JPH09234783A - Measuring method for drawdown of molten parison in direct blow molding - Google Patents
Measuring method for drawdown of molten parison in direct blow moldingInfo
- Publication number
- JPH09234783A JPH09234783A JP8043260A JP4326096A JPH09234783A JP H09234783 A JPH09234783 A JP H09234783A JP 8043260 A JP8043260 A JP 8043260A JP 4326096 A JP4326096 A JP 4326096A JP H09234783 A JPH09234783 A JP H09234783A
- Authority
- JP
- Japan
- Prior art keywords
- drawdown
- parison
- molten parison
- molten
- time
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 13
- 238000000071 blow moulding Methods 0.000 title description 6
- 230000001133 acceleration Effects 0.000 claims abstract description 10
- 238000005259 measurement Methods 0.000 abstract description 10
- 238000001125 extrusion Methods 0.000 abstract description 3
- 238000000465 moulding Methods 0.000 description 4
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
- B29C49/42—Component parts, details or accessories; Auxiliary operations
- B29C49/78—Measuring, controlling or regulating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
- B29C49/42—Component parts, details or accessories; Auxiliary operations
- B29C49/78—Measuring, controlling or regulating
- B29C2049/7873—Extrusion speed; Extruded preform position or length; Extrusion fall speed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
- B29C49/42—Component parts, details or accessories; Auxiliary operations
- B29C49/78—Measuring, controlling or regulating
- B29C2049/788—Controller type or interface
- B29C2049/78805—Computer or PLC control
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
- B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
- B29C49/04—Extrusion blow-moulding
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明はダイレクトブロー成
形における溶融パリソンのドローダウンを精度よく測定
する方法に関するものである。ドローダウンの発生はダ
イレクトブロー成形における困難な問題の一つであり、
ドローダウンの発生状況を正確に計測することは、ダイ
レクトブロー成形における成形条件の設定にとって重要
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for accurately measuring drawdown of a molten parison in direct blow molding. The occurrence of drawdown is one of the difficult problems in direct blow molding.
Accurate measurement of drawdown occurrence is important for setting molding conditions in direct blow molding.
【0002】[0002]
【従来の技術】ダイレクトブロー成形は、周知の如く、
押出機のダイから垂直下方に押出された溶融パリソンを
金型に収容し、次いで溶融パリソンに気体を吹込んで中
空容器を製造する成形法である。この成形法における困
難な問題の一つが、ドローダウンの発生である。ドロー
ダウンとは、押出機のダイから押出された溶融パリソン
が、自重により垂れ下る現象である。ドローダウンが発
生すると、パリソンの全長が押出し長さより長くなり、
かつパリソンの肉厚が局部的に変化するので、得られる
製品の品質に大きく影響する。従ってダイレクトブロー
成形に際しては、予めドローダウンの発生状況を計測し
て、その対策を講じておくことが必要である。2. Description of the Related Art Direct blow molding, as is well known,
In this molding method, a molten parison extruded vertically downward from a die of an extruder is housed in a mold, and then a gas is blown into the molten parison to manufacture a hollow container. One of the difficult problems in this molding method is the occurrence of drawdown. Drawdown is a phenomenon in which a molten parison extruded from a die of an extruder hangs down by its own weight. When drawdown occurs, the total length of the parison becomes longer than the extrusion length,
In addition, the thickness of the parison locally changes, which greatly affects the quality of the obtained product. Therefore, in direct blow molding, it is necessary to measure the occurrence of drawdown in advance and take measures against it.
【0003】従来、ドローダウンの発生状況の計測は、
押出機のダイから垂直下方に押出される溶融パリソンの
背後に目盛尺を設けておき、溶融パリソンの先端が目盛
尺に設けた上下の標点間を通過するのを測定者が目視で
観察し、その所要時間を計測することにより行ってい
た。すなわち、このような計測を、ノズルからの距離を
異にするいくつかの標点について行なえば、得られた測
定データに基づいて、溶融パリソンの先端がノズルを離
れてからの、各時点における先端の降下の速度や加速度
を算出することができる。Conventionally, measurement of the situation of occurrence of drawdown is
A scale is provided behind the molten parison extruded vertically downward from the extruder die, and the observer visually observes that the tip of the molten parison passes between the upper and lower gauges provided on the scale. , It was done by measuring the required time. That is, if such measurement is carried out for some reference points at different distances from the nozzle, based on the obtained measurement data, the tip of the molten parison leaves the nozzle at the tip at each time point. The descent speed and acceleration can be calculated.
