Laser transmission welding selected for TPMS sensors

“With innovative manufacturing processes optimally combining quality and quantity, we will continue to satisfy the world’s appetite for the corresponding sensors in the future,” confirmed Markus Schmid, Head of Marketing, Global Aftermarket. Production methods such as ‘laser transmission welding’ for plastic components in TPMS sensors play a part in this. With the globally active German company LPKF Laser & Electronics, headquartered in Garbsen, Germany, the suitable partner for production machines might just have been found. LPKF WeldingQuipment is a Fuerth, Germany-based subsidiary of LPKF Group with a specialisation in welding technology.

The company is up with the best in the world in terms of laser micromaterial processing technology and is the market leader in the manufacturing of laser welding systems. Sensata subsidiary Schrader mainly joins PA6 or PA6.6 polyamides in a laser welding process, for example, in the OE sensors Faraday, Gen Gamma, and the HSSI product line. On the machine side, the InlineWeld 6600 laser welding system developed by LPKF is employed. The high-power diode laser used in the system has a working wavelength of 980nm and a power output of 50–300W. This allows maximum strength and tightness – both crucial factors for air components – to be achieved. The joints meet the requirements for an IP67 rating, as do many high-end dustproof and waterproof smartphones. Other advantages of the process include welding with no surface marking and no mechanical loading of the joining partners. In addition, there is no damage to delicate components in the vicinity of the beam due to the precisely focused heat output.

Despite the high manufacturing quality, the process is extremely rapid and excellently suited to mass production. The InlineWeld 6600 enables quasi-simultaneous processing of two components, slashing cycle times and allowing for a welding time of a mere two seconds per unit. Schrader’s parent company, Sensata, employs 26 integrated laser welding systems, on which around 40 million parts have been manufactured up to now.

“The great flexibility and diversity of the laser transmission process give LPKF numerous possibilities for growth, not just in the automotive industry but also in the medical products and consumer goods industries. In China – one of the most important markets for our machines – we are optimally equipped with a broad setup and a local team,” added Georg Heissen, LPKF Sales Manager for Asia.

The global conquest of tire pressure monitoring systems began ten years ago in the US, when installation of the systems in new vehicles became mandatory. Europe followed in November 2014, and now even South Korean legislators are requiring the systems. China, by now the world’s largest auto market, will presumably be next. The technical standards were already put into place in the country in 2011. However, the corresponding sanctions are still missing, which is the reason why only the top vehicle classes are currently being equipped with tire pressure monitoring systems there. Until more penetration occurs for new vehicles, Schrader will continue furthering the democratisation of TPMSes. Thus, the company now offers three practical retrofitting kits in OE quality especially for China. Of course, laser welding systems 'Made in Germany' are also used in these sensors.