U.S. patent application number 10/190975 was filed with the patent office on 2004-01-08 for vertical stent cutting process.
Invention is credited to Merdan, Kenneth M..
Application Number | 20040004063 10/190975 |
Document ID | / |
Family ID | 29999938 |
Filed Date | 2004-01-08 |
United States Patent
Application |
20040004063 |
Kind Code |
A1 |
Merdan, Kenneth M. |
January 8, 2004 |
Vertical stent cutting process
Abstract
A system and method for processing a tubular member for
producing a medical device, wherein the tubular member is oriented
in a longitudinally vertical position during processing.
Inventors: |
Merdan, Kenneth M.;
(Greenfield, MN) |
Correspondence
Address: |
VIDAS, ARRETT & STEINKRAUS, P.A.
6109 BLUE CIRCLE DRIVE
SUITE 2000
MINNETONKA
MN
55343-9185
US
|
Family ID: |
29999938 |
Appl. No.: |
10/190975 |
Filed: |
July 8, 2002 |
Current U.S.
Class: |
219/121.67 |
Current CPC
Class: |
B23K 26/146 20151001;
B23K 2103/50 20180801; B23K 2103/42 20180801; B23K 26/38 20130101;
B08B 11/02 20130101; B23K 2101/06 20180801; A61F 2/91 20130101;
B23K 26/142 20151001; B23K 26/147 20130101; B23K 26/16
20130101 |
Class at
Publication: |
219/121.67 |
International
Class: |
B23K 026/38 |
Claims
1. A system for removing material from a tubular member according
to a predetermined pattern, the invention comprising orienting the
tubular member in a substantially longitudinal vertical position
during removal of the material.
2. The system of claim 1 further comprising a guide mechanism, the
guide mechanism defining a guide chamber, at least a portion of the
tubular member being inserted into the guide chamber.
3. The system of claim 1 further comprising a media flow, the media
flow being a fluid directed on or about the tubular member
insertion port.
4. The system of claim 3 wherein the fluid is selected from at
least one member of the group consisting of: a gas, a liquid, a
liquid solution, a suspension and any combination thereof.
5. The system of claim 2 wherein the guide chamber has a variable
diameter.
6. The system of claim 5 wherein the guide mechanism comprises at
least two portions, the at least two portions being moveable
relative to one another to provide for the variable diameter of the
guide chamber.
7. The system of claim 6 wherein the at least two portions define a
guide chamber having a substantially circular cross section.
8. The system of claim 6 wherein the at least two portions define a
guide chamber having a substantially diamond shaped cross
section.
9. The system of claim 8 wherein the guide chamber defines an
adjustable slot.
10. The system of claim 1 wherein an end of the tubular member is
removably engaged to a securement device, the securement device
being engaged to a drive shaft.
11. The system of claim 1 further comprising a laser, the laser
constructed and arranged to transmit laser energy to the tubular
member to thereby remove the material from the tubular member
according to a predetermined pattern.
12. The system of claim 10 wherein the laser is selected from at
least one member of the group consisting of YAG lasers, diode
lasers, CO.sub.2 lasers, IR lasers, UV lasers, laser/water jet
hybrids and any combinations thereof.
13. The system of claim 1 wherein the tubular member is constructed
at least partially from metal.
14. The system of claim 1 wherein the tubular member is constructed
at least partially from a polymer.
15. The system of claim 2 wherein the media flow is passed through
the tubular member.
16. The system of claim 2 wherein the media flow is constructed and
arranged to remove debris buildup within the tubular member.
17. The system of claim 2 wherein the media flow is constructed and
arranged to cool the tubular member during removal of the material
therefrom.
18. The system of claim 2 wherein the media flow is selected from
at least one member of the group consisting of: lubricants,
oxidizers, cleaners, polishing agents, pretreatments and any
combination thereof.
19. The system of claim 1 wherein the tubular member is a stent or
a component thereof.
20. The system of claim 1 wherein the tubular member is a catheter
or a portion thereof.
