JP4201099B2 - Measuring method and measuring apparatus of green compact density - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a production method for obtaining a predetermined shape by compressing and firing a powder, and is compression-molded into a complicated shape, or divided into predetermined samples after compression molding, It is a method for measuring the density of the green compacts, and in particular, relates to a technique that uses a non-polluting liquid that does not require special handling and is intended to measure with high work efficiency.
[0002]
When the green compact is fired to obtain a predetermined shape, the density of the green compact that has been compression-molded affects the size of the compact after firing. The density of each part of the green compact is a measured numerical value that should be strictly managed in this technical field in order to cause deformation and defects in shape and dimensions.
[0003]
[Prior art]
The following techniques are known as methods for measuring the density of green compacts that are compression-molded into a complicated shape or divided into predetermined samples after compression molding.
[0004]
1. Buoyancy method using liquid metal: When a green compact is immersed in mercury, which is a liquid metal at room temperature, buoyancy is generated. The buoyancy is equal to the weight of mercury in the same volume as the green compact. When submerged, there is a change in the measured value obtained by subtracting the weight of the green compact from the buoyancy. Actually, the buoyancy is better, so the green compact is pushed into the mercury. The buoyancy can be obtained by the sum of the change in the measured value, the volume of the green compact can be obtained by dividing the buoyancy by the specific gravity of mercury, and the density can be obtained by dividing the weight of the green compact by the volume of the green compact. However, mercury used in this measurement method is a toxic substance and requires special care and labor for handling and management. The green compact of the sample used for measurement must be discarded because it cannot be regenerated due to mercury penetration. There are disadvantages.
[0005]
2. Penetration method: The green compact is soaked and soaked in oil with good permeability (for example, kerosene), taken out after a predetermined time, the weight of the green compact soaked in oil is measured, and the green compact weighed before soaking in oil Subtracting the weight of the body gives the weight of the oil soaked. Dividing the weight of the soaked oil by the weight of the green compact gives the weight of the oil soaked per unit weight of the green compact (oil content and Compare the oil content of the green compacts after the same predetermined time and substitute for density comparison. However, if the shape and material of the green compact are different, the density comparison is not possible. In some cases, it cannot be substituted, and the predetermined time for soaking the oil into the green compact is long, and this is an inefficient technique for application at a manufacturing site where a quick comparison is desired.
[0006]
3. Volume displacement method: Let the green compact soak and soak in oil with good permeability (for example, kerosene), remove it after a sufficient soaking time, and wipe off the oil on the surface. Place an empty hanging net in the oil to a predetermined position while placing it on the weighing scale and weighing it. Hold the measured value at this time as a reference value, and then suspend the green compact that has soaked the oil and wiped the surface. The green compact placed on the lowering net and submerged in the oil to the predetermined position. The green compact is the position where the whole is submerged in the oil. The weight of the green compact is obtained by dividing this weight by the known specific gravity of the oil in advance.The weight of the green compact weighed before submerging in the oil is taken as the volume of the green compact. To get the density. There is an advantage that a relatively accurate density of the green compact can be obtained, but it takes a long time (for example half a day) until the green compact is sufficiently soaked with oil and no bubbles are generated. This is a technology that is difficult to apply at the manufacturing site, such as requiring time and effort to wipe off.
[0007]
4). Other: Japanese Patent Publication No. 6-23684, Japanese Patent No. 2544431, Japanese Patent No. 263174, and Japanese Patent Publication No. 6-52230 are known as measurement methods using X-rays and γ-rays. JP-A-9-54048, JP-A-9-89807, and JP-A-6-229984 are known as measuring methods using electromagnetic waves. Japanese Patent No. 2535702 and Japanese Patent Application Laid-Open No. 5-247922 are known as measurement methods using vibration. JP-A-9-170992 is known as a measuring method using electric resistance. Each of them has disadvantages such as being an expensive device, being applicable only to a specific material, or becoming a large-scale device.
