JPH08300416A - Method for designing injection molding die - Google Patents
Method for designing injection molding dieInfo
- Publication number
- JPH08300416A JPH08300416A JP11189695A JP11189695A JPH08300416A JP H08300416 A JPH08300416 A JP H08300416A JP 11189695 A JP11189695 A JP 11189695A JP 11189695 A JP11189695 A JP 11189695A JP H08300416 A JPH08300416 A JP H08300416A
- Authority
- JP
- Japan
- Prior art keywords
- thick
- wall part
- thin
- branch
- thick wall
- 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
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
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/38—Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
- B29C33/3835—Designing moulds, e.g. using CAD-CAM
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、薄肉部に対して部分的
に厚肉部を有する薄肉ガス注入成形品を製造する射出成
形用金型の設計方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for designing an injection molding die for producing a thin-walled gas injection molded product having a thick-walled portion partially with respect to a thin-walled portion.
【０００２】[0002]
【従来の技術】射出成形では、薄肉部の薄い成形品は極
端に充填圧力が高くなるため、その製造は難しい。2. Description of the Related Art In injection molding, it is difficult to manufacture a molded product having a thin portion because the filling pressure is extremely high.
【０００３】そこで、例えば射出成形後に部分的若しく
は全体的に圧縮をかけて薄肉部を形成するもの（特開平
３−８７２１７号公報）や、樹脂ゲート点数を増やすこ
とによって充填圧力を低くして充填し、薄肉部を形成す
るもの（特開平６−６４００２号公報）、また流動性の
極端によい樹脂を用いて薄肉部を形成するもの、等が提
案されている。Therefore, for example, one in which a thin portion is formed by partially or wholly compressing after injection molding (JP-A-3-87217), or by increasing the number of resin gates to lower the filling pressure and filling. However, there have been proposed one that forms a thin portion (Japanese Patent Laid-Open No. 6-64002), one that forms a thin portion using a resin having extremely good fluidity, and the like.
【０００４】また、部分的に厚肉部を設け、製品内ラン
ナーとして樹脂流動を支援して充填する試みも行われて
いる。Attempts have also been made to partially fill a thick portion and support the resin flow as a runner in the product to fill the product.
【０００５】[0005]
【発明が解決しようとする課題】このうち、部分的に厚
肉部を設ける方法では、厚肉部の流動支援効果により樹
脂は充填するが、厚肉部がひけてしまうといった問題が
あった。Among them, the method of partially providing the thick portion has a problem that the resin is filled due to the flow support effect of the thick portion, but the thick portion is collapsed.
【０００６】また、薄肉成形品では冷却の進行が早いの
で、十分な保圧を与えることが難しい。例えば、加圧流
体で保圧を行う場合、厚肉部への加圧流体の進入のバラ
ンスが悪いために、ガスの進入が大きい厚肉部と、ガス
の進入が小さい厚肉部とが同一成形品内に存在し、ガス
進入が小さい厚肉部では、ヒケが発生するといった問題
があった。Further, in a thin-walled molded product, it is difficult to give a sufficient holding pressure because the cooling progresses quickly. For example, when holding pressure with a pressurized fluid, the thick fluid portion with a large gas intrusion and the thick fluid portion with a small gas intrusion are the same because the pressurized fluid enters the thick wall portion out of balance. There is a problem that sink marks are generated in the thick portion existing in the molded product and having a small gas invasion.
【０００７】本発明は係る問題点を解決すべく創案され
たもので、その目的は、薄肉部の流動を支援するために
設ける厚肉部を調整して流動バランスをとり、同時充填
とすることで加圧流体の進入をバランスよく起こさせ、
ヒケの発生を防止した薄肉ガス注入成形品の製造が可能
な射出成形用金型の設計方法を提供することにある。The present invention was devised to solve the above-mentioned problems, and an object thereof is to adjust the thick portion provided to support the flow of the thin portion so as to balance the flow and perform simultaneous filling. Balances the entry of pressurized fluid with
An object of the present invention is to provide a method of designing an injection molding die capable of manufacturing a thin-walled gas injection molded product in which the occurrence of sink marks is prevented.
