Surgical needle abstract
A process for manufacturing a surgical needle incorporates at least
one pressing operation which, preferably, in conjunction with a
trimming and/or etching process, ultimately forms the sharpened
needle end. The grinding operation in the preferred process does
not produce the primary sharpened edges of the needle, but, rather
is incorporated, in one instance, to reduce excess needle material
prior to the pressing operation. Consequently, the amount of flash
material generated during pressing is substantially reduced. This
feature desirably enhances the subsequent trimming and etching operations,
and produces a needle which is extremely sharp, durable and exhibits
an improved retention of sharpness over periods of prolonged use.
Surgical needle claims
What is claimed is:
1. A process for manufacturing a surgical needle, comprising the
steps of: providing a surgical needle blank, the needle blank comprising
a biocompatible material; removing needle material from a peripheral
portion of one end of the needle blank to define a needle end having
a reduced cross-sectional dimension; pressing the needle end to
form at least three intersecting surfaces on the needle end; and
forming cutting edges adjacent areas of intersection of the at least
three surfaces to define a plurality of cutting edges on the needle
end.
2. The process according to claim 1 wherein the step of removing
the needle material includes grinding the peripheral portion of
the needle end of the needle blank.
3. The process according to claim 2 including the step of coining
the needle blank to define a needle end having first, second and
third sides, the step of coining being performed prior to the step
of removing the needle material.
4. The process according to claim 3 wherein the step of removing
the needle material includes grinding at least the second side of
the needle end to remove material adjacent the second side of the
needle end.
5. The process according to claim 4 wherein the step of removing
the needle material includes grinding the third side of the needle
end to remove material adjacent the third side of the needle end.
6. The process according to claim 5 wherein the step of pressing
the needle end includes form pressing the first, second and third
sides to produce the at least three surfaces on the needle end.
7. The process according to claim 6 including the step of providing
a die mechanism having a die arrangement with a die concavity therein,
the die concavity defining a tapered characteristic whereby the
cross-sectioned area occupied by the concavity decreases from one
end of the concavity to the other end of the concavity and wherein
the step of pressing includes positioning the needle end within
the die concavity to impart a tapered configuration to the needle
end.
8. The process according to claim 7 wherein the die concavity of
the die mechanism defines a general triangular configuration having
first and second pressing surfaces and wherein the step of pressing
includes positioning the needle blank within the concavity of the
die mechanism to impart a generally tapered triangular-shaped cross-section
to the needle end.
9. The process according to claim 8 wherein the die mechanism includes
a die punch positioned in opposition of the die concavity and wherein,
during the step of pressing, the die punch engages the first side
of the needle end upon relative movement of the die punch and the
die arrangement.
10. The process according to claim 9 wherein the die punch has
a radiused surface and wherein, during the step of pressing, the
radiused surface imparts an arcurate surface on the first side of
the needle end.
11. The process according to claim 6 wherein during the step of
pressing, excess needle flash material is created adjacent areas
of intersection of the first and second surfaces, and the first
and third surfaces of the needle end.
12. The process according to claim 11 including the step of trimming
the flash material from the areas of intersection.
13. The process according to claim 12 wherein the step of trimming
includes forming a crease line along each of the areas of intersection
of the first and second sides, and the first and third sides of
the needle end, the crease lines defining at least two cutting edges.
14. The process according to claim 13 including the step of etching
the needle end to further remove flash material and sharpen the
cutting edges.
15. The process according to claim 14 wherein the step of etching
includes introducing a first current into the acid bath for a first
determining period of time and introducing a second current into
the acid bath for a second predetermined period of time.
16. The process according to claim 13 including the step of flat
pressing the needle blank subsequent to the step of pressing the
needle end.
17. The process according to claim 16 wherein the flat press includes
at least one die, the at least one die defining a die cavity having
a pressing surface, the pressing surface inclined relative to an
axis of the at least one die whereby, during the step of pressing,
the pressing surface impacts the needle end to cause needle material
to flow such that at least portions of the at least two cutting
edges extend beyond a perimeter of the body of the needle blank.
18. The process according to claim 13 including the step of heat
treating the needle blank.
19. A surgical needle formed in accordance with the process of
claim 6.
20. A surgical needle formed in accordance with the process of
claim 17.
Surgical needle description
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention relates to a surgical suturing needle
for suturing cutaneous and subcutaneous tissue, and in particular,
relates to a process for manufacture of a surgical needle having
enhanced penetration characteristics and retention of needle sharpness
over prolonged use.