[0008]
[Problems to be solved by the invention]
The buoyancy method using liquid metal can obtain a relatively accurate density, but since mercury, which is a liquid metal at room temperature, is used, this mercury is a toxic substance. In addition, there is a problem that the green compact of the material used for the measurement has to be discarded because mercury penetrates and cannot be regenerated. The infiltration method uses oil and is not a toxic substance and is easy to handle and manage. However, a predetermined time is required to soak the oil into the green compact. The so-called volume substitution method, which is a so-called oil content and substitutes for comparing the density of green compacts, has the advantage that a relatively accurate density of the green compact can be obtained. It takes a long time until it soaks and no bubbles are generated (for example, half a day), and it takes time to wipe off the surface of the green compact. There are problems such as a large number of occurrences and reduced work efficiency. Regarding other measurement methods, measurement methods using X-rays and γ-rays are large, expensive, and dangerous. Measurement methods using electromagnetic waves can only measure green compacts that absorb electromagnetic waves. Measurement using vibration The method has a problem that the apparatus is too large, and the measuring method by electric resistance has a problem that only the green compact that conducts electricity can be measured.
[0009]
In view of the above points, the present invention does not require a toxic substance such as mercury, requires no special attention, labor, and expense for handling and management, and can obtain a relatively accurate density as in the volume replacement method. Measurement method that does not require a long time even if it is carried out, the measurement method that performs the permeation method for a relatively short predetermined time improves the disadvantage that only the so-called oil content is obtained, and the measurement method that can obtain an accurate density in a short measurement time And it aims at providing the measuring device.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 of the present invention is the first in a state where only a green compact is not submerged while a certain amount of liquid is accommodated in a container and placed on a scale for measurement. The measured value is obtained, the whole green compact is submerged in the liquid without contacting the container and the green compact is not weighed by its own weight, and the time when the green compact is submerged in the liquid is defined as a reference time point. And a plurality of measurement values measured by the scale in relation to the passage of time, and a trend of change indicated by the plurality of measurement values in association with the passage of time is estimated retroactively to the reference time point. 2 is obtained, the first measurement value is subtracted from the second measurement value to obtain a third measurement value, and the third measurement value is divided by the specific gravity of the liquid to reach the reference time point. Obtain an estimate of the volume of the liquid corresponding to the volume of the green compact, and calculate the weight of the green compact By dividing the volume estimates is a measurement method of the green compact molded density and obtaining a density of the green compact.
[0011]
According to the second aspect of the present invention, the time point when the green compact is submerged in the liquid is set as a reference time point, and it is determined that a predetermined time has elapsed or the weighing of the balance has not been possible. Then, the green compact molding density measuring method according to claim 1, wherein a plurality of measurement values measured by the balance are obtained in association with the passage of time.
[0012]
In the invention according to claim 3, the measurement value takes a difference from the previous measurement value in time series, and selects the measurement value in which the difference is more negative than a predetermined value, thereby making it possible to relate the measurement value to the passage of time. 3. The green compact density measuring method according to claim 1, wherein a plurality of measurement values to be measured are determined to be stable.
[0013]
According to a fourth aspect of the present invention, there is provided a liquid, a container containing a certain amount of the liquid, a balance including a balance dish on which the container is placed, and the balance dish surrounding the balance dish and placed on a gantry portion of the scale , A column that is erected and fixed to the column, a wire that hangs from above the column, and a net-made saucer that is suspended from the wire and is located in the liquid in the container And a computer comprising a storage means, and a cable connecting the scale and the computer, the scale transmits the weight placed on the weighing pan as a measurement value to the computer via the cable, The calculator receives the measurement value, obtains a first measurement value in a state where only the green compact is not submerged in the container containing a certain amount of the liquid, and transfers the whole green compact into the liquid. When placed on the saucer and submerged, the green compact A trend of a change in which a plurality of measured values measured by a scale in relation to the passage of time and the passage of time are obtained by relating the passage of time with the passage of time as a reference time point. The second measured value is estimated by going back to the reference time point, the third measured value is obtained by subtracting the first measured value from the second measured value, and the third measured value is obtained as the liquid. The estimated volume of the liquid corresponding to the volume of the green compact goes back to the reference time by dividing by the specific gravity of, and the weight of the green compact measured in advance and stored in the storage means is the volume. The green compact density measuring apparatus is characterized in that the green compact density is obtained by dividing by the estimated value.
[0014]
The invention according to claim 5 is the green compact density measuring apparatus according to claim 4, wherein the liquid is a liquid whose viscosity is 50 to 200 times that of water.
