JP2006043793A - Blasting apparatus and blasting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blasting apparatus and a blasting method, stably maintaining fixed separation effect even if the particle size distribution of blasting material varies with the repeated and circulated use, thereby performing uniform blasting. <P>SOLUTION: This blasting apparatus 100 includes: a blasting chamber 10 and a blasting material tank 20, wherein the blasting material 1 is circulated through pipelines 11a, 11b to perform blasting. The apparatus includes a blasting material supply device for throwing unused blasting material 1A. According to this blasting method, while the blasting material 1 is circulated between the blasting chamber 10 and the blasting material tank 20 through the pipelines 11a, 11b, the blasting is performed. After the used blasting material 1 is collected from the blasting chamber 10, unused blasting material 1A is put in the used blasting material 1 before the collected blasting material is stored in the blasting material tank 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a blasting apparatus and a blasting method (hereinafter, also simply referred to as “apparatus” and “processing method”, respectively), and more specifically, paint peeling in various coated products, surface polishing of various tools and jigs, surface of a mold, and the like. The present invention relates to a blasting apparatus and a blasting method used for various purposes such as cleaning, dirt / rusting, deburring of molded products, peening or product reuse.

  Conventionally, blasting is known as one of various surface treatment methods such as paint peeling, mold cleaning, and peening. Blasting is a processing method that polishes and grinds the surface of a projection material mixed with compressed air and sprays it onto the object to be projected. Various types such as a pressure type, a suction type (suction type), a centrifugal type, a barrel, and a tumbler are known. In particular, in a blasting apparatus such as a direct pressure type or a suction type, a spray material is sprayed onto a work (projected object) using an injection nozzle.

  On the other hand, the projection material used for the blast treatment includes a metal type and a non-metal type, and the type, the particle size, and the shape are properly used according to each application. As a non-metallic projection material, one using a thermosetting resin is known as a projection material having relatively high hardness and excellent polishing and grinding effects. For example, Patent Document 1 discloses a thermosetting resin. An abrasive comprising a pulverized product having a particle size of 5 to 100 mesh is described. In addition, as a projection material with improved chargeability, Patent Document 2 describes a projection material obtained by mixing a thermosetting resin with conductive fibers, powder particles, or fine powder.

In the direct pressure type or suction type blasting apparatus, the sprayed material after spraying is often collected and circulated. For example, Patent Document 3 discloses polishing that is jetted from a plurality of blast nozzles by compressed air. There is described an air blasting apparatus configured to spray a material onto the outer surface of a workpiece to perform surface processing, and then to collect the sprayed abrasive and circulate it again to be ejected from a blast nozzle.
Japanese Patent Laid-Open No. 4-101776 (Claims etc.) JP 2002-79467 A (Claims etc.) JP-A-6-79629 (Claims, [FIG. 1], etc.)

  However, in the method in which the projection material is circulated and used repeatedly as described above, particularly in the case of a resin-based projection material, the projection material itself is crushed by a collision at the time of injection, and the particle size becomes smaller for each number of times of projection. Will go. As a result, the particle size distribution of the entire circulating projection material shifts in a smaller direction. As a result, a phenomenon occurs in which the projection material injection amount, which is a constant amount under a constant pressure at the start of blasting, gradually increases.

  In this case, if the average particle size is decreased by repeated use in a state where the injection amount is adjusted to match the initial average particle size of the projection material, the peeling ability is reduced due to the decrease in the particle size itself. Along with this, the increase in the injection amount as described above causes a decrease in the injection speed due to a deviation in the balance between the injection amount and the air amount, that is, a reduction in the peeling force. There has been a problem that the peeling effect decreases with repeated circulation use.

  As described above, when the peeling effect is reduced with repeated circulation use, a desired peeling process cannot be performed in an automatic blasting apparatus or the like, and there is a possibility that a problem such as a peeling residue may occur. As a means for preventing this, it is conceivable to adjust the balance between the amount of the projection material injected from the injection nozzle and the amount of air in accordance with the decrease in the particle size of the projection material. And the air amount must be automatically adjusted according to the measurement, which is substantially impossible from the viewpoint of cost.

