July 27, 2023 - NewTek Sensor Solutions has designed a custom LVDT position sensor for resistance spot welding machines used in automotive plants to detect missing or misaligned parts in nut and stud welding. Cars contain hundreds of welded nuts and studs that hold them together. Properly securing the right nut and stud to different car components is critical to safe operations. Working in conjunction with the resistance weld control equipment, the NewTek custom LVDT detects and reports different conditions including: weld pin extended position, double part, misloaded part, incomplete weld, weld pin retraction, upside down nut, wrong or missing part. Based on programmed system spec limits, the position sensor will trigger a go/no go response with each pass.
Designed to fit inside the weld body of the machine, the AC-operated LVDT sensor has a very high stroke length ratio and excellent repeatability that is critical to the application. Remote signal conditioning allows the LVDT to fit inside the small space while being resilient to high levels of shock. With extremely high measurement resolution of ~0.0009” (0.02mm), the position sensor detects minute changes in process conditions.
As is fundamental with all LVDTs, the sensor has no contact between its core and coil structure so parts do not rub together or wear life for longer mechanical life. The linear variable displacement transformer also has internal magnetic shielding that reduces effects of AC or DC fields. NewTek possess the inhouse engineering and domestic manufacturing capabilities to design and build customized AC- and DC-operated LVDT Position Sensors that may include radiation and submersion resistance, higher temperature exposures, ratiometric output, high stroke-to-length ratios and specific electrical output requirements. Sensors can be constructed ceramic and special core materials, with alloys such as Monel, Inconel, Hastelloy and Titanium used in the sensor body.
