JPH10329181A - Injection moldilng machine - Google Patents
Injection moldilng machineInfo
- Publication number
- JPH10329181A JPH10329181A JP11864598A JP11864598A JPH10329181A JP H10329181 A JPH10329181 A JP H10329181A JP 11864598 A JP11864598 A JP 11864598A JP 11864598 A JP11864598 A JP 11864598A JP H10329181 A JPH10329181 A JP H10329181A
- Authority
- JP
- Japan
- Prior art keywords
- injection
- pressure
- load pressure
- control valve
- stroke
- 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.)
- Granted
Links
Landscapes
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、射出シリンダ（油
圧シリンダ）を射出用アクチュエータとする射出成形機
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine using an injection cylinder (hydraulic cylinder) as an injection actuator.
【０００２】[0002]
【従来の技術】該種油圧駆動式の射出成形機において
は、型締シリンダ（油圧シリンダ）によって型締を行な
い、この後の適宜射出タイミングで、射出シリンダ（油
圧シリンダ）によって溶融樹脂を型締された金型内の成
形空間（キャビティ）ヘ射出・充填するようにしてい
る。2. Description of the Related Art In this type of hydraulically driven injection molding machine, mold clamping is performed by a mold clamping cylinder (hydraulic cylinder), and the molten resin is clamped by an injection cylinder (hydraulic cylinder) at an appropriate injection timing thereafter. The mold is injected and filled into the molding space (cavity) in the mold.
【０００３】図３は、斯る従来の射出成形機の射出シリ
ンダ系統の油圧回路を示す図で、同図において、１は油
圧ポンプ、２は圧力制御弁（電磁比例リリーフ弁）、３
は流量制御弁、４は方向切替弁、５は射出シリンダ（油
圧シリンダ）である。上記射出シリンダ５のピストンロ
ッド５ａには、インラインスクリュータイプの射出成形
機においては図示していないが公知のように、加熱シリ
ンダ内に配設されたスクリューの根本部分が適宜連結手
段を介して連結されている。FIG. 3 is a diagram showing a hydraulic circuit of an injection cylinder system of such a conventional injection molding machine. In FIG. 3, 1 is a hydraulic pump, 2 is a pressure control valve (electromagnetic proportional relief valve), 3
Is a flow control valve, 4 is a direction switching valve, and 5 is an injection cylinder (hydraulic cylinder). Although not shown in the in-line screw type injection molding machine, a root portion of a screw provided in the heating cylinder is connected to the piston rod 5a of the injection cylinder 5 through a connecting means as appropriate. Have been.
【０００４】図３の構成において、型締完了後の所定秒
時をおいたタイミングで、前記方向切替弁４が中立位置
から左位置に切替えられて、前記油圧ポンプ１からの圧
油が射出シリンダ５の前進用油室に供給され、これによ
って、前記ピストンロッド５ａと共に図示せぬスクリュ
ーが一体となって前進し、溶融樹脂が同じく図示せぬ加
熱シリンダ先端のノズルから型締された金型間のキャビ
ティ（成形空間）に射出・充填される。そして、このス
クリュー前進による射出・充填行程（１次射出行程）に
よってキャビティ内に溶融樹脂を充填し終わると、公知
の保圧行程（２次射出行程）に切替えられて、スクリュ
ーの押圧力によってキャビティの溶融樹脂に所定の保圧
圧力をかけ、樹脂の冷却固化に伴う収縮等を補うように
される。In the configuration shown in FIG. 3, the directional control valve 4 is switched from the neutral position to the left position at a predetermined time after the completion of the mold clamping, and the hydraulic oil from the hydraulic pump 1 is supplied to the injection cylinder. 5, a screw (not shown) moves forward together with the piston rod 5a, and molten resin is fed from the nozzle at the tip of the heating cylinder (not shown) between the molds. Is injected and filled into the cavity (molding space). When the injection of the molten resin into the cavity is completed by the injection / filling process (primary injection process) by the advancement of the screw, the pressure is switched to the known pressure-holding process (secondary injection process). A predetermined holding pressure is applied to the molten resin to compensate for shrinkage and the like accompanying cooling and solidification of the resin.
【０００５】ところで、上記した射出・充填行程（１次
射出行程）期間中は、従来、射出速度を重視することが
多く、このため、射出・充填行程期間は、スクリュー
（射出シリンダ５のピストンロッド５ａ）の前進位置
（ストローク）に応じて設定された設定速度に従うよう
に、射出速度を前記流量制御弁３によってコントロール
するようにしていた。また、前記保圧行程は圧力制御を
重視するため、公知の保圧切替え点以降は、時間による
圧力制御を前記圧力制御弁２によって行うようにしてい
る。In the meantime, during the above-mentioned injection / filling stroke (primary injection stroke), the injection speed is often regarded as important. Therefore, during the injection / filling stroke, the screw (the piston rod of the injection cylinder 5) The injection speed is controlled by the flow control valve 3 so as to follow the set speed set according to the forward position (stroke) of 5a). In addition, since the pressure-holding process emphasizes pressure control, pressure control based on time is performed by the pressure control valve 2 after a known pressure-holding switching point.