  Therefore, an object of the present invention is to maintain a constant peeling effect stably even when the particle size distribution of the projection material changes with repeated circulation use, thereby performing a uniform blasting process. An object of the present invention is to provide a blasting apparatus and a blasting method which can be performed.

  In order to solve the above-mentioned problems, the present inventor has intensively studied. As a result, the unused projection material is automatically added according to the amount of consumption of the repeatedly circulated projection material, and the particle size distribution in the entire projection material is made uniform. As a result, it was found that injection from the injection nozzle can be stabilized, and uniform blasting can be performed without reducing the peeling effect, and the present invention has been completed.

  That is, the blasting apparatus of the present invention includes a blasting chamber and a blasting material tank, and a blasting material supply device for introducing an unused blasting material in a blasting device that performs blasting while circulating the blasting material through a pipe. It is characterized by providing.

  In the apparatus of this invention, it is preferable to provide the said projection material supply apparatus between the said blast chamber and a projection material tank, Comprising: In the middle of piping which goes to this projection material tank from this blast chamber. It is also preferable that the projection material tank includes a level sensor that detects the amount of the projection material inside. The apparatus of the present invention preferably ejects the projection material by any method selected from the group consisting of a direct pressure type, a suction type, and a centrifugal type.

  Further, the blasting method of the present invention is a blasting method in which a blasting process is performed between a blasting chamber and a blasting material tank while circulating the blasting material through a pipe. After the collection, before being accommodated in the projection material tank, an unused projection material is put into the used projection material.

  In the processing method of the present invention, it is preferable to start the unused projection material by detecting the amount of the projection material in the projection material tank, and preferably the unused projection material is used as the projection material. Add a fixed amount larger than the amount of projectile reduction per fixed time in the tank.

  According to the present invention, by adopting the above-described configuration, it is possible to prevent and stabilize the particle size distribution of the projection material that is likely to occur particularly when the resin-based projection material is repeatedly circulated and used. It is possible to stabilize the injection amount and appropriately adjust the relationship between the particle size and the injection amount. Accordingly, a blasting apparatus that can maintain optimum injection conditions in the blasting process, stably exhibit a certain peeling effect even during repeated use, and can stably perform uniform blasting as a result. And it became possible to realize the blasting method.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
In FIG. 1, the schematic block diagram of an example of the blasting apparatus of this invention is shown. As shown in the figure, a blasting apparatus 100 of the present invention includes a blast chamber 10 and a projecting material tank 20, and performs a blasting process while circulating the projecting material 1 through pipes 11a and 11b.

  As shown in the figure, the blasting apparatus 100 of the present invention is characterized in that it includes a projection material supply device 30 for introducing the unused projection material 1A. In other words, in the present invention, the projection material supply device 30 automatically supplies unused projection material 1A in accordance with the amount of consumption of the projection material 1 circulating in the blasting device 100, so that the particle size of the entire projection material 1 is increased. It is possible to realize a blasting apparatus 100 that prevents fluctuation in distribution, prevents a reduction in peeling effect, and can stably perform uniform blasting.

  In the circulation type blasting apparatus 100 as shown, the projection material 1 is supplied from the projection material tank 20 to the injection nozzle 12 via the pipe 11b and is injected into the projection object 13 in the blast chamber 10. Then, it is recovered through the pipe 11a and is accommodated in the projection material tank 20 again. At this time, in the used projection material 1 collected from the blast chamber 10, the delamination object 2 from the projection object 13 generated by surface cleaning by blasting, paint delamination, and the like, and dust generated due to wear of the projection material 1 itself. 3 is mixed. Therefore, these mixtures are usually used in the separating device (bead cleaner) 40 after being collected from the blast chamber 10 and before being stored in the projecting material tank 20, the separated projecting material 2, the exfoliated material 2 and the dust. 3 is separated. The separated exfoliated material 2 is collected by the dust collector 50, and the dust 3 is collected in the dust box 60 through the filter 61. Further, the air used to circulate the projection material 1 and the like is similarly discharged from the discharge port 62 to the outside through the filter 61.