【０００８】[0008]
【課題を解決するための手段】上記課題を解決するた
め、本発明に係わる射出成形用金型の設計方法は、金型
形状データ、樹脂物性データ、成形条件データ等の各種
データに基づき、差分法や有限要素法等を用いて樹脂流
動時の圧力損失を求める第１の工程と、求めた圧力損失
が前記厚肉部の水力相当直径と前記薄肉部との積に反比
例する領域と、反比例しない領域との境界付近で薄肉部
と厚肉部との大きさを決定する第２の工程と、前記薄肉
部のみで形成された形状に対して、ゲートから流動解析
で求めた最終充填位置まで前記厚肉部を設ける第３の工
程と、この第３の工程で設けた厚肉部にあらかじめ決め
られた分岐点から成形品の周縁に向かって分岐厚肉部を
設ける第４の工程と、前記分岐点から前記厚肉部の最終
充填位置までの長さと水力相当直径との比に等しくなる
ように、前記分岐厚肉部の水力相当直径を求める第５の
工程と、このようにして求めた成形品の形状に対して流
動解析を行い、前記分岐点が複数個ある場合には、前記
ゲートから最も遠い分岐点側から前記第４の工程と前記
第５の工程とを繰り返し行って全ての分岐厚肉部を設け
るものである。In order to solve the above problems, a method of designing an injection molding die according to the present invention is based on various data such as mold shape data, resin physical property data and molding condition data. The first step of obtaining the pressure loss when the resin flows by using the finite element method or the finite element method, and the area where the obtained pressure loss is inversely proportional to the product of the hydraulic equivalent diameter of the thick portion and the thin portion, and the inverse proportion The second step of determining the sizes of the thin wall portion and the thick wall portion in the vicinity of the boundary with the non-walled region, and from the gate to the final filling position obtained by the flow analysis for the shape formed by only the thin wall portion. A third step of providing the thick portion, and a fourth step of providing the thick branch portion from the predetermined branch point to the peripheral edge of the molded product in the thick portion provided in the third step, Length from the branch point to the final filling position of the thick portion A fifth step of obtaining the hydraulic equivalent diameter of the thick branched portion so as to be equal to the ratio to the hydraulic equivalent diameter, and a flow analysis is performed on the shape of the molded product thus obtained, and the branch point When there are a plurality of branch thick portions, all the thick branch portions are provided by repeating the fourth step and the fifth step from the branch point side farthest from the gate.
【０００９】[0009]
【作用】圧力損失が厚肉部の水力相当直径と薄肉部との
積に反比例する領域と、反比例しない領域との境界付近
で薄肉部と厚肉部との大きさを決定し、薄肉部のみで形
成された形状に対して、ゲートから流動解析で求めた最
終充填位置まで厚肉部を設ける。そして、この厚肉部に
あらかじめ決められた分岐点から成形品の周縁に向かっ
て分岐厚肉部を設け、この分岐点から厚肉部の最終充填
位置までの長さと水力相当直径との比に等しくなるよう
に、分岐厚肉部の水力相当直径を求める。このようにし
て求めた成形品の形状に対して流動解析を行い、分岐点
が複数個ある場合には、ゲートから最も遠い分岐点側か
ら分岐厚肉部の形成と水力相当直径とを求める処理を繰
り返し行って全ての分岐厚肉部を設ける。[Function] The size of the thin portion and the thick portion is determined near the boundary between the region where the pressure loss is inversely proportional to the product of the hydraulic equivalent diameter of the thick portion and the thin portion, and the region which is not inversely proportional, and only the thin portion is determined. A thick portion is provided from the gate to the final filling position obtained by the flow analysis for the shape formed in (3). Then, a thick-walled portion branched from a predetermined branch point toward the peripheral edge of the molded product is provided in this thick-walled portion, and the ratio of the length from this branch point to the final filling position of the thick-walled portion and the hydraulic equivalent diameter is calculated. The equivalent hydraulic diameters of the branched thick wall parts are calculated so that they are equal. A flow analysis is performed on the shape of the molded product obtained in this way, and when there are multiple branch points, the formation of a thick branch portion and the hydraulic equivalent diameter are calculated from the side of the branch that is farthest from the gate. Repeatedly to provide all the branched thick parts.
