201103676 35139pif 六、發明說明： 【發明所屬之技術領域】 本發明有關於一種在工具電極與導電性的工件之間产 生放電來對工件進行加工的放電加工方法。特別是，本^ 明有關於一種使用工具電極來在工件上形成針點繞口 point gate)的方法。 【先前技術】 放電加工裝置是對包含鋼鐵或者超硬合金的工件精笔 地進行加工的工作機械。超硬合金是將金屬碳化物的粉j 燒結而成的合金。工具電極通常安裝在放電加工裝置 軸碩。工具電極的材料爲例如石墨（graptlite)、鋼鋼义 金。工件配置在貯存著介電液（dielectric fluW)、= £ 工槽中。介電液爲例如燈油（lamp 〇丨丨丨 雨力 ( . v 4有比電[I」 (specm口esistanee)高的水。使卫具電極移 接近於工件的位置。形成在工具電極與工件 空隙被稱作“加工間隙”。 ]的嘁小6 在，電力二中，放電加U對加施加電動 隙产m 果’介電㈣絕較叫如在加工f =枓炫融除去。通過反復進行放電，而在工 ，大小，伴隨工件材料的除去=:=隙_ 進。工具電極的前進方向通常爲鉛直向下。、°向工件商 注射成形（lnjectionmolding)裝置是向模具的空啦 4 201103676 35139pif (cavity)中注入樹脂幷進行成形的機械。空腔的入口被稱 作澆口（gate)或者注口（pouringgate)。向澆口導引樹 脂的通道被稱作澆道（runner)或者注道。針點澆口是一 種澆口，其具有p爲〇. 3 mm〜1. 2 mm的小開口。針點澆口 也被稱作針澆口（pin gate)。圖1 (I)中的參照編號44 表示針點澆口的一例。針點澆口 44伴隨有澆道43。 日本公開專利公報11-058114中，揭示有加工出針點 〉堯口的特殊的中心鑽（center drill)。然而’一般而言’ 具有針點澆口的模具是通過放電加工裝ϊ來製作的。圖3 表示用以放電加工出針點澆口的工具電椏的一例。由銅構 成的工具電極10通過手柄（shank) 8爽持在放電加工裝 置的主轴頭（未圖示）。工具電極1〇具有20°角的前端。 除前端以外工具電極1〇的側面傾斜2。。工具電極10具有 較大的長寬比（aspect ratio)，因此其剛性較小。 工具電極在放電加工中會産生消耗。消耗率是工具電 極的消耗重量（g)相對於工件的損耗量（g)的比率（％)。 或者’消耗率是工具電極的長度的减少量（mm)相對於工 件中所形成的孔的深度（mm)的比率（％)。對於具有較大 的長寬比的工具電極10而言，採用後一消耗率。在大部分 情况下，考慮到工具電極的消耗，爲形成一個針點澆口而 準備著多個工具電極。 日本公開專利公報2〇〇2 —059316號中，揭示有一種用 以使具有微細的直徑的工具電極成形的放電加工裝置，。然 而’此種放電加工裝置難以筆直地製作細長的錐形 201103676 35139pif (tapered)工具電極。因此，細長的錐形工且 =加工來製作的。進行此種機械加工的工;乍機=通: 車床或者力H (machining⑽恤）。_械爲例如 —圖4表示形成針點洗口的以往的方法。圖中 不工具電極移動的方向。圖4中的工 月1 、 m:圖3中的工具電極1〇相同。如圖二狀中 =具電 隙産生放電。如圖加電=料’會在加工間 於固定，使ΐ具電工裝置爲將加工間隙的大小維持 木 χ、電極Η 一點點地向下方前進。 4(C)中所示，在工"疋考慮到消耗率等來規定的。如圖 孔4i。如圖4 A :所2_上，狀與工具電極11 -致的 杨12向孔41 \不電加工裝置使第二個卫具電 數放電是在=間在放一多 【發明内容】 ⑽、中均勻地産生。 是’在新的二 分集中産生放電。特別 電產生部位容易偏移成的孔41中的情况下，放 集中部位移動。並沾果， 使新的工具電極向放電 孔也彎曲。圖4 ;、E)° ,夸贤二電極彎曲，工件上所形成的 特別是，推=過=；表示1 曲的工具電極U。 機械加工來製作的工具電極因具有 201103676 35139pif 壓縮應力（comPressive stress)而容易彎曲。本發明的 目的在於提供一種使用通過機械加工製作的工具電極來筆 直地形成針點澆口的放電加工方法。 根據本發明的一方面，在工件（2)上形成針點澆口（ 44) 的方法依序包括如下步驟：通過機械加工來製作工具電 極’使用工具電極對與工件相比消耗率小的犧牲材料（3、 4)進行放電加工來向工具電極導入拉伸應力（tensiie stress);及使用工具電極來對工件進行放電加工。 針點逢口只要是具有P小於等於1. 2 mm的開口的洗口 2可。工具電極包含銅，卫件只要是包含鋼鐵或者超硬合 ^可。犧牲材料只要技含喊者鋅合金即可。優選在 導入拉伸應力（tensile stress、沾半挪士 , S1：ress)的步驟中，形成在犧牲 材科”工具電極之間的加工間隙被介電油充滿。 ㈤^據本發明的另"'方面，在卫件（2)上形成針點洗口 (44)的方法包括如下步驟：通過機械加功製 2工具電極（11、aV蚀田给1 弟i及第 )，使用第1卫具電極⑴）對工件進 ^放電加工純工件中形成孔（41);使 = 12)，件相比消耗率小的犧牲材料(3、4)進= 加工來向第2卫具電極導人拉伸應力；及使用導入 應力的第2工具電極來將所述孔向更深處加工。有拉伸 [發明的效果] 動》其他優點將於以下的說明中部分性地記^。的"p位移 7 201103676 35139pif 為讓本發明之上述特徵和優點能更明顯易懂，下文特 牛實施例，並配合所附圖式作詳細說明如下。 【實施方式】 、_參照圖1對在工件上加工針點紗的製程（process) 進仃說明q個細長的錐社具電極n、12、13的形狀、 =材，圖3中的工具電極1〇相同。這些工具電極 掣作的13疋通過使用車床或者加工中心機的機械加工來 第-個工具電極U安1在放電加卫裝置的主轴頭（未 •不。工件2固定在貯存著介電油的加工槽（未圖示）中。 σ圖1 (A)中所示，使工具電極u移動到接近於工件2 I、置形成在工件2與工具電極π之間的加工間隙被介 锚滿。工件2只要是包含適於注射成形用的模具的鋼 ，戴或者超硬合請可。實施财，功2的材技相當於 日本工業標準的SKD11的鋼鐵。工件2的厚度爲32咖。 〜放電加工裝置對工具電極11與工件2之間施加電壓脈 衝。其結果，介電油的絕緣受到破壞而在加工間隙産生放 電机過加工間隙的電流脈衝的峰值（peak)設定爲9 A。 放電加工裝置爲將加工間隙維持在固定的大小，伴隨工件 的材料的除去而使工具電極11向下方移動。當工具電極 u到達設定深度時，結束使用工具電極n所進行的粗加 工。設定深度是考慮到所推測的消耗率來規定的。如圖i (B)中所不，通過反復進行放電，而在工件2上形成形狀 與工具電極11 一致的孔41。孔41的加工所需的時間爲約 8 201103676 35139pif 2· 8小時。測定的結果爲孔4 代替工具電極U，而魅：罝度在谷_内。 電加工裝置的主軸頭。犧牲f 電極12安裝在放 1⑹中所示，使工具=4上:定在加工槽中。如圖 的位置。形成在犧牲材料3 ^^到材料3 被介電油充滿。犧牲材料：電:八 =之：的加工間隙 率小的材質即可。犧牲與工件2相比消耗 金’實施例中爲I呂：二3相的门材，如喊者鋅合 32 mm〇 與件2相同，犧牲材料3的厚度爲 電：：ΐ =具電極12與犧牲材料3之間産生放 二Li中所示，通過反復進行放電，而在犧 ^材科3上形成形狀與工具電極12 — =電的面上存在拉伸應力。