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
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/30—Features relating to electrodes
• • 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
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/30—Features relating to electrodes
  • B23K11/3063—Electrode maintenance, e.g. cleaning, grinding
• • 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
  • B23K11/00—Resistance welding; Severing by resistance heating
• • 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
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/10—Spot welding; Stitch welding
  • B23K11/11—Spot welding
• • 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
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/36—Auxiliary equipment

Definitions

• the invention relates to a method for cleaning an electrode used in resistance spot welding, according to the preamble of claim 1, an electrode for resistance spot welding according to the preamble of claim 8, a cap for plugging onto an electrode according to the preamble of claim 9 and a device for resistance spot welding according to claim 12.
• Such electrodes or electrode caps used in resistance spot welding are known, for example, from US Pat. No. 5,387,774 A.
• welding spatter occurs, which settles in and on functional parts of the welding machine, which, for example, settle on the electrode of a resistance spot welding machine or on the gas nozzle of an arc welding machine and must be removed from time to time.
• Mechanical cleaning typically uses a rotating tool, such as a cap mill, that fits the contour of the electrode or cap is adjusted.
• the disadvantage of mechanical processing is that the surfaces to be cleaned can be damaged and roughened by the attacking tool, such as milling cutters, knives or brushes, which can lead to even faster and stronger contamination.
• the tools must be adapted to the respective geometry of the electrode, which is associated with a corresponding outlay.
• an object of the invention to provide a method for cleaning an electrode, in particular a cap that can be plugged onto the electrode, specifically for resistance spot welding, that enables effective cleaning without major interruption of the workflow of the welding device. It is also an object of the invention to provide an electrode and a cap by means of which the method can be carried out. In addition, it is an object of the invention to provide a device for resistance spot welding which is suitable for the method.
• a method which has the features mentioned in claim 1.
• the method is characterized in that a cold medium is applied to the electrode and / or the cap, the temperature difference between the cold medium and the functional parts to be cleaned being greater than 80 Kelvin and the temperature of the functional parts being above room temperature.
• the supply of cold medium through the electrode or through the cap does not lead to the feared embrittlement of these components, as well as further plastic parts or electronic components that may be acted upon.
• the existing supply devices for supplies for the welding machine can be used during the cleaning phase.
• the cold medium is fed from the current supply side of the electrode and / or laterally to it. Since in this embodiment a feed from the front, that is to say via the end face of the electrode or the cap, is avoided, the electrode can remain aligned in its welding position for cleaning, so that this results in a considerable time advantage compared to a front end feed of the medium.
• the temperature of the medium is less than 77 Kelvin. With these temperatures for the medium, a particularly effective and quick cleaning of the electrode or its cap can be carried out.
• the medium is a mixture that consists of a carrier medium and particles in the solid or liquid phase.
• the cleaning effect can be positively influenced in this way by the kinetic energy of the particles.
• Compressed air and / or carbon dioxide is advantageously used as the carrier medium, which is available almost everywhere in automated systems, in particular in the case of compressed air.
• dry ice, dry ice pellets and / or carbon dioxide snow is used as the medium or as particles of the mixture.
• the dry ice pellets or the carbon dioxide snow generate mechanical energy when they hit the surface to be cleaned, which additionally reinforces the cleaning effect.
• the medium is pressurized carbon dioxide in liquid form.
• the electrode has a supply device known per se for supplying a coolant, in particular in the region of the electrode tip.
• the supply device is designed for supplying cold medium according to claims 1 to 7.