【００１０】これにより、薄肉ガス注入成形品に流動支
援を行う厚肉部を同時充填するように設けることができ
るので、ガスの進入がバランスよく行われ、厚肉部のヒ
ケを解消することが可能となる。As a result, the thin-walled gas injection molded product can be provided so as to be simultaneously filled with the thick-walled portion for supporting the flow, so that gas can be introduced in a balanced manner and sink marks in the thick-walled portion can be eliminated. It will be possible.
【００１１】[0011]
【実施例】以下、本発明の一実施例を図面を参照して説
明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
【００１２】本実施例では、薄肉成形品１として、例え
ば縦３００ｃｍ、横２００ｃｍ、肉厚１．５ｍｍの平板
を射出成形で成形する場合の射出成形用金型について説
明する。In this embodiment, as the thin-walled molded product 1, for example, an injection mold for molding a flat plate having a length of 300 cm, a width of 200 cm and a wall thickness of 1.5 mm by injection molding will be described.
【００１３】図１は、本発明に係わる射出成形用金型の
設計方法の手順を示すフローチャート、図２は、肉厚と
リブサイズによる圧損とのコンター図表、図３乃至図５
は厚肉部の形成過程を示す説明図であり、以下の説明に
おいては、これらの図面を適宜参照して説明を行うもの
とする。FIG. 1 is a flow chart showing the procedure of a method for designing an injection molding die according to the present invention, FIG. 2 is a contour chart of wall thickness and pressure loss due to rib size, and FIGS.
FIG. 4 is an explanatory diagram showing a process of forming a thick portion, and in the following description, description will be given with reference to these drawings as appropriate.
【００１４】まず、上記形状の平板部（薄肉部）に、さ
まざまな大きさの厚肉部が設けられた金型形状データ、
樹脂物性データ、成形条件データ（樹脂温度、金型温
度、射出量プロファイル等）を初期条件として、差分法
若しくは有限要素法を用いて、樹脂が薄肉部及び厚肉部
を同時に流れているときの圧力損失を求める（ステップ
Ｓ１，Ｓ２）。First, mold shape data in which thick parts of various sizes are provided on the flat plate part (thin part) of the above shape,
Using the difference method or the finite element method with the resin physical property data and molding condition data (resin temperature, mold temperature, injection amount profile, etc.) as initial conditions, when the resin is flowing through the thin wall portion and the thick wall portion at the same time. The pressure loss is obtained (steps S1 and S2).
【００１５】次に、厚肉部の水力相当直径と薄肉部との
積の逆数でプロットを行い、ステップＳ２で求めた圧力
損失が比例する領域Ａと、比例しない領域Ｂとを求める
（図２参照）。そして、この領域の境界付近で、薄肉部
及び厚肉部の大きさを決定する（ステップＳ３）。Next, the reciprocal of the product of the hydraulic equivalent diameter of the thick wall portion and the thin wall portion is plotted to obtain a region A in which the pressure loss obtained in step S2 is proportional and a region B in which the pressure loss is not proportional (FIG. 2). reference). Then, the sizes of the thin portion and the thick portion are determined near the boundary of this region (step S3).
【００１６】ここで、厚肉部の水力相当直径ＤS は、次
式によって求められる。Here, the hydraulic equivalent diameter D S of the thick portion is obtained by the following equation.
【００１７】[0017]
【数１】ＤS ＝４Ｓ0 ／Ｌ0 ただし、Ｓ0 は厚肉部の断面積であり、Ｌ0 は伝熱に寄
与する周囲長である。## EQU1 ## D S = 4S 0 / L 0 where S 0 is the cross-sectional area of the thick portion, and L 0 is the peripheral length that contributes to heat transfer.
【００１８】上式より、厚肉部の断面形状は、特に制限
はないものの、冷却の影響を考慮すると、半円形が望ま
しい。From the above equation, the cross-sectional shape of the thick portion is not particularly limited, but a semicircular shape is desirable in consideration of the influence of cooling.