  When the type of the projection 13 and the blasting conditions (injection amount, nozzle type, injection pressure, blasting distance / angle, etc.) are determined, the recovered dust 3 is generated at a constant amount per hour during the process. Become. Accordingly, the amount of the dust 3 generated every hour corresponds to the amount of consumption of the projection material 1, and the unused projection material 1A substantially equal to the amount of the dust 3 is placed in the blasting device 100 at regular intervals. By putting it in, the particle size distribution of the projection material 1 circulating in the apparatus 100 can be made substantially constant. A uniform and stable blasting process can be realized by adjusting the injection amount according to the conditions (workpiece, nozzle type, etc.) while the particle size distribution is constant. In addition, by supplying a fixed amount of the unused projection material 1A according to the present invention, it becomes possible to automatically supply the projection material 1, and the trouble of stopping the apparatus and introducing the projection material each time can be saved. Can also contribute.

  As shown in the figure, the location where the projection material supply device 30 is provided and the unused projection material is introduced is between the blast chamber 10 and the projection material tank 20 and is connected to the projection material tank 20 from the blast chamber 10. It is preferable to be in the middle. For example, although it is possible to directly put into the projection material tank 20, in this case, the used projection material 1 and the unused projection material 1A are not sufficiently mixed, resulting in local nonuniformity in the particle size distribution. There is a fear. By using the unused projection material 1A in the mixture of the used projection material 1 collected from the blast chamber 1, the exfoliated material 2 and the dust 3, and thereafter being transferred to the projection material tank 20, it is used. The used projection material 1 and the unused projection material 1A are sufficiently mixed to be accommodated in the projection material tank 20 in a state where a uniform particle size distribution is formed.

  As described above, since a certain amount of the projection material 1 is consumed every certain time in the blasting device 100, an unused amount of projection material corresponding to this consumption amount is put into the blasting device 100 by a certain amount. Thus, fluctuations in the particle size distribution can be prevented. In addition, since there is an optimum injection amount depending on the particle size of the projection material and the nozzle inner diameter, the particle size distribution is stabilized by this quantitative supply, which makes it possible to adjust the appropriate injection amount according to each condition, and optimal It is possible to set appropriate injection conditions. Preferably, the amount of quantitative supply is larger than the actual amount of projection material consumption. That is, it is preferable that the unused projection material 1 </ b> A is charged in a fixed amount that is larger than the projection material reduction amount per fixed time in the projection material tank 20.

  In addition, a method for charging the unused projection material 1A in the projection material supply device 30 is not particularly limited. For example, a level sensor (not shown) that detects the amount of projection material in the projection material tank 20 is used. In this way, it is possible to detect the decrease in the amount of projection material in the projection material tank and to start feeding unused projection material. After starting the injection when the amount of projection material in the projection material tank falls below a certain level, stop the introduction by detecting the signal from the level sensor in the same way when the amount of projection material increases to the predetermined amount of projection material, or , It may be stopped at a predetermined time after the start of charging. In addition, since the purpose is to make the particle size distribution in the circulated projection material as uniform as possible for each input amount from the start to the stop of the input, the input amount is small, for example, an amount of about 200 g or less. It is preferable that the above-mentioned fixed amount is achieved as a whole by introducing them at regular intervals. This one-time charging amount and charging interval can be appropriately adjusted.

  For example, when the projection material 1 having an initial particle size of about 30 mesh (particle size of 850 to 500 μm) mainly composed of a thermosetting resin is injected by an injection nozzle having a pressure of 0.5 MPa and an inner diameter of φ6 mm, 30 to 100 g / About 3 minutes of dust 3 is generated. Here, the relationship between the particle size and the injection amount of the projection material and the peeling effect is shown in the graphs of FIGS. 2A (in the case of an injection nozzle having an inner diameter of φ6 mm) and (b) (in the case of an injection nozzle having an inner diameter of φ8 mm). Street. From these graphs, it can be seen that there is an optimum injection amount for each particle size of the projection material and the inner diameter of the injection nozzle, and it is preferable that the smaller the particle size, the smaller the injection amount, regardless of the inner diameter of the injection nozzle.