孔51的放電加1是向工具電 極12的側面導入拉伸應力。 如圖1(E)巾所示，使導人有拉伸應 :=移動。放電加工裝置使用工具電極12 = 1如圖1 (F)中所示，在工件2上形成比 孔41更冰的孔42。測定的結果爲孔41 圍内。、推測因拉伸應力而使得工具電極12不^曲在合轴 代替工具電極12，而將第三個工具電極13安裝在放 電加工裝置的主軸頭。爲將拉伸應力導入工具電極！3的側 面而使用形成著孔51的犧牲材料3。如圖！⑹情示， 201103676 35l39pif 使工具電極13向孔5i令移動。 裝置不使工具電極13向下方 放電加工中，放電加工 加搖動（orbiting)。搖動9和 而疋對工具電極13施 的軌跡上移動。 疋θ工具電極在水平面内的規定 J在工具電極13的整個BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machining method in which a discharge is generated between a tool electrode and a conductive workpiece to process a workpiece. In particular, the present invention relates to a method of using a tool electrode to form a point gate on a workpiece. [Prior Art] The electric discharge machining apparatus is a work machine that precisely processes a workpiece containing steel or a super hard alloy. A superhard alloy is an alloy obtained by sintering a powder j of a metal carbide. The tool electrode is usually mounted on the EDM. The material of the tool electrode is, for example, graphite (graptlite), steel and steel. The workpiece is placed in a dielectric fluid (dielectric fluW), = £ work tank. The dielectric fluid is, for example, kerosene (lamp 〇丨丨丨 rain force (.v 4 has water higher than electric [I" (specm port esistanee). The guard electrode is moved closer to the workpiece. It is formed on the tool electrode and the workpiece. The gap is called the "machining gap".] The small 6 in the power 2, the discharge plus the U plus the application of the electric gap produces the result 'dielectric (four) is more called as in the processing f = 枓 融 融. The discharge is performed, and the work, size, and accompanying removal of the workpiece material =: = gap _ advance. The advance direction of the tool electrode is usually vertically downward. ° ° Injection molding (Injectionmolding) device is empty to the mold 4 201103676 35139pif (cavity) A machine for forming a resin crucible for forming. The entrance of the cavity is called a gate or a pouring gate. The passage for guiding the resin to the gate is called a runner or Note: The pin point gate is a gate having a small opening with a p of 3 mm to 1. 2 mm. The pin gate is also called a pin gate. Figure 1 (I) The reference numeral 44 in the middle shows an example of a pin point gate. The pin point gate 44 is accompanied by a runner 43. In the publication of the Japanese Patent Publication No. 11-058114, there is disclosed a special center drill in which a needle point and a mouth are processed. However, 'generally' a mold having a pin point gate is made by an electric discharge machining device. Fig. 3 shows an example of a tool socket for electrically discharging a pin point gate. The tool electrode 10 made of copper is held by a spindle (header) 8 on a spindle head (not shown) of the electric discharge machining apparatus. Tool electrode 1〇 has a front end with an angle of 20°. The side of the tool electrode 1〇 is inclined by 2 except for the front end. The tool electrode 10 has a large aspect ratio, so its rigidity is small. The tool electrode will be in the electric discharge machining. The consumption rate is the ratio (%) of the weight of the tool electrode (g) to the amount