【0004】[0004]
【発明が解決しようとする課題】しかしながら、測定者
が目視で観察する方法は、測定者や目視位置の差などに
左右され測定の精度が低い。通常は精度を上げるために
測定を反復するが、それでも精度はそれほど向上しな
い。従って本発明は、ドローダウンの発生状況を精度よ
く、しかも簡単に計測することのできる方法を提供せん
とするものである。However, the method of visually observing by the measurer is low in the accuracy of measurement depending on the difference between the measurer and the visual position. Usually, the measurement is repeated to improve the accuracy, but the accuracy is not improved so much. Therefore, the present invention is intended to provide a method capable of accurately and easily measuring the situation of occurrence of drawdown.
【0005】[0005]
【課題を解決するための手段】本発明によれば、押出機
のダイから垂直下方に押出される溶融パリソンの降下状
況をカメラで経時的に撮影し、この撮影データに基づい
て溶融パリソンが各時点においてダイからどの位降下し
ているかを求め、このデータに基づいて溶融パリソンの
自重による降下速度、更には降下の加速度を求めること
により、ドローダウンの発生状況を容易に計測すること
ができる。According to the present invention, the descending state of a molten parison extruded vertically downward from a die of an extruder is photographed with a camera over time, and the molten parison is analyzed based on the photographed data. It is possible to easily measure the occurrence of drawdown by obtaining how much the die is descending from the die at the time point, and then obtaining the descending speed due to the weight of the molten parison and the descending acceleration based on this data.
【0006】[0006]
【発明の実施の形態】本発明について詳細に説明する
と、本発明では溶融パリソンの降下状況を目視で観察す
る代りに、カメラで経時的に撮影する。従って短い時間
間隔でのデータを容易に得ることができる。撮影により
得られた画像データは、画像処理装置で処理して、各撮
影時点におけるパリソンの降下量(押出機のダイからの
降下距離又は前回の撮影時点からの降下距離)を算出す
る。通常はパリソンの全長を撮影して降下量を算出する
が、パリソンの背後に目盛板を設置しておきパリソンの
先端が目盛板上のどこに対応するかを測定するようにし
てもよい。撮影は、パリソンの背後にパリソンと反射率
の異なるボード、例えばつや消しの黒色板を設置して、
通常のCCDカメラで行なうことができる。所望ならば
パリソンに着色して周囲と区別がつくようにすることも
できる。またパリソンは周囲よりも高温なので、赤外線
カメラで撮影することもできる。このようにして得られ
た撮影時点とその時点におけるパリソンの降下量とに関
する一群のデータに基づいて、パリソンの各時点におけ
る降下速度や降下の加速度をコンピュータで自動的に算
出させる。通常は押出機から溶融パリソンを一定速度で
押出すので、溶融パリソンの降下速度から押出し速度を
差引いたものが自重による降下速度となる。この自重に
よる降下速度の変化を経時的に追跡することにより、ド
ローダウンの発生状況を把握できる。またドローダウン
の詳細は、降下の加速度を検討することにより把握でき
る。BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail. In the present invention, instead of visually observing the descending state of the molten parison, images are taken with a camera over time. Therefore, it is possible to easily obtain data at short time intervals. The image data obtained by photographing is processed by the image processing device to calculate the amount of fall of the parison at each photographing time point (the distance from the die of the extruder or the distance from the previous photographing time). Normally, the entire length of the parison is photographed and the amount of descent is calculated, but it is also possible to install a scale plate behind the parison and measure where the tip of the parison corresponds to the scale plate. For the shooting, we installed a board with a different reflectance from the parison behind the parison, for example, a matte black plate,
It can be performed with a normal CCD camera. If desired, the parison can be colored to distinguish it from the surroundings. Also, since the parison is hotter than the surroundings, it can be taken with an infrared camera. The descent speed and descent acceleration at each time point of the parison are automatically calculated by a computer based on a group of data relating to the shooting time point thus obtained and the parison descent amount at that time point. Usually, since the molten parison is extruded from the extruder at a constant speed, the descending speed due to its own weight is obtained by subtracting the extruding speed from the descending speed of the molten parison. By tracking the change in the descending speed due to its own weight over time, the occurrence of drawdown can be grasped. The details of drawdown can be grasped by examining the descent acceleration.
