JPH06198418A - Method for separating out sprue parts from cast product - Google Patents

Abstract

PURPOSE:To separate out sprue parts from a cast product by resonating a whole cast product in a high temp. range indicating the strength having about a half of the strength at a room temp. CONSTITUTION:A spheroidal graphite cast iron product 1 is in a molding sand, and when the temp. thereof is the lower transition temp., i.e., about 500-600 deg.C, the sprue part 2 is held therebetween by chuck mechanism 7 and the vibration having about 120Hz frequency is imparted to the cast product 1-4. Gates of the sprue parts preformed to the smallest cross section are used as joints and the gates are easily broken by the resonance, and the sprue parts and the cast product part can be separated with a small exciting device. By selecting the temp. range showing about <=1/2 of the tensile strength at the room temp. in the intermediate range between an upper transition temp. where the tensile strength starts to suddenly increase after the molten metal passes through the solidified point from the high temp. range and the lower transition temp. where the changing degree of the strength suddenly starts to slow down after the temp. further lowers, the cast product is given to the resonant condition.

Description

Detailed Description of the Invention

[0001]

SUMMARY OF THE INVENTION The present invention relates to a method for removing a sprue system part from a cast product in a casting manufacturing process, and is particularly intended to provide a new separating method suitable for automatic mechanization. .

[0002]

2. Description of the Related Art Among various metal products such as manufacturing machine parts, automobile parts, consumer machine parts, etc., casting products have a very long history as one of important metal products indispensable due to their manufacturing method and properties. , Has continued to support our industry. In the manufacturing process of such castings, the process of melting metal, pouring it into a mold, solidifying it to remove the mold, removing excess parts and inspecting, cleaning, and finishing is basically the same as before and now. Therefore, as long as you follow this series of work steps, the harmful effects on the work environment due to high temperatures, noise, bad odors, dust, fumes, residue contamination, etc., are of course still present, and how to eliminate them Whether to overcome it has been a long-standing concern in the foundry industry.

In particular, the Japanese economy is undergoing a high economic growth, which is rare even in the world, and even if it is not so, a large amount of labor is leaked to the tertiary industry. While the whole is in labor shortage, even if it can guarantee a high wage provisionally, as long as it continues to work as an industry that is forced to work in an environment where poor and severe labor is forced, It is shunned as an industry that does not meet the working conditions, and the prospect of securing a future labor force will not be cut off. In addition, the cost performance under the rising wages of the Japanese industry as a whole is one of the extremely important management stabilization requirements for any industry, and especially due to the strict economic philosophy, work is especially important. In the foundry industry, which is in a typical position due to the poor environment, it is an urgent need to rationalize and automate the manufacturing process before the old model, regardless of whether they like it or not.

Due to such requirements, the melting process, the mold forming process, the pouring process, the mold releasing process, the casting surface cleaning process, and the flash finishing process have already been automated as much as possible, and have already been rationalized. It has a great effect. Also, regarding the removal and removal process of the sprue system part, for example, in the case of a material with high ductility such as spheroidal graphite cast iron, copper alloy, aluminum alloy casting, mainly by cutting treatment, and for gray cast iron and malleable cast iron In the case of brittle materials such as white pig iron, there are cases in which the shape and dimensions of the weir have been devised in advance and a shake-out machine or a mold tumbler has been adopted to succeed in automating the casting. Depending on the type, it may be possible to automate all steps. However, in the case where the sprue system has a large cross-sectional area, even if it is a fragile material, it cannot be removed by the above-mentioned means, and while casting the product on the slat conveyor, it can be manually hammered. It is usual to fold it, so the reality is that automation for these has not yet been realized.

As a result of continuing intensive research and development in order to deal with the above situation, the present invention finally does not depend on human labor even in the case of a cast product with a large cross-sectional area of the temporary sprue system part. We have succeeded in realizing an extremely practical method for removing the sprue system part of a cast product by a mechanizable work process of chucking → excitation, and the results will be detailed below.

As can be understood from the several embodiments of the present invention shown in the drawings, the present invention basically has the following structure. That is,
After pouring molten metal into the mold, leave it for a predetermined time to solidify,
Cast product (entire part poured into the mold, that is, cast product part and sprue, strainer, riser, runner, weir, etc.)
Is a method for removing a sprue system part of a cast product, in which the sprue system part is separated from the cast product part by causing the entire cast product to resonate in a high temperature region at least higher than or equal to the lower transition temperature of the transition temperature peculiar to.

