GB2297817A

GB2297817A - Removing spatter from welding torches using a vibrating tool

Info

Publication number: GB2297817A
Application number: GB9502403A
Authority: GB
Inventors: Gordon Thomas Dyos
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-02-08
Filing date: 1995-02-08
Publication date: 1996-08-14
Also published as: GB9502403D0

Abstract

A reamer 1 which is vibrated magnetically or mechanically and whose position can be controlled either magnetically or mechanically. The reamer 1 may be hollow and attached to a hollow ferromagnetic tube 2 which is surrounded by a solenoid 4 to which an alternating current is applied. A second solenoid (10, Fig.2) may be used to position the reamer. The vibrating reamer may be used to remove spatter from the inside or outside of the nozzle of a welding torch nozzle 14 as typically used in by robotic assembly production lines.

Description

WELDING TORCH NOZZL REAMER This invention relates to a vibrating reamer for a welding torch.

As is well known in the welding industry the nozzles of welding torches become contaminated with spatter as they are being used. The spatter disturbs and restricts the shielding gas flow allowing impurities to enter the weld puddle. This results in a poor quality weld giving rise to lost production time due to rework and possible equipment damage, particularly when the welding is being done on by a robotic unit on a production line.

Nozzle cleaning reamers are used in production lines to remove spatter build up on the inside of robotic welding torch nozzles. The majority of automatic reamers involve the robot welder placing its welding torch in a holding chuck and a rotating cutter then moves up the inside of the torch nozzle and removes the spatter. The disadvantage of this system is that if the nozzle is not aligned concentrically with the cutter, possibly because a piece of spatter is underneath one of the jaws of the chuck, or loss of the tool centre point occurs, then the cutter removes part of the nozzle wall. This then produces thermal distortion in the nozzle leading to rapid welding torch failure. The commercially available reamer systems are complex in that they involve pneumatics, motors, electrical circuitry and many moving mechanical components.

An objective of this invention is to produce a reamer whereby the complex pneumatic, electrical and mechanical system of present systems is replaced by a single moving component controlled by one or two magnetic fields.

According to a first aspect of the invention there is provided a method of causing vibrations to be introduced magnetically into a ferromagnetic tube attached to a hollow reamer for the purpose of shearing the spatter from the inside wall of the welding nozzle. This magnetic vibration is the property that when a ferromagnetic material is magnetised, or if its magnetisation is changed, a change in the physical dimensions of the material occurs. This change in dimension which affects both the length and cross-sectional area of the material is caused by the magnetic domains in the material aligning themselves with the applied magnetic field.Thus the application of an alternating current to a coil surrounding a magnetic bar will cause the magnetic bar to change length at twice the frequency of the applied magnetic field, as the domains will oscillate twice for each complete cycle of the applied magnetic field. This system is used commercially as a transducer to produce ultrasonic waves below 25 khz.

According to a second aspect of the invention there is provided a second magnetic field acting on a lower part of the ferromagnetic tube which causes the said tube to move vertically, both upwards and downwards in a controlled fashion by varying the current to the magnetic coil.

According to a third part of the invention the loose spatter falls down the centre ofthe hollow ferromagnetic tube and is collected in a waste collector for later disposal.

The optimum system design may be determined through mathematical, computer or experimental modelling so that the device materials and type of controlling means employed may be suitably selected to give the optimum operating conditions.

This invention allows the use of an alternating magnetic field to vibrate a ferromagnetic tube and a constant magnetic field, whose strength can be controlled, to both act upon the same ferromagnetic tube and produce a vibrating rod whose position can be controlled. The purpose of which is to move the vibrating reamer head in a controlled fashion inside the welding nozzle for the purposes of shearing and removing the splatter in a controlled fashion.

The present invention will now be described further, by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic cross-section of the basic design of the vibrating reamer and Figure 2 is a schematic of a magnetically movable reamer and Figure 3 is a schematic of the vibrating reamer inside a MIG welding nozzle.

Referring to Figure 1, a hardened hollow reamer 1 is attached to a hollow ferromagnetic tube 2. The tube 2 is secured to the outer casing 5 by typically a threaded portion 8. Surrounding the tube 2 is a former 3 upon which is wound a solenoid 4, the solenoid 4 is held in place by the tapered cap piece 6 secured by screws 7.

Figure 2 illustrates a further development whereby the tube 2 is extended through the body 5 of the vibrating solenoid to the lower case 13 housing the solenoid 10. A restoring spring 11 is housed in the upper housing 6 and acts upon the tube 2. Thus when a ramp waveform direct current is applied to the solenoid 10 it causes the tube 2 and reamer 1 to be moved vertically upwards in a controlled manner whilst still being vibrated by the solenoid 3.

By adding a second magnetic module it is now possible to move the ferromagnetic rod vertically by feeding this coil with a ramp current waveform, as illustrated in Figure 3. Thus the depth and speed of penetration of the cutter into the nozzle can be controlled by the voltage and time of the ramp applied to the lower solenoid.

Figure 3 illustrates the application of a single vibrating reamer unit inside the nozzle 14. In this case the robotic arm holding the welding torch is guided onto the reamer and lowers itself, in a controlled manner, onto the reamer. Also the hollow diameter of the reamer can be greater than the diameter of the electrode 15 so allowing the electrode to pass into the reamer centre if desired.

This system is simpler than existing devices, has only one moving component, no rotating cutter, is simple to control and would be much easier to manufacture and cheaper than commercially available robotic nozzle reamers.

Thus it will be appreciated that the present invention is not intended to be restricted to the above described embodiment which is described by way of example only.

Claims

1 A reamer which is vibrated either magnetically or by some other means to remove the spatter from the inside or outside of the nozzle of a welding torch.

2 A magnetically or mechanically controlled means of causing the vibrating reamer as claimed in Claim 1 to move in a controlled manner into the inside and/or outside of the nozzle.

3 A combination of magnetically or mechanically controlled vibrating reamer and a method of moving the reamer in a controlled manner as claimed in Claim 1 and Claim 2.

4 A hollow vibrating reamer, as claimed in Claim 2 or Claim 3 so as to enable the spatter to be removed from the area of the nozzle in a safe and collectible manner.

5 A vibrating reamer substantially as described herein with reference to Figures 1 - 3 of the accompanying drawing.