JP2753002B2 - Thickness inspection device for synthetic resin containers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thickness inspection apparatus for measuring the thickness of a synthetic resin container, particularly a polyethylene terephthalate-based synthetic resin container (hereinafter, referred to as a PET container). The present invention relates to an apparatus for measuring the thickness of a synthetic resin container for measuring the thickness of the container.

[Conventional technology]

A conventional thickness inspection apparatus will be described with reference to FIG. 8 and FIG.

In FIG. 8, the thickness inspection apparatus 300 includes a measuring infrared ray 308.
, A light projecting unit 302 that is inserted into the PET container 307 and emits infrared rays for measurement on the body wall of the PET container 307, and a PET container with a predetermined interval between the light projecting unit 302. Light receiving unit 303 that receives measurement infrared light 308 that is projected outside 307
And an arithmetic unit 304 for calculating the thickness based on the output signal of the light receiving unit 303, an elevating device 305 for integrally raising and lowering the light source unit 301, the light emitting unit 302 and the light receiving unit 303, and a PET container 307 at the time of measurement.
And a rotation device 306 for rotating the rotation in the circumferential direction.

 Next, the operation will be described.

The PET container 307 is placed on the rotating device 306, and the light source unit 301, the light projecting unit 302, and the light receiving unit 303 are lowered integrally by the elevating device 305. At the same time as the descent, the rotation device 306 starts rotating, and when a certain rotation is reached, the measurement is started. Infrared light generated by the light source passes through the translucent section 302 and is
After passing through the torso wall of 307 and being partially absorbed, the light reaches the light receiving unit 303 and is converted into an electric signal. The arithmetic unit 304 calculates the thickness and ends the processing.

FIG. 9 shows an outline of a conventional PET container manufacturing system.

The PET container manufacturing system m includes a raw material supply device 37 for supplying a synthetic resin raw material, a molding device 38 including an injection molding device and a blow molding device, a control device 39 for controlling molding conditions of the molding device, and an inspection of the molded PET container. Inspection device 40, and a sorting device 42 that sorts out non-defective products and defective products based on the results of the inspection.
In addition, a thickness inspection device 300 for measuring the thickness of the PET container by manual sampling as needed was provided separately.

The raw material supply device 37 supplies a synthetic resin raw material to an injection molding machine of a molding device 38, and the injection molding device of the molding device 38 produces a parison, and is stretch-blow molded by a blow molding device to be molded into a container shape.

Note that the molding conditions of these molding devices are controlled by the control device 39.

The molded PET container is sent to the inspection device 40, where the sorting device 4
Goods and defectives are sorted out by 2. The PET container is sampled manually if necessary, and the PET container is
It was carried to 00 and the thickness was measured individually.

[Problems to be solved by the invention]

The above-described conventional apparatus for inspecting the thickness of a synthetic resin container has a problem that if the measurement time is prolonged, the measured value fluctuates due to ambient temperature conditions, heat generation of the light source itself, and the like, and the measured value becomes inaccurate.

Therefore, an object of the present invention is to provide an apparatus for inspecting the thickness of a synthetic resin container which can obtain a stable measured value even when the ambient temperature condition changes.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention relates to a thickness inspection of a synthetic resin container in which an inspection light is transmitted through a body wall of a synthetic resin container, and a thickness of the container is measured by measuring an amount of the transmitted light. In the apparatus, a light source unit having an infrared light source for measurement, a thermostat containing the infrared light source, a planar heating element provided on an outer surface of the thermostat, and a thermostat measuring the temperature in the thermostat. A bath temperature measuring unit, and a light source unit temperature control unit that controls the planar heating element based on the temperature measured by the constant temperature bath temperature measuring unit, and a light receiving unit that receives light from the light source unit through a container. An infrared sensor that changes an output electric signal according to the amount of incident infrared light, a light-receiving unit temperature measuring unit that measures the ambient temperature of the infrared sensor, and an electronic cooling unit that keeps the ambient temperature of the infrared sensor constant. , The temperature measuring means Configured to include a light receiving portion temperature control means for controlling the electronic cooling means based on a more measured temperature.

