JPS641234B2 - - Google Patents
Info
- Publication number
- JPS641234B2 JPS641234B2 JP1404083A JP1404083A JPS641234B2 JP S641234 B2 JPS641234 B2 JP S641234B2 JP 1404083 A JP1404083 A JP 1404083A JP 1404083 A JP1404083 A JP 1404083A JP S641234 B2 JPS641234 B2 JP S641234B2
- Authority
- JP
- Japan
- Prior art keywords
- cathode
- plasma
- nozzle
- arc
- airflow
- 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
Links
- 238000000034 method Methods 0.000 claims description 10
- 230000007704 transition Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/06—Arrangements or circuits for starting the arc, e.g. by generating ignition voltage, or for stabilising the arc
- B23K9/067—Starting the arc
- B23K9/0672—Starting the arc without direct contact between electrodes
- B23K9/0673—Ionisation of the arc gap by means of a tension with a step front (pulses or high frequency tensions)
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Plasma Technology (AREA)
Description
【発明の詳細な説明】
本発明は陰極外套を有するプラズマトーチのス
タート法に関し、詳しくは陰極棒の外周に配置し
た陰極外套を仮想陰極とするプラズマトーチのス
タート法に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for starting a plasma torch having a cathode mantle, and more particularly to a method for starting a plasma torch in which a cathode mantle disposed around the outer periphery of a cathode rod serves as a virtual cathode.
プラズマトーチによる工業材料の加工は、加工
材への熱影響が少いことも主要な特長となつてい
る。この特長は、小電流で集中度の高いマイクロ
プラズマトーチで最も発揮される。例えば、直径
が0.1〜0.2mmというノズルで1000A／mm2〜350A／
mm2という高い電流密度のプラズマアーク（移行型
作業）を発生すると、金属箔から10mm程度の鉄板
まで良質な切断加工が可能となる。又、プラズマ
シエツト（非移行型作業）では、熱衝撃に弱いセ
ラミツク、ガラス或いは燃焼し易い衣料、木材、
プラスチツク等の加工も可能になる。 A major feature of processing industrial materials using a plasma torch is that there is little thermal influence on the processed materials. This feature is best demonstrated by the microplasma torch, which uses a small current and has a high degree of concentration. For example, a nozzle with a diameter of 0.1 to 0.2 mm can produce 1000A/mm 2 to 350A/
By generating a plasma arc (transition type work) with a high current density of mm 2 , it is possible to perform high-quality cutting on everything from metal foils to steel plates of about 10 mm. In addition, in plasma shielding (non-transfer type work), materials such as ceramics, glass, which are susceptible to thermal shock, clothing that is easily combustible, wood,
It also becomes possible to process plastics, etc.
狭搾ノズルと陰極棒から成る通常のマイクロプ
ラズマトーチの動作特性は、陰極棒の形状や狭搾
ノズルと陰極棒の相対位置によつて影響をうけ、
殊に狭搾ノズルの直径が小さくなるほど敏感にそ
の影響をうける。更に重要な問題は、使用時間が
経つにつれて陰極棒が消耗、変形することであつ
て、そのため陰極棒の寿命が１〜２時間と短いこ
とである。 The operating characteristics of a typical microplasma torch consisting of a constriction nozzle and a cathode rod are affected by the shape of the cathode rod and the relative position of the constriction nozzle and cathode rod.
In particular, the smaller the diameter of the narrowing nozzle, the more sensitive it is to the effect. A more important problem is that the cathode rod wears out and deforms over time, resulting in a short life span of 1 to 2 hours.
本発明者は先に、このような陰極棒に起因する
動作特性の不安定性を除去する方法を開発した
（特許第663311号）、その方法は陰極棒の外周に陰
極外套を設け、この陰極外套を仮想陰極としてア
ークを発生させてトーチを操作することである。
しかし、ノズルの直径が0.1〜0.2mm程度に小さい
プラズマ外套内に陰極外套を設けると、そのよう
なマイクロプラズマトーチはスタートすることが
不可能となる。 The present inventor has previously developed a method to eliminate instability in operating characteristics caused by such cathode rods (Patent No. 663311). The torch is operated by generating an arc using the arc as a virtual cathode.
However, if the cathode mantle is provided within the plasma mantle where the nozzle diameter is as small as 0.1-0.2 mm, it becomes impossible to start such a microplasma torch.
第１図は、陰極外套を有するプラズマトーチの
断面図と電気回路図である。 FIG. 1 is a cross-sectional view and electrical circuit diagram of a plasma torch with a cathode jacket.