[0015]
A sixth aspect of the present invention is the green compact density measuring apparatus according to the fourth aspect, wherein the tray is a wire mesh tray, and the mesh size of the wire mesh is 1 mm or more.
[0016]
According to a seventh aspect of the present invention, the saucer has a relationship of (outer diameter / depth of dent) ≧ 3, wherein the center with respect to the outer diameter forms a part of a sphere to form a dent. It is set as the measurement apparatus of the green compact molding density of description.
[0017]
In the invention according to claim 8, the wires hanging down from above the support pillar are a plurality of wires hanging down from the wire fulcrum of the support pillar, and the plurality of hanging wires are at lower ends at different positions in the tray. The green compact molding density measuring device according to claim 4, 6 or 7, wherein the measuring device is fixed and the tray is supported by a triangular structure.
[0018]
A ninth aspect of the present invention is the green compact density measuring device according to the fourth, sixth, seventh or eighth aspect, wherein a weight of 50 to 300 g is attached to the tray.
[0019]
According to a tenth aspect of the present invention, there is provided the green compact density measuring apparatus according to the fourth or fifth aspect, wherein the liquid is silicon oil.
[0020]
According to an eleventh aspect of the present invention, the means for measuring the weight of the green compact places the green compact on the weighing pan on which the container is placed, and the difference between the measured values of the balance three times or more is the difference. If it is within the resolution of the scale, it is judged to be stable, and the measured value of the weight obtained by adding the green compact to the container is taken. If the compared difference is within the resolution of the scale, it is judged to be stable, and the weight is measured without adding the green compact to the container, and the green compact is added from the measured weight with the green compact added. 5. The green compact molding density measuring apparatus according to claim 4, wherein the weight of the green compact is obtained by subtracting the measured value of the weight that is not present.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a method for measuring a green compact density according to the present invention and an apparatus for measuring the same will be described below.
[0022]
FIG. 1 shows an outline of the measuring apparatus 1. The measuring device 1 includes a calculator 11, a cable 12, a precision balance 13, and a jig 14. The computer 11 is a so-called personal computer provided with storage means, and is connected to the precision balance 13 via the cable 12. The precision balance 13 converts the measured value into electrical digital information and transmits it to the computer 11 via the cable 12. The computer 11 receives the measurement value from the precision balance 13 as electrical digital information, and via the cable 12, the computer 11 receives the measurement value from the precision balance 13 as electrical digital information. When the operator operates from the operation screen 30 of the computer 11, the measured value of the precision balance 13 is received by the computer 11, a predetermined calculation process is executed, and the density of the green compact as a calculation result is displayed on the operation screen 30. The calculation result to be displayed can be printed or transmitted to another computer.
[0023]
FIG. 2 shows the configuration of the jig 14 and its surroundings, that is, the support column 17 is placed on the frame portion of the precision balance 13 so as to surround the balance plate 15, and the support column 17 and the balance plate 15 have a predetermined interval. The three columns 16 have the same shape, and the upper part is circular. The columns 16 are vertically installed and fixed at three points that divide the column base 17 into three equal parts along the circumference. The weighing pan 15 is bent at a right angle to the central axis direction of the weighing pan 15 and has a wire retaining hole 19 in the bent portion. On the other hand, a plate 18 is placed on the upper surface of the balance pan 15, and a container 20 is placed on the upper surface of the plate 18 so as to be partially visible in a cross-sectional view. 15, the plate 18 has a protruding portion 181, and the plate 18 does not interfere with the column base 17 and the column 16. When the green compact is placed on the protruding portion 181, the weight of the green compact is determined by the balance. The container 20 contains a predetermined amount of the liquid 21 that can be transferred to the pan 15 and can be measured. The liquid 21 is preferably, for example, silicon oil, but may be other oil. The weight 25 and the wire mesh tray 23 are integrally suspended. The weight 25 may be, for example, 50 to 300 g. The upper end of the wire 24 is fixed to the wire retaining hole 19 and the lower ends of the two weights are lowered. Multiple fasteners on the circumference of 25 Each of the two wires 24 weighted from the respective wire fastening holes 19 fixed to 6 has a dotted line for explanation shown with a symbol W, which is fixed to separate fasteners 26 with a distance extended at the lower end. As shown, the wire 24 forms a triangular structure. The wire 24 supports the weight 25 and the wire mesh tray 23 parallel to the bottom of the container 20 at a predetermined distance. The wire triangle structure swings the weight 25 and the wire mesh tray 23. It is a structure to prevent.