• the cold medium is used to clean the electrode, in particular the tip of the electrode, since the electrode and the impurities adhering to the electrode experience a different material expansion due to their different material properties due to the rapid cooling (shock freezing), which means that the impurities occur a greater shrinkage than with the electrode, which leads to a detachment of the impurities.
• the electrode according to the invention now offers the advantage that cleaning can be carried out in a simple manner without structural changes to the electrode.
• the feed device leads cooling medium, for example cooling water, into the electrode or into the electrode tip.
• cooling medium for example cooling water
• the same feed device then leads into the electrode during a cleaning process instead of cooling medium, in particular the cold medium.
• the cold medium it is also possible for the cold medium to also cool the electrode during the welding process, so that the cooling medium or water can be dispensed with.
• a cap for attaching to an electrode used in resistance spot welding is further proposed according to claim 9.
• the cap is characterized by a supply device for supplying cold Medium according to claims 1 to 7 in the cap.
• the cap is cleaned, ie the contaminants adhering to the surface of the cap are detached.
• By feeding the cold medium into the cap it is of course also possible to detach contaminants on the surface of the electrode that is not covered by the cap — if there are any — from the electrode surface.
• the feed device is formed by at least one feed channel.
• the supply channel enables the cold medium to be fed into the cap in a targeted manner, so that an optimal supply of the cold medium to the cap can be ensured in this way.
• the feed channel can be designed as a through hole.
• the through-hole allows the electrode or the cap to pass through with the cold medium.
• the feed channel can also be designed as a blind hole.
• the blind hole is particularly useful when the cold medium is fed into the feed channel at intervals by pressure surges. Between the pressure surges, the cold medium lies essentially without pressure on the feed channel, so that there is a backflow of the previously supplied cold medium during the interval breaks. If the cold medium, in particular C0 2 , is fed to the feed device in the liquid phase, the pressure is released during the feed process and thus sublimation of the medium from liquid to CO 2 snow to gaseous. During the interval breaks, the now gaseous medium then flows back out of the feed device or the blind holes.
• the feed channel is arranged in such a way that the cold medium enters the cap laterally from the power supply side of the electrode.
• the power supply side is to be understood here as the side that extends over the central axis of the electrode or essentially over the central axis of the electrode.
• the cap according to the invention also has the advantage that it can also be used to cool the electrode tip during the welding process. It can be provided here that cooling water or another cooling medium is applied to the cap instead of the cold medium during the welding process and the cold medium is used in the cleaning case. Of course, it is also possible for the cap to use the cold medium for both cleaning and cooling the electrode during the welding process.
• a device for resistance welding is proposed to solve the problem.
• the device has an electrode according to the features of claim 8 or a non-coolant-guided electrode and optionally a cap placed on the electrode according to the features of claims 9 to 11 and a control device.
• the control device is operatively connected to the electrode and the cap. It is further provided that the control device is designed to control the supply and the shut-off for the cold medium according to the features of claims 1 to 7.
• the control device already present on the resistance spot welding device or the welding system is also used for the supply of the cold medium.
• FIG. 1 shows a possible embodiment of an electrode for resistance spot welding designed for the cleaning method according to the invention in longitudinal section
• Figure 2 shows a possible embodiment of a cap designed for the cleaning method according to the invention to be placed on an electrode with water cooling in longitudinal section and
• Figure 3 shows the cap of Figure 2, placed on an electrode without water cooling.
• FIG. 1 shows the end of an electrode 1 used for resistance spot welding, which faces the welding workpiece during welding.
• a cap 2 which is placed on the end of the electrode 1, is located centrally on the longitudinal axis of the electrode 1.