プラズマトーチは、陰極棒１と電気的に絶縁さ
れ且つその外周に第１の環状通路２を形成し先端
に第１のノズル３を有する陰極外套４、及び陰極
外套４と電気的に絶縁され且つその外周に第２の
環状通路５を形成し先端に第２のノズル６を有す
るプラズマ外套７から成り、第１の環状通路２に
スタート気流８を、第２の環状通路５にプラズマ
気流９をそれぞれ供給管１０，１１から流すよう
に構成されている。電源１２の負端子は陰極棒１
に接続され、電源１２の正端子はスイツチ１３を
経て陰極外套４及びスイツチ１４を経てプラズマ
外套７にそれぞれ接続されている。 The plasma torch includes a cathode mantle 4 which is electrically insulated from the cathode rod 1, has a first annular passage 2 formed on its outer periphery, and has a first nozzle 3 at its tip; It consists of a plasma mantle 7 with a second annular passage 5 formed on its outer periphery and a second nozzle 6 at its tip. They are configured to flow from supply pipes 10 and 11, respectively. The negative terminal of the power supply 12 is the cathode rod 1
The positive terminal of the power source 12 is connected to the cathode jacket 4 via a switch 13 and to the plasma jacket 7 via a switch 14, respectively.
なお、図示していないが陰極外套４とプラズマ
外套７は水冷されている。 Although not shown, the cathode mantle 4 and the plasma mantle 7 are water-cooled.
このように構成されたプラズマトーチは、次の
ようにして操作される。 The plasma torch configured in this way is operated as follows.
(1) スタート気流８を流し、スイツチ１３を閉じ
電源１２を動作させる。(1) Flow the start airflow 8, close the switch 13, and operate the power supply 12.
(2) 電源１２に内蔵した高周波発振器により、陰
極棒１と陰極外套４間にアーク１５を発生させ
る。(2) An arc 15 is generated between the cathode rod 1 and the cathode mantle 4 by a high-frequency oscillator built into the power supply 12.
(3) スイツチ１４を閉じ、スイツチ１３を開くと
アーク１５は陰極棒１とプラズマ外套７間に移
行しアーク１６となる。(3) When the switch 14 is closed and the switch 13 is opened, the arc 15 moves between the cathode rod 1 and the plasma mantle 7 and becomes an arc 16.
(4) プラズマ気流９を流すと同時に若しくはその
後でスタート気流８を停止する。(4) The start airflow 8 is stopped at the same time as or after the plasma airflow 9 is started.
この動作状態では陰極外套内、すなわち第１の
環状通路２には気流は流れていない。無気流中の
アークはアーク入力と陰極外套内壁の冷却とが平
衡する。したがつて、トーチから放出されるエネ
ルギーは第１のノズル３の下端とプラズマ外套７
間のアーク柱の入力に依存する。しかも、プラズ
マ気流の通路は冷却された陰極外套外壁とプラズ
マ外套内壁とで形成されているので、消耗した
り、変形したりすることはない。このようにして
陰極外套４は消耗や変形のない仮想陰極を形成す
るのである。 In this operating state, there is no air flow within the cathode envelope, ie the first annular passage 2. In the arc in no air flow, the arc input and the cooling of the inner wall of the cathode envelope are in equilibrium. Therefore, the energy emitted from the torch is transferred to the lower end of the first nozzle 3 and to the plasma mantle 7.
Depends on the input of the arc column between. Moreover, since the plasma air flow path is formed by the cooled outer wall of the cathode jacket and the inner wall of the plasma jacket, it will not be worn out or deformed. In this way, the cathode jacket 4 forms a virtual cathode that does not wear out or deform.
ところで、上述のスタート操作において、第２
のノズル６の直径を次第に小さくしていくと、ア
ーク１６の発生が因難となりスタート操作が殆ん
ど不可能となる。 By the way, in the start operation mentioned above, the second
If the diameter of the nozzle 6 is gradually reduced, the generation of the arc 16 becomes a problem and the starting operation becomes almost impossible.