of loss (g) of the workpiece. Or the 'consumption rate is the amount of reduction in the length of the tool electrode (mm) relative to the workpiece. The ratio (%) of the depth (mm) of the hole. For the tool electrode 10 having a large aspect ratio, the latter consumption rate is employed. In most cases, in consideration of the consumption of the tool electrode, a Needle point pouring An electric discharge machining device for forming a tool electrode having a fine diameter is disclosed in Japanese Laid-Open Patent Publication No. 2-059316. However, it is difficult to form such an electric discharge machining device. Straight to make the elongated tapered 201103676 35139pif (tapered) tool electrode. Therefore, the slender conical work = machining to make. This kind of machining work; machine = pass: lathe or force H (machining (10) shirt) . For example, Fig. 4 shows a conventional method of forming a needle spot washing. The direction in which the tool electrode does not move. The months 1 and m in Fig. 4 are the same as the tool electrodes 1 in Fig. 3. As shown in Figure 2, there is a gap to generate a discharge. As shown in the figure, the material is fixed in the processing room, so that the electric cooker can keep the size of the machining gap and the electrode Η a little downward. As shown in 4(C), the work "疋 takes into account the consumption rate and the like. Figure 4 hole. As shown in Fig. 4A: on the 2_, the shape and the tool electrode 11 - the Yang 12 to the hole 41 \ non-electric processing device so that the second power amplifier discharge is in the middle of the more than one [inventive content] (10) Uniformly produced. Yes, produces a discharge in the new dichotomy. In the case where the electric generating portion is easily displaced into the hole 41, the concentrated portion moves. And the fruit is applied, so that the new tool electrode is also bent toward the discharge hole. Fig. 4;, E)°, the bending of the two electrodes, which is formed on the workpiece, in particular, push = over =; represents a tool electrode U of 1 curve. The tool electrode fabricated by machining is easily bent due to the 201103676 35139pif compressive stress. SUMMARY OF THE INVENTION An object of the present invention is to provide an electric discharge machining method in which a pin point gate is formed straight by using a tool electrode fabricated by machining. According to an aspect of the invention, the method of forming a pinpoint gate (44) on a workpiece (2) sequentially comprises the steps of: fabricating a tool electrode by machining; using a tool electrode pair to sacrifice a small consumption rate compared to the workpiece The materials (3, 4) are subjected to electrical discharge machining to introduce tensile stress to the tool electrode; and the tool electrode is used to discharge the workpiece. The pinch point is as long as it is a mouthpiece having an opening of P less than or equal to 1.2 mm. The tool electrode contains copper, and the guard is only required to contain steel or super hard. Sacrificial materials can be used as long as the technology contains the zinc alloy. Preferably, in