【００１９】次に、上記寸法の薄肉成形品を薄肉部のみ
で形成した形状に対して、ゲート２から流動解析を行っ
て最終充填位置Ａ１〜Ａ４を求め、ゲート２からこれら
最終充填位置Ａ１〜Ａ４に向かって図２に示す領域を満
たす厚肉部３を設ける（ステップＳ４）。Next, a flow analysis is performed from the gate 2 to obtain final filling positions A1 to A4 with respect to the shape of the thin-walled molded product having the above-mentioned dimensions formed only from the thin-walled portions, and from the gate 2, the final filling positions A1 to A1 A thick portion 3 that fills the area shown in FIG. 2 is provided toward A4 (step S4).
【００２０】このようにして設けた厚肉部３について
は、図３に符号Ｎ１，Ｎ２で示すように、あらかじめ分
岐点の数及び形成位置が決められているものとする。本
実施例では、ゲート２より遠い位置からＮ１，Ｎ２と２
個設けている。With respect to the thick wall portion 3 thus provided, the number of branch points and the forming position are preliminarily determined, as indicated by reference numerals N1 and N2 in FIG. In this embodiment, N1, N2 and 2 are located from a position farther from the gate 2.
I have an individual.
【００２１】そこで、まずゲート２から最も遠い位置に
ある分岐点Ｎ１から、成形品１の周縁部１ａに向かって
垂直に分岐厚肉部４ａ（図４参照）を設ける（ステップ
Ｓ５，Ｓ６）。このとき、分岐厚肉部４ａは、厚肉部３
の最終充填位置Ａ１〜Ａ４までの長さＬ1 と水力相当直
径ＤS との比に等しくなるように、分岐厚肉部４ａの水
力相当直径ＤS1を求める( ステップＳ７）。Therefore, first, a branch thick portion 4a (see FIG. 4) is provided vertically from the branch point N1 located farthest from the gate 2 toward the peripheral edge 1a of the molded product 1 (steps S5 and S6). At this time, the branched thick portion 4a is the thick portion 3
The hydraulic equivalent diameter D S1 of the thick branched portion 4a is obtained so as to be equal to the ratio of the length L 1 from the final filling positions A1 to A4 to the hydraulic equivalent diameter D S ( step S7).
【００２２】そして、このようにして求めた成形品の形
状（図４に示す形状）に対して流動解析を行い（ステッ
プＳ８）、次の分岐点Ｎ２から、成形品１の周縁部１ａ
に向かって垂直に分岐厚肉部４ｂ（図５参照）を設ける
（ステップＳ９，Ｓ１０，Ｓ６）。このとき、分岐厚肉
部４ｂの水力相当直径ＤS2は、分岐点Ｎ２から先（各最
終充填位置Ａ１〜Ａ４）の厚肉部３と分岐厚肉部４ａと
を考慮した見かけ上の水力相当直径と長さ（Ｌ2 ＋Ｌ3
＋Ｌ4 ）との比に等しくなるように決定する（ステップ
Ｓ７）。Then, a flow analysis is performed on the shape of the molded product thus obtained (the shape shown in FIG. 4) (step S8), and from the next branch point N2, the peripheral edge 1a of the molded product 1 is obtained.
A thick-walled branch portion 4b (see FIG. 5) is provided vertically toward (steps S9, S10, S6). At this time, the hydraulic equivalent diameter D S2 of the branched thick portion 4b is an apparent hydraulic equivalent considering the thick portion 3 and the branched thick portion 4a ahead of the branch point N2 (each final filling position A1 to A4). Diameter and length (L 2 + L 3
+ L 4 ) and the ratio thereof are equal (step S7).
【００２３】このように、分岐点が複数個ある場合に
は、ゲート２から最も遠い分岐点側からステップＳ６〜
ステップＳ１０を繰り返し行って、全ての分岐点につい
て分岐厚肉部を設ける。In this way, when there are a plurality of branch points, the branch point farthest from the gate 2 starts from the step S6.
Step S10 is repeated to provide branch thick parts at all branch points.
【００２４】これにより、樹脂の充填が成形品１の端部
（周縁部１ａ及び各最終充填位置Ａ１〜Ａ４）で同時に
終了することになる。また、同時充填とすることで、厚
肉部３及び各分岐厚肉部４ａ，４ｂでの圧力差が小さく
なり、バランスよくガスの進入が行われることになる。As a result, the resin filling ends at the end of the molded article 1 (peripheral edge 1a and each final filling position A1 to A4) at the same time. Further, the simultaneous filling reduces the pressure difference between the thick wall portion 3 and each of the branched thick wall portions 4a and 4b, so that gas can be introduced in a well-balanced manner.