  Therefore, under the above blasting conditions, for example, in order to stabilize the injection with a particle size distribution of 500 to 300 μm and an injection amount of about 1.2 kg / min, the unused projection material can be charged as follows. First, when the amount of the projection material in the projection material tank 20 is reduced to about 50% of the initial capacity is detected by a signal from the level sensor, the introduction of the unused projection material is started at an input amount of about 50 to 150 g / time. . The charging is performed at a predetermined interval, for example, at intervals of 5 to 10 seconds, and detected again by a signal from the level sensor, or stopped after a predetermined time, for example, 1 to 3 minutes have elapsed after starting the charging. Good.

  Further, for example, when the projection material 1 having an initial particle size of about 30 mesh (particle size of 850 to 500 μm) mainly composed of a thermosetting resin is injected by an injection nozzle having a pressure of 0.5 MPa and an inner diameter of φ4 mm, 30 to 40 g. / 3 minute dust 3 is generated. In order to stabilize this with, for example, a particle size distribution of 500 to 300 μm and an injection amount of about 0.6 kg / min, the amount of the projection material in the projection material tank 20 is about 50% of the initial capacity, as in the above case. Is detected by a signal from the level sensor, and the injection of the unused projection material is started at an input amount of about 50 to 60 g / time, and after the input is performed at a predetermined interval, for example, an interval of 5 to 10 seconds, Detection may be stopped again by a signal from the level sensor, or may be stopped after a predetermined time, for example, 1 to 3 minutes have elapsed after the start of injection.

  About the specific apparatus structure of the blasting apparatus of this invention, it does not restrict | limit in particular except providing the said projection material supply apparatus 30, What is necessary is just to comprise similarly to a conventionally well-known blasting apparatus. For example, the blasting apparatus of the present invention includes a direct pressure type that pressurizes the projection material tank 20, a suction type (suction type) that depressurizes the projection material tank 2, a weight type based on the weight of the projection material, and a rotor in the injection nozzle 3. Provided, among the centrifugal type that uses the rotational centrifugal force of the rotor, an appropriate injection method can be selected according to the processing purpose, the object, etc., preferably, the direct pressure type or the suction type, It is suitable for a blasting apparatus using a direct pressure type as shown.

  In the illustrated apparatus 100, the projection material tank 20 is composed of two tanks, an upper tank 20a and a lower tank 20b. This is because the projection is recovered by increasing or decreasing the pressure via the upper tank 20a. The adjustment of the pressure difference between the separation device 40 and the lower tank 20b when the material 1 is accommodated is made smooth, and a continuous blasting process is performed. Furthermore, the adjustment of the injection amount can be performed by adjusting the amount of beads using a bead valve (not shown) provided in the pipe 11b connected to the injection nozzle 12 from the lower tank 20b. Separation of the material 1 from the exfoliated material 2 and the dust 3 is performed by blowing out and sucking air.

  The projection material 1 applicable to the blasting apparatus and the blasting method according to the present invention is not particularly limited, and includes a resin-based projection material mainly composed of a thermosetting resin, due to wear during blasting. Applicable to all projectiles that are consumed. For example, as a thermosetting resin used for a thermosetting resin-based projection material, melamine resin (melamine-formaldehyde resin), urea resin (urea-formaldehyde resin), polycarbonate resin, phenol resin, unsaturated polyester resin, An acrylic resin, a guanamine resin, an epoxy resin, a polyurethane resin, and the like can be given. In addition, resins having hardness comparable to these can also be used. These resins can be used alone or in appropriate combination in several combinations having different hardness, specific gravity and viscosity. Moreover, pulp, glass fiber cloth fragments, carbon, artificial graphite, metal fibers, and the like can be appropriately blended in the thermosetting resin according to the use.

  As such a resin-based projection material, specifically, for example, a pulverized product of a thermosetting resin molded product having a particle size of about 1000 to 50 μm, and each particle is surrounded by a sharp edge. In addition, a fine polyhedron and a material that is almost homogenized within a certain particle size range for each classification step can be preferably used. Particularly preferably, a resin plate-shaped molded product obtained by blending melamine resin and one or both of urea resin and phenol resin is pulverized, or different plate-shaped molded products of melamine resin, urea resin and phenol resin are respectively obtained. After roughly crushing, mixing, and crushing to form an irregular polyhedral fine material, the projection material can be used. The projection material made of such a pulverized product can be obtained by the method described in WO00 / 45994.

