Chemistry: electrical and wave energy – Processes and products – Electrostatic field or electrical discharge
Patent
1992-09-04
1994-08-02
Niebling, John
Chemistry: electrical and wave energy
Processes and products
Electrostatic field or electrical discharge
2041291, 20412975, B23H 900
Patent
active
053342941
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of processing wire material and a processing device therefor at the times of intending to make the tip of wire materials such as guide wire for catheter thin and flexible by tapering, and the like.
BACKGROUND TECHNIQUES
For the guide wire for a catheter used for interposing into a human body, etc., it is required to be interposed easily making the tip portion of wire material thin and flexible by tapering. As an example, a portion of 100 to 200 mm at the tip of wire material of around 0.5 mm.phi. is tapered so that the diameter of the utmost tip portion is around 0.12 mm.phi. is used.
Traditionally, this tapering has been made first by mechanical polishing, but the mechanical polishing has a drawback of losing the superelasticity for the Ni-Ti superelastic alloy used usually as a guide wire for a catheter. Recently, therefore, an electrolytic polishing method by batch process is adopted, wherein the tip portion of a wire material is dipped, for example , into a polishing solution having a composition comprising 92% of CH.sub.3 COOH and 8% of HClO.sub.4, into a polishing solution having a composition comprising 20% of HF and 80% of HNO.sub.3, or into a polishing solution having a composition comprising 60% of H.sub.2 SO.sub.4, 30% of HF and 10% of glycerine.
This traditional electrolytic polishing method is however a method of polishing batch wise by dipping one by one into the electrolytic polishing bath while moving up and down manually. Hence, there arise the problems that the shape of the tapered portion varies widely and many workers are required, thus resulting in a high cost.
Moreover, traditional electrolytic polishing baths have the following problems. Namely, the acetic acid-perchloric acid bath has a strong bad smell and gives somewhat poor surface gloss after polishing, and the fluoric acid-nitric acid bath has a strong bad smell, gives poor surface gloss after polishing and requires high cost for effluent treatment to avoid a pollution problem. The sulfuric acid-fluoric acid-glycerine bath has no bad smell, but it gives poor surface gloss and requires high cost for effluent treatment.
DISCLOSURE OF THE INVENTION
The invention has been made as a result of diligent investigations to solve such problems and is concerned with a method of continuously processing wire material characterized in that, in the method of processing part of the wire material by electrolytic polishing, a long wire material is passed continuously through the electrolytic polishing bath with a cathode installed therein and electricity is turned on only when the processing portion passes through said electrolytic polishing bath.
Here, it is preferable from the point of efficiency that, when the nonprocessing portion passes through the electrolytic polishing bath, the wire speed is made high.
Further, the invention is concerned with a device for continuously processing wire material characterized in that an electrolytic tub having the same length as that of a processing portion of wire material, a wire material-advancing device for allowing the wire material to pass through the electrolytic tub, a cathode provided in the electrolytic tub, an anodic electricity-supply device for wire material and a power source generating device are equipped.
Here, as the shapes of processing portion, for example, tapered portion, grooved portion, etc. are intended, and, in order to make this tapered shape, grooved shape or the like arbitrarily variable the feeding speed of wire material-advancing device is desirable to be variable and the generating current of power source-generating device is also desirable to be variable.
Besides, as the composition of wire material, a super-elastic alloy comprising 50.5 to 53.0 at % of Ni and the balance of Ti, or a superelastic alloy substituted part of Ni and/or Ti in 50.5 to 53.0 at % of Ni and 49.5 to 47.0 at % of Ti with any one kind or two or more kinds of Cr, Fe, Co, Mo, V, Pd, W and Cu within a range of 0.01 to 5.0 at % of each can be u
REFERENCES:
patent: 2605218 (1952-07-01), Gibbs et al.
patent: 5066370 (1991-11-01), Andreshak et al.
NTIS Tech Notes, Nov. 1986, J. L. Watkins, "Electrochemical Process Makes Fine Needles", p. 1218.
Iwai Hirohisa
Matsuda Akira
Nakamura Takeo
Shirakawa Ryotomo
Shiroyama Kaisuke
Mayekar Kishor
Niebling John
The Furokawa Electric Co., Ltd.
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