【００２５】なお、上記実施例における薄肉成形品１の
肉厚については、成形品の大きさや成形材料の流動性等
によって異なるため、一概に規定することはできない。
また、このとき必要とされる分岐点の数や形成位置につ
いても、成形品の形状や大きさによって異なり、これも
一概に規定することはできない。The thickness of the thin molded product 1 in the above embodiment cannot be unconditionally specified because it depends on the size of the molded product and the fluidity of the molding material.
Further, the number of branch points and formation positions required at this time also differ depending on the shape and size of the molded product, and this cannot be unconditionally specified.
【００２６】次に、このような形状の射出成形用金型に
よって薄肉成形品１をガス保圧で成形する方法について
述べる。Next, a method of molding the thin-walled molded product 1 with a gas holding pressure by using an injection molding die having such a shape will be described.
【００２７】保圧をガスで行う場合、ガスを注入する位
置や数により、厚肉部の形成位置も異なるが、ガスを注
入する位置が１点の場合には、全ての厚肉部が連通して
いることが必要となる。さもなければ、１点で全ての厚
肉部にガスを進入させることはできない。When the holding pressure is performed by gas, the formation position of the thick wall portion differs depending on the position and number of gas injection, but when there is only one gas injection position, all the thick wall portions communicate with each other. It is necessary to do it. Otherwise, it is not possible for gas to enter all thick parts at one point.
【００２８】この場合、厚肉部を連通させるために設け
る連通用厚肉部は、ガスが進入できればよく、厚肉部の
水力相当直径と薄肉部との積の逆数に圧力損失が比例す
る領域でなくてもよい。このときガスは、樹脂ゲートよ
り上流側、若しくは樹脂ゲート近傍のキャビティー内か
ら注入される。In this case, the thick portion for communication provided for communicating the thick portion only needs to allow gas to enter, and the pressure loss is proportional to the reciprocal of the product of the hydraulic equivalent diameter of the thick portion and the thin portion. It doesn't have to be. At this time, the gas is injected from the upstream side of the resin gate or from the inside of the cavity near the resin gate.
【００２９】また、ガスを注入する位置が複数箇所の場
合には、全ての厚肉部が連通する必要はなく、各厚肉部
に各々ガスが注入できればよい。ガスを注入する位置が
製品設計上制限される場合には、両者を組み合わせれば
よい。Further, when the gas is injected at a plurality of positions, it is not necessary for all the thick portions to communicate with each other, and it is sufficient that the gas can be injected into each thick portion. When the position where gas is injected is limited in product design, both may be combined.
【００３０】まず、図５に示すような薄肉成形品１の形
状に形成された金型のキャビティーに樹脂を射出する。
このとき射出される樹脂の量は、キャビティーを体積的
に満たすのに十分な量若しくは不充分な量のどちらでも
よいが、ヘジテーションラインを無くすためには十分な
量を射出する方が好ましい。First, a resin is injected into a cavity of a mold formed in the shape of the thin molded product 1 as shown in FIG.
The amount of resin injected at this time may be either sufficient or insufficient to fill the cavity in volume, but it is preferable to inject a sufficient amount to eliminate the hesitation line.
【００３１】次に、キャビティー内に設けられたガス注
入口（本実施例では、ゲート２とほぼ同じ位置）からガ
スを注入する。注入されたガスは、樹脂がキャビティー
を満たすように、若しくは樹脂の収縮を補うように進入
していく。そして、このガスで一定時間保圧を行った
後、ガスを排気して金型を開き、薄肉成形品１を取り出
すものである。Next, gas is injected from a gas injection port (in this embodiment, the same position as the gate 2) provided in the cavity. The injected gas enters so that the resin fills the cavity or compensates for the shrinkage of the resin. Then, after holding pressure with this gas for a certain period of time, the gas is exhausted to open the mold, and the thin-walled molded product 1 is taken out.
