The wire feeding system is mainly composed of wire feeding mechanism (including motor, reducer straightening wheel, wire feeding wheel), wire feeding hose, welding wire reel and so on.
Uniform and stable wire feeding speed
Convenient and flexible speed regulation
The wire feeding structure is firm, light and reliable
According to different wire feeding methods, the wire feeding system can be divided into four types: push wire type, wire draw type, push pull type and planetary type, as shown in Figure Schematic diagram of wire feeding method and Figure Working diagram of three-wheel planetary wire feeding mechanism.
The wire-pushing type is one of the most widely used wire feeding methods for semi-automatic MIGA welding. The structure of the welding torch of this wire feeding method is simple and light, and the operation and maintenance are relatively convenient.
However, the resistance to feeding the welding wire is relatively large. If the wire feeding hose is too long, the stability of wire feeding will deteriorate. Generally, the length of the wire feeding hose is 3 to 5 m.
The wire drawing type can be divided into three forms: one is to separate the welding wire reel from the welding torch, and the two are connected by a wire feeding hose; the other is to install the welding wire reel directly on the welding torch, both of which are suitable for semi-automatic Welding; there is another kind that not only separates the wire reel from the welding torch, but also separates the wire feeding motor from the welding torch. This wire feeding method can be used for automatic MIGA welding.
The push-pull wire feeding hose can be extended to about 15m, which expands the operating distance of semi-automatic welding. The advance of the welding wire depends on both the thrust from the back and the pull from the front. The combined force of these two forces is used to overcome the resistance of the welding wire in the hose. During wire feeding, always keep the welding wire straightened in the hose. This wire feeding method is often used in semi-automatic MIGA welding.
The three-wheel planetary wire feeding mechanism is shown in Figure Working diagram of three-wheel planetary wire feeding mechanism, which is designed by using the principle that the axially fixed rotating nut can axially push the screw. Three mutually 120° rollers are installed on the block base crosswise to form a driving disc. This drive plate is equivalent to a nut, which is a key part of the planetary wire feeding mechanism, and the welding wire passing through the middle of the three rollers is equivalent to a screw. The driving disc is driven by a small electric motor, and the main shaft of the electric motor is required to be hollow. After the drive plate is mounted on one or both ends of the motor, a planetary wire feeding mechanism unit is formed.
When the wire feeding mechanism is working, the welding wire enters from the drive plate at one end, passes through the hollow shaft of the motor, and is sent out from the drive plate at the other end. There is a preset helix angle between the three rollers on the drive disc and the welding wire. When the main shaft of the motor drives the drive disc to rotate, the three rollers apply an axial thrust to the welding wire to push the welding wire forward. During the wire feeding process, the three rollers revolve around the welding wire on the one hand, and propel themselves around their own axes on the other hand. The wire feeding speed can be adjusted by adjusting the motor speed.
According to the surface shape and structure of the wire feed wheel, the push wire feed mechanism can be divided into two categories:
There is a V-shaped groove cut on the wire feed roller, and the wire is fed by the friction force of the two side contact points between the welding wire and the V-shaped groove, as shown in Figure Flat wheel V-groove wire feeding mechanism. Due to the small friction force, the wire feeding speed is not stable enough. When the clamping force of the wire feed roller is too large, the welding wire is easily clamped and flattened, or even straight edges are pressed out, which will aggravate the wear of the inner hole of the welding wire nozzle. At present, most wire feeding mechanisms adopt this wire feeding method.
The specially designed hyperbolic wire feed roll (Fig.wire feeding) keeps the welding wire in line contact with the wire feed roll. The wire feed friction is large, the speed is uniform, the wire feed distance is large, the wire has no indentation, and the wire can be straightened. It has derusting effect on the welding wire with slight rust spots, and the wire feeding mechanism is simple and reliable in performance, but the design and manufacture of the hyperbolic wire feeding wheel are troublesome.