HF/Heat Welding Machines – regardless of their type – perfectly meet the needs of the industrial and production market or smaller requirements, e.g. in the commercial sales sector. The quick connection of the given elements – from metal to foil – ensures long-lasting and durable parts or materials.

The welding technology comes down to a permanent connection of given elements and structures using temperature. Metal and plastic elements are a natural area of ​​use. With the use of machines and tools profiled in this respect, they ensure permanent connection by transforming the plastic state of a given object. After reaching this stage, the welding machines – by pressing the elements together – connect them together in order to achieve the effect of elasticity at the point where two surfaces meet. Welding machines, thanks to the variety of technology used, can be perfectly adapted to the implementation of any given project.

Types of welding: from induction to friction

Although welding machines are commonly perceived through the prism of heat, the technology is much broader. It includes electric resistance welding with the use of a hot plate or heated air, as well as induction and spark solutions. Among the types of welding, there are also methods:

• diffusive,
• focal lengths,
• current – using high frequency,
• frictional; including the usage of sealing material,
• ultrasonic,
• explosive,
• vibrating,
• short-circuit compression.

The variety of solutions allows for free adaptation of the welding technology to specific needs. Nevertheless, HF/heat welding machines can be considered as tools necessary for the connection process using:

• heat sources,
• pressure forces,
• heating parent material to the softening state.

On this basis, welding – as well as welding machines – can be divided into solutions such as:

• resistance,
• friction,
• ultrasonic,
• diffusive,
• explosive,
• flame.

Types of welding machines and methods of heat treatment

Due to possibilities of use, three types of welding machines dominate the market.

High frequency welders

Dielectric devices – also known as capacitive or high frequency welders – consist of power units, high frequency generator unit, matching system, and working electrodes. The energy supplying the high frequency welder is converted by the first unit; in the second stage, the high-frequency generator produces energy with parameters – most often – 27.12 MHz. It ensures effective welding of plastics. The specificity of operation makes high-frequency welding machines perfect, e.g. in the plastics processing industry. The variety of possibilities increase with the optimization of the heating process itself – incl. in terms of adapting this method to new materials.

Impulse welders

Devices operating on the principle of an electromagnetic impulse are most often portable, more mobile and adapted to welding, e.g. foil. The operating time is signaled by a diode, which is located on the transformer. It informs the user about the operating status of the welding machine – it indicates the time when the clamped jaws of the device can be opened, which generates an impulse for joining two layers. Impulse welders with adjustable welding time are suitable for closing foil bags or other machinery actions that require similar air flow restrictions. In addition, the device may be equipped with an additional and covered mechanism that ensures the cutting of excess foil.

Heat sealers

Industrial devices enabling fast and hermetic closing of the packaging. As a result, these solutions are recommended for connecting thick foil – including aluminum foil. Constant heat welding – also referred to as resistance or hot electrode welding – is performed with the use of table, hand, jaw and rotary devices. Usually, the process consists of pressing the given elements with a heated strip to a cooler substrate or squeezing the surfaces between two previously heated strips.

As a result, for the effectiveness of resistance welding, the point of contact is crucial – the gap, due to the resistance of the current, is significantly heated. At the moment when the contact temperature changes the state of the metal into a more plastic one, an appropriate connection is obtained with pressure. An important feature of such solution is also the precision and accuracy of the process.

What to pay attention to when using welding machines

During planning the fusion of any given elements – regardless of the chosen method – one should pay attention to the factors determining the quality of the connections. This includes cross-sectional forces that occur in connected elements or analysis of cross-sectional durability of connected parts. The concentration of stresses or the behavior of the material as a result of increasing load are also important. Heaters should also be selected taking into consideration pliability of the connection which may occur during standard utilization.