JPH07171743A - Nozzle for workpiece processing - Google Patents

Abstract

PURPOSE: To provide an inexpensive and highly durable working nozzle for workpiece provided with a sensor for supplying working laser beam to a workpiece and measuring the relative position with the workpiece. CONSTITUTION: A retaining element 3 consists of a conductive material, and an electrically insulated surface coating is applied thereto except the part with which the contact elements 9, 13 of a nozzle body 2 makes contact and the part to which a sensor element 4 is connected. Accordingly, the nozzle body 2 is insulated from the retaining element 3, and the contact elements 9, 13 are electrically connected to the retaining element 3 and the sensor element 4. The measurement signal of the sensor element 4 inputted through a coaxial plug socket 5 and the inquiry current for confirming the connection or disconnecting of the retaining element 3 are transmitted by use of the internal conductivity of the retaining element 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a workpiece machining nozzle for supplying a machining laser beam or the like to a workpiece, and more particularly to a workpiece machining nozzle equipped with a sensor for measuring a relative position to the workpiece. Regarding improvement.

[0002]

2. Description of the Related Art A nozzle for processing a workpiece, which has a sensor for measuring a relative position to a workpiece, is already known from German Patent Publication No. 4201640. This known nozzle has a nozzle body, which has at least contact elements electrically insulated from it. In addition, a holding element made of a ceramic material is held at the tip of the nozzle body. The holding element itself holds the sensor element, which is electrically connected to the contact element. That is, the sensor element is connected to the contact element via a conductor passing through a channel extending in the retaining element.

If the nozzle is firmly connected to a tool which is a machining means, it is possible to position the tool with respect to the workpiece in order to machine the workpiece in a suitable manner. This positioning is performed by a controller that receives the measured distance between the sensor element and the workpiece as an actual (actual) value, and controls the nozzle position by comparing a preset set value with the actual value.

The tool can be, for example, a laser cutting unit or the like for generating a laser beam that can cut or otherwise machine the work piece.

The distance between the sensor element and the work piece is measured by the capacitance method. for that reason,
A measuring voltage is applied to the sensor element. In that case, a shield potential is applied to the nozzle body to protect the measured voltage against external influences. In that case, the shield potential can also be an active shield potential.
The shield potential is guided by a wechrelformige measuring voltage, for example via a capacitor and an amplifier with an amplification factor V ≧ 1. The sensor element is electrically isolated from the nozzle body.

[0006]

The holding element of the nozzle is made of a ceramic material in order to obtain an insulating property. It is therefore relatively expensive to manufacture. Further, since the ceramic material is relatively brittle, if the tip of the nozzle is carelessly applied to the workpiece (workpiece structure), the holding element may be easily damaged.

[0007] The present invention has been made to solve the above problems, and provides a nozzle for processing a workpiece, which has a holding element which can be manufactured inexpensively and which has a durable holding element. With the goal.

[0008]

The solution to this problem is set forth in the characterizing part of claim 1. Advantageous embodiments of the invention are apparent from the dependent claims.

The nozzle according to the invention is characterized in that the holding element is made of an electrically conductive material and holds an electrically insulating surface coating at least in the area of the nozzle body facing (connecting). There is.

Retaining elements made of, for example, aluminum are much simpler and cheaper to manufacture than retaining elements made of ceramic. And because it is more durable than a ceramic part, the risk of nozzle damage during inadvertent movement of the workpiece structure is significantly reduced. The application of the surface coating on the holding element is also not very difficult and the manufacturing cost of the holding element according to the invention is only slightly higher. The surface coating can be, for example, an oxide layer. For example, in the case of a holding element made of aluminum, an anodized layer, a thin Teflon layer, etc.

The sensor potential is conducted to the sensor element via a contact element and a holding element made of a conductive material. In that case, the holding element itself is electrically insulated from the nozzle body by the surface coating.

The preferred retaining element retains an electrically insulating surface coating on all surfaces. The areas in contact with the contact element and the sensor element are then excluded from this surface coating.