[0024]
FIG. 3 shows an operation screen 30 of the computer 11. The operation screen 30 has the following display windows: a liquid temperature display 31, a work instruction display window 33, an input data display window 36, and an output display window 38. Further, there are a liquid temperature adjustment button 32, a start button 34, a stop button 35, and an end button 37, which have the following operation buttons that can be operated by placing the cursor on the screen.
[0025]
The above-described measuring apparatus 1 of the present invention explains how to solve the problem. Conventionally, when oil is used, the volume of the green compact that requires a long time for measurement can be obtained in a short time. It takes a long time to saturate the oil into the oil, and when the green compact is immersed in the oil, the oil penetrates into the voids of the green compact, but air exists in the voids and there are bubbles in the oil. This is because it takes a long time for the oil to permeate there and fill the voids. This means that if the whole green compact is submerged in a certain amount of oil, the oil will fill the volume of the green compact. The corresponding amount will increase, but the amount corresponding to the volume of the green compact will decrease as the oil penetrates into the voids of the green compact, so a certain amount of oil will be accommodated in the container Place it on the scale and weigh it, The whole green compact is submerged, but the green compact itself does not touch the container. By doing so, the amount of oil corresponding to the volume of the green compact has increased in the container. As a result, the scale shows a measurement with an increased amount of oil corresponding to the volume of the green compact. The volume of the green compact that you want to know should be shown in the equivalent of the oil increase just before the bubble comes out, but when the green compact is submerged in the oil The weighing of the scale is shaken, it is not in a very measurable state, the oil has already started decreasing when the weighing of the scale is not possible, so the time from when the green compact is submerged in oil And the scale of the scale After determining that the oil is out of swing, obtain the weighing of the scale indicating the decrease in oil as multiple weighing values associated with the passage of time. Regression analysis from the multiple weighing values associated with the passage of time. Applying the above method, estimate the oil increase equivalent when the green compact is submerged in oil. This oil increase equivalent is the volume indicated by the external shape of the green compact. The density can be obtained by dividing the body weight by the volume. This method can be applied at the beginning of the oil penetration into the green compact, and an accurate density can be obtained in a short time.
[0026]
A specific measurement procedure will be described. First, silicon oil is stored as a liquid 21 in the container 20 of the jig 14 of the measuring apparatus 1 until a predetermined amount is reached, and then the computer 11 is activated and the operation screen 30 is displayed. Next, the precision balance 13 is started. The precision balance 13 measures the weight of the plate 18, the container 20, and the liquid 21 placed on the balance dish 15, and the measured value is converted into electrical digital information. Is transmitted to the computer 11. The computer 11 receives the measurement values from the precision balance 13 via the cable 12 at 0.1 second intervals. On the operation screen 30 of the computer 11, the measurement values transmitted by the measuring device 1 are transmitted to the computer 11. The operation can be received, and the measured value, the set value, and the estimated calculated value can be viewed from the display window of the operation screen 30. First, the thermometer is manually inserted into the liquid 21 and the temperature is measured (always measured). Sent to calculator 11 The temperature of the liquid 21 on the operation screen 30 is adjusted so that the temperature of the liquid 21 is displayed on the display 31 by operating the up and down arrows of the liquid temperature adjustment button 32. Match. When a message “Place a sample on the plate and press the Start button” is displayed on the work instruction display window 33, and the green compact is placed on the protruding portion 181 of the plate 18 and the start button 34 is operated, the work instruction display window 33 is displayed. "Wait" is displayed, the precision balance 13 transmits a measured value obtained by adding the weight of the green compact to the weight of the plate 18, the container 20, and the liquid 21, and the computer 11 receives the measured value at intervals of 0.1 second. The measured value is compared with a total of four measured values in the past three times, and if the difference between the received measured value and the measured value in the past three is within 1 mg, it is determined to be stable (with the precision balance 13 having a resolution within 1 mg). The computer 11 executes this calculation and determination at intervals of 0.1 second during operation. Thus, the measurement value received and determined to be stable is used as the first measurement value in the computer 11. Stored in the storage device.