【００３２】このような薄肉形成品１の成形に用いられ
る樹脂としては、射出成形可能な樹脂であれば特に限定
されない。例えは、ポリエチレン、ポリプロピレン、ポ
リブテン、ポリスチレン、ポリエチレン系アイオノマ
ー、エチレン−酢酸ビニル共重合体、エチレン−アクリ
ル酸メチル共重合体、塩化ビニル系樹脂、塩素化塩化ビ
ニル系樹脂、フッ化ビニリデン系樹脂、ポリテトラフル
オロエチレン、ポリフェニレンエーテル、ポリフェニレ
ンサルファイド、ポリアミド、ポリサルフォン、ポリエ
ーテルサルフォン、ポリエーテルイミド、ポリエーテル
エーテルケトン、ＡＢＳ（アクリロニトリル−ブタジエ
ン−スチレン共重合体）、ポリカーボネート、ポリエチ
レンテレフタレート、液晶ポリマー等の熱可塑性樹脂、
あるいはこれらの樹脂にガラス繊維、タルク等の充填材
を充填した材料、安定剤、滑剤、難燃剤、改質剤、顔
料、染料等の着色剤等を配合した材料、さらにはこれら
を組み合わせたポリマーアロイ、場合によっては熱硬化
性樹脂も用いられる。The resin used for molding the thin-walled article 1 is not particularly limited as long as it is a resin that can be injection-molded. Examples include polyethylene, polypropylene, polybutene, polystyrene, polyethylene ionomer, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, vinyl chloride resin, chlorinated vinyl chloride resin, vinylidene fluoride resin, Polytetrafluoroethylene, polyphenylene ether, polyphenylene sulfide, polyamide, polysulfone, polyether sulfone, polyetherimide, polyether ether ketone, ABS (acrylonitrile-butadiene-styrene copolymer), polycarbonate, polyethylene terephthalate, liquid crystal polymer, etc. Thermoplastic resin,
Alternatively, a material in which a filler such as glass fiber or talc is filled with these resins, a material in which a stabilizer, a lubricant, a flame retardant, a modifier, a pigment, a colorant such as a dye, or the like is blended, and a polymer in which these are combined Alloys and, in some cases, thermosetting resins are also used.
【００３３】溶融樹脂中に圧入される加圧流体として
は、一般的に窒素、アルゴン、二酸化炭素系の不活性ガ
スが好ましいが、乾燥した空気その他の反応性に乏しく
成形温度条件下で樹脂の劣化を起こさないガス体であれ
ば構わない。液体としては、水、アルコール、油等が使
用される。As the pressurized fluid to be pressed into the molten resin, nitrogen, argon and carbon dioxide type inert gas are generally preferable, but dry air and other reactive gases are poor in reactivity and the resin can be treated under molding temperature conditions. Any gas that does not deteriorate may be used. As the liquid, water, alcohol, oil or the like is used.
【００３４】〔実験例１〕本実験に用いた薄肉成形品１
は、図５に示す形状のものであり、金型のキャビティー
寸法は、縦３００ｃｍ、横２００ｃｍ、幅１．５ｍｍで
ある。流動を支援するための厚肉部は、厚肉部３ではＲ
２．３ｍｍ、分岐厚肉部４ａ，４ｂではＲ１．０ｍｍで
設計した。[Experimental Example 1] Thin-walled molded article 1 used in this experiment
5 has the shape shown in FIG. 5, and the cavity dimensions of the mold are 300 cm in length, 200 cm in width, and 1.5 mm in width. The thick part for supporting the flow is R in the thick part 3.
It was designed to be 2.3 mm, and R1.0 mm for the branched thick portions 4a and 4b.
【００３５】成形機には、各機３５０ｔ射出成形機を用
いた。成形に使用した材料はポリカーボネートとＡＢＳ
のアロイ（サイコロイＭＣ５００５：日本ＧＥ社製）を
用いた。また、成形条件は以下の通りである。Each molding machine used was a 350-ton injection molding machine. Materials used for molding are polycarbonate and ABS
Alloy (Psycholoy MC5005: manufactured by GE Japan) was used. The molding conditions are as follows.