[Action]

The thickness inspection apparatus for a synthetic resin container has a light source section, a thermostat containing an infrared light source, a planar heating element provided on an outer surface of the thermostat, and a thermostat measuring the temperature in the thermostat. A bath temperature measuring unit; and a light source unit temperature control unit that controls the planar heating element based on the temperature measured by the constant temperature bath temperature measuring unit. An infrared sensor that changes a signal, a light-receiving unit temperature measuring unit that measures the ambient temperature of the infrared sensor, an electronic cooling unit that keeps the ambient temperature of the infrared sensor constant, and a temperature measured by the temperature measuring unit. And a light-receiving unit temperature control means for controlling the electronic cooling means on the basis of which it is possible to continuously obtain stable measurement values over a long period of time, and perform highly reliable measurement even when incorporated in a production line. Can do That.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the thickness inspection apparatus 1 comprises a control operation unit 2 for performing overall control and data arithmetic processing, and an inspection unit 3 for inspecting the thickness.

The control calculation section 2 includes a light source section temperature control section 400 for controlling the temperature of the light source section 19, a sensor light receiving section temperature control section 401 for controlling the temperature around the sensor in the sensor light receiving section 13, and a main control section for controlling the entire apparatus. 4, an interface control unit (IF control unit) 5 for controlling the exchange of data with the inspection unit 3, etc., a chopper drive unit 6 for driving a chopper, a chopper output signal and an output signal from a sensor light receiving unit described later into a DC waveform. It comprises a signal processing section 7 for conversion, a rotary encoder 8 for detecting the rotational position of a continuous automatic container rotating / conveying section 50 described later, an arithmetic processing section 9 for performing data arithmetic processing, and a correction input device 402 for performing correction input. I have.

The light source unit temperature control unit 400 detects the temperature in a constant temperature bath provided outside the light source unit, and controls the planar heating element 34 provided on the outer surface of the constant temperature bath to reduce the temperature around the casing by about 40 ° C.
℃.

The sensor light receiving unit temperature control unit 401 detects the temperature in the sensor light receiving unit and controls the cooling element provided in the sensor light receiving unit to maintain the temperature in the sensor light receiving unit at about 10 ° C.

The chopper driving unit 6 controls the number of rotations of the motor by a rotation control signal 15.
, The chopper plate 11 is rotated at a constant rotation speed, and at the same time, a timing signal 12 corresponding to the chopping cycle is output to the signal processing unit 7.

The signal processing unit 7 converts the sensor output signal 14 from the sensor light receiving unit 13 into a DC waveform (peak hold waveform) based on the timing signal 12, and outputs it to the main control unit 4 via the IF control unit 5.

The rotary encoder 8 is a continuous automatic container rotating / conveying unit 50
The rotational position of is detected, converted into an electric signal,
And outputs the result to the main control unit 4.

The inspection unit 3 includes an insertion tube 17 inserted into the PET container 16, an insertion tube elevation control unit 18 for inserting the insertion tube 17 into and removing the insertion tube 17 from the PET container, and a light source unit for generating an infrared ray 21 for measurement. 19.Sensor light receiving unit that converts the amount of transmitted infrared light that has passed through the body wall of the PET container 16 through the light projecting unit 20 and the insertion tube 17 that emits measurement infrared light to the insertion tube 17 into an electric signal by a sensor.
Consists of thirteen.

The insertion tube 17 has a cylindrical shape, and a reflection mirror is provided inside the insertion tube 17, and measurement is performed by the insertion tube elevation control unit 18.
It is inserted into the PET container 16 and guides the measurement infrared ray 21 into the PET container 16.

Note that a lens group may be formed in the insertion tube 17 if necessary, or a prism may be used instead of the reflecting mirror.

 FIG. 2 shows an outline of the sensor light receiving section 13.