【0007】本発明の実施の態様の1例を図に基づいて
説明すると、図1において1は押出機、2は押出機のダ
イ、3は降下しつつある溶融パリソン、4は溶融パリソ
ンの降下状況を撮影するためのカメラ、5はカメラ
(4)にノイズとなる有害光が入射するのを防止するた
めの黒色のバックボード、6は画像処理装置、7はモニ
ターテレビ、8はプリンターである。先ず押出機より溶
融パリソンを押出し、定常的に押出される状態になった
時点で、溶融パリソンをダイ出口の位置で切り離す。引
続き押出しを続行し、溶融パリソンの先端が計測開始点
を通過した時点からカメラを作動させて、溶融パリソン
を撮影し且つその撮影時刻を記録する。撮影は溶融パリ
ソンの先端が計測終了点を通過するまで続行する。な
お、上述の如く、通常は溶融パリソンがダイ出口から一
定距離だけ降下した位置から撮影を開始するが、溶融パ
リソンがダイ出口に出現した時点から計測を開始しても
よい。カメラにより得られた画像は、画像処理装置7で
処理して、各撮影時点における溶融パリソンの長さ又は
先端位置を求める。この撮影時点とその時点での溶融パ
リソンの長さ又は先端位置のデータに基づいて、溶融パ
リソンの各時点における降下速度及び降下の加速度を算
出すると、ドローダウンがどの時点で発生し、かつどの
ように進行するかを正確に把握することができる。An example of an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, 1 is an extruder, 2 is an extruder die, 3 is a descending molten parison, and 4 is a descending of the molten parison. A camera for photographing the situation, 5 is a black backboard for preventing harmful light that becomes noise from entering the camera (4), 6 is an image processing device, 7 is a monitor TV, and 8 is a printer. . First, the molten parison is extruded from the extruder, and when it reaches a state of being constantly extruded, the molten parison is separated at the position of the die exit. Then, the extrusion is continued, and the camera is operated from the time when the tip of the molten parison passes the measurement starting point to photograph the molten parison and record the photographing time. Shooting continues until the tip of the molten parison passes the measurement end point. Note that, as described above, the photographing is normally started from the position where the molten parison is lowered from the die exit by a certain distance, but the measurement may be started from the time when the molten parison appears at the die exit. The image obtained by the camera is processed by the image processing device 7, and the length or the tip position of the molten parison at each image capturing time is obtained. Calculating the descent rate and the descent acceleration at each time of the melting parison based on the data of the length or the tip position of the melting parison at the time of this shooting and at that time, and at what time the drawdown occurs, and how You can know exactly how to proceed.
【0008】例えば図2は、固有粘度1,130(dl
/g)のポリエチレンテレフタレートを、同一の押出機
からスクリュー回転数10,20,30rpmで押出
し、降下する溶融パリソンを本発明方法によりCCDカ
メラで経時的に撮影し、得られた画像を画像処理して、
降下距離とその時点における降下の加速度との関係を算
出したものである。この図から、降下の加速度が10m
m/sec2 の時点でパリソンを金型に収容するとする
と、10rpm又は20rpmで押出した場合にはパリ
ソン長は375mmとなるが、30rpmで押出した場
合にはパリソン長は330mmにしかならないことが分
る。なお、押出機の設定温度は10rpmの場合が23
4℃,20rpmの場合は243℃,30rpmの場合
は248℃である。このように本発明によれば、ドロー
ダウンがどのように進行するかが正確に測定できるの
で、適正な成形条件を設定することができる。For example, FIG. 2 shows an intrinsic viscosity of 1,130 (dl
/ G) polyethylene terephthalate is extruded from the same extruder at screw rotation speeds of 10, 20, 30 rpm, and the molten parison that descends is photographed with a CCD camera over time by the method of the present invention, and the obtained image is subjected to image processing. hand,
The relationship between the descent distance and the descent acceleration at that time is calculated. From this figure, the acceleration of descent is 10m
If the parison is housed in the mold at m / sec 2, the parison length becomes 375 mm when extruded at 10 rpm or 20 rpm, but it becomes only 330 mm when extruded at 30 rpm. It In addition, the set temperature of the extruder is 23 in the case of 10 rpm.
The temperature is 243 ° C. at 4 ° C. and 20 rpm, and 248 ° C. at 30 rpm. As described above, according to the present invention, since it is possible to accurately measure how the drawdown progresses, it is possible to set appropriate molding conditions.
【図1】本発明方法を実施する態様の1例を模式的に示
すものである。FIG. 1 schematically shows an example of an embodiment for carrying out the method of the present invention.
【図2】本発明方法により得られた、溶融パリソンの降
下距離と降下の加速度との関係の1例を示すグラフであ
る。FIG. 2 is a graph showing an example of the relationship between the descent distance and the descent acceleration of the molten parison obtained by the method of the present invention.