【０００６】図４は、図３の構成によって射出を行った
際の射出速度と負荷圧（射出シリンダ５の前進用油室の
圧力）との関係を示すグラフ図である。同図に示すよう
に、射出・充填行程期間においては速度制御を行ってい
るため、速度の実測データは同図の実線に示すように各
ゾーンＡ’，Ｂ’，Ｃ’毎に設定された設定速度値にほ
ぼ倣った特性カーブを示す。一方、このように射出・充
填行程期間においては速度を優先した制御を行っている
ため、換言するなら負荷圧にかかわりなく位置による速
度制御を行っているので、負荷圧を正確にはコントロー
ルできない。また、流量制御弁３の上流側圧力を下流側
圧力よりも相当大きくする（所謂差圧を大きくする）
と、充填途上中には負荷圧は射出・充填行程時の最適充
填圧を超えないが、キャビティ内に樹脂が行きわたった
（つまった）充填完了の手前からは負荷反力（樹脂圧
力）が高まるため、負荷圧は急速に大きくなって射出・
充填行程時の最適充填圧を上回ってしまうことが多い。FIG. 4 is a graph showing the relationship between the injection speed and the load pressure (the pressure of the forward oil chamber of the injection cylinder 5) when the injection is performed by the configuration of FIG. As shown in the figure, since the speed control is performed during the injection / filling stroke period, the measured speed data is set for each zone A ', B', C 'as shown by the solid line in the figure. 6 shows a characteristic curve substantially following the set speed value. On the other hand, during the injection / filling stroke period, the control is performed with priority given to the speed. In other words, since the speed is controlled by the position irrespective of the load pressure, the load pressure cannot be accurately controlled. Further, the pressure on the upstream side of the flow control valve 3 is made considerably higher than the pressure on the downstream side (so-called differential pressure is increased).
During the filling process, the load pressure does not exceed the optimal filling pressure during the injection / filling process, but the load reaction force (resin pressure) starts before the resin is filled (clogged) in the cavity and the filling is completed. As the load pressure increases, the load pressure increases
It often exceeds the optimum filling pressure during the filling process.
【０００７】[0007]
【発明が解決しようとする課題】上述した従来技術にお
いては、射出・充填行程（１次射出行程）時には速度を
優先した制御を行っているので、射出速度を重視する成
形品、換言するならレンズ、家電製品等のように寸法精
度や外観（ウエルドライン，フローマーク，シルバー
等）を重視する成形品の製造には好適である。In the prior art described above, control is performed with priority given to speed during the injection / filling process (primary injection process). Therefore, a molded product that emphasizes the injection speed, in other words, a lens. It is suitable for the manufacture of molded products such as home electric appliances and the like in which dimensional accuracy and appearance (weld line, flow mark, silver, etc.) are emphasized.
【０００８】しかしながら、射出・充填行程期間中には
負荷圧を正確にはコントロールできないので負荷圧が安
定せず、従って成形品密度がバラツキ易く、充填圧力
（負荷圧）を重視する成形品、換言するならＣＤ、薄肉
製品等のように重量精度や変形（ソリ等）防止を重視す
る製品には適さないという問題があった。However, during the injection / filling process, the load pressure cannot be accurately controlled, so that the load pressure is not stable, so that the density of the molded product tends to vary, and in other words, a molded product in which emphasis is placed on the filling pressure (load pressure). If this is the case, there is a problem that it is not suitable for a product such as a CD or a thin-walled product that emphasizes weight accuracy and prevention of deformation (such as warpage).
【０００９】また、射出・充填行程（１次射出行程）時
に速度を優先した制御を行っているので、保圧切替え点
近傍では負荷圧が最適充填圧を大きく上回る傾向があ
り、充填圧が過剰となって成形品にバリが発生し易く、
且つ、キャビティ内のゲートに近い部分の密度が過剰と
なるためソリも発生し易く、斯様なバリ、ソリ等による
成形品不良が発生し易いという問題もあった。さらに、
保圧切替え点近傍では負荷圧が最適充填圧を大きく上回
っているため、保圧行程に入ってから負荷圧が保圧設定
値に落着くまでの時間Ｔ2 が比較的大きく且つ安定しな
いため、この点でも薄肉成形品の品質に悪影響を与える
という問題があった。In addition, since control is performed with priority given to speed during the injection / filling stroke (primary injection stroke), the load pressure tends to greatly exceed the optimum filling pressure near the holding pressure switching point, and the filling pressure becomes excessive. As a result, burrs are likely to occur on molded products,
In addition, since the density of the portion near the gate in the cavity becomes excessive, warpage is likely to occur, and there is also a problem that a molded article defect due to such burrs and warpages is apt to occur. further,
Since in the vicinity hold pressure replacement point load pressure is far above the optimum filling pressure, since the load pressure from entering the higher coercive stroke is the time T 2 of the in settled bear coercive pressure setpoint does not relatively large and stable, Also in this respect, there is a problem that the quality of the thin molded product is adversely affected.
【００１０】本発明は上記の点に鑑みなされたもので、
その目的とするところは、重量精度や変形（ソリ等）防
止を重視する成形品のための充填圧力（負荷圧）制御を
優先した射出・充填（１次射出）を可能とし、さらに、
この圧力優先制御の際に、１次射出行程の実測射出速度
が概略所望の特性線を描いて、射出速度も安定したもの
となり得る、動作信頼性の高い且つ良品成形が達成可能
な射出成形機を提供することにある。さらに、本発明の
目的とするところは、上記の目的に加えて、重量精度や
変形（ソリ等）防止を重視する成形品のための充填圧力
（負荷圧）制御を優先した射出・充填（１次射出）と、
寸法精度や外観を重視する成形品のための射出速度制御
を優先した射出・充填（１次射出）とが、同一のマシン
で選択的にとり得る射出成形機を提供することにある。[0010] The present invention has been made in view of the above points,
Its purpose is to enable injection / filling (primary injection) with priority given to filling pressure (load pressure) control for molded products that emphasize weight accuracy and prevention of deformation (such as warpage).