[0003] 2. Background of Related Art
[0004] Suturing needles for applying sutures, or stitches, by hand
in cutaneous and subcutaneous tissue are well known in the art.
The suturing needles are typically used to close wounds or adjoin
adjacent tissue, often at the conclusion of a surgical procedure.
Suturing needles are usually made from a cut blank of material such
as stainless steel. The cut blank is metal-worked using well known
machining techniques to form the suturing needle. The needle generally
includes a shaft, a rear end portion with an aperture or channel
to secure a suture thread and a needle head at a front end portion
for puncturing skin and for passing through tissue. The needle head
typically incorporates a sharpened needle tip at its distal end
and cutting edges. Alternatively, the needle tip may be of a tapered
configuration. Straight and curved needles including multiple curved
configurations are also known the art.
[0005] Conventional methods for needle manufacture include subjecting
a needle blank to a series of grinding operations to form the desired
needle edges and needle point. However, the grinding operations
are often operator dependent thereby increasing the potential for
needle defects. In addition, sharpened needle edges formed via conventional
operations fail to retain their sharpness over extended use.
SUMMARY
[0006] Accordingly, the present disclosure is directed to a process
for manufacturing a surgical needle and a surgical needle thereby
produced. The preferred process incorporates at least one pressing
operation which, preferably, in conjunction with a trimming and/or
etching process, ultimately forms the sharpened needle end. The
grinding operation in the preferred process does not produce the
primary sharpened edges of the needle, but, rather is incorporated,
in one instance, to reduce excess needle material prior to the pressing
operation. Consequently, the amount of flash material generated
during pressing is substantially reduced. This feature desirably
enhances the subsequent trimming and etching operations, and produces
a needle which is extremely sharp, durable and exhibits an improved
retention of sharpness over periods of prolonged use.
[0007] In one preferred embodiment, the process for manufacturing
a surgical needle includes the steps of providing a surgical needle
blank of biocompatible material, removing needle material (e.g.,
through a grinding process) from a peripheral portion of one end
of the needle blank to define a needle end having a reduced cross-sectional
dimension, pressing the needle end to form at least three intersecting
surfaces on the needle end and forming cutting edges adjacent areas
of intersection of the at least three surfaces to define a plurality
of cutting edges on the needle end. The process may also include
the step of coining the needle blank prior to grinding to define
a needle end having first, second and third sides. Preferably, the
second and third sides are subjected to a grinding process to remove
material adjacent the respective sides.
[0008] In a preferred embodiment, the step of pressing includes
form pressing the first, second and third sides to produce the at
least three surfaces of the needle end. A die mechanism having a
die arrangement with a die concavity therein may be provided. The
die concavity defines a tapered characteristic whereby the cross-sectioned
area occupied by the concavity decreases from one end of the concavity
to the other end of the concavity. The needle end is positioned
within the die concavity to impart a tapered configuration to the
needle end. Preferably, the die cavity of the die mechanism defines
a general triangular configuration having first and second pressing
surfaces. The needle blank is positioned within the concavity of
the die mechanism to impart a generally triangular-shaped cross-section
to the needle end. The die mechanism may include a die punch positioned
in opposition of the die concavity. The die punch engages the first
surface of the needle end upon relative movement of the die punch
and the die mechanism. The die punch may have a radiused surface
to impart an arcurate surface on the first surface of the needle
end.
