JPH10128667A - Polishing method and device, and abrasive therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate handling and easily remove residual abrasive grains by using polyvinyl alcohol as abrasive grains. SOLUTION: Granular material of polyvinyl alcohol which is abrasive grains is obtained by polymerizing, saponifying, separating and drying vinyl acetate obtained by interaction of ethylene, oxygen in the air and acetic acid. Burr 11 between leads 10 can be removed by continuously spraying the above abrasive grains to a molded part 9 of the lead frames. The lead frames from which burr is removed are washed by water or hot water, whereby abrasive grains remaining on the lead frames are dissolved to be removed. At this time, the abrasive grains of polyvinyl alcohol are easily dissolved in water to be surely removed from the lead frames. Further, vinyl alcohol dissolved in water is harmless.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method, a polishing apparatus, and a polishing material. For example, a surface of a resin molded part such as a resin molded body is polished by blowing a granular polishing material (media) through air. TECHNICAL FIELD The present invention relates to an air blowing type polishing method and apparatus and an abrasive material thereof.

[0002]

2. Description of the Related Art As a conventional air blowing type polishing apparatus,
Abrasive particles (eg, polyethylene terephthalate particles or walnut shell particles, glass beads, mixed sand, etc.) are sprayed from a nozzle onto a workpiece (eg, a molded product such as a plastic molded product) moving on a transport path through a nozzle through air from a blower. An air blast type deburring apparatus that continuously removes burrs from a resin mold portion by spraying a medium is used.

However, according to this conventional technique, there is a problem of abrasive grains such as polyethylene terephthalate remaining on a work after removing burrs. In particular, when the work is a molded body of an electronic component such as an IC, for example, the finer pitch of the IC leads makes it easy for abrasive grains to remain between the leads, and this abrasive grain hinders IC processing in the next step. And the quality and characteristics of the IC may be adversely affected.

[0004] Such an operation for removing residual abrasive grains is performed by an IC.
Or, with the miniaturization of other products, it has become cumbersome and troublesome, and it has become difficult to reliably remove them.
Therefore, instead of the above-mentioned abrasive particles such as polyethylene terephthalate granules, water-soluble abrasive particles made of sugar, salt, starch or caustic soda are used, and after removing burrs, the product is washed with water or hot water to remove the abrasive particles. A method of dissolving and removing is considered.

Further, a polishing means using ultra-high pressure water has been put to practical use as another deburring method or another polishing and grinding method.

On the other hand, polyvinyl alcohol (PVA: so-called poval) is generally known as a material for glue, paint, adhesive, emulsion, coating material, binder, modified resin, finishing agent, film and the like. This PVA
Is a polymer compound obtained by saponifying polyvinyl acetate with an alkali, an acid, aqueous ammonia or the like.

[0007]

However, the above-mentioned prior art improvement using the water-soluble abrasive grains such as sugar and starch as the abrasive grains may cause the following disadvantages.

[0008] That is, conventional water-soluble abrasive grains such as sugar,
1. The hardness and weight may be slightly insufficient, and depending on the material of the mold, the performance as abrasive grains may be insufficient. 2. Since it easily becomes powder, its life as abrasive grains is short, and it must be replenished frequently, which increases the running cost. 3. Inconvenient and poor handling. 4. When it becomes powder, it needs to be powdered, which makes maintenance difficult. 5. If the sugar or the like remaining on the object to be polished is washed away, the next step may be adversely affected when the object to be polished is, for example, an electronic component.

Further, according to the prior art using the ultrahigh-pressure water, the apparatus is large and complicated, the cost is high, and the handling (water pressure adjustment, water quality selection adjustment, etc.) is difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has a simple structure, is inexpensive, is easy to handle, and has an air blast capable of easily removing residual abrasive grains (media). It is an object of the present invention to provide a polishing method and apparatus of the type and abrasive grains which have a long life and do not affect the next step.

[0011]

SUMMARY OF THE INVENTION The present invention relates to polyvinyl alcohol which has been used as a pasting agent or the like.
Focusing on its hardness, specific gravity, workability and water solubility, this polyvinyl alcohol is used as abrasive particles to solve various problems in the aforementioned deburring and other polishing air blasting equipment, It is intended to realize a useful polishing method and apparatus.

That is, in order to achieve the above object, the present invention provides a polishing method in which abrasive grains made of polyvinyl alcohol are used in a polishing method for blowing abrasive grains onto an object to be polished by an air flow. I do.

Further, according to the present invention, there is provided a polishing apparatus having an air blowing means for blowing an air flow containing abrasive grains to an object to be polished, wherein the abrasive grains are made of polyvinyl alcohol. I will provide a.

[0014] Further, the present invention provides an abrasive comprising a granular material of polyvinyl alcohol.

In a preferred embodiment, the abrasive of the present invention is characterized in that it is used as abrasive particles which are blown onto an object by air flow.

In the present invention, the term "polishing" refers to polishing such as surface polishing, finishing or roughening of a workpiece, grinding for shaping an outer shape, and polishing removing for removing burrs and other unnecessary portions. Is included.