In this pressure priority control, the injection speed measured in the primary injection stroke draws a roughly desired characteristic line, and the injection speed can be stabilized. Is to provide. Further, the object of the present invention is to provide, in addition to the above-mentioned objects, injection / filling (1) which prioritizes filling pressure (load pressure) control for a molded article that emphasizes weight accuracy and prevention of deformation (such as warpage). Next injection)
An object of the present invention is to provide an injection molding machine in which injection and filling (primary injection) with priority given to injection speed control for a molded product in which dimensional accuracy and appearance are emphasized can be selectively performed by the same machine.
【００１１】[0011]
【課題を解決するための手段】本発明は上記した目的を
達成するため、油圧ポンプもしくはアキュームレータか
らの圧油を、流量制御弁を介して射出シリンダに供給し
て射出を行う射出成形機において、流量制御弁と射出シ
リンダとの間の油路に負荷圧制御弁を設け、キャビティ
内に溶融樹脂を射出・充填する１次射出行程を、射出シ
リンダのピストンロッドの前進位置に応じて設定された
設定負荷圧特性線に一致するように、負荷圧制御弁を制
御することによる圧力優先制御によって実行するよう
に、構成される。さらに、前記設定負荷圧特性線は、１
次射出行程の実測射出速度が概略所望の特性線を描くよ
うに、例えば折線による特性線によって設定するよう
に、構成される。さらに、１次射出行程を、前記圧力優
先制御、または、射出シリンダのピストンロッドの前進
位置に応じて設定された速度設定値に一致するように、
流量制御弁を制御することによる速度優先制御、の何れ
か一方に選択可能であるように、構成される。According to the present invention, there is provided an injection molding machine for performing injection by supplying pressure oil from a hydraulic pump or an accumulator to an injection cylinder through a flow control valve. A load pressure control valve is provided in an oil passage between the flow control valve and the injection cylinder, and a primary injection stroke for injecting and filling the molten resin into the cavity is set according to the advance position of the piston rod of the injection cylinder. It is configured to execute by pressure priority control by controlling the load pressure control valve so as to match the set load pressure characteristic line. Further, the set load pressure characteristic line is 1
The measured injection speed in the next injection stroke is set so as to roughly draw a desired characteristic line, for example, by a characteristic line by a broken line. Further, the primary injection stroke, the pressure priority control, or to match the speed set value set according to the forward position of the piston rod of the injection cylinder,
It is configured such that either one of speed priority control by controlling the flow control valve can be selected.
【００１２】本発明では、射出シリンダの前進用油室に
供給する油圧をコントロールする電磁比例リリーフ弁よ
りなる負荷圧制御弁を設け、充填圧力（負荷圧）を重視
する成形品を製造する際には流量制御弁を開放状態にし
て、１次射出行程（射出・充填行程）を、負荷圧制御弁
によって、速度にかかわりなく、油圧シリンダのピスト
ンロッドの前進位置に応じて設定された各設定負荷圧に
基づく圧力制御によって実行する。これによって、１次
射出行程区間においては、射出シリンダへ供給される油
圧（負荷圧）が、設定された負荷圧に一致するような圧
力制御に基づく射出・充填が行われ、射出速度は負荷圧
に依存する形で間接的にコントロールされる。この結
果、１次射出行程（射出・充填行程）中における射出速
度の正確な制御は行えないが、負荷圧は設定負荷圧にほ
ぼ倣う形で１次射出行程（射出・充填行程）の全区間
中、常時良好なものに安定し、従って充填圧が安定して
（金型内樹脂圧が安定して）成形品密度のバラツキがな
くなって製品重量精度が向上し、且つソリ等の変形の発
生も可及的に抑止可能となる。すなわち、薄肉製品等を
高品質で歩留まり良く製造可能となる。また、キャビテ
ィ内に樹脂が行きわたった（つまった）充填完了の手前
から負荷反力（樹脂圧力）が高まっても、射出シリンダ
へ供給される油圧（負荷圧）が設定負荷圧を超えること
がなく（過剰充填圧となることがなく）、さらに保圧行
程に入ってから保圧設定値に落着くまでの時間も安定す
るので、バリやソリの発生もなく、総じて、成形品密度
が安定して薄肉成形品等の品質が向上する。According to the present invention, a load pressure control valve comprising an electromagnetic proportional relief valve for controlling a hydraulic pressure supplied to a forward oil chamber of an injection cylinder is provided, and when a molded product in which a filling pressure (load pressure) is emphasized is manufactured. With the flow control valve in the open state, the primary injection stroke (injection / filling stroke) is controlled by the load pressure control valve, regardless of the speed, in accordance with each set load set according to the forward position of the piston rod of the hydraulic cylinder. This is performed by pressure control based on pressure. Thus, in the primary injection stroke section, injection and filling are performed based on pressure control such that the hydraulic pressure (load pressure) supplied to the injection cylinder matches the set load pressure, and the injection speed is reduced to the load pressure. Is controlled indirectly depending on the As a result, accurate control of the injection speed during the primary injection stroke (injection / filling stroke) cannot be performed, but the load pressure substantially follows the set load pressure in all sections of the primary injection stroke (injection / filling stroke). Medium and stable at all times, so that the filling pressure is stable (the resin pressure in the mold is stable), the density of the molded product is no longer uneven, the product weight accuracy is improved, and deformation such as warpage is generated. Can be suppressed as much as possible. That is, it is possible to manufacture thin products and the like with high quality and high yield. Also, even if the load reaction force (resin pressure) increases from just before the filling of the resin in the cavity (clogging), the hydraulic pressure (load pressure) supplied to the injection cylinder may exceed the set load pressure. (There is no excess filling pressure), and since the time from the start of the pressure-holding process to the time when the pressure-holding value is settled is stable, there is no burr or warpage, and the molded product density is generally stable. As a result, the quality of thin molded products and the like is improved.