According to a very advantageous refinement of the invention, in the area of the contact element, at least one contact pin is inserted in the holding element and, via an electrically insulating surface coating, the holding element. The contact element and the contact pin are adapted to come into contact when firmly attached to the nozzle body. The contact pins make a better electrical connection between the contact element and the holding element. In particular, better electrical connections are made when the contact areas of the contact pins with the contact elements are gold-plated. The contact pin is then
After manufacture of the retaining element, it can be easily mounted simply by inserting it through the surface coating.

The sensor element and the retaining element are preferably screwed together and electrically connected to each other in the threaded area. In that case, the sensor element can be screwed into the threaded hole of the holding element or can be screwed into the external thread of the holding element. Other connection methods between the holding element and the sensor element are also conceivable. For example, a clamp / lock connection. What is important is that the holding element and the sensor element are in direct conductive contact with each other.

[0015]

The invention will be described in more detail below with reference to the drawing.

FIG. 1 shows the principle structure of a nozzle according to the invention. The nozzle 1 includes a nozzle body 2 made of metal. At the tip of the nozzle body 2 is a holding element 3, which is also made of a conductive material, for example aluminum, and is electrically insulated from the nozzle body 2. The holding element 3 further holds at its tip a sensor element 4, which sensor element 4 is made, for example, of copper. In that case, the holding element 3 and the sensor element 4 are in direct conductive contact with each other.

The entire nozzle 1 has an internal tunnel, not shown in FIG. 1, through which a laser beam, and possibly a processing gas, passes for processing the workpiece.

A coaxial plug socket 5 is on the side wall of the nozzle body 2. The coaxial plug socket 5 has a signal line terminal 6 and another line terminal 7. A coaxial plug (not shown) can be connected to the coaxial plug socket from the outside, the coaxial plug is connected to one end of the coaxial cable, and the other end of the coaxial cable is a sensor electronic device (sensor drive device). Connected to the sensor electrode of. Coaxial cable center bar;
The center conductor) then contacts the signal line terminal 6, while the shield of the coaxial cable contacts the line terminal 7. This shield is, for example, at ground potential or, as already mentioned, at an active shield potential.

In order to measure the capacitance (electrostatic container) of the distance between the sensor element 4 and the tool, an alternating measurement signal (measurement voltage) is sent from the sensor electronics via the center bar of the coaxial cable and the signal line terminal 6. Sensor element 4
And this signal is evaluated in a conventional manner. For example, when it has a constant frequency, its amplitude can be detected for distance measurement.

The transmission of the alternating measuring signal from the signal line terminal 6 to the sensor element 4 takes place via a first line 8 extending from the signal line terminal 6 to the contact element 9,
The contact element 9 itself is electrically insulated from the nozzle body 2. The contact element 9 is in conductive connection with the holding element 3 and is in contact with the holding element 3 so that the measurement signal reaches the sensor element 4.

The holding element 3 is in contact with the first line 8 via a second contact element 13 which is in contact with a second line 11 spaced apart. This second contact element is likewise electrically insulated from the nozzle body 2. The other end of the second line 11 is connected to the resistor 14, and the other end of the resistor 14 passes through the other portion of the second line 11 and then the line terminal 7 of the coaxial plug socket 5.
It is connected to the. Further, since the nozzle body 2 is made of metal, the other end of the line 11 may be directly connected to the nozzle body 2 instead of being connected to the second line terminal 7.

In order to check whether the holding element 3 is connected to the nozzle body 2 as specified, the interrogation current (interrogation voltage) is passed from the sensor electronics via the signal line terminal 6.
Will be sent. If there is a proper connection between the nozzle body 2 and the holding element 3, this interrogation current will flow from the signal line terminal 6 to the first
Line 8, holding element 3, second line 11 and resistor 1
After that, it returns to the line terminal 7 of the coaxial plug socket 5. Since the magnitude of the resistor 14 and the interrogation voltage are known, it can be checked in this way whether there is a legitimate connection between the holding element 3 and the nozzle body 2. Such contact is necessary in order to be able to provide full distance control, or in general to be able to perform full distance measurement or process control.