The sensor light receiving unit 13 includes a casing 22, an interference filter 23 for cutting off infrared rays other than a specific frequency range, a PbS (lead sulfide) infrared sensor 24 for converting into an electric signal corresponding to an amount of incident infrared rays, and a surrounding temperature of the PbS infrared sensor 24. Electronic cooling element 25 using Peltier effect to keep constant, amplification amplifier 26 to amplify output signal of PbS infrared sensor 24, temperature sensor 403 to measure ambient temperature of PbS infrared sensor 24, PbS
A power connector 27 for supplying power to the infrared sensor 24 and the amplifier 26, an output connector 28 for outputting the sensor output signal 14 amplified by the amplifier 26, and cooling control for controlling the thermoelectric cooler 25. Connector
It consists of 29.

The center transmission wavelength of the interference filter 23 is about 2.6 μm, and the amount of infrared light transmitted through the interference filter 23 is converted into an electric signal by the PbS infrared sensor 24, and the amplified amplifier 26
, And output to the main control unit 4 via the IF control unit 5.

At this time, in order to operate the PbS infrared sensor 24 stably, the ambient temperature of the PbS infrared sensor 24 is
And the temperature control device 401 of the sensor light receiving unit is controlled by the thermoelectric cooler 25 using the Peltier effect in accordance with the measured temperature.
And the temperature near the PbS infrared sensor 24 is maintained at about 10 ° C. In this case, the sensor light receiving unit temperature control device
When the control cannot be performed only by the control of 401, the control can also be performed by the input data from the correction input device 402.

FIG. 3 shows an outline of the light source unit 19, the light projecting unit 20, and the constant temperature bath 404.

The light source unit 19 is a light source composed of a casing 30 and a filament.
31, a concave mirror 32 located above the light source 31, a chopper 33 located below the light source 31, and a circulation fan f attached to a side plate of the casing 30, and a light projecting portion 20 is provided below the light source portion 19. positioned. As the light source 31, for example, a light source that emits infrared light such as a nichrome wire is used. It is desirable to use infrared rays having a wavelength of 2 to 5 μm.

The concave mirror 32 is for collecting infrared rays from a light source.

The chopper 33 includes the chopper plate 11 and the rotation motor 10, and is used for chopping the infrared light collected by the concave mirror 32 into intermittent light (light seeding waveform). The reason for chopping is
This is because drift and offset occur due to the characteristics of the PbS infrared sensor 24, so that the waveform is temporarily converted to a cross-seeding waveform, and fluctuation factors such as drift and offset are removed to perform highly accurate measurement. Examples of the type of the chopper include a mechanical type as in this embodiment, an electric type for electrically chopping the light source, and the like.

The light projecting unit 20 includes a reflecting mirror 35 and a lens group 36, and uses an infrared ray generated by the light source 31 as parallel light as an insertion tube.
Communicate to 17.

The planar heating element 34 is provided on the entire surface or several surfaces of the constant temperature bath 404, and the temperature in the constant temperature bath 404 is measured by the temperature sensor 405, and the temperature in the constant temperature bath is maintained at about 40 ° C. Air at a constant temperature in the constant temperature bath is introduced into the casing 30 of the light source unit by the circulating fan f of the light source unit to keep the temperature inside the casing 30 constant, suppress fluctuations of the light source 31, etc., and improve measurement stability. I keep it.

FIG. 4 is a principle explanatory diagram in the case where the synthetic resin container thickness inspection apparatus of the present invention is incorporated in a synthetic resin container manufacturing system.

The synthetic resin container manufacturing system M includes a raw material supply device 37 for supplying a synthetic resin raw material, a molding device 38 including an injection molding device and a blow molding device, a control device 39 for controlling molding conditions of the molding device, and a molded PET container. Inspection device 4 for inspection
0, a thickness inspection device 1 for measuring the thickness of the PET container, a continuous automatic container transport rotation device 41 for automatically and continuously transporting the PET container to a measurement position and rotating the PET container during measurement, P
It comprises a sorting device 42 for sorting non-defective and defective ET containers.