[0009] Excess needle flash material may be created adjacent areas
of intersection of the first and second surfaces, and the first
and third surfaces of the needle end during the pressing step. This
excess flash material is removed through a trimming operation. The
trimming step or trimming operation preferably includes forming
a crease line along the areas of intersection of the first and second
sides, and the first and third sides of the needle end. The needle
blank may then be subjected to an etching process to remove excess
flash material and/or sharpen the cutting edges. Heat treating the
needle blank is also preferable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments
of the disclosure and, together with a general description of the
disclosure given above, and the detailed description of the embodiment(s)
given below, serve to explain the principles of the disclosure,
wherein:
[0011] FIG. 1 is a block diagram of a preferred embodiment of a
process of manufacturing a surgical needle in accordance with the
principles of the present disclosure;
[0012] FIG. 2A is a plan view of the coining dies utilized in the
coining operation of the process of FIG. 1;
[0013] FIG. 2B is an axial view of the needle end subsequent to
the coining operation;
[0014] FIG. 3A is a top schematic view of the relief grind mechanism
used in the relief grind operation of the process of FIG. 1;
[0015] FIG. 3B is a side schematic view illustrating the arrangement
of the collet and collet holder relative to the grind wheel of the
relief grind mechanism;
[0016] FIG. 3C is an axial schematic view illustrating the arrangement
of the needle blank relative to the grind wheel of the relief grind
mechanism;
[0017] FIG: 3D is an axial end view of the needle blank subsequent
to the relief grind operation;
[0018] FIG. 4A is a plan view of the bayonet die configuration
used in the press operation of the process of FIG. 1;
[0019] FIG. 4B is a cross sectional view of the needle end engaged
by the upper press during the press operation;
[0020] FIG. 5A is a perspective view of the lower dies used in
the trim operation of the process of FIG. I;
[0021] FIG. 5B is an end axial view of the needle end subsequent
to the trim operation;
[0022] FIG. 6 is a side plan view of the needle end subsequent
to the quick grind operation of the process of FIG. 1;
[0023] FIG. 7A is a side view of a pair of dies utilized in the
flat press operation of the process of FIG. 1;
[0024] FIG. 7B is a top plan view of the needle end subsequent
to the flat press operation; and
[0025] FIG. 7C is a cross-sectional view taken along lines 7C-7C
of FIG. 7B illustrating the configuration of the main body of the
needle.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0026] Preferred embodiments(s) of the process for manufacturing
a surgical needle of the present disclosure will now be described
in detail with reference to the drawings wherein like reference
numerals identify similar or like elements throughout the several
views.
[0027] Referring now to the block diagram of FIG. 1 there is illustrated
a preferred process for needle manufacture in accordance with the
principles of the present disclosure. A needle blank in the form
of a cylindrical rod having a desired or predetermined length is
provided. The needle blank is to be eventually formed into a surgical
needle. The needle blank may be cut from suitable biocompatible
needle stock, including stainless steel, titanium or titanium alloys.
The needle blank also preferably has a drilled recess (e.g., through
laser drilling) in one end for receiving a surgical suture to attach
the suture to the needle. It is also contemplated that the needle
blank may have an open channel, an eye, etc. for receiving and attaching
the suture as is known in the art.
[0028] With reference to FIGS. 1 and 2A, the first step in the
preferred process is a coining operation 100. The coining operation
imparts a desired cross-sectional configuration to needle blank
10. The needle blank 10 is preferably placed within a collet (not
shown in FIG. 2A). Any conventional collet adapted to secure a needle
blank in fixed relation may be utilized. The collet may be indexed
to determine and/or control orientation of the needle blank 10 relative
to a collet holder employed in the remaining operative steps. The
collet and needle blank 10 are mounted in relation to a die mechanism
102 of the coining operation. In one embodiment, the collet may
be mounted within a collet holder (not shown) of the die mechanism.
[0029] The preferred die mechanism 102 includes two lower dies
104 and a planar upper die 106. Lower dies 104 incorporate inclined
swaging or coining surfaces 108 which extend at respective angles
.theta.,-.theta. relative to transverse axis "r" of the
dies 104. Coining surfaces 108 define a concavity or recess 110
within lower dies 104. Angles .theta.,-.theta. may be any oblique
angle. Preferably, angles .theta.,-.theta. have an absolute value
ranging from about 40.degree. to about 70.degree. relative to axis
"r". In one preferred embodiment, the absolute value of
angles .theta.,-.theta. is about 58.degree.. Other angular orientations
are also envisioned. Dies 104 106 are preferably formed of a carbide
material although other materials are envisioned as well.
[0030] Needle blank 10 is positioned within concavity 110. The
die mechanism is actuated to advance upper die 106 toward lower
dies 104 to swage or coin at least the needle end 12. This coining
operation 100 imparts a generally triangular shaped cross-section
to the needle end 10. FIG. 2B illustrates in axial view the configuration
of the needle end 12 of the needle blank 10 subsequent to the coining
operation. As appreciated, the end surface 14 of needle end 12 is
substantially planar or flat. The three sides of needle end 12
namely sides 1 2 and 3 generally define an equilateral triangle.
For reference purposes, side 1 of needle end 12 is the surface directly
engaged by upper die 106 and sides 2 3 are the surfaces contacted
by coining surfaces 108 of lower dies 104.
