JPH0243652Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a media used for barrel polishing such as deburring and rounding of metal.

[Conventional technology and its problems]

In general, barrel polishing involves the use of free abrasive grains called media (or chips) in a rubber-lined barrel tank, water in the case of a wet method, a compound added as necessary, and a workpiece ( In this method, barrel polishing is performed using the interaction between the media and the workpiece caused by motion such as rotation and vibration. This barrel polishing process is used for deburring, rounding, descaling, polishing, etc. of iron, steel parts, eyeglass frames, buttons, etc., and has a specific purpose of loosening clothing such as jeans and removing fluff. It is also used to remove color or bleach the color.

By the way, the media used for barrel polishing vary in size from those with irregular shapes to those with specified shapes, and each has characteristics in specific gravity and hardness, making it suitable for specific workpieces. Match is used. Among these, artificial media with a specific shape is also often used, which is made by bonding artificial abrasives or natural abrasives of arbitrary particle size with a binder, and the shape is triangular. It comes in a wide variety of shapes, including cylindrical, cubic, etc.

On the other hand, plastic is used as a binder for molding such artificial media. That is, media made of a composite of abrasive material and plastic powder have been well-received because they can be appropriately abraded without causing large fractures, and furthermore, they can be applied using a dry method without problems with wastewater treatment. Therefore, many technologies have been developed regarding media using such plastic as a binder. For example, Japanese Patent Publication No. 50-39870, Japanese Patent Publication No. 51-
Publication No. 147093, Japanese Patent Application Publication No. 55-57459, Japanese Patent Application Publication No. Sho
See Publication No. 59-129659 and Japanese Patent Application Laid-open No. 60-242960.

By the way, in the above-mentioned Japanese Patent Application Laid-open No. 60-242960,
Silica is selected as the abrasive material, unsaturated polyester resin and vinyl chloride resin are selected as the plastic materials, and expanded polystyrene resin is selected for forming the air bubbles.These powders are mixed, and the mixture is poured into a mold using its own weight to form the product. and then heating,
Dry porous resin media are introduced.

However, in such porous resin media, only the expanded polystyrene resin is added (for example, 1% weight ratio in the example), and the blending ratio of the abrasive material and plastic powder is limited. Compared to other countries, the proportion of highly foamed polystyrene is about 30%, and the foamed polystyrene resin accounts for a large portion, and the abrasive material is scattered around, making it impossible to increase grinding efficiency. There was a problem that the method was not suitable and was mainly used for kneading and loosening jeans, etc., and the mixing time of the powder was also extended.

Furthermore, in such conventional porous resin media,
In order to apply it to loosening jeans, etc., it has been made lightweight with a true specific gravity of 1 or less, so if it is used for deburring metal, there will be a large difference between the specific gravity of such porous resin media and the specific gravity of metal workpieces. There was a problem in that if both were vibrated in the barrel tank, the workpiece would sink and contact with the media would not be good. Furthermore, in conventional porous resin media, the molding process involves pouring it into a casting mold and heating it, which inevitably precludes the application of high-frequency heating, resulting in general external heating. There is a temperature difference between
If the inside is heated sufficiently, a skin layer will form on the surface side, which is disadvantageous for polishing.Moreover, if this skin layer is avoided, the inside will not be heated enough, and the binding as a binder will be insufficient, making the media brittle. There was a problem.

[Means for solving problems]

Therefore, the present invention was devised with a focus on eliminating the above-mentioned drawbacks in media made of powdered abrasive material and plastic material. A barrel polishing medium consisting of a powdered binder plastic material having a power factor (10 ^C/S to 10 ^{6 C/S} ) of 0.02 or more, and porously dispersed microbubbles, When the powder of abrasive material and plastic material is mixed and poured into the mold by its own weight, the air mixed in with the plastic material, which is internally melted by short-term high-frequency heating that does not form a skin layer, causes the microbubbles to form. Barrel polishing media used for deburring, polishing, etc. of metals is characterized by the following structure:

〔Example〕

The structure of the media of the present invention will be explained in detail based on the manufacturing process shown in the attached FIG. FIG. 1 shows a process diagram for manufacturing media 1, in which 2 is:
Powdered abrasive material (for example, abrasive material a whose main component is zirconia-based, alumina-based, titanium-based, or silicon-based ceramics, etc., preferably 60 to 1500
A hopper is shown for supplying 240 mesh (preferably 240 mesh).

3 is a powdered plastic material (having a dielectric loss (power factor) (10 ^C/S to 10 ^{6 C/S} ) of about 0.02 or more, for example, as a binder for binding the abrasive material a,
A hopper is shown for supplying powder b) of phenolic resin, urea resin, melamine resin, epoxy resin, cellulose triacetate resin, polyvinyl chloride resin, polycarbonate resin, methacrylic resin, nylon-6 resin, or nylon-12 resin.

