JP2004065750A - Method for manufacturing gradient magnetic field coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a gradient magnetic field coil which can exactly, surely and automatically remove few cutting burrs even if the few cutting burr occurs when a coil is cut out from a metal plate by a cutting machine. <P>SOLUTION: The method for manufacturing the gradient magnetic field coil having the steps of mounting a cylinder 1 previously formed in a bent state on a jig 2 and cutting the cylinder 1 in a coil winding pattern 4 formed at the mounted cylinder 1 includes the steps of cutting the cutting burrs generated when a coil winding part 8 is formed by cutting along the coil winding pattern 4 formed at the cylinder 1 by using a surface treating unit 13, and then removing cutting scraps by using a cleaning means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a gradient magnetic field coil applied to a magnetic resonance imaging apparatus.
[0002]
[Prior art]
In a magnetic resonance imaging apparatus MRI (Magnetic Resonance Imaging), a very strong static magnetic field is required for a subject. In response to such a demand, in a conventional magnetic resonance imaging apparatus, a static magnetic field is strengthened by adding a time-varying gradient magnetic field.
[0003]
The magnetic resonance imaging apparatus in which the static magnetic field is strengthened in this manner applies a high-frequency magnetic field to the subject, generates a high-frequency magnetic resonance signal from the subject, detects this signal, and captures a tomographic image of the subject. Configuration.
[0004]
By the way, in a magnetic resonance imaging apparatus, a static magnetic field strength is generally required to be about kilogauss to about 10 kilogauss (one terrace). Further, spatial uniformity of the static magnetic field is required, and uniformity of several tens of ppm or less is required. Also, the required spatial area is often of a spherical size with a diameter of 50 cm.
[0005]
In recent magnetic resonance imaging apparatuses, high-speed switching of a gradient magnetic field and higher strength are indispensable as imaging techniques become faster. For this reason, since a high voltage is applied to the gradient coil, the distance between the copper wire patterns of the gradient coil is also becoming narrower.
[0006]
Under such a technical background, a method for manufacturing a higher performance gradient magnetic field coil is disclosed in, for example, JP-A-2000-82627.
[0007]
The method of manufacturing this gradient magnetic field coil is to fix a metal plate formed into a curved shape to a jig, cut the curved metal plate along a spiral coil winding pattern with a cutting machine, and perform coil winding. A simple and short manufacturing process by leaving the wire alone on the jig, applying an adhesive to the coil winding, attaching the insulating sheet to the jig, and then peeling off the insulating sheet from the jig Is realized.
[0008]
[Problems to be solved by the invention]
Although the method of manufacturing a gradient magnetic field coil disclosed in Japanese Patent Application Laid-Open No. 2000-82627 is significant in that a simple and short manufacturing process is realized as compared with the related art, it still has some problems. One of them is a cutting burr generated when a metal is cut from a metal plate by a cutting machine.
[0009]
Conventionally, when a coil is cut from a metal plate such as a copper plate formed in a curved shape, for example, by a cutting machine such as a high-speed milling, cutting is performed at a high speed, so that cutting burrs are generated even if not so much. Sometimes.
[0010]
In this case, the generated cutting burrs were manually removed, but it took a lot of time and was sometimes overlooked.
[0011]
As in recent years, higher-speed imaging has been required, higher voltages have been applied, and the distance between the coil winding patterns has become even smaller. This may cause the image to be unclear, for example.
[0012]
The present invention has been made based on such circumstances, and when a coil is cut from a metal plate by a cutting machine, even if slight cutting burrs are generated, an inclined surface that can be accurately and reliably removed automatically. An object of the present invention is to provide a method for manufacturing a magnetic field coil.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, a method for manufacturing a gradient magnetic field coil according to the present invention, as described in claim 1, attaches a previously formed tubular body to a jig, and attaches the fitted tubular body to the jig. In the method of manufacturing a gradient magnetic field coil that performs cutting along a coil winding pattern to be formed, the gradient magnetic field coil is generated when cutting is performed along a coil winding pattern formed on the cylindrical body to form a coil winding portion. This is a method in which cutting burrs are cut using a surface treatment device, and then cutting chips are removed using a cleaning unit.
[0014]
Further, in order to achieve the above object, the method for manufacturing a gradient magnetic field coil according to the present invention, as described in claim 2, attaches a previously formed tubular body to a jig, and attaches the attached tubular body to the jig. In a method of manufacturing a gradient magnetic field coil that is cut along a coil winding pattern formed on a body, a cutting process is performed along a coil winding pattern formed on an outer surface of the cylindrical body to form a coil winding portion. After the cutting burrs generated at the time of cutting are cut using a surface treatment device, and the cutting chips after the cutting process are removed using a cleaning means, the inner surface side of the cylindrical body is also cut with the surface treatment device. This is a method of removing the cutting debris after removing the cutting burrs by using a cleaning means.