Hereinafter, the present invention will be described specifically by way of examples.
(Example)
In the direct pressure type blasting apparatus 100 shown in FIG. 1, the coating product is peeled off using Bridgestone Co., Ltd. product name MG-03 having an initial particle size of about 30 mesh (particle size 850 to 500 μm) as the projection material 1. Processed. In addition, a level sensor for detecting the amount of internal projection material was provided in the projection material tank 20 of the apparatus 100. When injection was performed using an injection nozzle with an inner diameter of φ6 mm, a pressure of 0.5 MPa, and a bead valve adjusted to an injection amount of 1.2 kg / min, dust 3 (about 100 μm or less) of about 100 g / min was generated. .

  When the amount of the projection material in the projection material tank 20 is reduced to about 50% of the initial capacity, it is detected by a signal from the level sensor, and the projection material supply device 30 uses it at an input amount of 150 g / time, every 8 seconds. The projection material 1A was charged and stopped 2 minutes after the charging was started. As a result, the particle size distribution was stable around 500 to 300 μm, and the blasting treatment could be performed while maintaining the peeling effect constant at an injection amount of 1.2 kg / min. There was no problem. FIG. 3A shows the particle size distribution of the projection material immediately after the start of blasting, at each of the 10th, 20th, and 30th blasting times. Moreover, the average particle size distribution of the said projection material at the time of performing the fixed supply obtained from this result is combined with FIG.3 (b), and is shown.

(Comparative example)
On the other hand, when the blasting process was performed without introducing the unused projection material 1A under the same blasting conditions as described above, the blasting process was repeated about 10 times, and the particle size of the circulating projection material 1 was about 300 to 100 μm. At that time, the injection amount increased to 1.5 to 2.5 kg / min. For this reason, the peeling effect was greatly reduced by the synergistic effect of the decrease in the particle size and the increase in the injection amount, and blasting defects such as peeling residue occurred.

It is a schematic structure figure showing one suitable example of a blasting device of the present invention. (A) is a graph which shows the relationship between the particle size and injection quantity of a projection material, and a peeling effect in the case of an injection nozzle with an internal diameter of φ6 mm, and (b) in the case of an injection nozzle with an internal diameter of φ8 mm. (A) is a graph which shows the particle size distribution of the projection material in each time of the 10th, 20th, and 30th blast immediately after the start of blasting in the examples, and (b) is a graph of the projection material at the time of quantitative supply. It is a graph which shows an average particle size distribution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projection material 2 Separation thing 3 Dust 10 Blast chamber 11a, 11b Piping 12 Injection nozzle 13 Projection object 20 (20a, 20b) Projection material tank (upper tank, lower tank)
30 Projection Material Supply Device 40 Separation Device 50 Dust Collector 60 Dust Box 61 Filter 62 Discharge Port 100 Blasting Device

Claims (7)

  A blasting apparatus comprising a blasting chamber and a blasting material tank, wherein the blasting device performs a blasting process while circulating the blasting material through a pipe, and includes a blasting material supply device for introducing an unused blasting material. .   The blasting device according to claim 1, wherein the blasting material supply device is provided between the blasting chamber and the blasting material tank and in the middle of piping from the blasting chamber toward the blasting material tank.   The blasting device according to claim 1, wherein the projection material tank includes a level sensor that detects the amount of the projection material inside.   The blasting device according to any one of claims 1 to 3, wherein the projection material is ejected by any method selected from the group consisting of a direct pressure type, a suction type, and a centrifugal type.   In the blasting method in which the blasting process is performed while circulating the blasting material through the pipe between the blasting chamber and the blasting material tank, after the used blasting material is collected from the blasting chamber, A blasting method, wherein an unused projection material is put into the used projection material before being housed.   The blasting method according to claim 5, wherein the injection of the unused projection material is started by detecting the amount of projection material in the projection material tank.   The blasting method according to claim 5 or 6, wherein the unused projection material is introduced in a constant amount larger than a projection material reduction amount per fixed time in the projection material tank.

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