1 押出機 2 ダイ 3 溶融パリソン 4 カメラ 5 バックボード 6 画像処理装置 7 モニターテレビ 8 プリンター 1 Extruder 2 Die 3 Melting parison 4 Camera 5 Backboard 6 Image processing device 7 Monitor TV 8 Printer
───────────────────────────────────────────────────── フロントページの続き (72)発明者 島田 正義 神奈川県茅ヶ崎市円蔵370番地 三菱化成 エンジニアリング株式会社湘南技術開発セ ンター内 (72)発明者 浴 幸司 神奈川県茅ヶ崎市円蔵370番地 三菱化成 エンジニアリング株式会社湘南技術開発セ ンター内 (72)発明者 川上 武 神奈川県茅ヶ崎市円蔵370番地 三菱化学 株式会社茅ヶ崎事業所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayoshi Shimada, 370 Yenzo, Chigasaki City, Kanagawa Prefecture Mitsubishi Kasei Engineering Co., Ltd. Shonan Technology Development Center (72) Inventor, Koji Yuba, 370 Yenzo, Chigasaki City, Kanagawa Mitsubishi Kasei Engineering Co., Ltd. Company Shonan Technology Development Center (72) Inventor Takeshi Kawakami 370 Enzo, Chigasaki City, Kanagawa Prefecture Mitsubishi Chemical Co., Ltd. Chigasaki Plant
Claims (4)
溶融パリソンの降下状況を経時的にカメラで撮影し、こ
の撮影データに基づいて溶融パリソンのドローダウンの
発生状況を計測することを特徴とするドローダウンの測
定方法。1. A method in which a descending state of a molten parison extruded vertically downward from an extruder die is photographed with a camera over time, and a drawdown occurrence state of the molten parison is measured based on the photographed data. How to measure drawdown.
溶融パリソンをカメラで経時的に撮影して、各時点にお
ける溶融パリソンの降下量を求め、このデータから各時
点における溶融パリソンの降下速度を算出することを特
徴とするドローダウンの測定方法。2. A molten parison extruded vertically downward from an extruder die is photographed with a camera over time to determine the amount of molten parison fall at each time point, and from this data the descent rate of the molten parison at each time point is determined. A method for measuring drawdown, which comprises:
溶融パリソンをカメラで経時的に撮影して、各時点にお
ける溶融パリソンの降下量を求め、このデータから各時
点における溶融パリソンの降下の加速度を算出すること
を特徴とするドローダウンの測定方法。3. A molten parison extruded vertically downward from an extruder die is photographed with a camera over time to obtain the amount of molten parison drop at each time point, and from this data, the molten parison drop at each time point is calculated. A drawdown measuring method characterized by calculating an acceleration.
より得られたパリソンの画像を画像処理して得たデータ
に基づいて行なうことを特徴とする請求項2又は3に記
載のドローダウンの測定方法。4. The drawdown according to claim 2 or 3, wherein the amount of fall of the molten parison is calculated based on data obtained by image-processing an image of the parison obtained by photographing. Measuring method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8043260A JPH09234783A (en) | 1996-02-29 | 1996-02-29 | Measuring method for drawdown of molten parison in direct blow molding |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8043260A JPH09234783A (en) | 1996-02-29 | 1996-02-29 | Measuring method for drawdown of molten parison in direct blow molding |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH09234783A true JPH09234783A (en) | 1997-09-09 |
Family
ID=12658888
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP8043260A Pending JPH09234783A (en) | 1996-02-29 | 1996-02-29 | Measuring method for drawdown of molten parison in direct blow molding |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH09234783A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017047250A1 (en) * | 2015-09-15 | 2017-03-23 | 八千代工業株式会社 | Parison foreign matter detection system |
IT201600099416A1 (en) * | 2016-10-04 | 2018-04-04 | Soffiaggio Tecnica Srl | EXTRUSION AND BLOWING MACHINE WITH CONTROL DEVICE |
-
1996
- 1996-02-29 JP JP8043260A patent/JPH09234783A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017047250A1 (en) * | 2015-09-15 | 2017-03-23 | 八千代工業株式会社 | Parison foreign matter detection system |
JPWO2017047250A1 (en) * | 2015-09-15 | 2018-06-14 | 八千代工業株式会社 | Parison foreign object detection system |
US10286592B2 (en) | 2015-09-15 | 2019-05-14 | Yachiyo Industry Co., Ltd. | Parison foreign matter detection system |
IT201600099416A1 (en) * | 2016-10-04 | 2018-04-04 | Soffiaggio Tecnica Srl | EXTRUSION AND BLOWING MACHINE WITH CONTROL DEVICE |
EP3305503A1 (en) * | 2016-10-04 | 2018-04-11 | S.T. Soffiaggio Tecnica S.r.l. | Extrusion and blow molding machine with control device |
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