【００１３】一方、射出速度を重視する成形品を製造す
る際には、負荷圧制御弁の上限規制値を最大に設定し
て、１次射出行程（射出・充填行程）を、流量制御弁に
よって、負荷圧にかかわりなく、油圧シリンダのピスト
ンロッドの前進位置に応じて設定された各設定速度に基
づく速度制御によって実行する。これによって、１次射
出行程区間においては、射出シリンダのピストンロッド
の前進速度が、設定された射出速度に一致するような速
度制御に基づく射出・充填が行われる。この結果、１次
射出行程（射出・充填行程）中における負荷圧の正確な
制御は行えないが、射出速度は設定速度にほぼ倣う形で
１次射出行程（射出・充填行程）の全区間中、常時良好
なものに安定し、従って最後まで射出速度が安定して
（金型内での溶融樹脂の流動挙動が安定して）、寸法精
度が安定し、且つ、ウェルドラインやフローマーク等の
外観不良の発生も可及的に抑止可能となる。すなわち、
家電製品等の寸法精度と外観とを重視する成形品を歩留
まり良く製造可能となる。On the other hand, when manufacturing a molded product in which the injection speed is important, the upper limit value of the load pressure control valve is set to the maximum, and the primary injection stroke (injection / filling stroke) is controlled by the flow control valve. , Irrespective of the load pressure, is executed by speed control based on each set speed set according to the forward position of the piston rod of the hydraulic cylinder. Thus, in the primary injection stroke section, injection / filling is performed based on speed control such that the forward speed of the piston rod of the injection cylinder matches the set injection speed. As a result, accurate control of the load pressure during the primary injection stroke (injection / filling stroke) cannot be performed, but the injection speed during the entire section of the primary injection stroke (injection / filling stroke) substantially follows the set speed. , Always stable to good, so the injection speed is stable to the end (the flow behavior of the molten resin in the mold is stable), the dimensional accuracy is stable, and the weld line and flow mark The occurrence of poor appearance can be suppressed as much as possible. That is,
It is possible to manufacture a molded product, such as a home electric appliance, in which dimensional accuracy and appearance are important, with a high yield.
【００１４】[0014]
【発明の実施の形態】以下、本発明の１実施形態を図１
および図２によって説明する。図１は本実施形態に係る
射出成形機の射出シリンダ系統の油圧回路を示す説明図
であり、図２は射出・充填行程時の負荷圧（射出シリン
ダ５の前進用油室の圧力）と射出速度との関係を示すグ
ラフ図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIG.
And FIG. FIG. 1 is an explanatory diagram showing a hydraulic circuit of an injection cylinder system of an injection molding machine according to the present embodiment, and FIG. 2 is a diagram showing load pressure (pressure of a forward oil chamber of an injection cylinder 5) and injection during an injection / filling stroke. It is a graph which shows the relationship with speed.
【００１５】図１において、１，２，３，４，５，５ａ
は、前記図３の構成とそれぞれ均等な油圧ポンプ，圧力
制御弁（電磁比例リリーフ弁），流量制御弁，方向切替
弁，射出シリンダ（油圧シリンダ），ピストンロッドで
あり、６は、流量制御弁３と射出シリンダ５の前進用油
室との間の油路（流量制御弁３から見た下流側の油路）
に設置された電磁比例リリーフ弁よりなる負荷圧制御弁
であり、また、７は、ピストンロッド５ａの位置を検出
する射出ストローク検出センサ（例えばエンコーダ）で
ある。In FIG. 1, 1, 2, 3, 4, 5, 5a
Is a hydraulic pump, a pressure control valve (electromagnetic proportional relief valve), a flow control valve, a direction switching valve, an injection cylinder (hydraulic cylinder), and a piston rod, each of which is equivalent to the configuration of FIG. Oil passage (oil passage on the downstream side as viewed from the flow control valve 3) between the cylinder 3 and the forward oil chamber of the injection cylinder 5
Is a load pressure control valve formed of an electromagnetic proportional relief valve installed in the control unit, and 7 is an injection stroke detection sensor (for example, an encoder) for detecting the position of the piston rod 5a.
【００１６】上記した電磁制御弁群２，３，４，６は、
マシン全体の制御を司る図示せぬマイクロコンピュータ
（マイコン）によって、それぞれ適宜ドライバ回路を介
して独立してコントロールされるようになっており、マ
イコンの指令に応じて、流量制御弁３よる速度（速度に
対応する流量）や圧力制御弁２，６による油圧上限規制
値を可変設定できるようになっており、また、方向切替
弁４の切替え位置が選択できるようになっている。な
お、前記射出ストローク検出センサ７による計測データ
は、上記したマイコンに取り込まれ射出ストローク（位
置）が認知されるようになっている。The above-mentioned electromagnetic control valve groups 2, 3, 4, 6
The microcomputer (microcomputer), which is not shown, controls the entire machine, and is independently controlled via a driver circuit as appropriate. The speed (speed) of the flow control valve 3 is controlled according to a command from the microcomputer. ) And the upper limit pressure value of the hydraulic pressure by the pressure control valves 2 and 6 can be variably set, and the switching position of the direction switching valve 4 can be selected. The measurement data obtained by the injection stroke detection sensor 7 is taken into the above-mentioned microcomputer, and the injection stroke (position) is recognized.