[0027]
Next, the message “Please lift the sample” appears in the work instruction display window 33. When the green compact is lifted from the protruding portion 181 of the plate 18, the message “Please wait” appears in the work instruction display window 33. The balance 13 transmits the measured values of the weight of only the plate 18, the container 20, and the liquid 21, and the calculator 11 compares the measured values received at intervals of 0.1 second with the four measured values in the past three times, and receives them. If the difference between the measured value and the measured value of the past three is within 1 mg, it is determined to be stable. In this example, 1 mg corresponds to the resolution of the precision balance 13. Execute at intervals of 1 second, and store the measurement value received and determined to be stable in the storage device in the computer 11 as the second measurement value. Subsequently, the calculator 11 subtracts the second measured value from the first measured value stored in the storage device, and the value obtained by this subtraction is the weight of the green compact. Is stored as the weight of the green compact.
[0028]
Subsequently, the message “Please input sample” appears in the work instruction window 33. The green compact is put into the liquid 21 accommodated in the container 20 and placed on the wire mesh tray 23. Is carefully placed in the liquid 21, the green compact is gently placed on the liquid 21 surface and then released. The green compact sinks into the liquid 21 under its own weight and is a wire mesh tray. However, the impact of the green compact on the liquid level of the liquid 21, the fluctuation of the liquid level when the green compact passes through the liquid 21, and the green compact abuts against the wire mesh tray 23. The impact until the device is placed in a stable posture, and such an unstable state cannot obtain an accurate measurement value. The computer 11 determines when the green compact is put into the liquid 21, but in time series. Take the difference between the three measured values and the current measured value. That a measurement of three seconds from the reference time point (30 at 0.1 second intervals) are not used in the regression analysis. Further, after 3 seconds, the measured value is stored in the storage device in the computer 11 to be used for regression analysis. However, even if the green compact is placed on the wire mesh tray 23 in a stable posture, the liquid 21 fluctuates. It is determined whether there are fluctuations in the measured values due to the difference between the previous measured value and the received measured value in the time series, and the difference is temporarily stored in the time series. The memorized difference is stored as a measured value to be used for regression analysis in a storage device in the computer 11 for the difference memorized immediately before and the consecutive measurable value that is more negative than 1 mg.
[0029]
The calculator 11 stores the measurement values used for the regression analysis from 3 seconds to 10 seconds from the reference time point. In total, 70 measurement values are obtained, and whether or not to use for the regression analysis is determined. About 60 to 70 measurement values are stored in the storage device in the computer 11 as the measurement values used for the regression analysis. Thereafter, the measurement values are arranged based on the passage of time, and changes in the arranged measurement values are performed. The regression analysis is performed to obtain the estimated value by tracing the trend of the change back to the reference time point. This estimated value is added to the equivalent of the increase in the liquid 21 before the bubble is generated by submerging the green compact in the liquid 21. When the second measured value indicating the weight measured value of only the plate 18, the container 20, and the liquid 21 is called from the estimated value and is subtracted from the estimated value, the bubble is traced back to the reference time point. Equivalent amount of increase in liquid 21 before occurrence An estimated amount of liquid is obtained. By dividing the estimated weight of the equivalent of the increase in the liquid 21 by the specific gravity of the liquid 21, an estimated volume of the equivalent of the increase in the liquid 21 is obtained, which is regarded as the estimated volume of the green compact. The specific gravity of the liquid 21 is the specific gravity at the temperature of the display 31 indicating the temperature of the liquid. Then, the density of the green compact can be obtained by dividing the weight of the green compact from the storage device of the computer 11 by the estimated volume of the green compact.