• the electrode 1 has a feed device 4 for feeding a coolant in the direction of the arrows 5.
• the coolant is used to cool the electrode 1, in particular the electrode tip, during the welding process. Cooling water is usually used as the coolant.
• the feed device leads the coolant via a cooling channel 6 into the end region 7 of the electrode 1. There it flows around this end region 7, is deflected in the direction of arrow 8 and flows back via return channels (not shown here), that is to say starting from the electrode tip backwards.
• the feed device is designed in such a way that a cold medium can be fed to clean welding spatter adhering to the electrode. This is done in a timed manner, in such a way that the cold medium during the Cleaning phase and the coolant are supplied during the welding operation.
• the cold medium is preferably liquid carbon dioxide or a phase mixture of carbon dioxide. The coldness of the medium is caused by the fact that the carbon dioxide relaxes when it emerges from a carbon dioxide bottle, as a result of which the evaporation cold that occurs cools the liquid carbon dioxide or phase mixture of carbon dioxide. Depending on the degree of relaxation and the evaporation cold that occurs, cooling down to below 210 Kelvin can be achieved, so that dry snow is formed.
• the cleaning of electrode 1 or cap 2 is based on so-called shock freezing, which leads to different degrees of shrinkage of electrode 1 or cap 2 and the adhering impurities, so that the latter can flake off or be blown off in a simple manner by means of compressed air.
• the embodiment shown in FIG. 2 differs from the embodiment in FIG. 1 in that here the cap 2 placed on the electrode 1 has a feed device 9 for feeding the cold medium, the feed into the cap 2 taking place.
• Feed device 9 is formed by a plurality of feed channels 10.
• the feed channels 10 are arranged at an angle ⁇ to the longitudinal axis 3 in such a way that the cold medium enters laterally from the longitudinal axis 3, which at the same time also forms the current supply side of the electrode.
• the angle ⁇ can be 10 degrees to 45 degrees; preferably it is 20 degrees.
• the feed channels 10 are arranged symmetrically over the circumference of the cap 2.
• the inlet part of the feed channels 2 is shown in FIG. 2.
• the cold medium enters the cap 2 via this part, specifically in a further part of the feed channels 10 (not shown in FIG. 2), via which the cold medium then in turn leads out of the cap 2 becomes.
• the entire supply of the cap 2 with cold medium takes place laterally from the cap 2.
• the end face of the cap 2 remains unchanged. Since the welding process is carried out over the cap 2, the cap 2 need not be removed from the electrode 1 for cleaning.
• the electrode 1 likewise has a feed device 4, as in FIG. 1, which supplies the electrode 1 with coolant during the welding process.
• the cleaning or the supply of the cold medium for cleaning is carried out via the cap 2 and the cooling of the electrode during the welding process via the feed device 4 independently of the feed device 9 of the cap 2.
• the feed device 4 of the electrode 1 - as described in FIG. 1 - is designed to feed the cold medium.
• the cold medium is fed into the cap and / or into the electrode 1.
• the electrode 1 is designed as an electrode without water cooling. In this embodiment, too, it is possible to loosen the impurities by supplying the cold medium to the cap 2 via the feed device 9. In any case, do not need separate, independent Cleaning devices for cleaning the electrode 1 or the cap 2 are provided.
• Electrode 5 - flow direction coolant 6 - cooling channel 7 - end region 8 - flow direction coolant 9 - supply device (cap)

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Resistance Welding (AREA)
• Manufacture Of Switches (AREA)
• Cleaning In General (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34967667

Family Applications (1)

Country Status (8)

Families Citing this family (4)

Family Cites Families (12)

• 2004
  • 2004-05-21 DE DE102004024979A patent/DE102004024979B3/de not_active Expired - Fee Related
• 2005
  • 2005-05-14 BR BRPI0510145-0A patent/BRPI0510145A/pt not_active Application Discontinuation
  • 2005-05-14 JP JP2007517061A patent/JP2007537884A/ja active Pending
  • 2005-05-14 CN CNA2005800160298A patent/CN1956815A/zh active Pending
  • 2005-05-14 US US11/596,774 patent/US20080257385A1/en not_active Abandoned
  • 2005-05-14 EP EP05742284A patent/EP1750889A1/de not_active Withdrawn
  • 2005-05-14 WO PCT/EP2005/005306 patent/WO2005113186A1/de active Application Filing
  • 2005-05-14 KR KR1020067023450A patent/KR20070030195A/ko not_active Application Discontinuation

Non-Patent Citations (1)

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