It is generally well known that the tensile strength of a metal material changes greatly in the process in which the molten metal begins to cool and solidify, and the temperature gradually decreases. The transition temperature refers to a temperature range around which the mutated tensile strength is abruptly mutated despite a constant temperature change, and in the process from the high temperature range where solidification begins to room temperature, The temperature range where the tensile strength begins to increase rapidly after passing the freezing point, that is, the upper transition temperature that appears on the freezing point side,
There is a temperature range around where the temperature further decreases and the tensile strength increases rapidly, and this sudden change in the tensile strength begins to suddenly become dull, that is, a lower transition temperature that appears on the normal temperature side, Both transition temperatures show different values depending on the type of casting.

For example, in the case of spheroidal graphite cast iron (FCD450, normal temperature tensile strength 450 newton / square grout) shown in the graph of FIG. 3, the upper transition temperature is about 700 degrees Celsius and the lower transition temperature is about 500 degrees Celsius. The tensile strength at the upper transition temperature is about 20% of that at room temperature,
It can be seen that at the lower transition temperature, the change in tensile strength during this period is about 80%, which is extremely large, and the change in tensile strength during that time is a substantially linear and rapid increase in strength, as shown in the graph.

In the present invention, of these two transition temperatures, at least the tensile strength of the cast product is at room temperature, which is at least higher than the lower transition temperature, preferably in the middle or higher temperature range. By selecting a temperature range exhibiting a value of about ½ or less of the tensile strength and applying vibration of the natural frequency of the casting to the entire casting, the entire casting is brought into a resonance state.

The cast product placed in this state is formed in advance to have the smallest cross-sectional area between the cast product part and the unnecessary part (gate part) such as the sprue, runner, riser and the like. With the weir as a node, the lump on either side, that is, the non-chucking side in the cast product part or the sprue system part, shows a peculiar resonance phenomenon and swings. Encourage the outbreak. However, since the cast product itself is in a high temperature range above the lower transition temperature, it can exhibit only an extremely fragile value (about 1/2 or less than the normal temperature tensile strength) from the inherent tensile strength. Since the vibration is applied to the object in a pre-regulated state, the weir breaks easily without being able to withstand this resonance phenomenon within a short time, and at least the gate system part and the casting product part are reliably separated. Will be done.

The impact acceleration received on the apparatus side while inducing this resonance state is much smaller than that of the hammer impact impact force and the air hammer impact force due to human power, which is a bottleneck of robotization. Since the shock absorption mechanism that has been made possible with the conventional method is extremely simplified unlike the conventional one, the resonance process in the regulated temperature range of the cast product is It is a very important constituent element that is indispensable as the technical idea of. In the following, a specific example based on the technical idea of the present invention will be explained with reference to two modeled examples.

[0011]

Example 1 As shown in the process charts of FIGS. 1A to 1D, a cast product, that is, a cast product part 1, and a sprue 2, a runner 3, a weir 4, etc. other than a part to be the cast product part 1 First, the technical idea of the present invention includes a case where the vibration is performed in the mold 5. That is, after cooling to a predetermined temperature range in the state of FIG. 1a (first step), the chuck portion 71 of the chuck mechanism 7 is thrust into the molding sand 6 which is a sand mold, and the sprue (if possible, another sprue system portion) The second step to attach 2 pieces.

Subsequently, the castings 1 to 4 are directly used as casting sand 6
A third step of applying a vibration of a predetermined frequency through the chuck mechanism 7 while keeping the inside (b in the figure). A temperature range convenient for realizing the technical idea of the present invention is, for example, spheroidal graphite cast iron (FCD45) shown in the graph of FIG.
0, normal temperature tensile strength 450 Newton / square) when manufacturing the casting product 1, the upper transition temperature range (about 700 degrees Celsius) is the chain double-dashed line α, and the lower transition temperature range (about Celsius) 500 degrees) is indicated by the chain double-dashed line β,
At least the lower transition temperature among those transition temperatures, that is, the high temperature region side of about 500 degrees Celsius or more, and preferably the tensile strength of the cast product shows a value of about ½ or less, that is, about In a high temperature range around 600 degrees Celsius or higher, which does not hinder chucking, a frequency of about 120 Hertz peculiar to the castings 1 to 4 is applied to the casting 1 through the chuck portion 71 of the chuck mechanism 7. ~ 4 is to be given to the whole.