[0030]
Here, it is necessary to obtain a good measurement value in order to obtain a highly accurate density of the green compact. In order to obtain a good measurement value, the movement of the liquid level immediately after the green compact is put into the liquid 21 is quickly calmed down. In addition, it is necessary to quickly attenuate the impact of the green compact contacting the liquid surface or the wire mesh tray 23, and the posture of the green compact needs to be quickly stabilized on the wire mesh tray 23. In order to quickly attenuate the fluctuation of the liquid level immediately after the addition, it is preferable to use a liquid whose viscosity is 50 to 200 times that of water. If the viscosity of the liquid 21 is low, the liquid 21 does not attenuate quickly, and the viscosity of the liquid 21 is high. Then, it adheres to the green compact after measurement and hangs down when taken out from the liquid 21. Also, the larger the mesh of the metal mesh tray 23 of the green compact attenuated quickly without hindering the movement of the liquid 21 immediately after the green compact was put in. Therefore, the size of the metal mesh of the metal mesh tray 23 was reduced to 1 mm. The wire mesh tray 23 has an outer diameter in contact with the weight 25, and the center with respect to the outer diameter forms part of a sphere in the direction of the bottom of the container 20 to form a recess. It is important for the green compact to contact and stabilize the posture, that is, (outer diameter / depth of dent) ≧ 3 is the optimum configuration. Furthermore, if the wire mesh tray 23 suspended from the support 16 by the wire 24 and placing the green compact is subject to vertical movement, torsional movement, and back-and-forth and left-right shaking, the liquid 21 is moved and accurate measurement cannot be performed. In order to reduce the vertical movement of the wire mesh tray 23, the accuracy of the powder density is reduced, a weight 25 or more weight 25 is attached to the wire mesh tray 23, and the wire mesh tray 23 is pulled downward in advance to perform the vertical motion. It is difficult to shake when the wire suspended from the column 16 forms a triangular structure as indicated by the dotted line for explanation shown by the symbol W so that the wire mesh tray 23 is not easily shaken by the twisting motion and the swinging back and forth and left and right that can be reduced. became.
[0031]
The density calculated by the regression analysis from the measured value determined whether or not to use for the regression analysis by the configuration of the measurement apparatus 1 described above and the measurement method described using the measurement apparatus 1 is sufficiently reliable. It became high-density data with high accuracy. In general, when measuring the weight, the scale of the scale is set to 0 in advance, and then the weight is measured by placing a sample. However, it takes time to set the scale to 0 each time, but the efficiency is high. In order to work well, the measuring method described using the measuring device 1 here does not require the trouble of setting the scale to 0 each time measurement is performed. Although the specific gravity of the liquid 21 changes due to the temperature change, a temperature correction is incorporated when measuring the temperature of the liquid 21 and calculating the estimated volume of the green compact, and the liquid 21 has a clear correlation between temperature and specific gravity. In addition, for example, silicon oil is used whose specific gravity does not easily change with respect to temperature, thereby reducing the influence of temperature change and change with time.
[0032]
【The invention's effect】
As described above, conventionally, a measurement method using mercury, which is a buoyancy method using a liquid metal, can obtain a relatively short measurement time and a relatively high accuracy. For example, the time required for obtaining the density of the green compact is 30 seconds to It was about 1 minute and the accuracy was slightly different depending on the green compact, but was about ± 1.35%. However, according to the measuring method and the measuring apparatus of the present invention, mercury is not used, so it is special in handling and management. Liquids that do not require special attention, labor, and cost can be used, and a shorter measurement time and higher accuracy can be obtained than the measurement method using mercury. For example, the time required to obtain the density of the green compact is about 10 seconds. The accuracy varies slightly depending on the green compact, but is about ± 0.5%. The required time can be shortened to 1/6 to 1/3, and the accuracy is better. In addition, the conventional infiltration method and volume replacement method use liquids that do not require special care, labor, and expense for handling and management, but the infiltration method compares the oil content between green compacts when the required time is shortened. The volume replacement method can provide a certain degree of accuracy, but the time required for obtaining the density of the green compact is as long as half a day, and the liquid adhering to the surface of the green compact is wiped off. However, the present invention can obtain the same or better accuracy as the volume replacement method, and the time required for obtaining the density of the green compact is about 10 seconds, and the time required for the volume replacement method is half a day. It has the effect of being too short to compare with something. Further, the present invention is not an expensive device as compared with other conventionally known means, and can be applied only to a specific material of the green compact, and there is an effect that it does not become a large-scale device.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a measuring apparatus according to the present invention.
FIG. 2 is a configuration diagram of a jig 14 and its surroundings.
3 shows an operation screen 30 of the computer 11. FIG.