スタート気流量ｌとトーチ内圧力（第１と第２
の環状通路２，５の圧力）Ｐは、第２のノズルの
断面積をＳとすると、
ｌ∝Ｓ×Ｐ1/2
で表わされ、スタート気流量ｌを一定にすると、
トーチ内圧力Ｐは第２のノズルの断面積Ｓに反比
例する。第１のノズル３からスタート気流８によ
つて放出されるプラズマ流はトーチ内圧力Ｐに比
例して減衰し、第２のノズル６に達する。従つて
第１のノズル３と第２のノズル６との間のプラズ
マ流による導電性はトーチ内圧力が高い程低下す
る。このため、一定の断面積以下ではアーク１５
が移行してアーク１６となることができず結局ト
ーチのスタートが殆んど不可能となる。通常、第
２のノズル６の直径が0.2mm以下（この値は参考
値であつて、ノズル長及び第１と第２のノズル間
の距離によつて変化する）になると、第２のアー
ク１６は発生しなくなり、スタート操作は不可能
となる。 Starting air flow rate l and torch internal pressure (first and second
When the cross-sectional area of the second nozzle is S, the pressure in the annular passages 2 and 5 of
The torch internal pressure P is inversely proportional to the cross-sectional area S of the second nozzle. The plasma flow discharged from the first nozzle 3 by the starting air flow 8 is attenuated in proportion to the torch internal pressure P and reaches the second nozzle 6 . Therefore, the conductivity due to the plasma flow between the first nozzle 3 and the second nozzle 6 decreases as the torch internal pressure increases. Therefore, below a certain cross-sectional area, the arc 15
cannot transition to arc 16, and in the end it becomes almost impossible to start the torch. Normally, when the diameter of the second nozzle 6 is 0.2 mm or less (this value is a reference value and varies depending on the nozzle length and the distance between the first and second nozzles), the second arc 16 will no longer occur, and the start operation will no longer be possible.
このように、陰極外套を有するプラズマトーチ
は、従来のトーチに比較して多くの利点をもつに
もかゝわらず、プラズマ外套７のノズル６の直径
を小さくしたマイクロプラズマトーチの場合に
は、スタート操作が著しく困難或いは不可能にな
るという問題があつた。 As described above, although a plasma torch with a cathode jacket has many advantages compared to conventional torches, in the case of a microplasma torch in which the diameter of the nozzle 6 of the plasma jacket 7 is reduced, There was a problem in that starting operations were extremely difficult or impossible.
本発明は上記に鑑みてなされたもので、陰極外
套を有するプラズマトーチのスタート操作を確
実・容易にする方法を提供することを目的とす
る。 The present invention has been made in view of the above, and it is an object of the present invention to provide a method for reliably and easily starting a plasma torch having a cathode jacket.
この目的は本発明に従つてトーチ内のアークの
移行前に、一旦スタート気流の供給を止め、第２
のノズルからの気流の排出がほゞなくなつてから
再びスタート気流を流すことによつて達成され
る。 The purpose of this is, according to the invention, to temporarily stop the supply of the starting air flow and to
This is achieved by supplying the starting airflow again after the airflow from the nozzle is almost exhausted.
以下、第１図に用いて本発明のスタート操作法
詳しく説明する。 Hereinafter, the start operation method of the present invention will be explained in detail with reference to FIG.
本発明によるスタート操作は次のようにして行
われる。 The start operation according to the present invention is performed as follows.
(1) スタート気流８を流し、スイツチ１３を閉じ
電源１２を動作させ、電源１２に内蔵した高周
波発振器により、陰極棒１と陰極外套４間にア
ーク１５を発生させる（バルブ２０開、バルブ
１８閉）。(1) Flow the start airflow 8, close the switch 13, operate the power supply 12, and use the high frequency oscillator built in the power supply 12 to generate an arc 15 between the cathode rod 1 and the cathode mantle 4 (valve 20 open, valve 18 closed). ).
(2) バルブ２０を閉じスタート気流８の供給を一
旦止める。(2) Close the valve 20 and temporarily stop the supply of the start airflow 8.
(3) このスタート気流の供給の停止の前又は後
に、スイツチ１４を閉じ陰極棒１とプラズマ外
套７間に電圧を印加する。(3) Before or after the supply of the start airflow is stopped, the switch 14 is closed and a voltage is applied between the cathode rod 1 and the plasma mantle 7.
(4) 第２のノズル６からの気流の排出がほゞなく
なつてから（つまり、第１と第２の環状通路
２，５内に残存するスタート気流がほゞなくな
つてから）、バルブ２０を開いて再びスタート
気流８を流し、つづいてスイツチ１３を開く
と、陰極棒１とプラズマ外套７間のアーク１６
に移行する。(4) After the airflow from the second nozzle 6 is almost exhausted (that is, after there is almost no starting airflow remaining in the first and second annular passages 2 and 5), the valve 20 is opened to flow the start airflow 8 again, and then the switch 13 is opened, the arc 16 between the cathode rod 1 and the plasma mantle 7 is
to move to.