[0015]
Further, in the method for manufacturing a gradient magnetic field coil according to the present invention, in order to achieve the above-described object, as described in claim 3, the surface treatment device uses any one of a blast treatment device and a polishing device. Is the way.
[0016]
In order to achieve the above object, the method for manufacturing a gradient magnetic field coil according to the present invention is configured such that, as described in claim 4, the blast processing device includes any one of air blast, shot blast, and wet blast. The method is characterized in that:
[0017]
Further, in the method of manufacturing a gradient magnetic field coil according to the present invention, in order to achieve the above-mentioned object, as described in claim 5, the cleaning means is ultrasonic cleaning.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a method of manufacturing a gradient magnetic field coil according to the present invention will be described with reference to the drawings and reference numerals attached to the drawings.
[0019]
The manufacturing method of the gradient magnetic field coil according to the present invention is a cutting machine for cutting a metal plate made of, for example, copper, which has been bent in advance into a cylinder or a long cylinder having the shape of the gradient magnetic field coil, along a spiral coil winding. In addition to cutting, unnecessary portions corresponding to excess portions are removed, and cutting burrs generated at that time are effectively removed using a surface treatment device.
[0020]
A specific example of the method for manufacturing a gradient coil according to the present embodiment having such a configuration will be described.
[0021]
FIG. 3 shows a cylinder 1 in which a cylinder or a long cylinder (elliptical cylinder) showing a prototype of a gradient magnetic field coil applied to the present embodiment is formed in a half-split shape. The half-split cylinder 1 is made of a metal such as copper, for example, and is formed in advance by a roller processing machine or the like.
[0022]
As shown in FIG. 4, the cylindrical body 1 formed by a roller processing machine or the like is coated with an adhesive on the surface of the jig 2, adhered and fixed.
[0023]
As shown in FIG. 6, the half-split cylindrical body 1 attached to the jig 2 is attached to a cutting machine 3 such as a milling machine. Cut along the contour.
[0024]
The cutting machine 3 includes a mandrel 6 for fixing the jig 2 and an end mill 5 for cutting the cylindrical body 1. The mandrel 6 is rotated about the Y axis, and the end mill 5 is moved in the X, Y, and Z axis directions. It can be freely rotated and moved.
[0025]
On the other hand, among the gradient magnetic field coils, a manufacturing procedure for manufacturing a saddle coil such as a Gx coil or a Gy coil is, as shown in FIG. 5, first, a cylindrical body cut along the contour of the coil winding pattern 4 described above. 1 is removed from the cutting machine 3 together with the jig 2, the unnecessary excess portion (metal portion) 7 other than the coil winding pattern 4 is peeled off from the cylindrical body 1, and only the spiral coil winding portion 8 is cured. Leave on tool 2.
[0026]
Next, after applying an adhesive on the coil winding portion 8, an insulating sheet 9 is put on the jig 2, and the coil winding portion 8 is put on the insulating sheet 9. In this case, the adhesive for attaching the insulating sheet 9 to the coil winding portion 8 has a stronger adhesive force than the adhesive for attaching the cylindrical body 1 to the jig 2. Here, the adhesive may be a double-sided adhesive sheet. The adhesive has a viscosity that does not protrude to the surface of the jig 2 other than the coil winding portion 8. Reference numeral 10 is a hole used to impregnate the resin.
[0027]
After the insulating sheet 9 is applied to the coil winding portion 8 and the insulating sheet 9 is peeled off from the jig 2 after a lapse of several minutes, the insulating sheet 9 is attached to the spiral coil winding portion 8 having the surface shape of the cylindrical body 1. It is glued and a saddle coil is manufactured.
[0028]
On the other hand, when the spiral coil winding portion 8 is cut off from the cylindrical body 1 by the cutting machine 3, cutting burrs often occur.
[0029]
When cutting burrs are visually confirmed, as shown in FIG. 1, the saddle coil includes a plurality of abrasives 11 that spray abrasives 11 from several positions obliquely rearward of the spiral coil winding portion 8 in the coil winding pattern 4. The surface of the helical coil winding portion 8 is treated by using a surface treatment device 13 having a nozzle 12 of, for example, a blast device such as air blast, shot blast, or wet blast, or a polishing device. For example, in the case of a blast device, the abrasive 11 is sprayed from the nozzle 12 to remove cutting burrs generated in the spiral coil winding portion 8.
[0030]
Then, when the removal of the first cutting burrs is completed, the surface treatment device 13 such as a blast device moves to the next cutting burrs.