【００３６】シリンダ温度 ２５０℃ 金型温度 ５０℃ 射出率 ５００ｃｃ／ｓ ガス圧力 １５０ｋｇ／ｃｍ3 ガス注入遅延時間 ０ｓ ガス注入時間 ２０ｓ なお、測定方法はＪＩＳＢ０６５１の測定機器を用いて
中心線平均あらさを測定した。Cylinder temperature 250 ° C. Mold temperature 50 ° C. Injection rate 500 cc / s Gas pressure 150 kg / cm 3 Gas injection delay time 0 s Gas injection time 20 s The measuring method is the center line average roughness using JISB0651 measuring equipment. did.
【００３７】この結果、ガスはバランスよく流れ、厚肉
部先端のヒケは１０μｍであった。As a result, the gas flowed in a good balance, and the sink mark at the tip of the thick portion was 10 μm.
【００３８】〔比較例１〕厚肉部３，４ａ，４ｂの大き
さを全てＲ２．３ｍｍとし、その他の条件は上記実験例
１と全く同様とした。Comparative Example 1 The sizes of the thick portions 3, 4a, 4b were all R2.3 mm, and the other conditions were exactly the same as in Experimental Example 1 above.
【００３９】この結果、ガスはバランスよく流れず、厚
肉部先端のヒケは２５０μｍであった。As a result, the gas did not flow in a balanced manner, and the sink mark at the tip of the thick portion was 250 μm.
【００４０】[0040]
【発明の効果】本発明に係わる射出成形用金型の設計方
法は、圧力損失が厚肉部の水力相当直径と薄肉部との積
に反比例する領域と、反比例しない領域との境界付近で
薄肉部と厚肉部との大きさを決定し、薄肉部のみで形成
された形状に対して、ゲートから流動解析で求めた最終
充填位置まで厚肉部を設け、この厚肉部にあらかじめ決
められた分岐点から成形品の周縁に向かって分岐厚肉部
を設け、この分岐点から厚肉部の最終充填位置までの長
さと水力相当直径との比に等しくなるように、分岐厚肉
部の水力相当直径を求めている。そして、このようにし
て求めた成形品の形状に対して流動解析を行い、分岐点
が複数個ある場合には、ゲートから最も遠い分岐点側か
ら分岐厚肉部の形成と水力相当直径とを求める処理を繰
り返し行って全ての分岐厚肉部を設けるようにしたの
で、薄肉ガス注入成形品に流動支援を行う厚肉部を同時
充填するように設けることができるため、ガスの進入が
バランスよく行われ、厚肉部のヒケの発生を抑えること
ができる。According to the method of designing an injection molding die according to the present invention, a thin wall is formed near a boundary between a region where a pressure loss is inversely proportional to a product of a hydraulic equivalent diameter of a thick wall portion and a thin wall portion, and a region where the pressure loss is not inversely proportional. The size of the thick part and thick part is determined, and for the shape formed by only the thin part, a thick part is provided from the gate to the final filling position determined by flow analysis, and this thick part is predetermined. A thick wall portion is provided from the branch point toward the peripheral edge of the molded product, and the length of the thick branch portion is made equal to the ratio of the length from the branch point to the final filling position of the thick portion and the equivalent hydraulic diameter. We are seeking the equivalent hydraulic diameter. Then, a flow analysis is performed on the shape of the molded product thus obtained, and when there are a plurality of branch points, the formation of the thick part of the branch and the hydraulic equivalent diameter are performed from the branch point side farthest from the gate. Since all the branched thick-walled parts are provided by repeating the required process, it is possible to simultaneously fill the thin-walled gas injection molded product with the thick-walled part that supports the flow, so that the gas intrusion is well balanced. Therefore, it is possible to suppress the occurrence of sink marks in the thick portion.
【図１】本発明に係わる射出成形用金型の設計方法の処
理手順を示すフローチャートである。FIG. 1 is a flowchart showing a processing procedure of a method for designing an injection molding die according to the present invention.
【図２】肉厚とリブサイズによる圧損とのコンター図表
である。FIG. 2 is a contour chart of wall thickness and pressure loss due to rib size.
【図３】厚肉部の形成過程を示す説明図である。FIG. 3 is an explanatory diagram showing a process of forming a thick portion.