[0017]

A particulate object of polyvinyl alcohol as abrasive particles is mixed with an air stream and sprayed on an object to be polished (work) placed on a polishing section to be polished. Thereby, when the work is a resin molded body, it is possible to remove burrs on the resin mold portion, and when the work is a metal or resin plate material or a member such as a mold or a precision part, Surface treatment, satin finishing, surface finishing, roughening, and the like can be performed, and further, polishing, polishing, and grinding can be performed.

After the polishing process such as deburring, surface polishing or roughening, the product is washed away with water or hot water, whereby the abrasive grains remaining in the product are dissolved in water and completely removed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention is applied to an air blast type polishing means for performing a polishing process by blowing abrasive grains using an air flow. The object to be polished is applicable to plastic molded bodies such as various electronic parts, other various resin products, metal products and the like.

As an example, the present invention can be used as a method for deburring an IC component. IC parts are usually
As shown in (1), it is continuously molded on a lead frame. As shown in the figure, the semiconductor lead frame 2 has a structure in which a plurality of leads 10 extend from both sides of a central mold portion 9 and are formed in a chain. As shown in FIG. 2, burrs 11 are formed between the leads 10 on the side surface of the molded portion 9 on the semiconductor lead frame 2 after the molding.

The polyvinyl alcohol granules of the present invention are obtained by polymerizing, saponifying, separating and drying vinyl acetate obtained by reacting ethylene, oxygen in the air and acetic acid. . The abrasive grains of this polyvinyl alcohol are white or cream-colored granules,
It is stable at 0 ° C. or lower, and water is generally used as the solvent. The abrasive grains are formed to have a predetermined particle size according to the application.

By continuously spraying the abrasive grains on the mold portion 9 of the lead frame 2, burrs 11 between the leads 10 are removed as shown in FIG.

The lead frame 2 from which the burrs have been removed is washed with water or hot water to dissolve and remove abrasive grains remaining on the lead frame. At this time, the abrasive grains of polyvinyl alcohol are easily dissolved in water and are reliably removed from the lead frame. Further, polyvinyl alcohol dissolved in water is harmless, and the aqueous solution does not affect the performance of the semiconductor device and does not hinder the operation of the processing device.

The abrasive grains of polyvinyl alcohol used here have a uniform particle size and can be efficiently used as abrasive grains for deburring between leads of a predetermined pitch. Further, since the hardness and weight are sufficient, sufficient performance as abrasive grains can be obtained, the life is long, and the next step is not adversely affected.

In the description of the above embodiment, abrasive grains of polyvinyl alcohol were used as a means for removing burrs.
It can be used for surface treatment and other general air blast polishing.

Further, the present invention is applicable to a method and an apparatus for performing polishing by blowing abrasive grains mixed in an air flow, using a nozzle or any other air blowing means.

The abrasive grains of the present invention are not limited to spherical shapes,
Aggregates such as fine crushed pieces having other grain shapes or sizes substantially uniform may be used.

[0028]

As described above, according to the present invention, abrasive particles made of polyvinyl alcohol are mixed with jet air and sprayed from the nozzle, for example, from a nozzle to the object to be polished. It can remove burrs from the mold part of the molded product, perform metal surface treatment (finishing or roughening, etc.), or grind, grind, and polisher molds and precision parts. Since it is possible to dissolve and remove the abrasive grains, the operation of removing the abrasive grains remaining on the processed product after polishing can be performed extremely simply and completely. Further, this makes it possible to realize an air blast type polishing apparatus which has a simple structure, is inexpensive and easy to handle.

Further, since polyvinyl alcohol can be easily granulated and its particle diameter can be easily made uniform, it can be easily adjusted to the shape and material of the product to be polished (for example, lead pitch for IC parts). Abrasive grains having an optimal grain size and abrasive grains having a grain size corresponding to the processing accuracy can be easily obtained, and the workability and handleability when forming the abrasive grains are improved, and the cost is reduced. Reduction is achieved. Further, the abrasive grains using the polyvinyl alcohol are hard and heavy, and therefore have sufficient performance as an abrasive, have a long life, and reduce running costs. Moreover, it is harmless because it dissolves in water, and even if it remains on the processed product or the aqueous solution remains, it does not adversely affect the next process, so that an excellent processed product is obtained without deteriorating quality or characteristics. be able to.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a semiconductor lead frame as an example of an object to be polished to which the present invention is applied.

FIG. 2 is an explanatory view showing a state where burrs are present in a mold portion of the semiconductor lead frame of FIG. 1;

FIG. 3 is an explanatory view showing a state in which burrs are removed from a mold portion of the semiconductor lead frame of FIG. 2 as a result of applying the present invention.

[Description of Signs] 2: Semiconductor lead frame (work) 9: Mold part 10: Lead 11: Burr

Claims (4)

[Claims] 1. A polishing method in which abrasive particles are blown against an object to be polished by an air flow, wherein abrasive particles made of polyvinyl alcohol are used. 2. A polishing apparatus having an air blowing means for blowing an air flow containing abrasive grains to an object to be polished, wherein said abrasive grains are made of polyvinyl alcohol. 3. An abrasive comprising a granular material of polyvinyl alcohol. 4. The abrasive according to claim 3, wherein the abrasive is used as abrasive particles sprayed on the object by air flow.