During the vibration in this step, the vibration is naturally transmitted to the molding sand 6 and the upper frame 51 and the lower frame 52 which are the mold 5 which have been compacted until then. Depending on the type of 5, the upper and lower frames 51, 52 may come off, or the entire mold 5 may start to dance around the castings 1 to 4, but the casting sand 6 that had been compacted and solidified until then. Collapsed and the upper flask 52
Since there is a risk of overflow and scattering from the equipment, effective measures that can deal with them should be taken in advance when the robot is used as a production line.

In this way, after an appropriate time (the time varies depending on the size, shape, material, temperature, etc. of the sprue system parts 2 to 4 and the casting product 1), the chucking mechanism as shown in FIG. 1c. 7 and the chuck part 71 holds the sprue system parts 2 to 4, and the mold 5 and the foundry sand 6 are held.
The 4th process that leaves you. Finally, as shown in FIG. 1d, if the fifth step of taking out the casting product 1 from the casting sand 6 and collecting it by a known means is completed, the method of removing the sprue system portion of the casting product of the present invention is completed. .

[0015]

Example 2 Next, as shown in FIGS.
There are also cases where vibrations to 4 are performed outside the mold 5,
This is included in the technical idea of this invention. That is, after cooling to a predetermined temperature range in the state of FIG. 2a (first step), the same b
As described above, the second step of thrusting the chuck portion 71 of the chuck mechanism 7 into the casting sand 6 which is a sand mold and sandwiching the sprue (other sprue system portion if possible) 2 therein. Subsequently, as shown in FIG. 7C, the cast products 1 to 4 held by the chuck portion 71.
Third step of taking the whole out of the mold 5. In order to make it easier to take out the entire castings 1 to 4 in the third step from the casting sand 6, if necessary, in the second step stage, the entire castings 1 to 4 can be appropriately supplied to the castings 1 to 4 through the chuck mechanism 7. It is also possible to apply vibration to break down the solidified molding sand 6 and at the same time remove the molding sand 6 adhering to the surfaces of the castings 1 to 4.

Thereafter, similar to the vibration process of the above-mentioned embodiment, an appropriate time (this time depends on the size, shape, and shape of the sprue system parts 2 to 4 and the casting product 1) is set according to the vibration frequency peculiar to the casting products 1 to 4.
The same as in the case of the first embodiment, which differs depending on the material, temperature, etc.) The fourth step of applying vibration through the chuck mechanism 7 (FIG. 2c). Then, while the vibration process for a predetermined time elapses, only the casting product part 1 is detached and recovered while holding the sprue system parts 2 to 4 on the chuck part 71 of the chuck mechanism 7 as shown in FIG. The above-described first to fifth steps, which are the following steps, complete the method of removing the sprue system portion of the cast product of the present invention.

As described above, the two embodiments representing the present invention are shown by the modeled process drawings. The stage after the first process and before the second process in the second embodiment, that is, the molding sand 6 Before clasping the cast articles 1 to 4 in place, the mold 5 and the molding sand 6 are removed in the same manner as the conventional unmolding, and the cast articles 1 to 4 are made naked, and then the chuck of the chuck mechanism 7 is used. The sprue part 71 (other sprue system parts if possible) 2
Even if the whole of the castings 1 to 4 after the second step of the above-mentioned Example 2 is put out of the mold 5, the same state as in Example 2 can be realized. Therefore, the technical idea of the present invention includes the vibrating step under regulated conditions, and the casting product part 1 to the sprue system part 2 in the process. The steps before and after the step of removing No. 4 are not restricted by the above-described example of the second embodiment.