12 is different from the conventional example of FIG. 12 in that the thickness inspection device 1 and the continuous automatic container transport rotation device 41 are provided between the inspection device and the sorting device.
Since the thickness can be automatically measured immediately after molding and the data can be fed back immediately, it is possible to quickly cope with the molding process.

The raw material supply device 37 supplies a polyethylene terephthalate-based synthetic resin as a main resin to the molding device.

The molding device 38 is composed of an injection molding device and a blow molding device. The injection molding device injects the resin supplied from the raw material supply device 37 to produce a parison for blow molding and sends it to the blow molding device. The parison sent to the blow molding device is stretch blow-molded and processed into a container shape. The molding conditions of these molding devices are controlled by the control device 39.

Next, the synthetic resin container molded by the molding device 38 is sent to the inspection device 40.

 FIG. 5 shows an outline of the continuous automatic container transport rotation unit 50.

The continuous automatic container transport / rotation device 50 is provided on the turntable 51, at every 90 degrees on the turntable 51, four grippers 52 for gripping and opening the PET container, introduction of the PET container,
Pressing portion 53 that presses the grip portion to release the grip portion during ejection
And a pressing cylinder portion 54 for operating the pressing portion 53.

Further, the turntable 51 has PET in its diameter direction.
Conveyors 55 and 56 for loading and unloading containers are connected.

The gripper 52 has a gripper 150 composed of a pair of three arms for gripping and opening the PET container by opening and closing operations. The gripper 150 includes a clamp arm 57 and a pressing portion 53.
An opening / closing arm 58 for opening and closing the clamp arm 57 by being pressed by the actuator, and a return arm 59 to which a return spring 62 for applying a biasing force for closing the clamp arm 57 are attached. The part 59 contacts the return position adjusting screw 63 at the time of return. Also, a pair of holding bodies
The driving rotary roller 60 rotates the PET container during measurement between 150
Is provided at the distal end of the clamp arm 57 to rotate the PET container in cooperation with the drive rotation roller 60.
The driven rotation rollers 61 are attached.

Next, the operation will be described with reference to the flowchart of FIG.

Preparation for Inspection First, preliminary operation of the light source 29 and the sensor light receiving unit 13 is performed to ensure the stability of measurement. As a result, it is possible to eliminate the initial fluctuation of the measurement and perform a more reliable inspection (step S1).

Loading of PET containers PET containers 16 are introduced at the loading conveyor 55 (Fig. 6) at the introduction position 9
When it is carried into 1 and this introduction is confirmed by a position detection sensor (not shown) (step S2), the pressing portion 53 is operated by the pressing cylinder portion 54 and moves to the PET container introduction position 91 of the automatic continuous thickness inspection device. The opening / closing arm portion 58 of a certain gripping body 150 is pressed by the pressing portion 53. As a result, the clamp arm 57 is pushed out around the pin 100 against the biasing force of the return spring 62, and the return arm 59
Is separated from the return position adjusting screw 63.

Next, the PET container 16 is maintained while being spread.
Is introduced into the pair of gripping bodies 150 by the carry-in conveyor 55, and when it is confirmed by the position detection sensor (not shown) that the PET container 16 has been introduced to the position where the PET container 16 comes into contact with the driving rotary roller 60, the pressing is performed. The portion 53 stops its pressing, the return arm portion 59 abuts the return position adjusting screw position 63 by the biasing force of the return spring 62, and the PET container 16 is driven by the driving rotary roller 60 and the driven rotary rollers 61, 61. Is securely held (step S3).

Next, the turntable 51 rotates clockwise in the drawing, and PE
The container is transported to the inspection position 92 while holding the T container 16, and the turntable 51 stops rotating (step S4).