21. A method for removing material from a tubular member according
to a predetermined pattern, the invention comprising the step of
orienting the tubular member in a substantially longitudinal
vertical position during removal of the material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] A stent is a radially expandable endoprosthesis which is
adapted to be implanted in a body lumen. Stents are typically used
in the treatment of atherosclerotic stenosis in blood vessels and
the like to reinforce body vessels and to prevent restenosis
following angioplasty in the vascular system. They have also been
implanted in urinary tracts, bile ducts and other bodily lumen.
They may be self-expanding or expanded by an internal radial force,
such as when mounted on a balloon.
[0004] Delivery and implantation of a stent is accomplished by
disposing the stent about a distal portion of the catheter,
percutaneously inserting the distal portion of the catheter in a
bodily vessel, advancing the catheter in the bodily lumen to a
desired location, expanding the stent and removing the catheter
from the lumen. In the case of a balloon expandable stent, the
stent is mounted about a balloon disposed on the catheter and
expanded by inflating the balloon. The balloon may then be deflated
and the catheter withdrawn. In the case of a self-expanding stent,
the stent may be held in place on the catheter via a retractable
sheath. When the stent is in a desired bodily location, the sheath
may be withdrawn allowing the stent to self-expand.
[0005] In the past, stents have been generally tubular but have
been composed of many configurations and have been made of many
materials, including metals and plastic. Ordinary metals such as
stainless steel have been used as have shape memory metals such as
Nitinol and the like. Stents have also been made of bio-absorbable
plastic materials. Stents have been formed from wire, tube stock,
etc. Stents have also been made from sheets of material which are
rolled.
[0006] A number of techniques have been suggested for the
fabrication of stents from sheets and tubes. One such technique
involves laser cutting a pattern into a sheet of material and
rolling the sheet into a tube or directly laser cutting the desired
pattern into a tube. Other techniques involve cutting a desired
pattern into a sheet or a tube via chemical etching or electrical
discharge machining.
[0007] Laser cutting of stents has been described in a number of
publications including U.S. Pat. No. 5,780,807 to Saunders, U.S.
Pat. No. 5,922,005 to Richter and U.S. Pat. No. 5,906,759 to
Richter. Other references wherein laser cutting of stents is
described include: U.S. Pat. No. 5,514,154, U.S. Pat. No.
5,759,192, U.S. Pat. No. 6,131,266 and U.S. Pat. No. 6,197,048.
[0008] An example of a conventional laser for cutting a stent is a
highly focused pulsed Nd:YAG laser which has a pulse duration in
the range of approximately 0.1 to 20 milliseconds. This is a long
pulse time for cutting and characteristically produces a relatively
large melt zone and heat affected zone (HAZ) on the metal. The
conventional laser cutting process typically results in the
formation of melt dross on the inside edge of the cut tube. This
dross must be cleaned off in subsequent processes.
[0009] Past laser cutting systems typically mount the tube to be
cut from a spindle shaft in a horizontal orientation wherein the
laser is mounted perpendicular to the longitudinal axis of the tube
in a downward looking configuration. Such a horizontal orientation
of the stent tube has many drawbacks.
[0010] For example, as the tube is being cut, dross and other
debris may accumulate in the tube interior. This requires a stream
of water to flush the tube to wash away the debris. The horizontal
orientation of the tube additionally exacerbates the problem of
ridding debris from the tube as debris must be actively driven out
the open end of the tube. This necessitates the flushing stream be
applied with significant pressure to ensure that debris does not
clog the tube end.
[0011] Another more serious drawback is that in some cases,
particularly in longer tubes, the tube may tend to bow as a result
of gravity. Such bowing may interfere with the precise nature of
the stent cutting process, resulting in cutting errors or more
significant damage to the tube/stent. In addition, as the tube is
rotated during cutting, any bowing of the tube will cause the
unsecured end of the tube to oscillate resulting in excess strain
being placed on the tube, and potentially leading to improper
cutting and/or the formation of cutting imperfections.