【００１７】ここで、本実施形態においては、負荷圧制
御弁６が、流量制御弁３よりも下流側の油路で射出シリ
ンダ５の前進用油室と直結する形で付加・設置されてい
るので、流量制御弁３による速度を優先した射出・充填
制御を行わない時には、圧力制御弁２を最大圧力、流量
制御弁３を最大流量に設定することにより、負荷圧制御
弁６で可変設定される油圧上限規制値に従った油圧（負
荷圧）を優先した射出・充填（１次射出）制御を行うこ
とが可能になっている。また、負荷圧制御弁６による圧
力を優先した射出・充填制御を行わない時には、負荷圧
制御弁６を最大圧力に設定することにより、流量制御弁
３で可変制御される流量値に従った射出速度を優先した
射出・充填（１次射出）制御を行うことが可能になって
いる。次に、上記構成に基づく１次射出（射出・充填）
動作を説明する。Here, in the present embodiment, the load pressure control valve 6 is added and installed so as to be directly connected to the forward oil chamber of the injection cylinder 5 on the oil passage downstream of the flow control valve 3. Therefore, when injection / filling control in which priority is given to speed by the flow control valve 3 is not performed, the pressure control valve 2 is set to the maximum pressure and the flow control valve 3 is set to the maximum flow rate, so that the load pressure control valve 6 is variably set. It is possible to perform injection / filling (primary injection) control giving priority to the hydraulic pressure (load pressure) in accordance with the hydraulic pressure upper limit value. Further, when the injection / filling control in which the pressure by the load pressure control valve 6 is prioritized is not performed, by setting the load pressure control valve 6 to the maximum pressure, the injection according to the flow value variably controlled by the flow control valve 3 is performed. Injection / filling (primary injection) control giving priority to speed can be performed. Next, primary injection (injection / filling) based on the above configuration
The operation will be described.
【００１８】〈圧力（負荷圧）制御を優先した１次射出
動作〉圧力（負荷圧）制御を優先した１次射出を行う際
には、少なくとも１次射出期間中は、前記したマイコン
によって、圧力制御弁２は最大圧力、流量制御弁３は最
大流量に設定される。<Primary injection operation giving priority to pressure (load pressure) control> When performing primary injection giving priority to pressure (load pressure) control, the microcomputer performs the pressure injection at least during the primary injection period. The control valve 2 is set at the maximum pressure, and the flow control valve 3 is set at the maximum flow rate.
【００１９】いま、型締完了後の所定秒時をおいたタイ
ミングで、前記方向切替弁４が中立位置から左位置に切
替えられて、前記油圧ポンプ１からの圧油が射出シリン
ダ５の前進用油室に供給され、これによって、前記ピス
トンロッド５ａと共に図示せぬスクリューが一体となっ
て前進し、溶融樹脂が同じく図示せぬ加熱シリンダ先端
のノズルから型締された金型間のキャビティ（成形空
間）に射出・充填され始める。この射出・充填行程（１
次射出行程）時には、図２に示すように射出・充填区間
（射出ストローク）を任意に分割した各ゾーンＡ，Ｂ，
Ｃ，Ｄごとで予め設定された設定負荷圧と、前記射出ス
トローク検出センサ７による前進位置検出情報とに基づ
き、前記したマイコンの指令で負荷圧制御弁６による上
限規制値が可変制御され、これによって負荷圧（射出圧
力たる充填圧）を制御することによる射出・充填行程が
実行される。すなわち、図２に示すように射出・充填行
程（１次射出行程）区間では、射出速度にかかわりな
く、設定負荷圧にほぼ倣うような圧力制御によって射出
・充填行程を実行させ、これにより射出・充填行程（１
次射出行程）中には、負荷圧を設定負荷圧に一致させて
安定した充填圧を維持するようになっている。At a predetermined time after completion of the mold clamping, the direction switching valve 4 is switched from the neutral position to the left position, and the pressure oil from the hydraulic pump 1 is used to move the injection cylinder 5 forward. The oil is supplied to the oil chamber, whereby the screw (not shown) advances together with the piston rod 5a, and the molten resin also flows into the cavity (molding) between the molds which are also clamped from the nozzle at the tip of the heating cylinder (not shown). Space) begins to be injected and filled. This injection and filling process (1
During the next injection stroke), as shown in FIG. 2, each of the zones A, B,
The upper limit value of the load pressure control valve 6 is variably controlled by a command of the microcomputer based on the set load pressure preset for each of C and D and the forward position detection information from the injection stroke detection sensor 7. The injection / filling process by controlling the load pressure (the filling pressure, which is the injection pressure) is executed. That is, as shown in FIG. 2, in the injection / filling stroke (primary injection stroke) section, regardless of the injection speed, the injection / filling stroke is executed by pressure control almost following the set load pressure. Filling process (1
During the next injection stroke), the load pressure is made to match the set load pressure to maintain a stable filling pressure.