[0031] With reference again to FIG. 1 the next step in the process
is a relief grind operation 200. The relief grind operation removes
excess material from needle end 12 and, optionally, may provide
a preliminary pointed configuration to the needle end 12. The removal
of needle material from needle end 12 greatly facilitates the subsequent
pressing (e.g., bayonet forming), trimming and/or acid etching operations
of the process. As best depicted in the top schematic view of FIG.
3A, the relief grind mechanism 202 of the relief grind operation
200 includes grind wheel 204. Grind wheel 204 is adapted to rotate
about rotational axis "w". Collet holder 206 secures collet
20 at a predetermined rotational or angular orientation relative
to the axis of the collet holder 206 to selectively present any
of the sides 1 2 3 to grind wheel 202. The rotational or angular
orientation may be determined by the indexing on the external surface
of collet 20. In addition, collet holder 206 may be arranged at
a predetermined positive angle "c" or pitch (FIG. 3B)
relative to the rotational axis "w" of grind wheel 204
to impart a tapered surface to any of the sides 123 of the needle
end 12. In a preferred arrangement, angle "c" ranges from
about 50.degree. to about 70.degree., and, preferably, is about
60.degree. relative to horizontal or transverse plane "t"
which intersects the rotational axis "w" of grind wheel
204. FIG. 3B illustrates schematically this pitched arrangement
of collet holder 206 collet 20 and needle end 14 relative to grind
wheel 204. Collet holder 206 is further displaceable in the "x"
direction toward grind wheel 204 of the relief grind mechanism.
[0032] Referring now to FIG. 3C, collet 20 is initially arranged
within collet holder 206 to present side 2 of needle end 12 to grind
wheel 204. In FIG. 3C, the collet 20 and collet 206 are not shown
for clarity purposes. As discussed above, indexing on collet 20
will facilitate obtaining the desired angular or rotational orientation
within collet holder 206. In a first preferred position, collet
20 is placed at an angle "d" to position side 2 in parallel
relation (e.g., horizontal) with the rotational axis "w"
of grind wheel 204. For reference purposes, the zero (0) position
of collet 20 corresponds to a horizontal or parallel arrangement
of side 1 relative to the axis "w" of the grind wheel
204. The mechanism 200 is actuated and collet holder 206 is advanced
along direction "x" such that grind wheel 204 contacts
side 2 of needle end 12. The grind operation removes a desired amount
of needle material from side 2. Thereafter, collet 20 is arranged
at a predetermined angular orientation "-.alpha." (e.g.,
-60.degree.) within collet holder 206 to present side 3 of needle
end 102 to grind wheel 204. Side 3 is also preferably arranged to
be in parallel relation to the rotational axis "w" of
grind wheel 202. The mechanism 200 is actuated to remove a predetermined
amount of material from side 3. FIG. 3D depicts an axial view of
the configuration of needle end 12 subsequent to the relief grind
process. As shown, sides 2 3 generally taper outwardly from end
surface 14 towards the rear or main body of needle 10 to define
a general pointed or tapered characteristic to needle end 12. It
is appreciated that more or less material may be removed from needle
end 12 and that end surface 14 of the needle end 10 may be more
or less pointed in configuration. This tapered configuration of
needle end 12 is achieved by virtue of the inclined orientation
or pitch "c" of collet holder 206 relative to the transverse
plane "p" of grind wheel 202.
[0033] With reference again to FIG. 1 the following step in the
process is a press operation which involves forming a bayonet point
on the needle end 12 (STEP 300). This operation incorporates a press
having two lower dies formed to define a cavity for the press operation.
With reference to FIG. 4A, the lower dies, i.e., left and right
dies, 302 304 of the press or bayonet form mechanism, each include
an angle cut 306 in their upper surfaces which when joined together
define a tapered, preferably, triangular-shaped recess 308 in cross-section.
Recess 308 gradually decreases in cross-section from front surfaces
302a, 304a of dies 302 304 to the middle die area where it terminates
in point 308p. The press further includes upper punch 310 which
moves to engage needle 10. Upper punch 310 includes radiused surface
312 having a slight radius of curvature "m". In one preferred
embodiment, the radius of curvature "m" ranges from about
0.250 inches to about 0.500 inches. Preferably, the radius of curvature
"m" is about 0.375 inches.
[0034] In operation, needle end 12 of needle blank 10 is placed
within triangular-shaped recess 308 of left and right dies 302
304 with side 1 of the needle end 12 directly opposing radiused
surface 312. With reference to FIG. 4B, the press is actuated such
that upper punch 310 advances to engage needle end 12 thereby swaging
the needle end 12 to a general bayonet or triangular shape shown.
