With HF induction welding, the induction coils must be located ahead of the tube mill's squeeze-roll assembly.
Although HF induction welding yields the highest stainless welding speeds at the lowest cost per unit length, cold-forming scrap rates can run as high as 20 percent.
This assures an intimate fit-up accompanied by a flow of shielding gas, unlike the lack of shielding, exposure to oxygen and coolant, and gapped edges with HF induction welding.
In induction welding, induction heating of a gasket, made of a ferromagnetic-powder-filled bonding material, placed at the interface of thermoplastic parts to be joined, is used to melt the interface; subsequent solidification of the melt results in a weld.
5 MHz electromagnetic field is used, while induction welding of thermoplastics uses higher frequencies in the 3-14 MHz range.
In principle, any thermoplastic can be welded by the induction welding process.
PhedCorp designed an in-line assembly and testing machine that would receive cap blanks from a centrifugal bowl feeder, load them onto conveyor pallets in pairs, threaded-end-down, then advance the pallets through a sequence of stations including a leak-testing station positioned immediately after induction welding
Historically, the electronic interference or "noise" that permeates industrial environments has hampered the development of reliable in-process weld-sensing controls for electromagnetic induction welding, according to Steve Chookazian, business manager of the Emabond Systems Business of Ashland Chemical.
In his view, electromagnetic induction welding overcomes those barriers by placing a thermoplastic compound filled with particles of a metal "susceptor" at the weld interface and subjecting it to a high-frequency magnetic field.