[0018]

With the method of removing the sprue system portion of the cast product of the present invention having the above-described structure, the molten metal cools and passes through its freezing point, and then the vertical transition temperature at which the tensile strength is rapidly changed, At least the lower transition temperature or higher, particularly preferably in the temperature range around the middle or higher temperature side, the tensile strength of the cast products 1 to 4 is substantially half or less than that of normal (normal temperature range). A new sprue system detachment method developed and completed based on the knowledge that it is placed under fragile properties and the knowledge that solids have a unique vibration range that causes resonance. For example, as in the two-step excitation method proposed in the invention of Japanese Patent Application Laid-Open No. 58-74270, no vibration that is substantially equivalent to a shock wave is required, let alone Japanese Patent Application Laid-Open No. 3-133.
The impact acceleration is about 15 like the knockout machine using the invention No. 561 and the air hammer which is already on the market.
Unlike the method of reaching 0 G and the like, the vibration impact applied to the chuck mechanism side, which is the vibrating device when carrying out the present invention, is much smaller.

Therefore, it is necessary to incorporate a large-scale shock absorbing mechanism in the conventional ones, and effective measures for preventing noise generated at that time are required. However, according to the method of the present invention, there are very few obstacles as those of the conventional ones, and more conveniently, the castings 1 to 4 remain in a predetermined posture in the mold 5. Due to the advantage that the chuck portion 71 of the chuck mechanism 7 can easily catch a predetermined place, the detaching process of the sprue system portions 2 to 4 left from the end to the cast product portion 1 is finally completed. With the prospect of automation, it is possible to automate the entire casting production line by continuing to the other steps of the already automated casting production process.

In particular, in Example 1 shown as one of typical examples for carrying out the present invention, the casting product part 1 is left in the casting sand 6 due to the step of vibrating in the mold 5. Since the cast product part 1 has a complicated shape and is a thin cast product, or a round product or a thick product that is unlikely to be deformed or cracked by a hot impact, the mold releasing method is selected as a pickup method. There is an advantage that it is possible to appropriately select whether to use the dumping method or the punch-down method, and according to the second embodiment, the casting product and the sprue system part can be separated and recovered regardless of the mold release. It will be possible, and it will bring out the characteristic that the method of assembling the automation line can be made orderly.

As described above, the method of removing the sprue system part of the cast product of the present invention is said to be one of the worst in the industrial environment in all industrial fields, which is largely due to the difficulty of automating the manufacturing process. It is expected that it will exert its great power to transform the foundry industry, which was considered to have been used in the past, into an industry with an environment similar to or close to other industries, and effective measures against labor shortages and product cost reduction. It is expected that it will be highly evaluated as a stabilizing factor.

[Brief description of drawings]

The drawings depict only a few typical embodiments of the process modeled to illustrate the invention.

FIG. 1 is a process diagram illustrating a separation method including first to fifth steps.

FIG. 2 is a process drawing explaining another separation method including first to fifth steps.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cast product 2 Gate 3 Runway 4 Weir 5 Mold 51 Same lower frame 52 Same upper frame 6 Foundry sand 7 Chuck mechanism 71 Same chuck part

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 2, 1993

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show merely some representative embodiments of the process modeled to illustrate the invention.

FIG. 1 is a process diagram illustrating a separation method including first to fifth steps.

FIG. 2 is a process drawing explaining another separation method including first to fifth steps.

FIG. 3 is a chart showing changes in tensile strength of spheroidal graphite cast iron.

[Explanation of symbols] 1 casting product 2 gate 3 runner 4 weir 5 mold 51 same lower frame 52 same upper frame 6 foundry sand 7 chuck mechanism 71 same chuck part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshie Tanaka, in front of the Numaki-shaped car, Yamagata City, 683 Yamagata Prefectural Industrial Technology Center (72) In front of, inventor, Ryo Yamada, 683 In front of the Numaki-shaped car, Yamagata City Industrial Technology, Yamagata Prefecture In the center (72) Inventor Tokurou Hisamatsu In front of the Numaki-shaped car in Yamagata 683 Inside the Yamagata Industrial Technology Center (72) In Seiya Kobayashi In front of the Numaki-shaped car in Yamagata 683 Inside the Industrial Technology Center in Yamagata

Claims (1)

[Claims] 1. The molten metal is poured into a mold and then allowed to stand for a predetermined time to be solidified, and the entire cast product is resonated in a high temperature range at least higher than the lower transition temperature of the transition temperature inherent to the cast product, A method of detaching a sprue system part of a cast product, in which the sprue system part is detached from a cast product part.