JPH0568335B2 - - Google Patents
Info
- Publication number
- JPH0568335B2 JPH0568335B2 JP61312736A JP31273686A JPH0568335B2 JP H0568335 B2 JPH0568335 B2 JP H0568335B2 JP 61312736 A JP61312736 A JP 61312736A JP 31273686 A JP31273686 A JP 31273686A JP H0568335 B2 JPH0568335 B2 JP H0568335B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- graphite
- injection molding
- molds
- plastic
- 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.)
- Expired - Lifetime
Links
- 239000004033 plastic Substances 0.000 claims description 13
- 229920003023 plastic Polymers 0.000 claims description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 12
- 229910002804 graphite Inorganic materials 0.000 claims description 12
- 239000010439 graphite Substances 0.000 claims description 12
- 239000007770 graphite material Substances 0.000 claims description 10
- 238000001746 injection moulding Methods 0.000 claims description 9
- 238000005452 bending Methods 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 2
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 2
- 239000000463 material Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000011164 primary particle Substances 0.000 description 3
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000011151 fibre-reinforced plastic Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 239000006253 pitch coke Substances 0.000 description 2
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000011162 core material Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000005087 graphitization Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000002994 raw material Substances 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
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/37—Mould cavity walls, i.e. the inner surface forming the mould cavity, e.g. linings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2883/00—Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as mould material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2907/00—Use of elements other than metals as mould material
- B29K2907/04—Carbon
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Description
〔産業上の利用分野〕
本発明は、プラスチツク射出成形用グラフアイ
ト型に関するものである。
〔従来の技術とその問題点〕
プラスチツクは、一般に軽量、経済性、加工
性、耐食性等種々の特性を有する材料であり、電
気、機械、自動車のあらゆる工業的用途から日用
品まで、極めて広範囲に使用されている。これら
各種のプラスチツク製品を成形するには、一般に
鉄及びその合金の金属材料で製作した型が用いら
れる。
この種の金属材料により製作された型（以下金
型と称する。）は、成形数が極めて多量の場合に
は、金型寿命の観点から型材が金属であることが
必要条件であつた。しかし、最近の多品種少量生
産の傾向にあつては型の試作の必要性が益々増大
し、従来の金型は過度の品質であり、成形品に
占める金型コストの占める割合が大きくなり、製
品コストを高くしている。また、金型の製作に
は多大の時間を必要とする欠点があつた。
したがつて、繊維強化プラスチツクの成形にお
いては、その芯型材料として鉄、アルミなどの金
属に代えて黒鉛を使用することが、既に知られて
いる（特開昭53−19383号公報）。しかしながら、
繊維強化プラスチツクの成形に比して、高圧状態
のプラスチツク材料を用い、大きな型締力を受け
る射出成形において、未だ、グラフアイト型の実
用化は実現されていない。
この発明は、従来の黒鉛、すなわちグラフアイ
ト材料からなるプラスチツク型の特性である、切
削加工が容易で、熱膨張率が小さく、熱伝導のよ
いという性質を失わず、プラスチツクの射出成形
用の型として利用することのできるグラフアイト
材料を実験の結果見い出し、実用化できるプラス
チツク射出成形用グラフアイト型を提供すること
を目的とするものである。
〔問題点を解決するための手段〕
この発明は、プラスチツク射出成形用グラフア
イト型を、平均粒子径１〜100μm、有孔率５〜20
％、密度1.70〜1.90g／cm3、曲げ強度400〜1000
Kg／cm2、そして、シヨア硬度40〜90のグラフアイ
ト材料で構成したことを特徴とするものである。
ここで、平均粒子径は、グラフアイト材料の表
面を偏光顕微鏡写真に撮り、微細な空隙等により
境界づけられた、一次粒子がバインダーによつて
凝集した粒子の径の平均値である。そして、有孔
率および曲げ強度はJISR7212によつて、また、
シヨア硬度はJISR7727によつてそれぞれ測定さ
れた値であり、密度はかさ密度の値である。
なお、このようなグラフアイト材料は、骨材と
してのコークスの粒度、成形圧力、焼成黒鉛化温