[0012] In light of the above a need exists to provide a laser
cutting/processing system wherein the potential for tube bowing and
tube oscillation is minimized or removed completely, and where
cutting debris such as melt dross is more easily and consistently
removed from the tube during processing.
[0013] All US patents and applications and all other published
documents mentioned anywhere in this application are incorporated
herein by reference in their entirety.
[0014] Without limiting the scope of the invention a brief summary
of some of the claimed embodiments of the invention is set forth
below. Additional details of the summarized embodiments of the
invention and/or additional embodiments of the invention may be
found in the Detailed Description of the Invention below.
[0015] A brief abstract of the technical disclosure in the
specification is provided as well only for the purposes of
complying with 37 C.F.R. 1.72. The abstract is not intended to be
used for interpreting the scope of the claims.
BRIEF SUMMARY OF THE INVENTION
[0016] The present invention is directed to a variety of
embodiments. In at least one embodiment the invention is directed
to a system for cutting, etching and/or otherwise processing a
hollow metal tube for manufacturing a stent, wherein the tube/stent
is positioned with its longitudinal axis in a vertical orientation
relative to the ground. Such vertical orientation allows gravity to
help maintain at least the free end the tube/stent in a stable
position through out the cutting process.
[0017] In some embodiments of the invention the tube being cut may
be at least partially, and even entirely, constructed of a
polymer.
[0018] Vertical orientation of the tube also encourages dross and
other debris formed during cutting to be gravitationally drawn out
of and away from the tube continuously through out the laser
cutting process.
[0019] In some embodiments a stream of fluid or other media may be
poured or injected through the lumen of the tube to cool the tube,
provide increased stability to the tube, and/or assist in removing
debris from the tube.
[0020] As indicated above, in some embodiments the tube is cut or
machined by a laser, such as a YAG, IR, UV, diode, CO.sub.2 or
other type of laser. In at least one embodiment the stent cutting
system utilizes a hybrid laser/water jet mechanism to direct laser
energy to the tube through a column of fluid such as water. Such
laser/water jet systems are known and are commercially available
from SYNOVA Inc., of Lausanne, Switzerland. The SYNOVA system
utilizes a laser beam that is contained within a water jet as a
parallel beam, similar in principle to an optical fiber.
[0021] In some embodiments the flow of fluid or other media through
the tube lumen will help protect the tube interior from potential
damage caused by the cutting laser by disrupting the water jet and
laser energy transmitted therethrough. Such use of a media flow in
conjunction with a laser/water jet hybrid system is described in
greater detail in a co-pending Patent Application filed
simultaneously herewith entitled Tubular Cutting Process and
System.
[0022] In some embodiments a collar or guide defines a chamber
which at least a portion of the free end of the tube is inserted.
The guide may be utilized to stabilize and/or minimize oscillations
or other disruptive movement of the free end of the tube during the
cutting process.
[0023] In some embodiments a nozzle or other attachment sprays a
fluid onto and/or through the tube.
[0024] Where a fluid is sprayed or otherwise directed onto or
through the tube, the fluid may be act as an oxidizer, cleaner,
polishing agent, pretreatment or other solution. In some
embodiments the fluid aids in removing debris from the tube during
processing.
[0025] In various embodiments the guide and the chamber defined
thereby, may have a variety of shapes and sizes to accommodate
tubes of different configurations. In at least one embodiment the
guide is split, having at least two portions. The portions may be
variably positioned to allow the guide to receive a wide variety of
tube diameters therein.
[0026] In at least one embodiment the guide is one or more coils of
a formed wire(s) which are disposed about at least a portion of the
tube.
[0027] These and other embodiments which characterize the invention
are pointed out with particularity in the claims annexed hereto and
forming a part hereof. However, for a better understanding of the
invention, its advantages and objectives obtained by its use,
reference should be made to the drawings which form a further part
hereof and the accompanying descriptive matter, in which there is
illustrated and described embodiments of the invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0028] A detailed description of the invention is hereafter
described with specific reference being made to the drawings.