[Explanation of symbols]
1 Measuring device
11 Calculator
12 Cable
13 Precision balance
14 Jig
15 Balance dish
16 props
17 Support stand
18 boards
181 Protruding part
19 Fastening holes
20 containers
21 liquids
23 Wire mesh tray
24 wires
25 Omori
30 Operation screen

Claims (11)

While measuring a certain amount of liquid in a container and placing it on a scale, the first measurement value is obtained in a state where only the green compact is not submerged,
The passage of time when the whole of the green compact is not in contact with the container in the liquid, and is submerged in a state where the green compact is not weighed by the weight, and the time when the green compact is submerged in the liquid is a reference time point. Obtain multiple weighing values that the scale weighs in relation to the passage of time,
A trend of change indicated by the plurality of measurement values in relation to the passage of time is estimated retroactively to the reference time point to obtain a second measurement value;
Subtracting the first measurement value from the second measurement value to obtain a third measurement value;
The third measured value is divided by the specific gravity of the liquid to obtain the estimated volume of the liquid corresponding to the volume of the green compact going back to the reference time point, and the weight of the green compact is divided by the estimated volume. To obtain a density of the green compact.   The time when the green compact is submerged in the liquid is used as the reference time, and it is associated with the passage of time after a predetermined time has passed or after it has been determined that the weighing of the scale has become unstable. The method for measuring a green compact density according to claim 1, wherein a plurality of measurement values measured by the balance are obtained.   The measurement value takes the difference from the previous measurement value in chronological order, and by selecting the measurement value that makes this difference more negative than the predetermined value, it is possible to stabilize the multiple measurement values that the scale measures in relation to the passage of time. The measuring method of the green compact molding density of Claim 1 or 2 to determine. A compacting density measuring device including a jig, a scale, a calculator, and a cable,
The jig is
Liquid,
A container containing a certain amount of the liquid;
A support stand that surrounds the balance pan,
A column that is erected and fixed on the column,
A wire hanging from above the support;
A net-made saucer that is suspended in the wire and is located in the liquid in the container and receives a green compact;
Have
The scale has a weighing pan,
The computer includes a storage means,
The cable connects the scale and the calculator,
The scale transmits the weight placed on the weighing pan as a measurement value to the computer via the cable,
The calculator is
Receiving the measurement value, obtaining a first measurement value in a state where only the green compact is not submerged in the container containing a certain amount of the liquid;
When the whole of the green compact is placed on the tray and sunk in the liquid, a plurality of scales are measured in relation to the passage of time with the time when the green compact is submerged in the liquid as a reference time point. To obtain a second measurement value by estimating a tendency of the change indicated by the plurality of measurement values in relation to the passage of time retroactively to the reference time point,
Subtracting the first measurement value from the second measurement value to obtain a third measurement value,
Dividing the third measurement value by the specific gravity of the liquid to obtain a volume estimate of the liquid corresponding to the volume of the green compact going back to the reference time point;
Dividing the weight of the green compact measured in advance and stored in the storage means by the volume estimated value to obtain the density of the green compact;
An apparatus for measuring a green compact density.   5. The green compact density measuring apparatus according to claim 4, wherein the liquid is a liquid whose viscosity is 50 to 200 times that of water.   6. The green compact density measuring apparatus according to claim 4, wherein the tray is made of a wire mesh, and the size of the wire mesh is 1 mm or more.   7. The powder compact according to claim 4, wherein a center of the outer diameter forms a part of a sphere to form a dent, and satisfies a relationship of (outer diameter / depth of dent) ≧ 3. Body molding density measuring device.   8. The wire according to claim 4, wherein the wire includes a plurality of wires, each of which is suspended from a wire fulcrum in the support column, a lower end is fixed at a different position in the tray, and the tray is supported in a triangular structure. The green compact density measuring device described in 1.   The apparatus for measuring a green compact density according to any one of claims 4 to 8, wherein a weight of 50 to 300 g is attached to the tray.   10. The green compact molding density measuring device according to claim 4, wherein the liquid is silicon oil. The green compact is placed on the balance pan on which the container is placed, and if the difference between the measured values of the scale is compared continuously three times or more is within the resolution of the scale, it is determined to be stable, and the green compact is placed in the container. Is the weight measurement plus
With the green compact not placed on the balance pan, if the difference between the measured values of the balance is compared three times or more is within the resolution of the scale, it is determined to be stable, and the green compact is not added to the container. As a measurement of weight,
The green compact density according to any one of claims 4 to 10, wherein the weight of the green compact is obtained by subtracting the measured value of the weight without adding the green compact from the measured value of the weight added with the green compact. measuring device.

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