このようにしてプラズマトーチをスタートさ
せ、それからバルブ１８を開き、プラズマ気流９
を流すと同時に若しくはその後でスタート気流８
を停止させ、第２のノズルからプラズマジエツト
２４を加工片２３に放出して作業する。 Start the plasma torch in this way, then open the valve 18 and open the plasma air stream 9.
Start airflow 8 at the same time as or after
The plasma jet 24 is discharged onto the work piece 23 from the second nozzle to perform the work.
本発明では、アーク１５を発生させたまゝの状
態で一旦スタート気流の供給を停止し、第１と第
２の環状通路２，５内の残存気流が第２のノズル
６から排出されてなくなつてから、つまりトーチ
内圧力が低下してから再びスタート気流を流すの
で、陰極棒とプラズマ外套間のアーク１６の発生
が容易となる。 In the present invention, the supply of the start airflow is temporarily stopped while the arc 15 remains generated, and the remaining airflow in the first and second annular passages 2 and 5 is discharged from the second nozzle 6 and disappears. Since the starting airflow is supplied again after the torch internal pressure has decreased, the arc 16 between the cathode rod and the plasma mantle is easily generated.
非移行型作業について説明したが、加工片２３
と電源１２の正端子をスイツチ２２を介して接続
しておき、このスイツチ２２を閉じ、スイツチ１
４を開けばプラズマアークが陰極１の先端と加工
片２３との間に確立されて移行型作業を実施でき
る。 Although we have explained non-transfer type work, work piece 23
and the positive terminal of the power supply 12 are connected through a switch 22, and this switch 22 is closed.
4 is opened, a plasma arc is established between the tip of the cathode 1 and the workpiece 23, and transfer-type operations can be performed.
第２図は特に移行型作業に適した電気回路の一
例であつて、補助電源２１を設け、アーク１６を
パイロツトアークとして常時発生させておき、い
つでも容易に移行型作業を実施できるようにした
ものである。すなわち、作業中スイツチ１４を投
入したまゝにしておけば補助電源２１によりアー
ク１６はパイロツトアークとして常に存在してい
る。このためスイツチ２２を投入すればいつでも
パイロツトアーク１６により加工片２３へ移行す
るプラズマアーク２５をつくつて移行型作業をす
ることができる。作業を中断したければスイツチ
２２を開くとプラズマアーク２５は消失し、パイ
ロツトアーク１６のみとなり移行型作業の再開に
備える。 Figure 2 shows an example of an electric circuit particularly suitable for transition type work, in which an auxiliary power source 21 is provided and the arc 16 is constantly generated as a pilot arc, so that transition type work can be easily carried out at any time. It is. That is, if the switch 14 is left on during work, the arc 16 always exists as a pilot arc due to the auxiliary power supply 21. Therefore, if the switch 22 is turned on, the pilot arc 16 can create a plasma arc 25 that transfers to the work piece 23 at any time to perform transfer type work. If it is desired to interrupt the work, the switch 22 is opened, and the plasma arc 25 disappears, leaving only the pilot arc 16 in preparation for restarting the transition type work.
なお、加工片２３への配線を点線１９で示すよ
うにプラズマ外套７に接続することにより、非移
行型作業においても同様に補助電源２１によるパ
イロツトアーク１６として、容易に作業を実施す
ることができる。 By connecting the wiring to the workpiece 23 to the plasma mantle 7 as shown by the dotted line 19, the work can be easily performed as a pilot arc 16 using the auxiliary power source 21 even in non-transfer type work. .
補助電源を使用するこの方法は、補助電源２１
の電流では第１のアーク１５が発生しない比較的
太い陰極棒を使用できる利点もある。 This method of using an auxiliary power source uses the auxiliary power source 21
There is also the advantage that a relatively thick cathode rod can be used, since the first arc 15 does not occur at a current of .
本発明は前述したように、プラズマ外套のノズ
ルの直径を小さくするマイクロプラズマトーチに
特にその効果を発揮するが、次のような場合にも
利点が得られる。 As described above, the present invention is particularly effective for microplasma torches in which the diameter of the nozzle of the plasma jacket is reduced, but advantages can also be obtained in the following cases.