4 is a mixer, which mixes the abrasive material a and plastic material b.
As described below, in some cases, it is not necessary to mix accurately and uniformly, and the operation time may be short.

5 is a flat mold with dielectric loss (10 ^C/S ~
10 ^{6 C/S} ) is approximately 0.02 or less and is made of a material that has heat resistance below the media molding temperature. Therefore, it is made of, for example, Teflon (trade name) or silicone rubber. This mold 5 has a large number of through holes 6 of a predetermined size for the media 1 formed therein. Here, if the material of the mold 5 is selected to have a dielectric loss of 0.02 or less, for example, if the mold 5 is made of styrene resin, the material can be heat-welded and bonded by the high-frequency heating device 7 described later. Since the mold itself melts due to the heat of the media 1, it was found that the material must be heat resistant to a temperature higher than the molding temperature of the media 1.

7 is a high frequency (or microwave is also included, but herein collectively referred to as high frequency heating) heating device, 8 is a variable capacitor, 9 is an inductance, 10 is an electrode, 11 is a high frequency oscillator,
The heating operation time does not have to be strict, and is set to 0.5 to 3 minutes, since the mixing ratio of abrasive material a and plastic material b, which will be described later, can be freely selected.

Note that 12 indicates a storage container.

However, abrasive material a and powdered plastic material b
are supplied to the mixer 4 and mixed appropriately, and then poured by its own weight into each through hole 6 of the mold 5 placed on a fixed rock (not shown). Therefore, air is also mixed in at the same time, and the remaining air forms microbubbles c in the completed media 1. Next, the mold 5 and the fixed rock are set in the high frequency heating device 7, and a heating operation is performed for 0.5 to 3 minutes. As a result, the plastic material b is melted and acts as a binder for each abrasive material a, and the media 1 having the microbubbles c formed therein can be molded. Here, if the plastic material b is heated for a long time of 0.5 to 3 minutes or more, the plastic material b will melt excessively and will also be welded to the through hole 6, which will not only make it difficult to take out the media 1 from the through hole 6. , a skin layer is created on the outer peripheral surface of the media 1 in contact with the mold 5,
It was found that this was not preferable in terms of barrel polishing.

Next, the mold 5 is taken out from the high-frequency heating device 7, and in order to shape the medium 1 while it is at high temperature, a press mold (not shown, but a flat plate with many protrusions protruding from the lower surface that can be loosely fitted into the through holes 6) is used. and press lightly.

Next, after the medium 1 is cooled, the press die is used to take out the medium 1 as shown in FIG. 2 from the mold 5.

That is, the media 1 of the present invention is composed of an abrasive material a, a fused plastic material b, and microbubbles c made of residual air.

In addition, if the media 1 obtained through the above manufacturing process has a size of 8 mmφ, the radius of the cut-out iron plate
It can be used for barrel polishing for attaching and removing burrs from castings. Alternatively, a 20 mm square media may be used.

The manufacturing process explained above uses the so-called batch method, but a mold is installed on the conveyor,
A continuous manufacturing process may be adopted in which a high-frequency heating device is placed over a conveyor.

[Effect of idea]

The media of the present invention has the following excellent effects.

Since the entrained air becomes microbubbles due to the internally melted plastic material caused by short-term high-frequency heating, there is no skin layer of plastic material on the surface of the media (molten resin is formed on the contact surface of the media with the mold). The abrasive material is exposed on the surface of the media and can improve the grinding effect, making it convenient for deburring and polishing metals.

The entrained air becomes microbubbles even in the plastic material that is internally melted by short-time high-frequency heating, so the microbubbles are dispersed in a uniform porous shape and have the effect of regenerating the grinding force during barrel polishing. (new abrasive material is exposed to the surface one after another).

Since the mixed air is formed into microbubbles by the internally melted plastic material due to short-term high-frequency heating, there is no need to separately mix in a foam molding material such as expanded polystyrene.
Not only can the mixing time of the abrasive material and the plastic material for the binder be shortened, but also high frequency insulation is not generated and internal melting does not occur.

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram for manufacturing the media of the present invention, and FIG. 2 is a sectional view of the media of the present invention. a...abrasive material, b...plastic material, c...microbubbles.

Claims (1)

[Scope of claim for utility model registration] Powdered abrasive material, powdered binder plastic material with a power factor (10 ^C/S to 10 ^{6 C/S} ) of 0.02 or more, and porously dispersed powder. For barrel polishing media consisting of microbubbles, when the powder of the abrasive material and plastic material is mixed and poured into the mold by its own weight, the air mixed in is exposed to a short period of high frequency that does not form a skin layer. A barrel polishing medium used for deburring, polishing, etc. of metal, characterized in that the microbubbles are made of the plastic material which is internally melted by heating.