[0029] FIG. 1 is a side view of an embodiment of the invention.
[0030] FIG. 2 is a cross-sectional view of an example of a guide
mechanism.
[0031] FIG. 3 is a perspective view of an example of a variable
diameter guide mechanism.
[0032] FIG. 4 is a top down cross-sectional view of the guide
mechanism of FIG. 3 shown in use with a tube of a first
diameter.
[0033] FIG. 5 is a top down cross-sectional view of the guide
mechanism of FIG. 3 shown in use with a tube of a second
diameter.
[0034] FIGS. 6 and 7 show an example shape of a guide
mechanism.
[0035] FIGS. 8 and 9 show an example shape of a guide
mechanism.
[0036] FIG. 10 shows another example of a guide mechanism.
DETAILED DESCRIPTION OF THE INVENTION
[0037] While this invention may be embodied in many different
forms, there are described in detail herein specific preferred
embodiments of the invention. This description is an
exemplification of the principles of the invention and is not
intended to limit the invention to the particular embodiments
illustrated.
[0038] For the purposes of this disclosure, like reference numerals
in the figures shall refer to like features unless otherwise
indicated.
[0039] As indicated above the present invention is directed to a
variety of embodiments. In at least one embodiment, shown in FIG.
1, the invention is directed to a mechanism (system), indicated
generally at 10, for processing and/or cutting a hollow tubular
body 12 into a medical device such as a stent.
[0040] In the embodiment shown, the hollow tubular body 12 may be
any type of tube suitable for laser processing and/or cutting. Such
a tube 12 may be a tubular member suitable for the construction of
a stent, graft, stent-graft, vena cava filter, hypo tube, catheter
or component thereof, or any other device suitable for insertion
and/or implantation into a body lumen. Where the tube 12 is
intended for the construction of a stent, the tube 12 will
typically be at least partially constructed from a metal such as
stainless steel, nickel, titanium, palladium, gold, tantalum, or
any other metal or alloy thereof. However, other materials may be
alternatively or additionally used, such as one or more polymers.
In at least one embodiment tube 12 is constructed of a
nickel-titanium alloy such as nitinol.
[0041] Where tube 12 is at least partially constructed from one or
more polymer substances, the substances may include, but are not
limited to the following examples: polyester/polyether elastomers
such as Arnitel.TM. available from DSM Engineering;
polyurethane-polyether polymers, such as Tecothane.TM. and/or
Tecoplastm both being available from Thermedics, Inc.;
polyester-polyurethanes, such as Pellethane.TM. sold by Dow
Chemical; polyester-polyurethanes, such as Estane sold by BF
Goodrich; polyether block amides (PEBA), such as Pebax.TM.
available from Elf Atochem; styrene15 butadien-styrene triblock
copolymers, such as Kraton.TM. sold by Shell Chemical company;
styrenic block copolymers; polyurethanes; silicone rubber; natural
rubber; copolyesters; polyamides; EPDM rubber/polyolefin; nitril
rubber/PVC; fluoroelastomers; butyl rubber; epichlorohydrin; block
copolymers; polyethylene terephthalate (PET); polyethylene
naphthalate (PEN); polybutylene terephthalate (PBT);
polytrimethylene terephthalate (PTT); poly lactic acid (PLA);
fluoropolymers; polyolefins; polystyrene; polyvinyl chloride (PVC);
acrylonitrile-butadiene-styrene polymers; polyacrylonitrile;
polyacrylate; vinyl acetate polymer; cellulose plastics;
polyacetal; polyethers; polycarbonates; polyphenylene sulfide;
polyarylethersulfones; polyaryletherketones;
polytetrafluoroethylene; polyamide copolymer, such as MXD6.TM.
available from Mitsubishi Gas Chemical Co. or Cristamid.TM.
available from Atofina; shape-memory polymers; liquid crystal
polymers; bio-absorbable polymers; radiopaque polymers; MRI-visible
polymers; etc.
[0042] Tube 12 may also include various coatings or surface
materials, such as drug and/or drug vectors, lubricants, etc.