陰極棒の偏位、変形、消耗等によつて、スター
ト気流を流した陰極外套内のアークによる気体加
熱効率が低下したとき、プラズマ外套のノズル６
の直径が比較的大きいときでもスタート操作に失
敗する。このような場合にも本発明は有効確実に
スタート操作を行なわせることができるので、長
時間の使用によつて陰極棒が消耗、変形しても陰
極棒の手入れは不要であるという利点が得られ
る。 When the efficiency of gas heating by the arc inside the cathode mantle through which the starting airflow flows is reduced due to deviation, deformation, wear, etc. of the cathode rod, the nozzle 6 of the plasma mantle
Start operation fails even when the diameter is relatively large. Even in such a case, the present invention can perform the start operation effectively and reliably, so there is an advantage that there is no need to maintain the cathode rod even if the cathode rod is worn out or deformed due to long-term use. It will be done.
第１図は陰極外套を有するプラズマトーチのス
タート法を説明するためのトーチの断面図と電気
回路図である。第２図は第１図の変形態様を示す
一例である。
図中の符号：１……陰極棒、２……第１の環状
通路、３……第１のノズル、４……陰極外套、５
……第２の環状通路、６……第２のノズル、７…
…プラズマ外套、８……スタート気流、９……プ
ラズマ気流。
FIG. 1 is a sectional view and an electric circuit diagram of a plasma torch for explaining a method of starting a plasma torch having a cathode jacket. FIG. 2 is an example showing a modification of FIG. 1. Codes in the diagram: 1... Cathode rod, 2... First annular passage, 3... First nozzle, 4... Cathode jacket, 5
...Second annular passage, 6...Second nozzle, 7...
...Plasma cloak, 8...Start airflow, 9...Plasma airflow.
Claims (1)
の環状通路を形成し先端に第１のノズルを有する
陰極外套、及びこの陰極外套を包囲しその外周に
第２の環状通路を形成し先端に第２のノズルを有
するプラズマ外套を備えたプラズマトーチのスタ
ート法において、前記第１の環状通路にスタート
気流を流して前記の陰極棒と前記の陰極外套間に
アークを発生させてから前記のスタート気流の供
給を止め、前記第２のノズルからの気流の排出が
ほゞなくなつてから前記のスタート気流を再び流
して、前記の陰極棒とプラズマ外套間にアークを
発生させることを特徴とするプラズマトーチのス
タート法。1 Cathode rod, surrounding this cathode rod and having a first
A plasma torch comprising: a cathode mantle forming an annular passage and having a first nozzle at its tip; and a plasma mantle surrounding the cathode mantle, forming a second annular passage around its outer periphery, and having a second nozzle at its tip. In the starting method, a starting airflow is caused to flow through the first annular passage to generate an arc between the cathode rod and the cathode jacket, and then the supply of the starting airflow is stopped, and the starting airflow is started from the second nozzle. A method for starting a plasma torch, characterized in that the starting airflow is caused to flow again after the airflow is almost exhausted to generate an arc between the cathode rod and the plasma envelope.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1404083A JPS59141371A (en) | 1983-01-31 | 1983-01-31 | Starting method of plasma torch having cathode sleeve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1404083A JPS59141371A (en) | 1983-01-31 | 1983-01-31 | Starting method of plasma torch having cathode sleeve |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59141371A JPS59141371A (en) | 1984-08-14 |
| JPS641234B2 true JPS641234B2 (en) | 1989-01-10 |
Family
ID=11849999
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1404083A Granted JPS59141371A (en) | 1983-01-31 | 1983-01-31 | Starting method of plasma torch having cathode sleeve |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59141371A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02272214A (en) * | 1989-04-11 | 1990-11-07 | Matsushita Electric Ind Co Ltd | Burning apparatus |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5166494A (en) * | 1990-04-24 | 1992-11-24 | Hypertherm, Inc. | Process and apparatus for reducing electrode wear in a plasma arc torch |
| US5396043A (en) * | 1988-06-07 | 1995-03-07 | Hypertherm, Inc. | Plasma arc cutting process and apparatus using an oxygen-rich gas shield |
| US6677551B2 (en) | 1998-10-23 | 2004-01-13 | Innerlogic, Inc. | Process for operating a plasma arc torch |
| US9949356B2 (en) | 2012-07-11 | 2018-04-17 | Lincoln Global, Inc. | Electrode for a plasma arc cutting torch |
-
1983
- 1983-01-31 JP JP1404083A patent/JPS59141371A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02272214A (en) * | 1989-04-11 | 1990-11-07 | Matsushita Electric Ind Co Ltd | Burning apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59141371A (en) | 1984-08-14 |
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