Surface 1 assumes a slightly curved appearance through its swaging
contact with radiused surface 312 of upper punch 310. Preferably,
radiused surface 312 of upper punch 310 contacts the center of the
needle end 12 to cause the needle material to more readily splay
within recess 308 of the left and right dies 302 304 i.e., by
virtue of the contour of the radiused surface 312 the radiused
surface 312 enters more deeply within the center of recess 308 and
into the needle end 12 which causes the needle material to flow
within the recess 308 in a uniform manner. The process, however,
also creates an overflow flash "f" on each side of needle
end 12 to thereby define the winged appearance shown in in FIG.
4B. The flash "f" extends radially outwardly from the
edges of the needle end 12 generally following the contour of radiused
surface 312 of upper punch 310. The flash material "f"
has a thickness "t" adjacent to intersecting edges of
sides 1 2 3 of about 0.002 inches. However, by virtue of the previous
relief grind operation, the amount of flash "f" generated
is substantially reduced as would normally be generated. As indicated
hereinabove, this greatly facilitates the remaining operations of
the preferred process by removing excess needle material which would
otherwise require removal by the forming, trimming and etching operations.
[0035] Referring now to FIGS. 5A-5B, the next step in the process
is a trim operation (STEP 400). The trim operation 400 incorporates
two lower dies 402 which are identical to the bayonet forming dies
302 304 of FIG. 4A. However, dies 402 also incorporate sharp raised
protrusions 404 which extend along the perimeter of the recessed
areas of each die and the flat remaining surfaces of the dies. The
raised protrusion(s) 404 is preferably formed by an (electrode depositing
machining EDM) process. The EDM process is coordinated to form a
crease line or protrusion 404 adjacent the outer perimeter of the
recess. Upon actuation of the press, the raised protrusion 404 forms
a corresponding crease and/or perforation in the flash material
adjacent location "p" (FIG. 5B) to trim the flash along
the protrusions 404. The crease lines eventually become peripheral
edges which serve as cutting edges in needle end 12. The thickness
"t" adjacent each crease line is substantially reduced
relative to corresponding thickness after the press operation 300
and may only be about 0.0005 inches thick. As appreciated, excess
flash material "f" generated during the press operation
300 may still be present.
[0036] Referring again to FIG. 1 the next step in the process
is a second grind operation (step 500). The second grind involves
lightly grinding the area (e.g., line) of intersection of sides
2 3 of the needle end 12 to reduce some excess flash material which
may be adjacent this area and to also form a second point on needle
end 12. The second grind operation may be performed with relief
grind mechanism 202 of the relief grind operation 200 discussed
hereinabove. In particular, needle blank 10 is arranged within collet
holder 206 to present the area or edge connecting sides 2 3 of
needle end 14 to grind wheel 204. The grind mechanism 202 is actuated
to grind a minimal amount of needle material from the edge.
[0037] FIG. 6 depicts in side plan view the configuration of needle
end 12 subsequent to the second grind operation 500. This light
grind step also forms a second needle point 18 on the needle end
12. The second needle point 18 is displaced from the first or distalmost
needle point 16 which is created during the press operation 300.
Second needle point 18 eventually defines secondary cutting edges
extending from the second needle point 18 to main body 22 of needle
blank 10. The grind surface 24 (i.e., the surface interconnecting
the two points 16 18) is at a minimal angle "j" preferably
about 3.degree. relative to the axis "z" of needle 10.
Preferably, the removed material is only about a few tenths of a
thousand of an inch.
[0038] Referring again to FIG. 1 the next step in the process
is a flat process operation 600. The flat press operation 600 includes
a gear-activated flat press. The press includes a box die set 602
which is best depicted in FIG. 7A. The box die is a two component
die. One of the die components (e.g., the upper) 604 is movable
while the second die component (e.g. the lower) 606 is stationary.
The upper die 604 has a flat pressing surface 604a. The lower die
606 includes a rectangular recess 606a having lower pressing surface
608. Lower pressing surface 608 is arranged at a slight taper or
angle to define an angulated punch. The angulated surface tapers
upwardly from the front surface of the die set 602 to the rear surface.
