JP2001074433A - Method for inspecting outer peripheral surface of stent and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for effectively inspecting the state of removing a fusing slag on the outer peripheral surface of a stent and its device. SOLUTION: In a method for inspecting a state of removing a fusing slag in a cylindrical stent 1 passing a step of removing the fusing slag created by a laser processing, there is provided a CCD camera 2 which rotatably supports the stent 1 by a horizontal state, and is connected to a computer 5 via an image processor 4, perpendicular to the axial line of the stenter 1, and the stent 1 is rotated at a prescribed angle, and an upper end part and a lower end part of a stent surface are fetched with band-like images, and in comparison with a permitted value of the fusing slag set previously, and a quality decision of the state of removing the fusing slag is made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for inspecting a finished state of an outer peripheral surface in manufacturing a stent to be implanted in a body cavity for maintaining patency of a body cavity such as a blood vessel.

[0002]

2. Description of the Related Art There are various stents used for treatment of atherosclerosis of blood vessels and the like. For example, JP-A-6-181993 and JP-A-10-15591 are known.
No. 5 discloses a cylindrical stainless steel manufactured by a laser beam.

In the manufacture of this stent, for example, a cylindrical stainless steel having an outer diameter of 1.5 to 1.7 mm, a thickness of 0.05 to 0.11 mm, and a length of about 30 mm is cut in an undulating pattern by a laser beam. Thus, a narrow groove is formed, and the molten slag or the like re-solidified along the groove is mechanically (eg, electrolytically polished) or chemically removed.

[0004] Since a serious problem occurs when the molten slag peels off after the stent is implanted in a blood vessel, the molten slag is surely removed. After the step of removing the molten slag, an inspection is performed on the state of removal of the molten slag to remove the insufficiently removed slag.

[0005] Inspection of the state of removal of the molten slag is performed by visual inspection using a magnifying glass or using an electron microscope, but a reliable inspection is required. After this inspection, a final inspection such as a durability test in accordance with a standard such as FDA is performed.

[0006]

However, there are various problems in the conventional inspection method for the state of removal of the molten slag. First, in a macroscopic inspection using a magnifying glass, the stent is fine, which requires a lot of man-hours, and it is difficult to judge the quality of the stent depending on the operator, and it cannot be said that the reliability is high. In addition, in the method using an electron microscope, not only is the apparatus large and expensive, but also operations such as adjustment of an inspection position, setting of a measurement range, and adjustment of a focal length are complicated and time-consuming.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In particular, it is an object of the present invention to provide a method and an apparatus for efficiently inspecting the removal state of molten slag on the outer peripheral surface of a stent. It is the purpose.

[0008]

In order to achieve the above object, the present invention employs the following means. That is, in a method of inspecting the state of removal of molten slag in a cylindrical stent that has undergone a step of removing molten slag created by laser processing, the stent is supported rotatably in a horizontal state, and a computer is connected via an image processing device. A connected CCD camera is provided perpendicular to the axis of the stent, the stent is rotated at a predetermined angle, and the upper end or lower end of the stent surface is captured in a band-shaped image, and compared with a preset molten slag allowable value. It is characterized in that the quality of the removal state of the molten slag is determined.

This inspection method is applied to a stent manufactured by laser processing. Molten slag created by laser processing is a serious problem if it is peeled off after being implanted in a blood vessel, for example, and must be sufficiently removed. Here, the image processing device converts the analog information from the CCD camera into a digital signal, and the computer compares the image information of the stent with a preset allowable value of the molten slag to determine the acceptability. It is provided.

In this inspection method, the upper end or the lower end of the stent surface is captured as a band-shaped image having a certain width by a CCD camera while rotating the stent by a predetermined angle, and the amount of projection of the image protruding from the outer peripheral surface is determined. For example, a cross-sectional area and a maximum height) are measured, and it is determined whether or not this exceeds an allowable value.

The band-like image is composed of a plurality of horizontal scanning lines in image processing, and its width may be set to such an extent that the allowable value of the height of the molten slag can be detected. This operation is performed until the stent makes one rotation while rotating the stent by a predetermined angle. When a molten slag exceeding the allowable value is detected, it is automatically determined that the molten slag is not sufficiently removed. Done.