度等の適宜組合せて得られるグラフアイトブロツ
クから選択するものである。
さらに、前記のグラフアイト材の形状部の表面
を炭化珪素に転化することにより、型寿命を向上
することができ、小ロツトの生産に最適である。
〔作用〕
平均粒子径を比較的小さな、１〜100μmの範囲
のものを選び、有孔率も５〜20％と小さなものと
し、密度を1.70〜1.90ｇ／cm3と大きく、しかも、
大きな曲げ強度400〜1000Kg／cm2と大きな硬度、
すなわちシヨア硬度40〜90のグラフアイト材料を
使用するので、射出成形時の圧力（通常1000Kg／
cm2以上）に対応する型締力に耐え、特に、高圧材
料の通る、ランナーおよびゲートなどの狭い通路
の磨耗にも耐えられることが判明している。な
お、曲げ強度を1000Kg／cm2以上、シヨア硬度を
90以上とすると、切削加工性が悪くなり、型を
安価に製造することができない。
なお、これらの範囲をはずれる材料は、いずれ
もグラフアイト型としての以下の特性を喪失する
かまたは実用的シヨツト回数の前に損壊するもの
である。
(1) 切削加工が容易である。
(2) 熱膨張係数が小さく、成形物の精度がよい。
(3) 比重が小さく、取り扱いが容易である。
(4) 熱伝導性がよく、高速サイクルの成形が可能
である。
次に本発明の最も代表的な実施例について説明
する。
〔実施例〕
グラフアイト材料は、いわゆる高強度材料の製
法として知られる、例えば、特開昭59−78914号
公報に開示されているような方法により、一次粒
子の平均粒径が15ミクロン以下の生ピツチコーク
スと同じく一次粒子の平均粒径が44ミクロン以下
のカ焼ピツチコークスとを主体とした配合物に粘
結剤を添加して加熱混練し、粉砕機で粉砕して原
料とし、これをラバープレス等で所定の形状に成
形する。このグラフアイト材料の中から、平均粒
子径が7μm、有孔率（気孔率）が14％であつて、
密度が1.80ｇ／cm3、曲げ強度が600Kg／cm2、シヨ
ア硬度が65のグラフアイトを選んで、小型プラス
チツクスイツチの射出成形用の型を製作し、これ
を用いてプラスチツク製品を成形した結果、グラ
フアイト型であつても少品種多量生産に十分耐え
得るものであることが判明し、長寿命の型が低コ
ストで得られた。
なお、比較例として同様の条件下で金型を製作
して比較した。
[Industrial Field of Application] The present invention relates to a graphite mold for plastic injection molding. [Conventional technology and its problems] Plastics are generally materials with various characteristics such as light weight, economic efficiency, workability, and corrosion resistance, and are used in an extremely wide range of applications, from electrical, mechanical, and automobile industrial applications to daily necessities. has been done. To mold these various plastic products, molds made of metal materials such as iron and its alloys are generally used. For molds made of this type of metal material (hereinafter referred to as molds), when the number of moldings is extremely large, it is necessary that the mold material be metal from the viewpoint of mold life. However, with the recent trend toward high-mix, low-volume production, the need for prototype molds is increasing, and conventional molds are of excessive quality, and mold costs account for a large proportion of the molded product. It makes the product cost high. Another disadvantage was that it required a great deal of time to manufacture the mold. Therefore, in the molding of fiber-reinforced plastics, it is already known to use graphite as the core material instead of metals such as iron and aluminum (Japanese Patent Application Laid-Open No. 19383/1983). however,
Compared to the molding of fiber-reinforced plastics, graphite molds have not yet been put to practical use in injection molding, which uses plastic materials under high pressure and is subjected to large mold clamping forces. This invention enables plastic injection molds to be used without losing the characteristics of conventional plastic molds made of graphite material: easy cutting, low coefficient of thermal expansion, and good thermal conductivity. The purpose of the present invention is to find out through experiments a graphite material that can be used as a plastic injection mold, and to provide a graphite mold for plastic injection molding that can be put to practical use. [Means for Solving the Problems] This invention provides a graphite mold for plastic injection molding with an average particle diameter of 1 to 100 μm and a porosity of 5 to 20 μm.
