantage including single step coating and does not require flipping of a stent 45 from end to end, consistent coating uniformity, compatibility with air-assist, ultrasonic and needle dispensing technology, PC control with touch screen operator interface, ease of maintenance and cleaning and precision operation that is ready for automated production use.

The descriptions above and the accompanying materials should be interpreted in the illustrative and not the limited sense. While the invention has

Claims

been disclosed in connection with the preferred embodiment or embodiments thereof, it should be understood that there may be other embodiments which fall within the scope of the invention.CLAIMSThe invention claimed is:

1. An apparatus for spraying a tubular article or device comprising a handler for holding and linearly and rotational moving the tubular article, and a sprayer for spraying the tubular article while it is being held in place or moved.

2. The apparatus of claim 1, wherein the tubular article or device is a medical stent.

3. The apparatus of claim 1, wherein the handler comprises an engagement assembly for holding the tubular article or device and an actuator for linearly and rotationally moving the engagement assembly with respect to the sprayer.

4. The apparatus of claim 3, wherein the engagement assembly comprises a pair of arms, each arm engaging an end of the tubular article or device.

5. The apparatus of claim 4, wherein the arms are separately movable to move towards or away from each other.

6. The apparatus of claim 4, wherein each arm has a collet for engaging the tubular article or device.

7. The apparatus of claim 6, wherein at least one collet has magnetic means to engage the tubular article or device.

8. The apparatus of claim 3, wherein the actuator comprises a rotary servo motor for rotating the tubular article or device, and a linear motor for linearly moving the engagement assembly.

9. The apparatus of claim 1, wherein the sprayer comprises a reservoir and a spray nozzle communicatively connected to the reservoir.

10. The apparatus of claim 9, wherein the spray nozzle is moveable with respect to the handler to adjust spray distance between the spray nozzle and the tubular article or device.

11. The apparatus of claim 1 , further comprising a holder for the tubular article or device, the mandrel being held and moved by the handler.

12. The apparatus of claim 11 wherein the holder comprises a mandrel upon which the tubular article or device is disposed.

13. The apparatus of claiml2, wherein the mandrel comprises a magnetic connection element and a wire element connected to and extending from the magnetic connection element, the tubular element being slidable over the wire element.

14. The apparatus of claim 1 , further comprising a loading and unloading mechanism for delivering the tubular article or device to the handler before spraying and for receiving the tubular article or device from the handler after spraying.

15. The apparatus of claim 14, wherein the loading and unloading mechanism comprises a first and second support devices which are each movable towards and away from the handler to deliver or receive the tubular article or device thereto or therefrom, respectively.

16. The apparatus of claim 1, wherein: a. the tubular article or device is a medical stent; b. the handler comprises an engagement assembly for holding the tubular article or device and an actuator for linearly and rotationally moving the engagement assembly with respect to the sprayer;

i.. wherein the engagement assembly comprises a pair of arms, each arm engaging an end of the tubular article or device; ii. wherein the arms are separately movable to move towards or away from each other; iii. wherein each arm has a collet for engaging the tubular article or device; iv. wherein at least one collet has magnetic means to engage the tubular article or device; and v. wherein the actuator comprises a rotary servo motor for rotating the tubular article or device, and a linear motor for linearly moving the engagement assembly. c. the sprayer further comprises a reservoir and a spray nozzle communicatively connected to the reservoir, and wherein the spray nozzle is moveable with respect to the handler to adjust spray distance between the spray nozzle and the tubular article or device; d. the apparatus further comprises a holder for the tubular article or device, the mandrel being held and moved by the handler; i. wherein the holder comprises a mandrel upon which the tubular article or device is disposed; and ii. wherein the mandrel comprises a magnetic connection element and a wire element connected to and extending from the magnetic connection element, the tubular element being slidable over the wire element; and e. the apparatus further comprises a loading and unloading mechanism for delivering the tubular article or device to the handler before spraying and for receiving the tubular article or device from the handler after spraying, and wherein the loading and unloading mechanism comprises a first and second support devices which are each movable towards and away from the handler to deliver or receive the tubular article or device thereto or therefrom, respectively.

17. A method for spraying a tubular article or device comprising the steps of holding and linearly and rotational moving the tubular article, and spraying the tubular article while it is being held in place or moved linearly and rotationally.

18. The method of claim 17, wherein the tubular article or device is a medical stent.

19. The method of claim 17, further comprising the step of placing the tubular article or device on a mandrel before holding and moving.

20. The method of claim 19 further comprising the step of automatically loading the mandrel before holding and moving the tubular article or device and automatically unloading the mandrel after spraying.