[0031]
At this time, the jig 2 is rotated and the nozzle 12 is moved, or the jig 2 is moved and the nozzle 12 is rotated, so that the entire surface of the saddle coil formed as the spiral coil winding portion 8 is formed. The surface treatment is performed by removing the cutting burrs over the entire surface.
[0032]
After performing the surface treatment of the outer surface of the saddle coil, as shown in FIG. 2, the inner surface side (the opposite side of the outer surface) is also subjected to removal of cutting burrs by a blasting machine or the like.
[0033]
At this time, the saddle coil is removed from the jig 2 after the insulating sheet 9 is attached to the cylindrical body 1, and the burrs are also removed from the back surface using a blasting machine or the like as described above. In removing the cutting burr, the jig 2 is rotated to move the nozzle 12, or the jig 2 is moved and the nozzle 12 is rotated to form the entire surface of the saddle coil formed as the spiral coil winding portion 8. Move over.
[0034]
Then, after removing the cutting burrs on the outer surface and the inner surface, the saddle coil is subjected to ultrasonic cleaning to remove the attached cutting chips and maintain high insulation.
[0035]
【The invention's effect】
As described above, the manufacturing method of the gradient magnetic field coil according to the present invention is to cut a preliminarily curved cylindrical body along a helical coil pattern to form a coil winding, and apply the cut coil winding to Since the generated cutting burrs are removed using the surface treatment device, even minute cutting burrs can be automatically and reliably removed.
[0036]
Further, the method for manufacturing the gradient magnetic field coil according to the present invention, when removing the cutting burrs generated in the coil winding cut from the cylindrical body using a surface treatment device, since the surface of the coil winding is roughened, When the insulating sheet is applied, the adhesive strength can be improved, and the adhesive strength and the adhesive strength with the impregnated resin can be further increased during assembly.
[0037]
Further, in the method for manufacturing a gradient magnetic field coil according to the present invention, since cutting burrs generated on the coil windings cut from the cylindrical body are removed using a surface treatment device and then ultrasonic cleaning is performed, cutting dust attached to the surface is removed. Can be reliably removed, and the insulating performance due to the attachment of the insulating sheet can be maintained even higher.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of performing a surface treatment on an outer surface of a saddle coil in a method of manufacturing a gradient magnetic field coil according to the present invention.
FIG. 2 is a conceptual diagram of performing a surface treatment on the back surface of the saddle coil in the method of manufacturing a gradient coil according to the present invention.
FIG. 3 is a conceptual diagram showing a processed cylinder applied to a saddle coil in the method of manufacturing a gradient coil according to the present invention.
FIG. 4 is a conceptual diagram of a coil winding part showing a shape in which the cylinder shown in FIG. 3 is fixed to a jig and the cylinder is cut along the coil winding part.
FIG. 5 is a conceptual diagram showing a manufacturing process of a saddle coil in which a surplus portion is peeled off from a cylindrical body after cutting, and an insulating sheet is applied to a coil winding portion.
FIG. 6 is a conceptual diagram showing a cutting machine used to cut a coil winding portion from the cylindrical body shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical body 2 Jig 3 Cutting machine 4 Coil winding pattern 5 End mill 6 Mandrel 7 Excess part 8 Coil winding part 9 Insulating sheet 10 Hole 11 Abrasive 12 Nozzle 13 Surface treatment device

Claims (5)

In a method for manufacturing a gradient magnetic field coil, in which a cylindrical body formed in a curved shape in advance is mounted on a jig and cut along a coil winding pattern formed on the mounted cylindrical body, a coil winding formed on the cylindrical body is provided. A gradient magnetic field characterized in that cutting burrs generated when forming a coil winding portion by cutting along a line pattern are cut using a surface treatment device, and then cutting chips are removed using cleaning means. Manufacturing method of coil. A method for manufacturing a gradient magnetic field coil, in which a cylindrical body formed in advance in a curved shape is mounted on a jig and cut along a coil winding pattern formed on the mounted cylindrical body, is formed on an outer surface of the cylindrical body. The cutting burrs generated when forming the coil winding portion by cutting along the coil winding pattern are cut using a surface treatment device, and the cutting chips after the cutting process are removed using cleaning means. A method of manufacturing a gradient magnetic field coil, further comprising removing cutting burrs on the inner surface side of the cylindrical body using a surface treatment device, and removing cutting chips from which cutting burrs have been removed using a cleaning unit. 3. The method for manufacturing a gradient magnetic field coil according to claim 1, wherein the surface treatment device uses one of a blast treatment device and a polishing device. The method for manufacturing a gradient magnetic field coil according to claim 1, wherein the blast processing device is any one of air blast, shot blast, and wet blast. 3. The method for manufacturing a gradient magnetic field coil according to claim 1, wherein the cleaning means is an ultrasonic cleaning.

Images