%, density 1.70-1.90g/ cm3 , bending strength 400-1000
Kg/cm 2 and is made of graphite material with Shore hardness of 40 to 90. Here, the average particle diameter is the average value of the diameter of primary particles aggregated by a binder, which are bounded by fine voids and the like, when the surface of the graphite material is photographed using a polarized light microscope. The porosity and bending strength are determined according to JISR7212, and
Shore hardness is a value measured according to JISR7727, and density is a value of bulk density. Incidentally, such a graphite material is selected from graphite blocks obtained by appropriately combining the particle size of coke as an aggregate, molding pressure, firing graphitization temperature, etc. Furthermore, by converting the surface of the shaped portion of the graphite material into silicon carbide, the life of the mold can be improved, making it ideal for small-lot production. [Function] Select a material with a relatively small average particle diameter in the range of 1 to 100 μm, a small porosity of 5 to 20%, a high density of 1.70 to 1.90 g/cm 3 , and
Great bending strength 400~1000Kg/ cm2 and great hardness,
In other words, since graphite material with Shore hardness of 40 to 90 is used, the pressure during injection molding (usually 1000 kg/
cm 2 or more), and has been found to withstand wear especially in narrow passageways such as runners and gates through which high-pressure materials pass. Note that if the bending strength is 1000 Kg/cm 2 or more and the shore hardness is 90 or more, the machinability becomes poor and the mold cannot be manufactured at a low cost. It should be noted that any material that falls outside these ranges will either lose the following characteristics as a graphite type, or will be damaged before the number of practical shots. (1) Easy to cut. (2) The coefficient of thermal expansion is small and the precision of the molded product is good. (3) It has a low specific gravity and is easy to handle. (4) It has good thermal conductivity and can be molded at high speed cycles. Next, the most typical embodiment of the present invention will be described. [Example] Graphite material is produced by a method known as a manufacturing method for so-called high-strength materials, such as that disclosed in Japanese Patent Application Laid-open No. 78914/1983, with an average primary particle diameter of 15 microns or less. A binder is added to a mixture consisting mainly of calcined pitchcoke with an average primary particle size of 44 microns or less, which is the same as raw pitchcoke, and the mixture is heated and kneaded, then crushed in a crusher to be used as a raw material, which is then processed into a rubber press. etc. to form it into a predetermined shape. Among this graphite material, the average particle diameter is 7 μm and the porosity is 14%.
We selected graphite with a density of 1.80g/cm 3 , a bending strength of 600Kg/cm 2 , and a shore hardness of 65 to create an injection molding mold for a small plastic switch, and used this to mold a plastic product. It was found that even the graphite type was able to withstand high-volume production of a small number of products, and a long-life mold was obtained at low cost. As a comparative example, molds were manufactured under the same conditions and compared.
以上のように、本発明によれば、ほぼ実用化で
きる成形可能数に耐えることのできる射出成形用
グラフアイト型が安価に得られるので、射出成形
品を安価に製造することができる。
As described above, according to the present invention, a graphite mold for injection molding that can withstand the number of molds that can be practically used can be obtained at a low cost, so that injection molded products can be manufactured at a low cost.
Claims (1)
度1.70〜1.90g／cm3、曲げ強度400〜1000Kg／cm2、
そして、シヨア硬度40〜90のグラフアイト材料で
構成したことを特徴とするプラスチツク射出成形
用グラフアイト型。 ２ 前記型の形状部表面を、炭化珪素に転化して
成ることを特徴とする特許請求の範囲第１項記載
のプラスチツク射出成形用グラフアイト型。[Claims] 1. Average particle diameter 1-100 μm, porosity 5-20%, density 1.70-1.90 g/cm 3 , bending strength 400-1000 Kg/cm 2 ,
And a graphite mold for plastic injection molding, characterized in that it is made of a graphite material having a shore hardness of 40 to 90. 2. The graphite mold for plastic injection molding according to claim 1, wherein the surface of the shaped part of the mold is converted to silicon carbide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31273686A JPS63162205A (en) | 1986-12-25 | 1986-12-25 | Graphite mold for plastic molding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31273686A JPS63162205A (en) | 1986-12-25 | 1986-12-25 | Graphite mold for plastic molding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63162205A JPS63162205A (en) | 1988-07-05 |
| JPH0568335B2 true JPH0568335B2 (en) | 1993-09-28 |
Family
ID=18032800
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31273686A Granted JPS63162205A (en) | 1986-12-25 | 1986-12-25 | Graphite mold for plastic molding |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63162205A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02270513A (en) * | 1989-04-13 | 1990-11-05 | Ibiden Co Ltd | Black lead mold for molding plastic |
| JP2794182B2 (en) * | 1989-02-13 | 1998-09-03 | イビデン株式会社 | Plastic mold |
| JP2849162B2 (en) * | 1990-02-27 | 1999-01-20 | 日本タングステン株式会社 | Mold for resin molding |
| WO2005070642A1 (en) * | 2004-01-20 | 2005-08-04 | Touchstone Research Laboratory, Ltd. | Carbon foam composite tooling and methods for using the same |
| JP5183301B2 (en) * | 2008-05-28 | 2013-04-17 | 地方独立行政法人 東京都立産業技術研究センター | Mold and manufacturing method thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5319383A (en) * | 1976-08-08 | 1978-02-22 | Sumitomo Electric Industries | Metaod of molding of plastic * reinforced with fiber |
-
1986
- 1986-12-25 JP JP31273686A patent/JPS63162205A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5319383A (en) * | 1976-08-08 | 1978-02-22 | Sumitomo Electric Industries | Metaod of molding of plastic * reinforced with fiber |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63162205A (en) | 1988-07-05 |
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