【００２０】なお、設定された負荷圧に一致するような
圧力制御に基づく射出・充填を行うと、射出速度は負荷
圧に依存する形で間接的にコントロールされる。よっ
て、設定負荷圧を任意の特性線に設定することによっ
て、正確ではないが或る程度所望の射出速度カーブを得
ることができる。例えば、図２に示す如く、１次射出行
程の実測射出速度が概略所望の特性線を描くように、設
定負荷圧の特性線を折れ線によって設定することで、射
出速度は負荷圧に依存する形で間接的にコントロールさ
れて、実測射出速度は概略所望の特性線を描くようにな
る。したがって、圧力優先制御の際に、１次射出行程の
実測射出速度が概略所望の特性線を描くようになって、
射出速度も安定したものとなり、動作信頼性の高い且つ
良品成形が達成可能となる。When injection / filling is performed based on pressure control that matches the set load pressure, the injection speed is indirectly controlled in a manner dependent on the load pressure. Therefore, by setting the set load pressure to an arbitrary characteristic line, it is possible to obtain a desired injection speed curve which is not accurate but to some extent. For example, as shown in FIG. 2, by setting the characteristic line of the set load pressure by a broken line so that the actually measured injection speed of the primary injection stroke draws a substantially desired characteristic line, the injection speed depends on the load pressure. , The measured injection speed roughly draws a desired characteristic line. Therefore, at the time of the pressure priority control, the actually measured injection speed of the primary injection stroke substantially draws a desired characteristic line,
The injection speed is also stable, and high-quality molding with high operation reliability can be achieved.
【００２１】そして、前記ピストンロッド５ａが射出・
充填行程区間の終端位置に至ったこと（保圧切替え点に
至ったこと）が、前記射出ストローク検出センサ７によ
って検知されると、前記マイコンは、時間による圧力制
御を行う保圧行程に入り、負荷圧制御弁６の上限制限値
を保圧設定値に制御して所定時間の保圧行程が実行され
る。この際、保圧切替え点での負荷圧は各ショット毎で
常に、射出・充填行程区間の終端位置の設定負荷圧にほ
ぼ一致した値で一定しているので、保圧行程に入ってか
ら負荷圧が保圧設定値に落着くまでの時間Ｔ1 は、従来
に比して安定し且つ短いものとなる。Then, the piston rod 5a is
When the injection stroke detection sensor 7 detects that the end position of the filling stroke section has been reached (it has reached the pressure holding switching point), the microcomputer enters a pressure holding stroke for performing time-based pressure control. The upper limit value of the load pressure control valve 6 is controlled to the set pressure value, and the pressure-holding process is performed for a predetermined time. At this time, the load pressure at the pressure holding switching point is always constant at a value substantially equal to the set load pressure at the end position of the injection / filling stroke section for each shot. time T 1 of the pressure in the settled bear coercive pressure setpoint is becomes stable and shorter than conventional.
【００２２】このように、射出・充填（１次射出）行程
を負荷圧優先制御で行うと、射出・充填行程中の充填圧
が安定して、且つ充填完了に近づいても充填圧が適正値
を超えることがなく、また、保圧行程に入ってから保圧
設定値に落着くまでの時間が安定する。従って、成形品
密度が安定し、ソリ、バリのない良好な成形品を製造す
ることが可能となり、以って、重量精度や変形（ソリ
等）防止を重視する薄肉製品等を、高品質で歩留まり良
く製造可能となる。また、１次射出行程（射出・充填行
程）とこれに続く２次射出行程（保圧行程）を共に圧力
制御で行っているので（１次射出行程終端の負荷圧が一
定しているので）、１次射出行程から２次射出行程への
切替え点の設定にさほど厳密な値を必要とせず、１次射
出行程から２次射出行程への切替え点の設定が至って簡
単・容易となる。As described above, when the injection / filling (primary injection) process is performed by the load pressure priority control, the filling pressure during the injection / filling process is stabilized, and the filling pressure is set to an appropriate value even when the charging is completed. , And the time from the start of the pressure-holding process until the pressure-holding set value is settled is stabilized. Therefore, it is possible to produce a good molded product having a stable molded product density and free of warpage and burrs. It can be manufactured with good yield. In addition, the primary injection stroke (injection / filling stroke) and the subsequent secondary injection stroke (pressure-holding stroke) are both performed by pressure control (since the load pressure at the end of the primary injection stroke is constant). The setting of the switching point from the primary injection stroke to the secondary injection stroke does not require a very strict value, and the setting of the switching point from the primary injection stroke to the secondary injection stroke is simple and easy.
【００２３】〈射出速度制御を優先した１次射出動作〉
射出速度制御を優先した１次射出を行う際には、１次射
出期間中は、前記したマイコンによって負荷圧制御弁６
の上限値は最大圧力に設定され、この間負荷圧制御弁６
は管路の破損を防止する単なる安全弁としてのみ機能す
るようにされる。<Primary injection operation giving priority to injection speed control>
When performing the primary injection giving priority to the injection speed control, the microcomputer controls the load pressure control valve 6 during the primary injection period.
Is set to the maximum pressure, during which the load pressure control valve 6
Is to function only as a simple safety valve to prevent line breakage.