the step of introducing tensile stress (tensile stress, immersion, S1: ress), the processing gap formed between the electrodes of the sacrificial material "tool" is filled with dielectric oil. (5) According to the present invention, The aspect of the method of forming the needle point washing (44) on the guard (2) includes the following steps: 2 mechanical electrodes (11, aV etch field to 1 brother i and the first), using the first The guard electrode (1)) forms a hole (41) in the pure workpiece of the workpiece into the electric discharge machining; so that = 12), the sacrificial material (3, 4) with a lower consumption rate is processed to guide the electrode to the second guard The tensile stress; and the second tool electrode that introduces the stress is used to process the hole deeper. There is a stretch [effect of the invention]. Other advantages will be partially described in the following description. p 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 Process for processing needle-point yarns (process) Advance description q elongated cones with electrodes n The shape of 12, 13 is the same as that of the tool electrode in Fig. 3. The 13 turns of these tool electrodes are processed by machining using a lathe or machining center to the first tool electrode U. Spindle head of the device (not required. The workpiece 2 is fixed in a machining tank (not shown) in which the dielectric oil is stored. As shown in Fig. 1 (A), the tool electrode u is moved to be close to the workpiece 2 I, The machining gap formed between the workpiece 2 and the tool electrode π is filled. The workpiece 2 is steel or a hard-wearing one, which is suitable for the mold for injection molding. The steel of SKD11 is equivalent to the Japanese industrial standard. The thickness of the workpiece 2 is 32. The electric discharge machining device applies a voltage pulse between the tool electrode 11 and the workpiece 2. As a result, the insulation of the dielectric oil is broken and is generated in the machining gap. The peak value of the current pulse of the motor over-machining gap is set to 9 A. The electric discharge machining apparatus maintains the machining gap at a fixed size, and moves the tool electrode 11 downward as the material of the workpiece is removed. Arrival At the depth, the roughing performed by the tool electrode n is completed. The set depth is defined in consideration of the estimated consumption rate. As shown in Fig. i (B), the shape is formed on the workpiece 2 by repeating the discharge. The hole 41 conforms to the tool electrode 11. The time required for the processing of the hole 41 is about 8 201103676 35139 pif 2·8 hours. The result of the measurement is that the hole 4 replaces the tool electrode U, and the charm: the twist is in the valley_. The spindle head of the device. The sacrificial f electrode 12 is mounted as shown in the discharge 1 (6), so that the tool = 4 is placed in the machining groove. Formed at the sacrificial material 3^^ to material 3 is filled with dielectric oil. Sacrificial material: electricity: eight =: the material with small processing gap rate can be. Sacrifice