[0043] Regardless of the particular composition or the type of
material used for tube 12, in accordance with the present invention
the tube is processed or cut while positioned in a substantially
longitudinal vertical orientation, such as is shown. Longitudinally
vertical position as used herein means that tube is positioned
relative to the ground such that the longitudinal axis of the tube
is substantially perpendicular to the plane of the ground.
[0044] Vertical orientation of the tube during the cutting process
provides an increase in processing efficiency, particularly by
employing gravity to prevent tube bowing, encourage dross removal
from the tube, and reduce oscillations at the free end of the tube
as it rotates.
[0045] In the embodiment shown the tube 12 is mounted at a first
end 14 to a affixing device 16 of a rotary spindle or shaft 18 of a
processing mechanism. During the cutting process the shaft maybe
rotated as well as moved vertically in an upwards and/or downwards
direction according to a predetermined pattern. The movement of the
shaft 18 causes the tube 12 to be moved relative to a laser or
other cutting mechanism 20.
[0046] In some embodiments the laser 20 may be moveable relative to
the tube 12. In some embodiments the laser 20 may be capable of
directing laser energy, indicated by arrow 22, to the tube 12 from
multiple angles and/or directions.
[0047] In the embodiment shown in FIG. 1, laser 20 directs laser
energy 22 to the tube 12. As tube 12 is moved via the predetermined
movement pattern of shaft 18 the laser energy 22 cuts a
corresponding pattern into the tube 12. As indicated above laser 20
may be any type of laser, such as a YAG, diode, IR, UV, CO.sub.2,
or other type of laser. In at least one embodiment laser 20 is a
hybrid laser/water jet such as is available from SYNOVA Inc., of
Lausanne, Switzerland and described in co-filed U.S. Patent
Application entitled Tubular Cutting Process and System.
[0048] Where laser 20 is a laser/water jet hybrid, in some
embodiments the vertical orientation of the tube 12 will help
prevent damage to the tube interior as gravity will tend to draw
the water column down and thus deflect the laser energy contained
therein. Deflection of the laser energy may be further encouraged
by applying a fluid or media flow through the tube interior such as
is described in greater detail below.
[0049] During the cutting process dross and other debris particles
24 are formed. The unique orientation of the tube 12 will assist in
the removal of dross from the tube 12 as gravitational pull will
tend to draw the dross downward and out of the tube 12. A flow of
fluid, such as a gas, liquid solution, suspension or other media,
indicated by arrow 26 and hereinafter referred to as a media flow,
may be applied to the tube to further encourage removal of debris
24. Media flow 26 may also act to cool the tube 12 during
processing.
[0050] In some embodiments, the media flow 26 is directed through
the lumen 28 that the hollow tube 12 defines. Dross and other
debris particles 24 that extend into the lumen 28 may be caught in
the media flow 26 and pass through the lumen 28 out the free end 30
of the tube 12. In some embodiments waste particles, such as debris
24 may be collected in a filter 32 which allows media flow 26 to
pass therethrough for reclamation or disposal. Filter 32 may also
be utilized to receive the tubular member 12 following
processing.
[0051] In some embodiments, media flow 26 may be directed to any
portion or surface of the tube 12.
[0052] The vertical orientation of the tube 12 allows system 10 to
operate by using gravity to drive media flow 26 through tube 12.
However, if desired media flow 26 may be applied under any desired
pressure.
[0053] As indicated above, in prior horizontal orientation tube
cutting systems, bowing of the tube during the cutting process may
result in significant damage to the tube resulting in the final
stent product being improperly cut. The vertical orientation
employed by the present system 10 avoids bowing of the tube 12 as
gravity will tend to keep the tube in its natural straight
orientation. However, it is recognized that in some cases the free
end 30 of the tube 12 or portions thereof, will whip or oscillate
as the tube 12 is spun and moved in accordance with the
predetermined cutting pattern. Such unrestricted movement may be
detrimental to accurate cutting.
