Humans have been welding since the Bronze Age with evidence seen by ancient Egyptians who welded bronze, and later iron in the Iron Age, who made everything from cooking pots to weapons. This took a lot of physical strength because their welding technique meant hammering two pieces of metal together under heat until they joined. Fast forward to the 1800s, and welding as we know it came to be, meaning using an electrical arc to fuse metal together, which made the welding process significantly easier. But what about plastic welding? You might be surprised to learn that the birth of plastic welding machines was due to a combination of a shortage of metal resources and a discovery by German chemists right before World War II.
The 1930s
The first record of plastic welding was in pre-WWII Germany when a shortage of non-ferrous metals (metals with no significant amount of iron that are more malleable) pushed Hitler’s chemists to find a substitute material. Polyvinyl chloride (PVC) production increased significantly in the 1930s, and it didn’t take long before researchers realized that PVC could easily be moulded and heat-formed to create multiple configurations and that it could be welded in very similar ways as metal. The birth of plastic welding had begun but was initially only used by Germany during WWII. During this time, the plastic welding machines were mostly in the form of fuel convection ovens, which were very basic. Infrared heating (IR) began being used at the start of WWII when it became clear that it was the fastest way to work with plastics, although the process was much more expensive. After the war, IR welding decreased, but in the 1990s IR welding became more popular thanks to a price decrease in the equipment used for IR plastic welding machines.
The 1950s
In 1956, the Soviet Union took the next step in the development of plastic welding machines with their experiments in friction welding (heat generated through mechanical friction), which is still being used today. American companies soon after realized the potential of friction welding, and some big name companies in welding and manufacturing started building their own friction-based plastic welding machines, and patents started to pour in from across the US and Europe.
The 1960s
Ultrasonic welding (heat generated from high-frequency mechanical motion) was the next big shift in plastic welding machines when hard plastics could be welded together using a more reliable, consistent, and repeatable method. In 1965, Robert Soloff, an American lab manager, accidentally made the discovery of ultrasonic welding when he unknowingly moved an ultrasonic probe close to a plastic dispenser and the joint of the dispenser welded together. This discovery revolutionized the plastic welding industry because excessive heat was no longer the only option to meld plastics. Prior to ultrasonic plastic welding machines, items that were welded were heavy and unwieldy. But with this new form of plastic welding, much lighter items were now able to be welded, such as toys which happened to be the first industry to take advantage of ultrasonic welding.
The 1970s and 1980s
In the 1970s, Leister (a manufacturer of hot air plastic welding equipment) launched two new plastic welding machines for roofing. The first to be launched was the Varius, which was an overlap welding machine that had a 40 mm nozzle and significant temperature adjustment, and it varied its welding speed along the seam. Six years later, Leister launched a more compact and lightweight overlap welding machine called the Variant. In the 1980s, Leister created a welding machine, called the Universal, for roofing, which had adjustable speeds and temperature, and the air volume could be adjusted in just two steps.
In 1986, Packweld (a plastic welding machine manufacturer in India) developed a new feature in the world of plastic welding machines. A plastic welding and creasing machine was created, which gave a huge boost to stationery manufacturers. The special kind of plastic welding machine creates lines on plastic sheets in order to be folded and formed in a variety of ways.
The First Decade of the 2000s
Leister continued to be a leader in plastic welding machines, especially with machines for roofing. In 2003, the Varimat V was a big breakthrough because of its patented pendular pressure roller that welded membranes together directly after melting. In addition to the speed and temperature being adjustable, the Varimat V could measure current voltage, which was valuable in areas where the electricity grid wasn’t stable, and warned the welder if there wasn’t enough voltage. Six years later, the Varimat V2 was created, and it was the first welding machine with a large display and e-drive functionality, and it had twice the welding performance of its predecessor.
Present Day – Laser Welding
Laser welding has become one of the more popular means of welding plastic. Due to the technical advantages of laser plastic welding machines, including producing superior weld joints in many applications and the drop-in equipment costs, more and more manufacturers are considering laser welding as a viable plastic welding option.
Plastic welding machines have come a long way since their inception. As technology evolves and equipment costs drop, plastic welding machines of all kinds are becoming easier and more convenient to use and are more popular than ever.