Conversely, due to vibrations or other phenomena, the retaining element 3 relaxes or the retaining element 3 causes the nozzle body 2 to
If not attached, the first line 8 and the second line 11 are no longer bridged by the holding element 3, so that no interrogation current can flow. This condition is detected by the sensor electronics, which then generate an error or alarm signal. This alarm signal can be used to switch off all equipment.

The interrogating current is DC and the measuring capacitance is between the signal line terminal 6 or the center bar of the coaxial cable and the work piece to be processed, while the resistance is finally the center bar or signal of the coaxial cable. Since it is between the line terminal 6 and the other line terminal 7 or the shield line, the inquiry current and the measurement signal of the alternating shape are
It should be pointed out that they do not interact. The distance measurement is
Since it is generated only from an alternating shape measuring signal which can be properly filtered, the measured value is not influenced by the DC voltage or the interrogating DC voltage at the signal line terminals.

FIG. 2 shows the principle of a nozzle according to the second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In the nozzle according to FIG. 2, the signal line terminal 6
There is a distinguishing resistor (Kennungswiderstand) 15 between this and the other line terminal 7 of the coaxial plug socket, which is actually in parallel to the series connection consisting of the resistor 14 and the elements 11, 13, 3, 9. is there. Various states of the nozzle can be recognized by the combination of the resistors 14 and 15. That is, it can be recognized by checking the inquiry DC current by the sensor electronic device.

If the nozzle 1 is not connected to the coaxial cable through the coaxial plug socket 5, the inquiry current does not flow, and as a result, an alarm is generated by the sensor electronic device,
Stop all equipment. On the contrary, when the nozzle 1 is connected to a coaxial cable or sensor electronics, but the holding element 3 is not on the nozzle body 2, normal distance measurement or distance control is not possible. In this case, the magnitude of the sensor current is determined only by the identification resistor 15, so that a second error signal is generated, which indicates an incorrect operating state of the nozzle 1. In the case of a correct connection between the holding element 3 and the nozzle body 2, on the contrary, the interrogation current is determined by the combination of the resistors 14 and 15, so that no error signal is generated in this case.

As already mentioned, the holding element 3 is removable from the nozzle body 2, so that there must be contact for the connection of the respective line portions of the first and second lines 8 or 11. . These contact parts are formed by the contact elements 9 and 13, which can have elastic elements, for example. Thus, various holding elements 3 with different sensor elements 4 can be attached to the nozzle body 2. In that case, the retaining elements 3 are all formed identically on the surface facing the nozzle body 2.

FIG. 3 shows the exact structure of the nozzle 2. The same parts as in FIGS. 1 and 2 are provided with the same reference numerals.

The nozzle body 2 comprises a substantially conically extending nozzle portion 16 of which the nozzle portion 1
6 is made of a conductive material, such as steel.
A fixing sleeve 17 is provided on the outer circumference of the thick end of the nozzle portion 16. The fixing sleeve 17 is formed in a cylindrical shape on the outer side, and holds an outer screw 18. The nozzle part 16 and the fixing sleeve 17 are firmly connected to each other so that the entire nozzle can be screwed into the holder by means of an external thread 18.

At the tip of the nozzle portion 16 there is a ring-shaped channel 19 in the peripheral direction, which serves to accommodate the electrical lead. A coaxial plug socket 5 (see FIGS. 1 and 2) is inserted in the outer wall 20 of the ring-shaped channel 19, and the socket 5 is externally connected to a coaxial cable. The ring-shaped channel 19 is likewise made of a conductive material. In that case, the line terminal 7 of the coaxial plug socket 5 is in direct electrical contact with the outer wall 20. In this way, the shield potential is transferred to and through the ring-shaped channel 19 through the nozzle portion 1.
Join 6 The nozzle part 16 and the ring-shaped channel 19 are conductively connected, for example by means of an external thread 21 of the nozzle part 16, on which the ring-shaped channel 19 is screwed.