[0054] To ensure that such unrestricted movement is minimized or
prevented, some embodiments of the present invention include a
guide mechanism or collar 40. Guide 40 is a tubular member which
defines a guide chamber 42 into which the free end 30 of the tube
12 or a portion thereof, is inserted. Preferably guide 40 is
fixedly mounted to a surface of mechanism 10, but in some
embodiments the guide may moveable relative to the tube 12. During
processing of the tube 12 the guide 40 prevents the free end 30 of
the tube 12 from experiencing excessive horizontal movement outside
the scope of the predetermined cutting pattern.
[0055] In another embodiment shown in FIG. 2, a fluid nozzle 48 may
be positioned adjacent to the guide 40. Nozzle 48 is utilized to
inject media flow 26 into and/or around tube 12 during
processing.
[0056] In some embodiments media flow 26 may also act as a
lubricant, oxidizer, cleaner, polishing agent, and/or
pretreatment.
[0057] In the embodiments shown in FIG. 2, the media flow 22
directed through or adjacent to the guide 40 may replace or be
supplementary to other media flows such as have been previously
described in relation to FIG. 1.
[0058] Guide 40 may have a variety of configurations and functions.
For example, in the embodiments shown in FIGS. 3-5 a guide 40
having a variable diameter to accommodate tubes of different
diameters is shown. In the embodiment shown, the guide 40 comprises
two portions 54 and 56 that may be moved toward or away from each
other to allow securement of a tube 12 of a larger diameter or a
tube 12 of a smaller diameter with equal ease such as is
illustrated in FIGS. 4 and 5 respectively.
[0059] It must noted that the two component configuration of a
guide 40 shown in FIGS. 3-5 represents merely one embodiment of the
guide 40. As desired, a variable diameter guide 40 may be equipped
with any number of portions or movement mechanisms. Additionally
the guide portions 54 and 56 may be provided with a variety of
shapes, some examples of which are shown in FIGS. 6-9.
[0060] In FIGS. 6 and 7 a variable diameter guide 40 is shown
wherein the chamber 42 comprises a diamond shape that may be
expanded or contracted in the manner shown.
[0061] In FIGS. 8 and 9 another embodiment of the variable diameter
guide 40 is shown wherein a first portion 54 defines a slot 58 into
which the second portion 56 is inserted to form the chamber 42.
[0062] In yet another embodiment, shown in FIG. 10, the guide 40
may comprise a wire 60 having one or more coils 62 which define the
chamber 42 into which the tube 12 is inserted. The coils 62 of the
wire may be contracted or expanded merely by increasing or
releasing tension on the wire ends 64.
[0063] The above disclosure is intended to be illustrative and not
exhaustive. This description will suggest many variations and
alternatives to one of ordinary skill in this art. All these
alternatives and variations are intended to be included within the
scope of the claims where the term "comprising" means "including,
but not limited to". Those familiar with the art may recognize
other equivalents to the specific embodiments described herein
which equivalents are also intended to be encompassed by the
claims.
[0064] Further, the particular features presented in the dependent
claims can be combined with each other in other manners within the
scope of the invention such that the invention should be recognized
as also specifically directed to other embodiments having any other
possible combination of the features of the dependent claims. For
instance, for purposes of claim publication, any dependent claim
which follows should be taken as alternatively written in a
multiple dependent form from all prior claims which possess all
antecedents referenced in such dependent claim if such multiple
dependent format is an accepted format within the jurisdiction
(e.g. each claim depending directly from claim 1 should be
alternatively taken as depending from all previous claims). In
jurisdictions where multiple dependent claim formats are
restricted, the following dependent claims should each be also
taken as alternatively written in each singly dependent claim
format which creates a dependency from a prior
antecedent-possessing claim other than the specific claim listed in
such dependent claim below.
[0065] This completes the description of the preferred and
alternate embodiments of the invention. Those skilled in the art
may recognize other equivalents to the specific embodiment
described herein which equivalents are intended to be encompassed
by the claims attached hereto.
* * * * *