【００２４】そして、この際も同様に型締完了後の所定
秒時をおいたタイミングで、前記方向切替弁４が中立位
置から左位置に切替えられて、前記油圧ポンプ１からの
圧油が射出シリンダ５の前進用油室に供給され、これに
よって、前記ピストンロッド５ａと共に図示せぬスクリ
ューが一体となって前進し、溶融樹脂が同じく図示せぬ
加熱シリンダ先端のノズルから型締された金型間のキャ
ビティ（成形空間）に射出・充填され始める。この射出
・充填行程（１次射出行程）時には、前記図４に示すよ
うに射出・充填区間（射出ストローク）を任意に分割し
た例えばゾーンＡ’，Ｂ’，Ｃ’ごとで予め設定された
設定速度と、前記射出ストローク検出センサ７による前
進位置検出情報とに基づき、前記したマイコンの指令で
流量制御弁３による流量規制値が可変制御され、これに
よって射出速度を制御することによる射出・充填行程が
実行される。すなわち、図４に示すように射出・充填行
程（１次射出行程）区間では、負荷圧にかかわりなく、
設定射出速度にほぼ倣うような速度制御によって射出・
充填行程を実行させ、これにより射出・充填行程（１次
射出行程）中には最後まで、射出速度を設定速度に一致
させて安定した射出速度を維持するようになっている。At this time, the direction switching valve 4 is switched from the neutral position to the left position at a predetermined time after completion of the mold clamping, and the hydraulic oil from the hydraulic pump 1 is injected. A screw (not shown) is fed together with the piston rod 5a into a forward oil chamber of the cylinder 5, whereby the molten resin is moved forward integrally with the piston rod 5a. The cavity (molding space) between them starts to be injected and filled. In the injection / filling stroke (primary injection stroke), as shown in FIG. 4, the injection / filling section (injection stroke) is arbitrarily divided, and for example, is set in advance for each of the zones A ′, B ′, C ′. Based on the speed and the advance position detection information from the injection stroke detection sensor 7, the flow rate regulation value by the flow rate control valve 3 is variably controlled by the microcomputer command, thereby controlling the injection speed, thereby controlling the injection speed. Is executed. That is, as shown in FIG. 4, in the injection / filling stroke (primary injection stroke) section, regardless of the load pressure,
Injection and control by speed control that almost follows the set injection speed
The filling process is executed, so that the injection speed is made to coincide with the set speed until the end during the injection / filling process (primary injection process) to maintain a stable injection speed.
【００２５】この後、前記ピストンロッド５ａが射出・
充填行程区間の終端位置に至ったこと（保圧切替え点に
至ったこと）が、前記射出ストローク検出センサ７によ
って検知されると、同様に前記マイコンは、時間による
圧力制御を行う保圧行程に入り、負荷圧制御弁６の上限
制限値を保圧設定値に制御して所定時間の保圧行程が実
行される。Thereafter, the piston rod 5a is ejected.
When the injection stroke detection sensor 7 detects that the end position of the filling stroke section has been reached (it has reached the pressure-holding switching point), the microcomputer similarly starts the pressure-holding process for performing time-based pressure control. Then, the upper limit value of the load pressure control valve 6 is controlled to a set pressure value, and a pressure holding process for a predetermined time is executed.
【００２６】このように、射出・充填（１次射出）行程
を速度優先制御で行うと、射出速度は設定速度にほぼ倣
う形で１次射出行程（射出・充填行程）の全区間中、常
時良好なものに安定し、従って最後まで射出速度が安定
する。このため、金型内での溶融樹脂の流動挙動が安定
して、以って寸法精度が安定し、且つ、ウェルドライン
やフローマーク等の外観不良の発生も可及的に抑止可能
となる。すなわち、家電製品等の寸法精度と外観とを重
視する成形品を歩留まり良く製造可能できる。As described above, when the injection / filling (primary injection) process is performed by the speed priority control, the injection speed always follows the set speed during the entire section of the primary injection process (injection / filling process). It stabilizes to a good one and therefore the injection speed stabilizes to the end. For this reason, the flow behavior of the molten resin in the mold is stabilized, so that the dimensional accuracy is stabilized, and occurrence of appearance defects such as weld lines and flow marks can be suppressed as much as possible. That is, it is possible to manufacture a molded product, such as a home electric appliance, in which dimensional accuracy and appearance are important, with a high yield.
【００２７】なお、上記した実施例においては、射出用
の圧油供給源として油圧ポンプを用いているが、これを
射出専用の圧油供給源としてのアキュームレータに代替
可能であること当業者には自明である。In the above embodiment, a hydraulic pump is used as a pressure oil supply source for injection. However, those skilled in the art can replace this with an accumulator as a pressure oil supply source dedicated to injection. It is obvious.
【００２８】[0028]
【発明の効果】以上のように本発明によれば、重量精度
や変形（ソリ等）防止を重視する成形品のための充填圧
力（負荷圧）制御を優先した射出・充填（１次射出）を
可能とし、さらに、この圧力優先制御の際に、１次射出
行程の実測射出速度が概略所望の特性線を描いて、射出
速度も安定したものとなり得、また、充填完了の手前か
ら負荷反力（樹脂圧力）が高まっても、射出シリンダへ
供給される油圧（負荷圧）が設定負荷圧を超えることが
なく（過剰充填圧となることがなく）、動作信頼性の高
い且つ良品成形が達成可能な射出成形機を提供すること
ができる。As described above, according to the present invention, injection / filling (primary injection) with priority given to filling pressure (load pressure) control for molded products in which weight accuracy and prevention of deformation (such as warpage) are emphasized. In addition, in this pressure priority control, the actually measured injection speed of the primary injection stroke draws a substantially desired characteristic line, and the injection speed can be stabilized. Even if the force (resin pressure) increases, the hydraulic pressure (load pressure) supplied to the injection cylinder does not exceed the set load pressure (no overfilling pressure), and high-quality molding with high operation reliability is achieved. An achievable injection molding machine can be provided.