In the bottom surface 22 of the ring-shaped channel 19, the contact elements 9 and 13 are inserted obliquely downward. The contact elements 9 and 13 have a ring-shaped channel 19
Alternatively, it is electrically insulated from the bottom surface 22. In other words, they are insulated by the insulating sleeves 23, in which the contact elements 9 and 13 are placed. Each of these contact elements 9 and 13 has a resilient contact piece 24 on its front face facing the nozzle tip, which contact piece 24 is shiftable in the axial direction of the contact elements 9 and 13.

On the front side of the contact elements 9 and 13 facing the contact piece 24, these contact elements 9 and 13 are connected to the first and second lines 8 and 11. The portion of line 8 in FIG. 3 is directly connected to the signal line terminal 6 of the coaxial plug socket 5 (see FIGS. 1 and 2), while the portion of line 11 in FIG. 3 is shown in FIG. Not connected to the end of the resistor 14 (see FIGS. 1 and 2). The rest of the electric circuit is constructed according to FIG. 1 or 2.

There is a projection 25 at the tip of the nozzle body 2 on which the holding element 3 can be mounted. Further, a cylindrical protrusion 26 is on the lower side of the bottom surface 22. This protrusion 26 has an external thread 27, and as will be described in more detail,
To fix the holding element 3 to the nozzle body 2, the external screw 2
The cap screw 29 shown in FIG. 4 can be screwed onto the device 7.

FIG. 4 shows a nozzle body according to FIG. 3 with a holding element 3 and a sensor element 4 mounted on the nozzle body 2.

The nozzle body 2, in the case of the embodiment according to FIG. 4, can be screwed onto the external thread 18 after the nozzle body 2 has been pushed together with its fixing sleeve through a suitable opening in the connecting head, not shown. Is for example flange 2
Held by 8.

As is apparent from FIG. 4, the holding element 3 made of, for example, aluminum is mounted on the protrusion 25 of the nozzle body 2. This holding element 3 has an electrically insulating coating on its entire surface, so that the holding element 3
There is no electrical short circuit between the nozzle body 2 and the nozzle body 2. However, in a small area of the holding element 3, no insulating layer is formed. That is, it is a region where the contact piece 24 and the sensor element 4 contact each other. By means of the cap screw 29, the holding element 3 is attracted to the nozzle body 2 or the projection 25. For this reason, the cap screw 29 is attached to the holding element 3.
Grips the flange 30 and is screwed into the external thread 27 of the cylindrical protrusion 26 on the other hand. Due to the electrically insulating surface coating of the holding element 3, this holding element 3
Are also electrically insulated from the cap screw 29. The holding element 3 has an axial through hole, which is provided with an internal thread 31 at its tip. The sensor element 4 made of, for example, copper is screwed into the inner screw 31 by a corresponding outer screw. The sensor element 4 has a through hole 32 in the axial direction, through which the laser beam,
In some cases, the processing gas passes through. The sensor element 4 and the holding element 3 are electrically conductively connected to each other in the region of the screw 31.

In order to achieve a better electrical contact between the contact elements 9 and 13 on the one hand and the holding element 3 on the other hand, the holding element 3 has contact pins (not shown),
The contact piece 24 pushes this pin. For this reason, the contact pins can be driven directly into the holding element 3. And
It can be driven through electrically insulating surface coatings. Since the contact pin can be gold-plated on its free front surface, a better contact with the contact piece 24 can be achieved.

In the simplest case, one contact element may be used instead of both contact elements 9 and 13. It is pointed out, for example, the contact element 9, by means of which the measuring potential is conducted to the holding element 3 and then to the sensor element 4. In this case, the resistor 14 of FIGS. 1 and 2 and the resistor 15 of FIG. 2 are unnecessary.