The measurement accuracy in this inspection depends on the length of the stent and the number of pixels handled by the CCD camera, but if the stent is longer than normal (50 mm or more), the CCD
Since the distance from the camera increases toward both ends of the stent, it is necessary to appropriately correct the captured image.
The method of this correction is described in, for example, a report of “Measurement of position and orientation angle by image processing method (1), (2)” by the Institute of Mechanical Engineers of the Industrial Science Institute [28th Automatic Control Union Lecture Meeting, 1985] And the 30th Automatic Control Federation Lecture Meeting in 1987].

Further, in order to more easily improve the accuracy, C
One measure is to install a plurality of CD cameras and divide the stent in the length direction to capture images. As a device for performing this inspection, a CCD camera is provided by providing a support for rotatably supporting the stent at predetermined angles in a horizontal state on a base and orthogonal to the axis of the stent, as described in claim 2. If a computer is connected to the CCD camera via an image processing device and compared with a preset allowable value of the molten slag to judge pass / fail, the inspection can be performed automatically, and the efficiency can be increased. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and apparatus for inspecting an outer peripheral surface of a stent according to the present invention will be described below with reference to the drawings. As shown in FIG.
Are provided horizontally, and a motor 8 for rotating the stent 1 is provided on one of the supports 7a.
Is provided. The driving and stopping of the motor 8 are performed by commands from the computer 5. Also, 9
Is an encoder, and a detection signal is sent to the computer 5.

A mount 10 on which the CCD camera 2 is mounted is provided in a direction orthogonal to the center of the stent 1.
The CCD camera 2 is connected to a computer 5 via an image processing device 4. The CCD camera 2 is provided with a convex lens 11 for photographing the stent 1 with light as parallel as possible.

The image processing device 4 converts analog information of the CCD camera 2 into a digital signal, and the signal is output to a computer 5. The allowable value of the molten slag of the stent 1 is set in the computer 5, and the pass / fail is determined by comparing with the image data transmitted from the image processing device 4.

On the back side of the stent 1 (as viewed from the CCD camera 2), a flat illuminating lamp 12 connected to a power source 3 is provided.
Is provided. Next, a method of inspecting the finished state of the outer peripheral surface of the stent by the inspection means configured as described above will be described.

The stent has a pattern width of 50 to 100 μm.
m, the length of the stent is generally 15 to 50 mm. First, the stent 1 is mounted on the supports 7a and 7b, and the upper end of the stent 1 is photographed by the CCD camera 2. The captured image is sent to the image processing device 4, converted into image data, and sent to the computer 5.

As the image data, strip-shaped data at the upper end of the stent 1, that is, the SL portion at the upper end of the stent 1 shown in FIG. The SL portion is composed of several horizontal scanning lines in image processing, and is set to have a width of about twice the allowable height of the molten slag.

FIG. 2 is an enlarged view of part A of the SL portion.
It is displayed as shown in (b), and C and D indicate a state in which the molten slag has not been removed by the molten slag. The computer 5 captures the molten slag portion from the image data, measures the area and the maximum height of the molten slag 7, compares them with the preset allowable values of the area and the maximum height of the molten slag, and judges the quality. Is made.

That is, the captured image data is shown in FIG.
Although the pattern of the upper end portion is displayed as shown in (a), only the upper end of the stent, that is, the portion above the outer peripheral surface S is cut off and left as shown in FIG. 3 (b). In this case, the captured image may slightly deviate from the image axis handled by the computer due to the mounting accuracy of the stent, but it is convenient to correct the coordinate axis of the captured image to simplify data processing. It is.

Then, the area and the maximum height H of the cut C and D are measured and compared with a preset allowable value to determine whether or not the molten slag has been removed. Next, the procedure of the above-described inspection method will be described together with a flowchart shown in FIG.

This inspection is automatically performed based on a procedure incorporated in the computer 5, and the operator simply attaches and detaches the stent 1 to and from the supports 7a and 7b. First, the operator sets the stent 1 on the supports 7a and 7b in step 110, and starts the inspection (step 12).
Press the button of 0). As a result, the motor 8 is driven to rotate the stent 1 by a predetermined angle.

