Vibration welding linear

There are two types of vibration welding Unear and axial. Linear vibration welding is most commonly used. Friction is generated by a linear, back and forth motion. Axial or orbital vibration welding allows irregularly shaped plastic parts to be vibration welded. In axial welding one component is clamped to a stationary structure the other component is vibrated with orbital motion. 

Joining of plastic pipes is shown to be done more effectively, economically and in a much shorter time on-site by linear vibration welding , rather than the conventional hot plate welding or electrofusion welding techniques. 

Figure 26.30 In linear vibration welding (left) the top part moves back and forth in a line, while in orbital vibration welding (right) every point on the moving part forms a small orbit around a fixed point on the stationary part.

In linear vibration welding, the surfaces to be joined are rubbed together in an oscillating, linear motion under pressure applied at a 90° angle to the vibration. Process parameters are the amplitude and frequency of this motion (weld amplitude and weld frequency), weld pressure, and weld time, all of which affect the strength of the resulting weld (Fig. 14.28). 

Figure 14.28 Linear vibration welding. Part surfaces are rubbed together in a longitudinal direction, along the z axis, generating heat through friction. Processing parameters are the weld amplitude, a, the weld frequency, n, the weld pressure, p, and weld time, f. Pressure is applied along the y axis, 90° to the vibration.

For linear vibration welding the two components are pressed together with a pressure of 0.5-14 MPa oscillated at a frequency of 100-500 Hz (120 and 240 Hz are industry standard freqnencies) and an amplitude of 0.5-5.0 mm for a times of the order of 10 s. The welding process is described as four stages ... 

Another variant of the friction welding process, linear friction welding, uses servo-hydrauHcs pumps to vibrate parts back and forth against each other. Bond areas of approximately 1000 mm can be joined the attachment of turbine blades to rotors is a prevalent apphcation of this technology. 

There are many different, cost-effective welding methods suitable for industrial mass production of plastics engineering components including ultrasonic, laser, spin, hot plate, linear and orbital vibration welding. Here we will deal with inexpensive manual methods for low quantities which can be carried out in small workshops or on site. 

The process parameters affecting the strength of the resulting weld are the amphtude and frequency of motion, weld pressure, and weld time. There are two types of vibration welding linear, in which friction is generated by a linear motion of the parts, and orbital, in which one part is vibrated using circular motion in all directions. Examples of these processes are illustrated in Figure 7.26. 

FIGURE 7.26 The vibration welding process. Linear vibration (left) is employed where the length to width ratio precludes the use of axial welding (right) where the axial shift is still within the width of the welded edge. 

However, the same mechanical techniques at the interface of two solid wood surfaces in the absence of any thermoplastic material, or any other binder, yields joints of considerable strength. " The equipment used for the mechanical vibration welding of wood in the absence of an adhesive is the same type of equipment as used for frictional welding of metals. Figure 1 shows the characteristic linear vibrational movement of the type of industrial metal welding machine used, as well as the frictional shift and force applied to the two pieces of wood during welding. 

Figure V.4 Linear and axial vibration welding of a two-part container. (Ref Scherer, R., Vibration Welding Could Make the Impossible Design Possible , Plastics World, September 1976)...

In spin or vibrational welding, heating is achieved by rubbing the two surfaces together at a sufficiently high speed to melt the polymer by friction. Spin welding is suitable for circular objects, whereas vibrational welding can be achieved by either circular or linear motion. Total cycle times are of the order... 

Figure 8.12 Linear and axial vibration welding of a two-part container. ...

Most equipment used in vibration welding produces linear vibratory motion. Equipment is elassified as low-frequency (120 to 135 Hz) or high-frequency (180 to 260 Hz) and can be variable frequency or fixed frequency. Variable-frequency equipment is electrically driven, and a dial adjustment is used to tune the frequency to match the part mass. 

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