consumption compared with the workpiece 2 'In the example, Ilu: two 3-phase door material, such as the caller zinc 32 mm 〇 is the same as the piece 2, the thickness of the sacrificial material 3 is electric:: ΐ = with electrode 12 The tensile stress is formed on the surface on which the shape of the tool electrode 12 is electrically connected to the tool electrode 12 by repeating the discharge as shown in the production of Li between the sacrificial material 3. The discharge plus 1 of the hole 51 introduces tensile stress to the side surface of the tool electrode 12. As shown in Figure 1 (E), the guide should have a stretch: = move. The electric discharge machining apparatus uses the tool electrode 12 = 1 to form a hole 42 which is iced more than the hole 41 on the workpiece 2 as shown in Fig. 1 (F). The result of the measurement was within the circumference of the hole 41. It is presumed that the tool electrode 12 is not bent in the shaft to replace the tool electrode 12 due to the tensile stress, and the third tool electrode 13 is attached to the spindle head of the discharge processing apparatus. To introduce tensile stress into the tool electrode! The sacrificial material 3 forming the hole 51 is used on the side of 3. As shown! (6) The situation, 201103676 35l39pif moves the tool electrode 13 to the hole 5i. The device does not cause the tool electrode 13 to be discharged downward, and the electric discharge machining is orbiting. Shake 9 and move on the trajectory applied to the tool electrode 13.疋θ Tool electrode in the horizontal plane J is in the entire tool electrode 13
圍產生放電所需的時間爲約3 5分鐘。由 :D 因此工具電極13幾乎不會產生消耗過n 是否r具電極13的整個侧面的=:) 士圖1(H)中所示’使導入有拉伸應力的工具電極 向孔42巾移動。放電加I裝置爲形成貫穿孔而制工具電 極13來對工件2進行粗加工。貫穿孔的形成所需的時間爲 數分鐘。測定的結果爲貫穿孔的真直度在容許範圍内。 放電加工裝置進行使貫穿孔的尺寸精度及表面粗链度 提高的精加工。第三個工具電極13也用於精加工。在工具 電極13的消耗所無法容許的情况下，也可使用第四個工具 電極。放電加工裝置對工具電極13的位置進行控制，以^ 使工具電極13的前端從工件2的底面突出超出〇 39麵。 在精加工中’將能量（energy)小的電流脈衝供給到加工 間隙。精加工分爲5個階段，越靠後的階段，將越小的能 201103676 35139pif 量的電流脈衝供給到加工間隙。 貫穿孔的表面粗經度被精加卫至5 _Rz。以如此 ==圖1⑴中所示形成伴隨著堯道43的針點洗口 . 心道43的人口與針贿π 44的轴心誤差爲^ ^咖。 限定於所揭示的形式。顯而易 可進灯多種改良及變形。例如’爲 a 洗口，也可使用祕材㈣Μ / 精度成針點 應力。更用犧牲材似向第-個工具電極u導入拉伸 犧牲材料的厚度也可不必與工件2相同。如 协爲向第二個工具電極12導入拉伸應力，也可使用 二：2的犧牲材料41牲材料4的材質爲鋁， 犧牲材枓4的厚度爲5 mm。 雷而，t卫裝置在卫具電極12與犧牲材料4之間產生放 電而在犧牲材料4上形成貫穿孔。其後，如圖 ^ 面=r_ 一面心 式私具電極12的整個侧 在更短的時間被導人有拉伸應力，因此幾乎不會産 雖:、、;本發明已以實施例揭露如上，然其並非用以限定 本n月，任何所屬技術領域中具有通常知識者，在不脫離 明之精神和範圍内，當可作些許之更動與潤飾，故本 X明之保護_當視後附之_請專利範_界定者為 L圖式簡單說明】 圖 1 U)、（B)、（C)、（D)、（E)、（F)、（G)、（h)、（i) 11 201103676 35139pif 是表示形成針點澆口的本發明的方法的一例的圖。 圖2 (A)、（B)是向工具電極導入拉伸應力的方法的 另一例的圖。 圖3是表示工具電極的一例的圖。 圖4 (A)、（B)、（C)、（D)、（E)是表示形成針點澆口 的以往的方法的圖。 【主要元件符號說明】The time required to generate a discharge is about 35 minutes. By: D, therefore, the tool electrode 13 hardly generates the consumption of n. Whether the r has the entire side of the electrode 13 =:) As shown in Fig. 1 (H), the tool electrode introduced with the tensile stress is moved toward the hole 42. . The discharge plus I device is formed by forming a through hole to form a tool electrode 13 for roughing the workpiece 2. The time required for the formation of the through holes is several minutes. As a result of the measurement, the