Next, at step 140, the state of the upper end of the stent 1 is sent to the image processing device 4 via the CCD camera 4. Then, it is converted into a digital signal, that is, image data, and sent to the computer 5. The computer 5 measures the state of the molten slag portion, that is, the area and the maximum height H of the molten slags C and D in FIG. 3 (step 150).

Next, in step 160, the area of the molten slag is set in advance and compared with the allowable value of the maximum height. Then, the inspection at this point is completed, and Step 130
Returned to Next, the motor 18 is driven to rotate the stent 1 by a predetermined angle (for example, 1 degree), and the next position is measured to determine the quality.

When the measurement and determination are performed until the stent 1 makes one round, the process proceeds to step 180, and the inspection is terminated.
The stent 1 is judged to be good with respect to the removal state of the molten slag on the surface, and is sent to the next step. On the other hand, when it is determined in step 160 that the molten slag exceeds the allowable value, the flow proceeds to step 180, and the measurement ends.

Then, the stent is returned to the previous step, that is, the step of removing the molten slag. The measurement accuracy in this test depends on the length of the stent and the number of pixels handled by the CCD camera.
A plurality of CD cameras are arranged to divide the length direction of the stent to capture images.

In the above embodiment, the image is taken from the upper end of the stent. However, the same operation can be performed at the lower end. As described above, the present invention is not limited to such embodiments at all, and can be implemented in various modes without departing from the gist of the present invention.

[0029]

As described above, according to the method for inspecting the outer peripheral surface of the stent of the present invention, a CCD camera connected to a computer via an image processing device is supported on the stent so as to be rotatable in a horizontal state. Provided orthogonally, rotate the stent at a predetermined angle, capture the upper end or lower end of the stent surface with a band-shaped image, compare it with a preset allowable value of molten slag, and judge the quality of the removal state of the molten slag. Since the inspection is performed, the inspection can be performed automatically without complicated visual judgment compared to the conventional inspection method using a magnifying glass or an electron microscope, there is no variation, and the reliability and efficiency of the inspection are improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an apparatus for performing a method for inspecting an outer peripheral surface of a stent according to the present invention.

FIG. 2 is a view showing a state in which data on an outer peripheral surface of the stent is taken.

FIG. 3 is an explanatory view showing a state of adhesion of molten slag on the outer peripheral surface of the stent.

FIG. 4 is a flowchart showing a flow of the inspection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Stent 2 ... CCD camera 3 ... Light source 4 ... Image processing apparatus 5 ... Computer 6 ... Base 7a, 7b ... Support body 8 ... Motor 9 ... Encoder 10 ... Stand 11 ... Convex lens 12 ... Lighting equipment

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Yoshio Fujisawa, Inventor 1-1, Sanbonmatsucho, Atsuta-ku, Nagoya, Aichi Prefecture Inside Japan Vehicle Manufacturing Co., Ltd. (72) Inventor Yasuyuki Furuta 1-1, Sanbonmatsucho, Atsuta-ku, Nagoya, Aichi Prefecture No. Japan Vehicle Manufacturing Co., Ltd. F term (reference) 2F065 AA25 AA49 AA58 BB08 CC00 DD06 EE08 FF02 FF04 GG18 HH15 JJ03 JJ05 JJ26 MM04 QQ03 QQ25 QQ31 TT03

Claims (2)

[Claims] 1. A method for inspecting the state of removal of molten slag in a cylindrical stent which has undergone a step of removing molten slag created by laser processing, wherein the stent is rotatably supported in a horizontal state and is connected to an image processing apparatus. A CCD camera connected to a computer is provided perpendicular to the axis of the stent, the stent is rotated at a predetermined angle, and the upper or lower end of the stent surface is captured in a band-like image, and a predetermined allowable value of the molten slag is set. A method for inspecting the outer peripheral surface of a stent, wherein the quality of the removed state of the molten slag is determined by comparison. 2. A support for rotatably supporting a stent at predetermined angles in a horizontal state is provided on a base, and a CCD camera is provided at right angles to the axis of the stent, and the CCD camera is preset through an image processing device. 2. An apparatus for implementing the method for inspecting an outer peripheral surface of a stent according to claim 1, wherein a computer for judging acceptability of the molten slag is compared with the allowable value of the molten slag.