【図４】厚肉部の形成過程を示す説明図である。FIG. 4 is an explanatory diagram showing a process of forming a thick portion.
【図５】厚肉部の形成過程を示す説明図である。FIG. 5 is an explanatory diagram showing a process of forming a thick portion.
１ 薄肉成形品 １ａ 周縁部 ２ ゲート ３ 厚肉部 ４ａ，４ｂ 分岐厚肉部 Ａ１〜Ａ４ 最終充填位置 1 Thin-walled molded product 1a Peripheral part 2 Gate 3 Thick part 4a, 4b Branch thick part A1-A4 Final filling position
Claims (1)
ス注入成形品を製造する射出成形用金型の設計方法であ
って、 金型形状データ、樹脂物性データ、成形条件データ等の
各種データに基づき、差分法や有限要素法等を用いて樹
脂流動時の圧力損失を求める第１の工程と、 求めた圧力損失が前記厚肉部の水力相当直径と前記薄肉
部との積に反比例する領域と、反比例しない領域との境
界付近で薄肉部と厚肉部との大きさを決定する第２の工
程と、 前記薄肉部のみで形成された形状に対して、ゲートから
流動解析で求めた最終充填位置まで前記厚肉部を設ける
第３の工程と、 この第３の工程で設けた厚肉部にあらかじめ決められた
分岐点から成形品の周縁に向かって分岐厚肉部を設ける
第４の工程と、 前記分岐点から前記厚肉部の最終充填位置までの長さと
水力相当直径との比に等しくなるように、前記分岐厚肉
部の水力相当直径を求める第５の工程と、 このようにして求めた成形品の形状に対して流動解析を
行い、前記分岐点が複数個ある場合には、前記ゲートか
ら最も遠い分岐点側から前記第４の工程と前記第５の工
程とを繰り返し行って全ての分岐厚肉部を設けることを
特徴とする射出成形用金型の設計方法。1. A method for designing an injection molding die for producing a gas injection molded article having a thick portion partially with respect to a thin portion, such as mold shape data, resin physical property data, molding condition data, etc. Based on the various data of 1st step, the first step to obtain the pressure loss during resin flow using the difference method or the finite element method, and the obtained pressure loss is the product of the hydraulic equivalent diameter of the thick part and the thin part. A second step of determining the sizes of the thin wall portion and the thick wall portion in the vicinity of the boundary between the region inversely proportional to and the region not inversely proportional, and the flow analysis from the gate for the shape formed only by the thin wall portion. The third step of providing the thick portion up to the final filling position obtained in step (3), and the thick portion for branching from the predetermined branch point of the thick portion provided in the third step toward the peripheral edge of the molded product. A fourth step of providing, and the final filling of the thick portion from the branch point. A fifth step of obtaining the hydraulic equivalent diameter of the thick branched portion so that the ratio to the position and the hydraulic equivalent diameter is equalized, and a flow analysis is performed on the shape of the molded product thus obtained. If there are a plurality of branch points, the fourth step and the fifth step are repeated from the branch point side farthest from the gate to provide all thick branch portions. Method for designing injection mold.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11189695A JPH08300416A (en) | 1995-05-10 | 1995-05-10 | Method for designing injection molding die |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11189695A JPH08300416A (en) | 1995-05-10 | 1995-05-10 | Method for designing injection molding die |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08300416A true JPH08300416A (en) | 1996-11-19 |
Family
ID=14572858
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11189695A Pending JPH08300416A (en) | 1995-05-10 | 1995-05-10 | Method for designing injection molding die |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08300416A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000006362A1 (en) * | 1998-07-28 | 2000-02-10 | Fujitsu Limited | Mold design system and computer-readable recording medium having mold design program recorded therein |
-
1995
- 1995-05-10 JP JP11189695A patent/JPH08300416A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000006362A1 (en) * | 1998-07-28 | 2000-02-10 | Fujitsu Limited | Mold design system and computer-readable recording medium having mold design program recorded therein |
| US6917905B2 (en) | 1998-07-28 | 2005-07-12 | Fujitsu Limited | Mold design system and computer-readable recording medium storing mold design program |
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