Thickness measurement The driving rotary roller 60 rotates and the PET container 1
6 and two driven rotation rollers 61 rotate (step S
5) At the same time, the insertion tube 17 is inserted into the PET container 16 by the insertion tube elevation control unit 18 (step S6). When it is confirmed from the output signal of the rotary encoder 8 that the rotation speed of the PET container has reached a certain rotation speed, the main control unit 4 instructs to start the thickness measurement (step S7).

The light source section maintained at a constant temperature by the constant temperature bath 404 generates a measuring infrared ray 21 (wavelength: 2 to 5 μm) having a stable light quantity,
After being condensed by the concave mirror 32 and chopped, the light is introduced into the light projecting section 20, converted into parallel rays by the reflecting mirror 35 and the lens group 36, and projected to the insertion tube 17. Further, the measurement infrared ray passes through the inside of the insertion tube 21 and is partially absorbed by the body wall of the PET container 16 and reaches the sensor light receiving section 13.

The measurement infrared light 22 is applied to the thermoelectric cooler 403 by the sensor
Is converted into an electric signal by the PbS infrared sensor 24 maintained at a constant temperature without being affected by the ambient temperature, and is output to the signal processing unit 7.

The signal processing unit 7 converts the input signal from the sensor light receiving unit into a DC waveform (peak hold waveform) based on the timing signal 12 corresponding to the chopping cycle of the chopper drive unit 6, Output to the control unit 4 (step S8).

At the same time, the rotary encoder 8 detects the rotation position of the continuous automatic container rotating / transporting unit 50, converts the rotation position into an electric signal corresponding to the rotation position, and outputs the electric signal to the main control unit 4 via the IF control unit 5.

Arithmetic Processing The main control unit 4 transfers the output signal data to the arithmetic processing unit 9 and instructs to convert the output signal data into thickness data. The arithmetic processing unit 9 converts the output signal data corresponding to the measured infrared ray amount into the thickness data according to the relationship shown in FIG. 7, and outputs it to the main control unit 4 (step S9). The main controller 4 outputs the thickness data to the controller 3 of the molding device 2 via the IF controller 5 (Step S10).

Pulling out the insertion tube After that, the insertion tube up / down controller 18 pulls out the insertion tube 17 (step S11), the driving rotary roller stops rotating, and the PET container 16
Stops the rotation (step S12).

Next, the turntable 51 rotates again while holding the PET container 16 and stops rotating when the holding body 150 reaches the discharge position 93 (step S13). When the pressing cylinder portion 54 is operated and the opening / closing arm portion 58 of the gripping body 150 is pressed by the pressing portion 53, the clamp arm portion 57 is pivoted about the pin 100 against the urging force of the return spring 62. The container is pushed open and the container is opened (step S14). At the same time, the return arm 59 is separated from the return position adjusting screw 63.

Next, the PET container is carried out of the clamp arm unit 57 by the carry-out conveyor 56 while maintaining the pushed state (step S15).

When the position detection sensor (not shown) confirms that the PET container 16 has been discharged to a predetermined position, the pressing cylinder unit 54 stops operating, the pressing unit 53 stops pressing,
The biasing force of the return spring 62 causes the return arm 59 to abut against the return position adjusting screw 63, and the clamp arm 57 is closed. After that, the turntable 51 rotates again and repeats the above operation.

The PET container 16 is transported to the next step by the unloading conveyor 42.

Feedback control On the other hand, the control device 3 of the molding device 2 that has received the thickness data
Controls the molding conditions based on the data.

〔The invention's effect〕

The present invention provides a light source unit, a thermostat containing an infrared light source, a planar heating element provided on an outer surface of the thermostat, a thermostat temperature measuring means for measuring a temperature in the thermostat, A light source unit temperature control unit that controls the planar heating element based on the temperature measured by the constant temperature bath temperature measurement unit; and an infrared sensor that changes an output electric signal in accordance with an amount of incident infrared light, and a light receiving unit. A light-receiving unit temperature measuring means for measuring the ambient temperature of the infrared sensor, an electronic cooling means for keeping the ambient temperature of the infrared sensor constant, and the electronic cooling means based on the temperature measured by the temperature measuring means. The light-receiving unit temperature control means for controlling the temperature of the synthetic resin container enables a stable temperature environment to be obtained. can it be done , It is possible to obtain a high measurement data reliable even when incorporated in-line wall thickness inspection apparatus manufacturing system of the synthetic resin container.

[Brief description of the drawings]

FIG. 1 is a schematic view of a thickness inspection apparatus of the present invention, FIG. 2 is a schematic view of a sensor light receiving section, FIG. 3 is a schematic view of a light source section, a light emitting section and a thermostat, and FIG. Schematic diagram of the system,
FIG. 5 is a schematic view of the container rotating / conveying device, FIG. 6 is a processing flowchart, FIG. 7 is a diagram showing the relationship between the output voltage of the sensor light receiving section and the thickness of the PET container, and FIG. FIG. 9 is a schematic diagram of a conventional synthetic resin container manufacturing system. DESCRIPTION OF SYMBOLS 1 ... Thickness inspection apparatus, 2 ... Control calculation part, 3 ... Inspection part, 4 ... Main control part, 5 ... Interface control part, 6
……………………………………………………………………………………………………………………… ·································································································································· 13
Sensor light receiving unit, 14: Sensor output signal, 15: Rotation control signal, 16: PET container, 17: Insertion tube, 18: Insertion tube elevating control unit, 19: Light source unit, 20: Throw Optical part, 21… Infrared for measurement, 22… Casing, 23… Interference filter, 24
…… PbS infrared sensor, 25… Electronic cooling element, 26 …… Amplification amplifier, 27… Power connector, 28 …… Output connector,
29: Cooling control connector, 30: Casing, 31:
Light source, 32: concave mirror, 33: chopper, 34: planar heating element, 35: reflective mirror, 36: lens group, 37: raw material supply device, 38: molding device, 39: control device , 40 ... inspection device, 41 ... continuous automatic container rotating and conveying device, 42 ... sorting device, 43 ... main control unit, 44 ... ultraviolet light source unit, 45 ... sensor light receiving unit, 46 ... light emitting unit 47, a rotating device, 48, a mixed resin layer, 49, a main resin layer, 50, a continuous automatic container conveying device, 51, a turntable, 52, a gripping portion, 53, a pressing portion, 54 … Cylinder for pressing, 55 …… Conveyor for loading, 56
…… Conveyor for unloading, 57 …… Clamp arm, 58 ……
Opening / closing arm part, 59 ... Return arm part, 60 ... Drive rotation roller, 61 ... Driving rotation roller, 62 ... Return spring, 63 ... Return position adjusting screw, 91 ... Introduction position, 92 ...
Inspection position, 93 discharge position, 100 pin, 150 gripper, 400 light source temperature control unit, 401 sensor light receiving unit temperature control unit, 402 correction input device, 403, 405 temperature Sensor, 404: constant temperature bath, f: circulation fan.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01B 11/00-11/30 G01N 21 / 88,21 / 89

Claims (1)

(57) [Claims] 1. A synthetic resin container thickness inspection apparatus for measuring the thickness of a container by transmitting inspection light through the body wall of the synthetic resin container and measuring the amount of the transmitted light. A light source unit provided with a light source, a thermostat containing the infrared light source, a planar heating element provided on an outer surface of the thermostat, a thermostat temperature measuring means for measuring a temperature in the thermostat, A light source unit temperature control unit that controls the planar heating element based on the temperature measured by the constant temperature bath temperature measurement unit, and a light receiving unit that receives light from the light source unit through a container.
An infrared sensor that changes an output electric signal according to the amount of incident infrared light, a light-receiving unit temperature measuring unit that measures the ambient temperature of the infrared sensor, and an electronic cooling unit that keeps the ambient temperature of the infrared sensor constant, A light-receiving unit temperature control unit that controls the electronic cooling unit based on the temperature measured by the temperature measurement unit.