straightness of the through hole was within the allowable range. The electric discharge machining apparatus performs finishing processing for improving the dimensional accuracy of the through hole and the surface roughness. The third tool electrode 13 is also used for finishing. The fourth tool electrode can also be used if the consumption of the tool electrode 13 is not acceptable. The electric discharge machining apparatus controls the position of the tool electrode 13 so that the front end of the tool electrode 13 protrudes from the bottom surface of the workpiece 2 beyond the surface of the crucible 39. In the finishing process, a current pulse having a small energy is supplied to the machining gap. The finishing process is divided into five stages. The lower the stage, the smaller the current pulse of the 201103676 35139pif amount is supplied to the machining gap. The surface longitude of the through hole is finely fixed to 5 _Rz. The needle point washing accompanying the tunnel 43 is formed as shown in Fig. 1 (1). The axial error of the population of the heart track 43 and the needle bribe π 44 is ^^. Limited to the disclosed form. It is obvious that many improvements and deformations can be made into the lamp. For example, 'for a wash, you can also use the secret material (four) Μ / precision needle point stress. Further, the thickness of the sacrificial material can be introduced to the first tool electrode u by the sacrificial material, and the thickness of the sacrificial material does not have to be the same as that of the workpiece 2. For the purpose of introducing tensile stress to the second tool electrode 12, it is also possible to use a sacrificial material of two: 2. The material of the material 4 is aluminum, and the thickness of the sacrificial material 4 is 5 mm. In addition, the t-device creates a discharge between the guard electrode 12 and the sacrificial material 4 to form a through hole in the sacrificial material 4. Thereafter, the entire side of the core-shaped private electrode 12 is guided to have a tensile stress in a shorter time, and thus is hardly produced. However, the present invention has been disclosed by way of example. However, it is not intended to limit the present month. Anyone who has the usual knowledge in the technical field can make some changes and refinements without departing from the spirit and scope of the Ming Dynasty. _Purchase patent _ definitive is a simple description of L schema] Figure 1 U), (B), (C), (D), (E), (F), (G), (h), (i) 11 201103676 35139pif is a view showing an example of the method of the present invention for forming a pin point gate. 2(A) and 2(B) are views showing another example of a method of introducing tensile stress to a tool electrode. 3 is a view showing an example of a tool electrode. 4(A), (B), (C), (D), and (E) are views showing a conventional method of forming a pinpoint gate. [Main component symbol description]
2 工件 3 ' 4 犧牲材料 8 手柄 10、 .11、 ‘ 12、13工具電極 41、 .42 子L 43 澆道 44 針點澆口 51 子L 122 Workpiece 3 ' 4 sacrificial material 8 handle 10, .11, ‘12, 13 tool electrode 41, .42 sub L 43 sprue 44 pin point gate 51 sub L 12