【００２９】さらにまた、１次射出行程全体を、射出シ
リンダのピストンロッドの前進位置に応じて設定された
設定速度あるいは設定負荷圧の何れか一方に基づく、速
度優先制御で行うかあるいは圧力優先制御で行うかが択
一的に選択可能なので、重量精度や変形（ソリ等）防止
を重視する成形品のための充填圧力（負荷圧）制御を優
先した射出・充填（１次射出）と、寸法精度や外観を重
視する成形品のための射出速度制御を優先した射出・充
填（１次射出）とが、同一のマシンで選択的にとり得る
ことになり、１台のマシンで汎用性の高い成形を行うこ
とが可能となる。また、速度優先制御あるいは圧力優先
制御の何れの場合も、射出シリンダのピストンロッドの
前進位置に応じて速度または圧力を設定して、１次射出
行程を制御するので、１次射出行程から保圧行程へ切り
替える保圧切替え位置（保圧切替え点）が常に一定した
ものとなり、安定な連続成形を行うことができる。Further, the entire primary injection stroke is performed by speed priority control or pressure priority control based on one of the set speed and the set load pressure set according to the forward position of the piston rod of the injection cylinder. Injection / filling (primary injection) with priority given to filling pressure (load pressure) control for molded products that emphasize weight accuracy and prevention of deformation (warpage, etc.), and dimensions Injection and filling (primary injection), which gives priority to injection speed control for molded products that place importance on precision and appearance, can be selectively performed by the same machine. Can be performed. In either case of speed priority control or pressure priority control, the primary injection stroke is controlled by setting the speed or pressure according to the advance position of the piston rod of the injection cylinder. The pressure-holding switching position (pressure-holding switching point) for switching to the process is always constant, and stable continuous molding can be performed.
【図１】本発明の１実施形態に係る射出成形機の射出シ
リンダ系統の油圧回路を示す説明図である。FIG. 1 is an explanatory diagram showing a hydraulic circuit of an injection cylinder system of an injection molding machine according to one embodiment of the present invention.
【図２】本発明の１実施形態による充填圧力（負荷圧）
制御を優先した場合の１次射出行程時の負荷圧と射出速
度を示すグラフ図である。FIG. 2 shows a filling pressure (load pressure) according to an embodiment of the present invention.
FIG. 4 is a graph showing a load pressure and an injection speed during a primary injection stroke when control is prioritized.
【図３】従来例に係る射出成形機の射出シリンダ系統の
油圧回路を示す説明図である。FIG. 3 is an explanatory diagram showing a hydraulic circuit of an injection cylinder system of an injection molding machine according to a conventional example.
【図４】従来の射出・充填行程時の射出速度と負荷圧を
示すグラフ図である。FIG. 4 is a graph showing a conventional injection speed and load pressure during an injection / filling stroke.
１ 油圧ポンプ ２ 圧力制御弁 ３ 流量制御弁 ４ 方向切替弁 ５ 射出シリンダ ５ａ ピストンロッド ６ 負荷圧制御弁 ７ 射出ストローク検出センサ DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Pressure control valve 3 Flow control valve 4 Direction switching valve 5 Injection cylinder 5a Piston rod 6 Load pressure control valve 7 Injection stroke detection sensor
Claims (4)
らの圧油を、流量制御弁を介して射出シリンダに供給し
て射出を行う射出成形機において、 前記流量制御弁と前記射出シリンダとの間の油路に負荷
圧制御弁を設け、キャビティ内に溶融樹脂を射出・充填
する１次射出行程を、前記射出シリンダのピストンロッ
ドの前進位置に応じて設定された設定負荷圧特性線に一
致するように、前記負荷圧制御弁を制御することによる
圧力優先制御によって実行するようにしたことを特徴と
する射出成形機。1. An injection molding machine for performing injection by supplying pressure oil from a hydraulic pump or an accumulator to an injection cylinder via a flow control valve, wherein an oil path is provided between the flow control valve and the injection cylinder. A load pressure control valve is provided, and the primary injection stroke of injecting and filling the molten resin into the cavity is adjusted so as to match a set load pressure characteristic line set according to a forward position of a piston rod of the injection cylinder. An injection molding machine characterized by being executed by pressure priority control by controlling a load pressure control valve.
が概略所望の特性線を描くように設定されることを特徴
とする射出成形機。2. The injection molding machine according to claim 1, wherein the set load pressure characteristic line is set such that an actually measured injection speed in a primary injection stroke draws a substantially desired characteristic line.
を特徴とする射出成形機。3. The injection molding machine according to claim 2, wherein the set load pressure characteristic line is set by a broken line.
て、 １次射出行程を、前記圧力優先制御、または、前記射出
シリンダのピストンロッドの前進位置に応じて設定され
た速度設定値に一致するように、前記流量制御弁を制御
することによる速度優先制御、の何れか一方に選択可能
であることを特徴とする射出成形機。4. The primary injection stroke according to claim 1, wherein the primary injection stroke coincides with a pressure set value set in accordance with the pressure priority control or a forward position of a piston rod of the injection cylinder. In addition, the injection molding machine can select any one of speed priority control by controlling the flow control valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11864598A JP3233608B2 (en) | 1998-04-28 | 1998-04-28 | Injection molding machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11864598A JP3233608B2 (en) | 1998-04-28 | 1998-04-28 | Injection molding machine |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3192735A Division JP2828801B2 (en) | 1991-07-08 | 1991-07-08 | Injection molding machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10329181A true JPH10329181A (en) | 1998-12-15 |
| JP3233608B2 JP3233608B2 (en) | 2001-11-26 |
Family
ID=14741693
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11864598A Expired - Fee Related JP3233608B2 (en) | 1998-04-28 | 1998-04-28 | Injection molding machine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3233608B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013097507A1 (en) * | 2011-12-27 | 2013-07-04 | 中联重科股份有限公司 | Oil line control apparatus and engineering machinery |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11203808A (en) | 1998-01-19 | 1999-07-30 | Matsushita Electric Ind Co Ltd | Information recording and reproducing device |
-
1998
- 1998-04-28 JP JP11864598A patent/JP3233608B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013097507A1 (en) * | 2011-12-27 | 2013-07-04 | 中联重科股份有限公司 | Oil line control apparatus and engineering machinery |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3233608B2 (en) | 2001-11-26 |
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|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |