WO2019225609A1

WO2019225609A1 - Resin blow-molded article inspection method, inspection device, and resin blow-molded article manufacturing device provided with said inspection device

Info

Publication number: WO2019225609A1
Application number: PCT/JP2019/020129
Authority: WO
Inventors: 利明朝倉; 雄大高橋
Original assignee: 株式会社フコク
Priority date: 2018-05-22
Filing date: 2019-05-21
Publication date: 2019-11-28
Also published as: JPWO2019225609A1

Abstract

An inspection method to be performed during the manufacture of a resin blow-molded article M in which blow-molding is performed by forming a parison P from a molten resin and blowing air into the parison P in a mold 24. The inspection method comprises: a temperature measurement step for measuring a surface temperature T of the resin blow-molded article M by means of a temperature sensor 32 after blow molding; and an anomaly determination step for determining whether there is an anomaly in the thickness t of the resin blow-molded article M on the basis of the degree of modulation of a circumferential temperature change in the surface temperature T of the resin blow-molded article M measured in the temperature measurement step.

Description

Resin blow molded product inspection method, inspection device, and resin blow molded product manufacturing apparatus equipped with the inspection device

The present invention relates to a resin blow molded product inspection method, an inspection device, and a resin blow molded product manufacturing apparatus including the inspection device.

Patent Document 1 discloses a method for producing a resin blow-molded product in which a parison is molded from a molten resin and blow-molded by blowing air into the parison in a mold. The resin blow-molded product manufactured by this method is determined by visual inspection for the presence or absence of mold deformation, the presence or absence of air accumulation, the presence or absence of wrinkles, the presence or absence of swelling.

Japanese Patent Laid-Open No. 2000-254962

There are some items that cannot be judged visually in the appearance inspection of resin blow molded products. Specifically, it is difficult to visually detect thinness and local thinness over the entire circumference of the resin blow molded product. Further, when the resin blow molded product is black, for example, or when the defective formation position is not visible, it is difficult to visually detect the presence of holes or foreign matters. When defects related to abnormal thickness due to such thin resin blow-molded products as a result of thinning of the entire circumference, local thinness, perforations, etc. are overlooked in the appearance inspection, defective products that do not satisfy the desired strength and durability are shipped. There is a risk of impairing the reliability of the resin blow molded product.

The present invention has been made in view of such problems, and can efficiently and reliably determine whether there is an abnormality in the thickness of the resin blow molded product, thereby improving the reliability of the resin blow molded product. An object of the present invention is to provide a resin blow molded product inspection method, an inspection device, and a resin blow molded product manufacturing apparatus including the inspection device.

The present invention can be realized as the following modes.
The inspection method for a resin blow molded product according to this aspect is an inspection method in a manufacturing process of a resin blow molded product in which a parison is molded from a molten resin and blown by blowing air into the parison in a mold. After molding, a temperature measurement step of measuring the surface temperature of the resin blow molded product with a temperature sensor, and a resin blow molded product based on the degree of modulation of the circumferential temperature change of the surface temperature of the resin blow molded product measured in the temperature measurement step And an abnormality determination step for determining whether there is an abnormality in the wall thickness.

In the above-described temperature measurement step according to this aspect, a measurement window is set in the surface temperature measurement region of the resin blow molded product, and the average surface temperature obtained by averaging the surface temperature measured by the temperature sensor in the measurement window is measured. In the abnormality determination step, it is determined whether there is an abnormality in the thickness of the resin blow molded product based on the average surface temperature.

Further, in the above-described temperature measurement step according to this aspect, a plurality of measurement windows are arranged in the vicinity of the circumferential direction of the resin blow molded product in the measurement region of the surface temperature in the resin blow molded product, and the average of the measurement windows is set. The surface temperature is measured, and in the abnormality determination step, it is determined that the thickness of the resin blow molded product is abnormal when the temperature difference between the average surface temperatures of at least adjacent measurement windows is equal to or greater than a predetermined first threshold value.

In addition, the inspection method according to the present aspect includes a predetermined reference temperature at which the surface of the blown resin molded product is born on the basis of a predetermined reference wall thickness set in advance in the circumferential direction of the blown resin molded product. In the abnormality determination step, when the temperature difference between the reference temperature estimated in the temperature estimation step and the surface temperature is equal to or greater than a predetermined second threshold, the thickness of the resin blow molded product is It is determined to be abnormal.

Moreover, the temperature sensor mentioned above which concerns on this aspect is a thermo camera which measures the surface temperature of a resin blow molded product non-contactingly.
Further, the above-described resin blow-molded product according to this aspect is provided integrally in a cylindrical shape between one end of the ring, the other end of the ring, and the one end and the other end. , A bellows portion comprising a valley portion and a bellows portion formed by repeatedly arranging an inclined surface portion connecting the mountain portion and the valley portion, and at least in the temperature measurement step, the mountain portion, the valley portion, and the slope The surface temperature of any of the surface portions is measured with a temperature sensor.

On the other hand, the inspection apparatus for a resin blow molded article according to this aspect is an inspection apparatus used for manufacturing a resin blow molded article that forms a parison from a molten resin and blow-molds the parison by blowing air in a mold. After the blow molding, the resin blow molding is performed based on the temperature measurement unit for measuring the surface temperature of the resin blow molded product with the temperature sensor and the modulation degree of the circumferential temperature change of the surface temperature of the resin blow molded product measured by the temperature sensor. An abnormality determination unit that determines whether there is an abnormality in the thickness of the product.

Further, the above-described temperature measurement unit according to this aspect sets a measurement window in the surface temperature measurement region in the resin blow molded product, and measures the average surface temperature obtained by averaging the surface temperature measured by the temperature sensor in the measurement window. The abnormality determination unit determines whether there is an abnormality in the thickness of the resin blow molded product based on the average surface temperature.

In addition, the above-described temperature measurement unit according to this aspect is configured by setting a plurality of measurement windows in the circumferential direction of the resin blow-molded product in the circumferential region of the resin blow-molded product and setting the average of the measurement windows. The surface temperature is measured by the temperature sensor, and the abnormality determination unit determines that the thickness of the resin blow molded product is abnormal when the temperature difference between the average surface temperatures of at least adjacent measurement windows is equal to or greater than a predetermined first threshold value. To do.

In addition, the abnormality determination unit according to the present aspect includes a predetermined reference on which the surface of the resin blow molded product after the blow molding is born, based on a predetermined reference thickness set in advance in the circumferential direction of the resin blow molded product. The temperature is estimated, and when the temperature difference between the estimated reference temperature and the surface temperature is equal to or greater than a predetermined second threshold, it is determined that the thickness of the resin blow molded product is abnormal.

Moreover, the temperature sensor mentioned above which concerns on this aspect is a thermo camera which measures the surface temperature of a resin blow molded product non-contactingly.
Further, the above-described resin blow-molded product according to this aspect is provided integrally in a cylindrical shape between one end of the ring, the other end of the ring, and the one end and the other end. The bellows part formed by repeatedly arranging the valley part and the inclined surface part connecting the mountain part and the valley part, the temperature measurement unit comprising at least the mountain part, the valley part, the inclination The surface temperature of any of the surface portions is measured with a temperature sensor.

On the other hand, the resin blow molded article manufacturing apparatus according to this aspect includes the inspection apparatus described in any one of the above.

According to the aforementioned resin blow molded product inspection method, inspection apparatus, and resin blow molded product manufacturing apparatus equipped with the inspection device of the present invention, the presence or absence of abnormalities in the thickness of the resin blow molded product can be efficiently and The determination can be made reliably, and the reliability of the resin blow molded product can be improved.

It is a block diagram when the manufacturing apparatus of the resin blow molded product provided with the inspection apparatus which concerns on each embodiment of this invention is seen from upper direction. It is a longitudinal cross-sectional view of a resin blow molded product. It is a longitudinal cross-sectional view of the principal part of the blow molding machine at the time of parison molding. It is a longitudinal cross-sectional view of the principal part of the blow molding machine at the time of shaping | molding of a resin blow molded product. It is a figure which shows the change of the surface temperature when changing the thickness of the resin blow molded product. It is a figure which shows the screen of the display part on which the resin blow molded product without thickness abnormality is displayed. It is a figure which shows the screen of a display part in the case of determining the thickness abnormality of the resin blow molded product in the abnormality determination unit of an inspection apparatus. It is a figure which shows a part of screen of the display part showing the resin blow molded product without thickness abnormality. It is a figure which shows a part of screen of a display part in the case of performing a perimeter thin wall determination in the abnormality determination unit of the test | inspection apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows a part of screen of a display part in the case of performing local thin wall determination in the abnormality determination unit of the test | inspection apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows a part of screen of a display part in the case of performing a hole opening determination in the abnormality determination unit of the inspection apparatus which concerns on 3rd Embodiment of this invention.

Hereinafter, a resin blow molded product inspection method, an inspection device, and a resin blow molded product manufacturing apparatus including the inspection device according to each embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a manufacturing apparatus 1 for a resin blow molded product M (hereinafter also simply referred to as a molded product M) as viewed from above. The manufacturing apparatus 1 includes a blow molding machine 2, an inspection apparatus 4, a processing machine 6, a measuring instrument 8, and the like.

In the manufacturing apparatus 1, a blow molding machine 2, an inspection apparatus 4, a processing machine 6, and a measuring instrument 8 are arranged in order on the conveyance path 10 for the molded product M. The molded product M after being molded by the blow molding machine 2 is transported through the transport path 10, the thickness is inspected by the inspection device 4, then processed by the processing machine 6, and then weighed by the measuring device 8. . In the manufacturing apparatus 1, the inspection device 4, the processing machine 6, and the measuring instrument 8 are arranged in this order. However, when the arrangement is rearranged as necessary, the processing machine 6 and the measuring instrument 8 may not be provided. possible. Further, as the transport path 10, a transport arm that grips the molded product M and transfers it may be used.

FIG. 2 is a longitudinal sectional view of the molded product M. The molded product M of the present embodiment is a cylindrical hollow product formed by melting a thermoplastic resin having elasticity, and has an annular one end portion 12, an annular other end portion 14, an end portion 12 and the other end. The bellows part 16 provided in the state communicated between the parts 14, ie, a cylindrical shape, is provided.

The molded product M is used, for example, as a bellows boot that covers and protects a constant velocity joint used for a drive shaft of a vehicle or covers a connecting portion of a steering of a vehicle. The bellows portion 16 is configured by repeatedly arranging a large-diameter peak portion 16a, a small-diameter valley portion 16b, and an inclined surface portion 16c connecting the peak portion 16a and the valley portion 16b in the height direction of the molded product M. ing.

Predetermined reference wall thicknesses t1, t2, and t3 (hereinafter, also referred to as reference wall thickness ts) are set in advance for each of the mountain portion 16a, the valley portion 16b, and the inclined surface portion 16c. In the molded product M of the present embodiment, the reference thickness ts is constant over the circumferential direction of the molded product M, and is set according to the strength, bending angle, etc. required for the molded product M as a product. .

FIG. 3 is a longitudinal sectional view of a main part of the blow molding machine 2 at the time of parison molding. The blow molding machine 2 forms the parison P by injecting the supplied molten resin, and further molds the molded product M by blow molding the parison P. Specifically, the blow molding machine 2 includes a molten resin supply source 18, a blow pin 20, an injection core 22, a mold 24, a drawer core 26 and the like in order from the bottom.

The supply source 18 supplies a high-temperature molten resin material to the injection core 22, and the molten resin is injected in an annular shape from the injection core 22. The drawer core 26 descends to reach the injection core 22 and rises while drawing the molten resin injected from the injection core 22. Thereby, as shown in FIG. 3, for example, a parison P forming a cylindrical hollow body of about 180 ° C. to 220 ° C. is formed.

The parison P is formed by injecting molten resin from the injection core 22 step by step in an appropriate amount, and being drawn out by the drawer core 26. The portion corresponding to the peak portion 16a is thicker than the portion corresponding to the valley portion 16b. It is getting bigger. This is to prevent the peak portion 16a from becoming too thin as compared to the valley portion 16b during blow molding.

The metal mold 24 is formed of two half mold parts 24a, and these half mold parts 24a are provided between the injection core 22 and the drawer core 26 when lifted. The half mold parts 24a are separated from each other before the parison P is formed, and after the parison P is formed, the half mold parts 24a move in a direction in which they abut each other as indicated by arrows.

FIG. 4 is a longitudinal sectional view of a main part of the blow molding machine 2 when the molded product M is molded. As the half mold parts 24 a move in the abutting direction, a cavity 28, which is a bellows-like space for forming the bellows part 16, is formed inside the mold 24. After the formation of the cavity 28, air at a predetermined temperature is blown from the blow pin 20 into the parison P in the direction indicated by the arrow for a predetermined time, whereby the parison P is expanded and pressed against the inner peripheral surface of the mold 24.

Then, when the half mold parts 24a are separated from each other, the molded product M having the bellows part 16 is blow-molded, and the molded product M before cooling after blow molding is conveyed to the inspection device 4. The series of operations described above is performed by the operation of a drive unit (not shown) included in the blow molding machine 2. In addition, the state before cooling after blow molding in the molded product M means a state in which the surface temperature of the molded product M is not lowered to at least the atmospheric temperature.

As shown in FIG. 1, the inspection device 4 includes a rotary table 30, a temperature measurement unit 31, and an abnormality determination unit 34. When the molded product M is transferred to the rotary table 30 through the conveyance path 10, the rotary table 30 clamps the molded product M by a clamping mechanism (not shown) and rotates the molded product M in the circumferential direction by a driving unit (not shown).

The temperature measuring unit 31 includes a thermo camera (temperature sensor) 32 disposed on the side of the molded product M. The thermo camera 32 measures the surface temperature of the molded product M along the circumferential direction by imaging the peripheral surface of the molded product M rotated on the turntable 30 after blow molding from the side (temperature measurement step).

The abnormality determination unit 34 is, for example, a computer including a display unit 34a including a display and an operation unit 34b including a mouse, a keyboard, and the like, and programs for performing various calculations and image processing are installed. . A thermo camera 32 is electrically connected to the abnormality determination unit 34, and the surface temperature data of the molded product M measured by the thermo camera 32 is taken into the processor of the abnormality determination unit 34. The configuration of the abnormality determination unit 34 is not limited to the content described above.

Then, the abnormality determination unit 34 determines whether there is an abnormality in the thickness of the molded product M based on the surface temperature of the molded product M measured by the thermo camera 32 (abnormality determination step). Such a thickness abnormality of the molded product M is caused by a shortage of the resin material supplied from the supply source 18 to the blow molding machine 2, and will be described in detail later. It is manifested as defects such as thinness of the entire circumference, local thinness, and perforation. Further, such a thickness abnormality is displayed on the display unit 34a as an alarm together with the surface temperature measured by the thermo camera 32.

The thermo camera 32 is, for example, an infrared camera, and detects infrared rays emitted from the surface of the molded product M being imaged as a wavelength distribution corresponding to the surface temperature of the molded product M. Thereby, the thermo camera 32 can measure the surface temperature of the molded product M rotated by the rotary table 30 continuously at a fixed point throughout its entire circumference. Further, by performing image processing according to the program of the abnormality determining unit 34, the infrared wavelength distribution of the rotating molded product M can be displayed in real time as a temperature distribution that can be visually identified on the display unit 34a.

The processing machine 6 cuts an unnecessary part of the molded product M that has passed through the inspection device 4 and finishes the molded product M into a final product M. The measuring device 8 measures the weight of the molded product M that has passed through the processing machine 6, and inspects whether or not the molded product M as a final product has a predetermined weight. The molded product M determined to be acceptable by the inspection device 4 and the measuring device 8 is transported to a shipping station (not shown) and shipped after being packed.

A molded product M that has been determined to have an abnormal thickness by the inspection device 4 or a molded product M that has been determined to be heavy by the measuring instrument 8 without being properly cut by the processing machine 6 is displayed on the display unit. An alarm is output to 34a and recognized as a defective product. Defective products are transported from appropriate locations on the transport path 10 to a discharge station (not shown) for appropriate processing.

Further, when the stop process of the manufacturing apparatus 1 or the defective product discharge process is executed by the output of an alarm, these processes may be performed manually or may be performed automatically using an alarm as a trigger.

Here, the molded product M shown in FIG. 2 has a different reference thickness ts in the height direction when clamped to the rotary table 30. As described above, in the parison P, the portion corresponding to the peak portion 16a is thicker than the portion corresponding to the valley portion 16b. However, in the case of the present embodiment, the reference thickness t1 of the peak portion 16a of the molded product M is slightly smaller than the reference thickness t2 of the valley portion 16b due to the blowing of air from the blow pin 20. Further, the reference thickness t3 of the two

inclined surface portions

16c and 16c sandwiching the mountain portion 16a is the same.

Note that the difference in the reference wall thickness ts in the bellows portion 16 of the molded product M is an example, and differs depending on the use mode and required performance. The reference thickness t3 of the two

inclined surface portions

16c and 16c sandwiching the mountain portion 16a may be made different, or the reference thickness may be set to be different in the height direction of the molded product M.

FIG. 5 is a diagram showing changes in the surface temperature T when the thickness t of the molded product M is changed, in which the temperature change of the peak portion 16a is plotted with ◯, and the temperature change of the valley portion 16b is plotted with x. doing. As apparent from FIG. 5, the surface temperature T increases as the wall thickness t increases in both the peak portion 16a and the valley portion 16b.

Since the temperature of the mold 24 is adjusted to about 10 ° C. to 13 ° C., for example, the parison P made of a molten resin of about 180 ° C. to 220 ° C. is absorbed by contact with the mold 24 at the time of blow molding. The outer surface of the article M is fixed. Due to heat transfer from the parison P to the mold 24, the molded product M immediately after blow molding has a peak portion 16a of, for example, about 40 ° C. to 50 ° C. and a valley portion 16b of, for example, about 100 ° C.

As apparent from FIG. 5, such a temperature difference between the peak portion 16a and the valley portion 16b is caused by a difference in the amount of retained heat based on the thickness difference between the peak portion 16a and the valley portion 16b in the molded product M. It is what happens. That is, since the valley portion 16b has a larger thickness t than the peak portion 16a, the surface temperature T is higher than that of the peak portion 16a. Other factors that cause the temperature difference include that the peak portion 16a has a larger surface area than the valley portion 16b, so that it is greatly stretched during blow molding and is easily cooled by the outside air.

FIG. 6 shows a screen of the display part 34a on which the bellows part 16 satisfies the reference wall thickness ts, that is, the molded product M having no wall thickness abnormality is displayed. In the display unit 34a, by performing display setting in the abnormality determination unit 34, it is possible to recognize the temperature difference of the molded product M by the change in color shade or color tone.

Specifically, in the case shown in FIG. 6, the valley portion 16 b has a larger thickness t, a larger amount of heat immediately after blow molding, and a higher surface temperature T than the peak portion 16 a. For this reason, the trough portion 16b is represented as a light gray line extending in the circumferential direction of the surface of the molded product M or a line close to white. On the other hand, the peak 16a has a smaller thickness t, a smaller amount of heat immediately after blow molding, and a lower surface temperature T than the valley 16b. For this reason, the peak 16a is represented as a line close to black extending in the circumferential direction of the surface of the molded product M.

In addition, in the case shown in FIG. 6, the inclined surface portion 16c has a thickness t and a retained heat amount between the valley portion 16b and the peak portion 16a, and the surface temperature T is lower than that of the valley portion 16b. Therefore, the temperature is higher than that of the mountain portion 16a. For this reason, the inclined surface portion 16c is represented as a line close to gray extending in the circumferential direction of the surface of the molded product M. In addition, by changing the display setting in the abnormality determination unit 34, not only the gray scale display described above, but also the display unit 34a with different color tones such as a high temperature portion represented by a red color and a low temperature portion represented by a blue color. Can also be displayed.

FIG. 7 shows a screen of the display unit 34a when the abnormality determination unit 34 determines the thickness abnormality of the molded product M. The abnormality determination unit 34 can set the measurement window 36 in the measurement region of the surface temperature T of the molded product M displayed on the screen of the display unit 34a. By operating the operation unit 34b, a large number of measurement windows 36 can be displayed at arbitrary positions on the screen of the display unit 34a. In the case shown in FIG. 7, two measurement windows 36 are arranged in the proximity positions of the peak portion 16 a, valley portion 16 b, and inclined surface portion 16 c of the bellows portion 16.

In each measurement window 36 fixedly arranged on the screen of the display unit 34a, an image of the surface of the molded product M being imaged by the thermo camera 32 and being rotated by the rotary table 30 is displayed. At this time, the abnormality determination unit 34 continuously calculates and measures the average surface temperature Ta obtained by averaging the surface temperature T of the molded product M measured at the fixed point by the thermo camera 32 in the measurement window 36. As shown in FIG. 7, the average surface temperature Ta is displayed in real time in a visible manner in each measurement window 36 as grayscale display shades.

Here, by using the surface temperature Ta averaged in each measurement window 36 and comparing the temperature of each part, it becomes possible to collect and compare the temperature difference of each part in a very short time. Further, when measuring the surface temperature T of the inclined surface portion 16c, the temperature varies greatly depending on the measurement position on the valley portion 16b side-mountain portion 16a side, but by using the averaged surface temperature Ta in the measurement window 36, It is possible to reduce the temperature deviation due to the measurement position and perform a highly accurate comparison. When the inspection apparatus 4 according to the present invention is incorporated in the manufacturing apparatus 1, there is no fear of delaying the product manufacturing cycle.

<First Embodiment>
Hereinafter, with reference to FIG.8 and FIG.9, the perimeter thin wall determination which concerns on 1st Embodiment performed in the abnormality determination unit 34 of the test | inspection apparatus 4 is demonstrated. In the screen of the display unit 34a, FIG. 8 shows a part of the screen of the display unit 34a in the case of a molded product M having no thickness abnormality, and FIG. 9 shows a case where the entire circumference thinness determination according to the first embodiment is performed. A part of the screen of the display unit 34a is shown. In the determination of the present embodiment, the presence / absence of an abnormality in the thickness t of the molded product M is determined based on the average surface temperature Ta in the measurement window 36.

Specifically, as shown in FIG. 9, for example, one measurement window 36 is set in the measurement region where the mountain portion 16 a is located by the operation of the operation unit 34 b. In the abnormality determination unit 34, a reference temperature Tr corresponding to the reference wall thickness ts under the same conditions is stored in advance in the memory of the abnormality determination unit 34.

For this reference temperature Tr, for example, the temperature at which the surface of the peak portion 16a having the reference thickness ts takes on (the reference temperature Tr) is estimated from the peak portion 16a of the molded product M manufactured under the same conditions (temperature estimation step). . The estimation of the reference temperature Tr may be obtained from the accumulation of past data or may be obtained from the first product in the production lot. The reference temperature Tr can be estimated by using FIG. 5 as a calculation map or by deriving an approximate expression for estimation from FIG.

And the temperature difference between the estimated reference temperature Tr of the peak 16a and the average surface temperature Ta in the measurement window 36 positioned at the peak 16a is a predetermined threshold value ΔTe (second threshold) ) When this is the case, it is determined that the thickness t of the molded product M is abnormal. By performing this determination, the thickness t of the peak portion 16a provided with the measurement window 36 is thin over the entire circumference (at least in a wide range in the circumferential direction), so to speak, it is possible to detect a defect in the entire circumference thin. it can.

In the case where the entire circumferential thin portion 38 surrounded by a broken line in FIG. 9 is present in the molded product M, the amount of heat of the entire circumferential thin portion 38 immediately after blow molding is the reference thickness positioned above and below the height direction of the molded product M. It becomes smaller than the calorie | heat amount of the same site | part which satisfy | fills ts. For this reason, on the surface of the all-around thin portion 38, there is formed an all-around low-temperature portion 40 that has a lower temperature than other upper and lower identical portions, that is, in the case of FIG. It becomes.

The all-around low temperature part 40 can be detected based on the temperature difference between the reference temperature Tr and the average surface temperature Ta in the measurement window 36. When visualized by the abnormality determination unit 34, as shown in FIG. 9, the all-around low temperature portion 40 has a darker gray or black color than the other peak portions 16a. It is possible to easily visually recognize the thinness of the entire circumference of the mountain portion 16a. By such gray scale display or alarm output on the display unit 34a, the existence of the thin part around the circumference 38 is recognized, and the thickness abnormality of the thin part around the circumference is determined. By performing the entire circumference thinness determination, defective products that do not satisfy the strength and durability required for the molded product M as a product can be efficiently and reliably eliminated.

Further, the reference temperature Tr of each part of the bellows part 16 is determined for each part 16a to 16c of the bellows part 16 based on the reference thickness ts of the peak part 16a, the valley part 16b, and the inclined surface part 16c of the bellows part 16 of the molded product M. Can be estimated. Then, the data of the reference temperature Tr of the reference wall thicknesses t1 to t3 corresponding to the parts 16a to 16c may be stored in the memory of the abnormality determination unit 34 in advance. If the measurement window 36 is set for each part of the molded product M having different reference wall thickness ts, the reference surface temperature Tr and the average surface temperature Ta in each measurement window 36 provided in each part of the bellows portion 16 are set. Can be compared, and it is possible to detect a defect of the entire circumference thin in each part of the molded product M.

Further, when estimating the reference temperature Tr, the blow time and blow temperature in blow molding may be taken into account as parameters relating to the estimation. The blow time and the blow temperature are determined according to the material and shape of the molded product M.

Further, the reference temperature Tr may be estimated according to the temperature of the mold 24 at the time of blow molding or the heat absorption amount based on the thermal conductivity of the mold 24. The surface temperature T of the molded product M immediately after blow formation becomes lower as the temperature of the mold 24 becomes lower and as the endothermic quantity based on the thermal conductivity of the mold 24 becomes larger. These parameters can also be used for setting the threshold value ΔTe.

As described above, in the present embodiment, by using the inspection device 4, the temperature measurement step of measuring the surface temperature T of the molded product M with the thermo camera 32 of the temperature measurement unit 31 after the blow molding is performed. The abnormality determination unit 34 determines whether there is an abnormality in the thickness t of the molded product M based on the degree of modulation of the temperature change in the circumferential direction of the measured surface temperature T (temperature change amount or temperature change rate per unit time). An abnormality determination step is performed.

Specifically, the molded product M immediately after blow molding is clamped on the rotary table 30, the molded product M is rotated in the circumferential direction by the rotary table 30, and the surface temperature T of the rotated molded product M is along the circumferential direction. The abnormality determination unit 34 determines whether there is an abnormality in the thickness t of the molded product M based on the surface temperature T measured by the thermo camera 32 and measured by the thermo camera 32.

This determination is based on the knowledge that the heat generated by the molded product M immediately after blow molding and before cooling is effectively used, and the surface temperature T of the molded product M is higher as the wall thickness t is larger. To do. Thereby, compared with the case where the molded product M is inspected by visual inspection, the presence or absence of an abnormality in the thickness t of the molded product M can be determined efficiently and reliably, and the reliability of the molded product M can be determined. Can be improved.

More specifically, the abnormality determination unit 34 sets the measurement window 36 in the measurement region of the surface temperature T in the molded product M, and averages the surface temperature T measured by the thermo camera 32 in the measurement window 36. The temperature Ta is calculated and measured, and the presence or absence of an abnormality in the thickness t of the molded product M is determined based on the average surface temperature Ta.

In addition, a reference thickness ts is set in advance in the circumferential direction of the molded product M, and a reference temperature Tr at which the surface of the molded product M immediately after the blow molding takes on is estimated based on the reference thickness ts. The And especially in this embodiment, when the temperature difference between the reference temperature Tr and the average surface temperature Ta is equal to or greater than the threshold value ΔTe, the abnormality determination unit 34 determines that the thickness t of the molded product M is abnormal with a thin wall on the entire circumference. judge.

By performing such a whole circumference thin wall determination, it is possible to efficiently and reliably determine the presence or absence of a whole circumference thin wall that is difficult to find by visual inspection of the molded product M. Therefore, even if there is a molded product M that can pass the appearance, defective products that do not satisfy strength and durability can be efficiently and reliably eliminated by the thin wall around the circumference, so the reliability of the molded product M is improved. can do.

Second Embodiment
Hereinafter, with reference to FIG. 10, the local thin wall determination according to the second embodiment performed in the abnormality determination unit 34 of the inspection apparatus 4 will be described mainly with respect to a configuration different from the first embodiment. FIG. 10 shows a part of the screen of the display unit 34a when performing local thin wall determination according to the second embodiment. Note that description of the same configuration as in the first embodiment may be omitted.

In the determination of the present embodiment, the two measurement windows 36 are arranged close to each other in the circumferential direction of the molded product M, and the temperature difference between the average surface temperatures Ta of the adjacent measurement windows 36 is a predetermined local thin wall determination threshold value ΔTs (first When it is equal to or greater than (threshold), it is determined that the thickness t of the molded product M is abnormal. By making such a determination, the thickness t of the peak portion 16a provided with the measurement window 36 of the molded product M is locally thin in the circumferential direction, that is, the molded product M having a locally thin wall, that is, the molded product M. Can be detected.

Specifically, when the molded product M has a local thin portion 42 surrounded by a broken line in FIG. 10, immediately after blow molding, the amount of heat of the local thin portion 42 is a portion satisfying the reference thickness ts in the same circumferential direction. It becomes smaller than the amount of heat. For this reason, the local low temperature part 44 is formed on the surface of the local thin part 42. The local low temperature portion 44 can be detected based on the temperature difference between the average surface temperatures Ta of the adjacent measurement windows 36 without referring to the reference temperature Tr as in the case of the first embodiment.

As shown in FIG. 10, when visualized by the abnormality determination unit 34, the local low temperature portion 44 has a dark gray color or a color close to black compared to the other mountain portions 16 a, so The defect of the local thin wall existing in the part 16a can be easily visually confirmed. The existence of the local thin portion 42 is recognized by the gray scale display and alarm output of the display portion 34a, and the thickness abnormality of the local thin portion is determined. By performing such local thin wall determination, defective products that do not satisfy the impact strength required for the molded product M as a product can be efficiently and reliably eliminated.

As described above, in the inspection apparatus 4 of the present embodiment, as in the case of the first embodiment, the abnormality determination unit 34 is based on the degree of modulation of the circumferential temperature change of the surface temperature T of the molded product M. The presence or absence of an abnormality in the thickness t of M is determined.

Specifically, the two measurement windows 36 are set so as to be close to each other in the circumferential direction of the molded product M, and when the temperature difference of the average surface temperature Ta of each measurement window 36 is equal to or greater than the threshold value ΔTs, the meat of the molded product M is It is determined that the thickness t is an abnormality of local thin wall. Thereby, it is possible to efficiently and reliably determine whether there is a local thin-wall defect that is difficult to find by visual inspection of the molded product M.

By performing such local thin wall determination, even if the molded product M can be acceptable in appearance, defective products that do not satisfy the impact strength strength due to the local thin wall can be efficiently and reliably excluded. The reliability of the molded product M can be improved. In the local thin wall determination, not only the two measurement windows 36 but also three or more measurement windows 36 may be set. In this case, it can be determined that there is a local thin-wall defect based on at least the temperature difference between the average surface temperatures Ta of the adjacent measurement windows 36.

Moreover, if two measurement windows 36 are set for each part of the bellows part 16, the presence or absence of local thin wall can be determined over the entire molded product M, and the reliability of the molded product M is further improved. Can do.

<Third Embodiment>
Hereinafter, with reference to FIG. 11, the configuration different from the first and second embodiments will be described mainly regarding the hole opening determination according to the third embodiment performed in the abnormality determination unit 34 of the inspection device 4. FIG. 11 shows a part of the screen of the display unit when the hole determination according to the third embodiment is performed. Note that descriptions of configurations similar to those in the first and second embodiments may be omitted.

In the determination of the present embodiment, the entire thinness determination described in the first embodiment and the local thinness determination described in the second embodiment are performed in combination, and it is determined that the thickness t of the molded product M is abnormal. . Specifically, a plurality of measurement windows 36 arranged in the circumferential direction are arranged on each peak 16a, each valley 16b, and each inclined surface 16c of the molded product M (see measurement window 36 in FIG. 7). . In FIG. 11, only three measurement windows 36 among these measurement windows 36 are displayed.

Then, the entire circumference thinness determination is performed in each of the measurement windows 36 arranged in the height direction, and then the local thinness determination is performed in the two measurement windows 36 arranged close to each other in each peak portion 16a, each valley portion 16b, and each inclined surface portion 16c. I do. In this case, in the circumferential measurement window 36, it is determined that there is an abnormality at a location where a rapid change (modulation) in temperature change is detected. A portion where the thickness t of the peak portion 16a provided with the measurement window 36 of the molded product M is zero, that is, the molded product M having a hole can be detected.

As shown in FIG. 11, when visualized by the abnormality determination unit 34, the local low temperature portion 50 has a lighter gray than the other inclined surface portions 16 c, while the local high temperature portion 54 The outer edge has a dark gray color or a color close to black as compared with the valley portion 16b. For this reason, even on the screen, it is possible to easily visually recognize the defect in the hole existing in the peak portion 16a.

As described above, the degree of modulation of the temperature of the measurement site by the measurement window 36 is detected, the temperature modulation is visualized, and the presence of the hole 46 is recognized by the gray scale display and alarm output of the display unit 34a. Then, the abnormal thickness of the hole is determined. By performing such hole opening determination, defective products that do not satisfy the strength and durability required for the molded product M as a product can be efficiently and reliably eliminated.

As described above, in the inspection device 4 of the present embodiment, the abnormality determination unit 34 is based on the degree of modulation of the circumferential temperature change of the surface temperature T of the molded product M, as in the first and second embodiments. The presence or absence of an abnormality in the thickness t of the molded product M is determined. Thereby, the presence or absence of the defect of the hole of the molded article M can be determined efficiently and reliably.

By performing such hole opening determination, not only defective products that do not satisfy the impact resistance strength due to hole opening, but also grease that has been applied to joints and joints during use as bellows boots may leak from the hole. Since the non-defective product can be efficiently and reliably excluded, the reliability of the molded product M can be improved.

Although the description of each embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in each of the above-described embodiments, the surface temperature T of the molded product M that is rotated by the turntable 30 by the thermo camera 32 is measured along the circumferential direction. However, the present invention is not limited thereto, and a temperature sensor other than the thermo camera 32 may be used as long as the surface temperature T of the rotated molded article M can be measured along the circumferential direction.

If the focal length problem can be solved, the entire molded product M can be photographed by the thermo camera 32, and the measurement window 36 can be set in the image (thermograph) for comparison. In this case, there is no need to install the rotary table 30.
Further, instead of rotating the molded product M, a plurality of temperature sensors are arranged around the molded product M, or the temperature sensors are moved along the circumferential direction of the molded product M, so that the surface temperature T is increased. It is also possible to measure along the direction.

Further, the size of the measurement window 36 is not particularly specified, and the surface temperature T of the molded product M may be measured in a pinpoint manner, or the temperature of the entire surface of the molded product M is measured to detect an abnormal thickness. You may make it perform determination of. In this case, it is not always necessary to calculate the average surface temperature Ta of the measurement window 36, and it may be determined whether the thickness is abnormal based on the surface temperature T of the molded product M itself.

Further, in each of the above-described embodiments, the abnormality determination unit 34 can determine whether the molded product M has an abnormal thickness, and whether or not the entire circumference is thin, local thin, and a hole is defective. However, the present invention is not limited to this, and it is possible to detect a thickness abnormality based on the foreign matter mixed in the molded product M by making a determination using a temperature threshold different from the hole opening determination by the abnormality determination unit 34. As a result, it is possible to efficiently and reliably eliminate defective products that do not satisfy the impact strength required for the molded product M as a product due to foreign matter contamination.

Further, in each of the above embodiments, a case is described in which the inspection apparatus 4 performs a thickness inspection of the molded product M that is a bellows boot such as a constant velocity joint boot or a steering boot. However, the present invention is not limited to this, and the inspection apparatus 4 can also perform the thickness inspection of other forms of resin blow-molded products having portions having different reference thicknesses ts.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 12 One end part 14 Other end part 16 Bellows part

16a Mountain part

16b Valley part 16c Inclined surface part 24 Die 30 Rotary table 31 Temperature measurement unit 32 Thermo camera (temperature sensor)
34 Abnormality judgment unit 36 Measurement window

Claims

It is an inspection method in a manufacturing process of a resin blow molded product in which a parison is formed from a molten resin, and blow molding is performed by blowing air into the parison in a mold,
After the blow molding, a temperature measurement step of measuring the surface temperature of the resin blow molded product with a temperature sensor;
An abnormality determination step of determining whether there is an abnormality in the thickness of the resin blow molded product based on the degree of modulation of the circumferential temperature change of the surface temperature of the resin blow molded product measured in the temperature measuring step, Inspection method for resin blow molded products.
In the temperature measurement step, a measurement window is set in the measurement region of the surface temperature in the resin blow molded article, and an average surface temperature obtained by averaging the surface temperature measured by the temperature sensor in the measurement window is measured.
The method for inspecting a resin blow molded product according to claim 1, wherein in the abnormality determination step, the presence or absence of an abnormality in the thickness of the resin blow molded product is determined based on the average surface temperature.
In the temperature measurement step, a plurality of measurement windows are set close to a circumferential direction of the resin blow molded product in the measurement region of the surface temperature of the resin blow molded product, and an average surface temperature of the measurement window is measured. And
In the abnormality determination step, it is determined that the thickness of the resin blow-molded product is abnormal when a temperature difference between the average surface temperatures of at least adjacent measurement windows is equal to or greater than a predetermined first threshold value. 3. A method for inspecting a resin blow molded article according to 1 or 2.
A temperature estimating step of estimating a predetermined reference temperature at which the surface of the resin blow-molded product after the blow molding takes on the basis of a predetermined reference thickness preset in the circumferential direction of the resin blow-molded product; ,
In the abnormality determination step, when the temperature difference between the reference temperature estimated in the temperature estimation step and the surface temperature is equal to or greater than a predetermined second threshold, it is determined that the thickness of the resin blow molded product is abnormal. The inspection method of the resin blow molded product as described in any one of Claims 1 thru | or 3.
5. The method for inspecting a resin blow molded product according to claim 1, wherein the temperature sensor is a thermo camera that measures the surface temperature of the resin blow molded product in a non-contact manner.
The resin blow molded product is
An annular end,
An annular other end,
Between the one end portion and the other end portion, it is integrally provided in a cylindrical shape, and is formed by repeatedly arranging a peak portion, a valley portion, and an inclined surface portion connecting the peak portion and the valley portion. A bellows boot composed of a bellows part,
The resin blow molding according to any one of claims 1 to 5, wherein, in the temperature measurement step, at least the surface temperature of any one of the peak portion, the valley portion, and the inclined surface portion is measured by the temperature sensor. Inspection method of goods.
It is an inspection apparatus used for manufacturing a resin blow-molded product that forms a parison from a molten resin and blow-molds the parison by blowing air in a mold.
After the blow molding, a temperature measurement unit that measures the surface temperature of the resin blow molded product with a temperature sensor;
A resin having an abnormality determination unit that determines whether there is an abnormality in the thickness of the resin blow-molded product based on the degree of modulation of the circumferential temperature change of the surface temperature of the resin blow-molded product measured by the temperature sensor. Blow molded product inspection equipment.
The temperature measurement unit sets a measurement window in the measurement region of the surface temperature in the resin blow molded product, measures an average surface temperature obtained by averaging the surface temperature measured by the temperature sensor in the measurement window,
The inspection apparatus for a resin blow molded product according to claim 7, wherein the abnormality determination unit determines whether there is an abnormality in the thickness of the resin blow molded product based on the average surface temperature.
The temperature measurement unit sets a plurality of measurement windows in the measurement region of the surface temperature in the resin blow-molded product in the circumferential direction of the resin blow-molded product and sets the average surface temperature of the measurement window. Measured by a temperature sensor,
The abnormality determination unit determines that the thickness of the resin blow molded product is abnormal when a temperature difference between the average surface temperatures of at least adjacent measurement windows is equal to or greater than a predetermined first threshold value. Or an inspection apparatus for a resin blow molded product according to 8.
The abnormality determination unit estimates a predetermined reference temperature at which the surface of the resin blow-molded product after the blow molding takes on the basis of a predetermined reference thickness set in advance in the circumferential direction of the resin blow-molded product. The thickness of the resin blow molded product is determined to be abnormal when a temperature difference between the estimated reference temperature and the surface temperature is equal to or greater than a predetermined second threshold value. The inspection apparatus for a resin blow molded product according to one item.
The inspection apparatus for a resin blow molded product according to any one of claims 7 to 10, wherein the temperature sensor is a thermo camera that measures the surface temperature of the resin blow molded product in a non-contact manner.
The resin blow molded product is
An annular end,
An annular other end,
It is integrally provided in a cylindrical shape between the one end and the other end, and is formed by repeatedly arranging a crest, a trough, and an inclined surface connecting the crest and the trough. A bellows boot composed of a bellows part,
The resin blow molding according to any one of claims 7 to 11, wherein the temperature measurement unit measures at least the surface temperature of any one of the peak portion, the valley portion, and the inclined surface portion with the temperature sensor. Product inspection equipment.
An apparatus for manufacturing a resin blow molded article, comprising the inspection apparatus according to any one of claims 7 to 12.