A preferred angle of taper ranges from about 1.degree. to about
3.degree., and is preferably about 2.degree.. This arrangement causes
a greater or heavier swaging effect adjacent needle end 12 and a
lighter swaging effect toward the back end of the needle 10. Accordingly,
the needle material adjacent the needle end 12 splays outwardly
to cause a portion of the needle end 12 to be wider than the remaining
body 22 of needle blank 10. In this manner, the cutting edges 4
5 at the intersections of sides 1 2 and sides 1 3 respectively
are wider than main body 22 of needle blank 10 and taper back toward
the body 22 to define a general spatula-head configuration.
[0039] In operation, needle blank 10 is placed within rectangular
recess 606a with side 1 contacting lower surface 608 of lower die
606. The press is activated. The opposing surfaces of the needle
10 are then pressed whereby the needle material flows to be captured
within rectangular recess 606a. Rectangular recess 606a thereby
provides a uniform collective pool for the needle 100. Due to the
inclined orientation of lower pressing surface 608 needle end 12
toward needle point 16 is pressed to a greater extent than the remaining
portion or main body 22 of needle 10. The result of this feature
is the formation of a spatula head on the needle end as depicted
in FIG. 7B. The spatula head is characterized by having outer cutting
edges 4 5 defined along the respective lines of intersections of
surfaces 1 2 and surfaces 1 3 which extend beyond the normal
periphery of the needle 10 or beyond the edges of the needle body
22. The main body 22 of needle 10 assumes the rectangular configuration
of rectangular recess 606a. FIG. 7C illustrates the cross section
of the rectangular configuration of main body 22 of needle 10 after
the flat press operation 600. Preferably, the cross-sectional dimension
or needle width "w1" across one surface of the needle
is less than the width "w2" across the other surface of
the needle. Other configurations are also envisioned.
[0040] Thus, the aforementioned operations of the preferred process
produce a needle having a spatula head configuration as depicted
in the views of FIGS. 5B (with the flash "f" material
removed), FIG. 6 FIG. 7B and FIG. 7C.
[0041] It is envisioned that the aforementioned operations may
be adapted to form other needle configurations besides the bayonet
or spatula configuration disclosed. These alternate designs may
be achieved by appropriate alternate design to the bayonet point
form press and/or the trimming/crease forming dies.
[0042] The next operation is to curve the needle. This step 700
may be formed by any conventional means. In one embodiment, a curving
mechanism is utilized to curve the needle body preferably along
side 1 of the needle end 12. One suitable curving mechanism is disclosed
in commonly assigned U.S. Pat. No. 5626043 to Bogart, the contents
of which are incorporated by reference. The curving step 700 is
optional.
[0043] It is envisioned that each of the above processing steps
may be performed at one work station, i.e., that each work station
or needle manufacturing apparatus may be adapted to perform each
of the steps (including coining, grinding and pressing) required
to manufacture a single needle in accordance with the preferred
process. The parameters of manufacture may be programmed into the
work station to control each operation based on needle type, size,
etc. Computer programming, software etc., in conjunction with associated
computer means, may be incorporated to coordinate the operation
of the work station.
[0044] With reference again to FIG. 1 it is also contemplated
that a heat treatment operation may be employed to treat the surgical
needle to enhance the strength of the needle and its surgical cutting
characteristics. The heat treatment operation 800 incorporates a
conventional heat treatment oven. The needles are heated in the
oven at a sufficient temperature for a sufficient period of time
to effectively treat the needle blank(s). The temperature ranges
and heating period are in conformance with the material of fabrication
of the needle blank, and may be readily determined by one skilled
in the art.
[0045] The next step in the process is a needle etching process
900. The needle etching process incorporates the step of submerging
the surgical needle in an acid bath. The first stage of the etching
or acid bath process is a high energy step 1000 where a relatively
high amperage current is introduced into the bath of approximately
5-6 amps for about 20-40 seconds, preferably, 30 seconds at 12V-DC.
The high energy phase aggressively moves excess flash material from
the needle. The second phase in this process is a low energy step
1100 and includes directing relatively low amperage current of approximately
1 amp into the acid bath for about five minutes. This phase produces
a matte-like finish on the needle. The needle may then be coated
with a suitable coating, e.g. a silicon coating, PTFE coating or
Teflon.RTM..
[0046] It will be understood that various modifications may be
made to the embodiments disclosed herein. Therefore, the above description
should not be constructed as limiting, but merely as exemplifications
of preferred embodiments. Those skilled in the art will envision
other modification within the scope and spirit of the claims appended
hereto. |