Of course, other geometric shapes of the holding element 3 are possible. That is, the cap screw 29 can be, for example, conically shaped and engage on the conical surface of the holding element 3. Since the cap screw 29 is also made of metal and can be conductively connected to the nozzle body 2 via the external screw 27, the shield potential is also in contact with the cap screw 29. In that case, the cap screw 29 can also be pulled down close to the sensor element 4. At that time, the cap screw is always
The electrically insulating surface coating of the holding element 3 makes it electrically insulating to the holding element 3. An active shield potential is preferably applied to the nozzle body 2 and the cap screw 29 in order to minimize the parasitic capacitance due to the use of the metal holding element 3.

The holding element 3 does not necessarily rotate on the side facing the nozzle body 2, so that there is a projection which engages in a corresponding groove of the nozzle body 2 or, conversely, a corresponding projection of the nozzle body 2. It is not necessary to provide a projecting opening. If a projection is present on the retaining element 3, this projection can also accommodate, for example, a contact pin that fits into the groove of the projection.

[0042]

As described above, since the holding element of the work piece processing nozzle is made of a conductive material and the surface thereof is coated with an insulating layer, compared with the conventional one made entirely of ceramics. The durability is improved and it can be manufactured at low cost.

Further, by partially excluding the coating of the insulating layer on the surface of the holding element, the electric connection between the sensor element and the contact element can be made through the holding element, so that the structure of the nozzle for processing a workpiece is formed. Can be simplified, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a principle structure in a case where a nozzle for processing a workpiece according to the present invention has a resistance for identifying a holding element.

FIG. 2 is an explanatory diagram illustrating a principle structure in the case where a nozzle for processing a workpiece according to the present invention has a resistance for identifying a holding element and a resistance for identifying a nozzle.

FIG. 3 is a cross-sectional view illustrating details of a nozzle body having two electrically insulated contact elements facing the nozzle body in the workpiece machining nozzle according to the present invention.

FIG. 4 is a cross-sectional view for explaining in detail a state in which a holding element and a sensor element are attached to the nozzle body shown in FIG.

[Explanation of symbols]

 1 Nozzle 2 Nozzle body 3 Holding element 4 Sensor element 5 Coaxial plug socket 6 Signal line terminal 7 Line terminal 8 First line 9,13 Contact element 11 Second line 14,15 Resistance

Claims (8)

[Claims] 1. A nozzle body having a contact element electrically insulated from at least one nozzle body, and a holding element held at the tip of the nozzle body and contacting the contact element. A workpiece processing nozzle having a sensor element electrically connected to the contact element and held by the holding element, wherein the holding element is made of a conductive material, and at least A nozzle for processing a workpiece, wherein an electrically insulating surface coating is held in a contact area with the nozzle body. 2. The nozzle for machining a work piece according to claim 1, wherein the retaining element retains an electrically insulating surface coating on its entire surface, in which case it contacts the contact element and the sensor element. Nozzle for processing a workpiece, wherein the area to be processed is removed from the surface coating. 3. The nozzle for processing a work piece according to claim 1 or 2, wherein the electrically insulating surface coating is an oxide layer, a ceramic layer or a Teflon (registered trademark) layer. Nozzle for product processing. 4. The workpiece machining nozzle according to claim 1, 2 or 3, wherein the holding element is made of aluminum. 5. A nozzle for machining a work piece according to claim 1, 2 or 3 or 4, wherein the holding element is in contact with the contact element through an electrically insulating surface coating. A nozzle for processing a work piece, wherein at least one contact pin is inserted. 6. The workpiece machining nozzle according to claim 5, wherein the contact pin is gold-plated in a contact region of the contact element. 7. The workpiece machining nozzle according to claim 1, 2 or 3, or 4 or 5 or 6, wherein the sensor element and the holding element are screwed into each other. ,
A nozzle for processing a workpiece, which is electrically connected in a thread region. 8. The workpiece machining nozzle according to claim 1, 2 or 3, 3 or 4, 5 or 6 or 7, wherein the nozzle body is actively shielded. A nozzle for processing a processed product, which is capable of supplying an electric potential.