Lowering costs is essential to the successful and profitable adoption of New Energy Vehicles/Electric Vehicle(EVs). Many consumers view the current offerings as too expensive relative to the utility they will derive from the products. While early adopters are already on board, as can be seen on Interstate 101 or 280 in the San Francisco Bay Area, EVs still represent a tiny fraction of overall new car sales. For most manufacturers this is arguably a good situation, as they have yet to get the cost structure to a point where the consumer price and the manufacturer’s margins are both attractive.
Since Henry Ford introduced the moving assembly line in 1913, the automotive industry and other industries have been ceaselessly trying to improve quality, accelerate production and lower cost. In the late 1950’s and early 1960’s a big thrust of this effort was to simplify and reduce the cost of assembly. A solution that came out of this era was the original TAPTITE® thread-forming fastener, a screw that could tap its own threads in untapped pilot holes or unthreaded nut members and provide a high-quality joint that is resistant to pull-out and vibrational loosening forces.
Conventional Machine Screw Process
TAPTITE® Thread-forming Process
This led to the adoption of TAPTITE® thread-forming fasteners by Ford in the 1964½ Mustang and by a company that later became part of AT&T (Western Electric) for affixing telecommunications equipment. Today, 50+ years later, the newest versions of TAPTITE® thread-forming fasteners, TAPTITE PRO® fasteners, are incorporated into Ford’s fastening standards as a general use and grounding thread-forming fasteners. AT&T still specifies TAPTITE® thread-forming fasteners in their Grounding and Bonding Requirements for Network Facilities specification to provide reliable quality at a compelling cost.
Leading global automotive OEMs including but not limited to BMW, Daimler, Peugeot, Renault, Hyundai, GM, FCA, Geely, Volvo, Jaguar Land Rover, and many other emerging electric vehicle manufacturers use TAPTITE® thread-forming fasteners for general use and grounding applications. Every year TAPTITE® thread-forming fasteners and POWERLOK® thread-locking fasteners are used globally by the billions across a multitude of industries.
Given the importance of the nascent EV industry to automotive manufacturers and tier suppliers, we engaged an independent lab to validate that both TAPTITE PRO® thread-forming fasteners and POWERLOK® II™ thread-locking fasteners provide exceptional grounding performance.
The testing was performed by Element Materials Technology in Warren, MI, an A2LA certified independent testing lab. The testing performed was as prescribed by SAE International in the Test Procedure for Electrical Ground Attachment specification also known as SAE/USCAR-26.
The test steps include voltage drop, thermal shock, random vibration, temperature/humidity, salt fog testing and a second voltage drop test.
The acceptance criteria are as follows:
- The maximum voltage drop recorded cannot exceed 1 mV per amp.
- The change in voltage drop from beginning to end of all conditioning procedures shall not exceed 0.5mV per amp.
- Samples shall not exhibit heavy corrosion that could result in mechanical or electrical failure.
- Sample groups shall conform to the statistical requirements, in summary 20 samples required, and multiple test cycles performed.
TAPTITE PRO® Samples Mounted to Text Fixture (Pretest)
The test compared the performance of 20 TAPTITE PRO® thread-forming fasteners in untapped steel weld nuts, 20 POWERLOK® II™ thread-locking fasteners in tapped weld nuts and 18 machine screws in tapped weld nuts. All nuts were E-coated, consistent with common automotive practices. Two of the terminals for machine screws were damaged during setup and not counted in the results.
The key takeaways are that TAPTITE PRO® thread-forming fasteners and POWERLOK® II™ thread-locking fasteners yielded 60% less voltage drop with 80% more consistency than conventional machine screws. This low voltage drop with low variability is important for grounding applications across industries.
Voltage Drop Test Data
Note that not only does this approach provide consistent grounding performance, it also reduces cost and weight. In transportation applications this translates into vehicle range and fuel efficiency, alongside margin improvement and/or pricing flexibility. There is also a reduced carbon footprint associated with this approach because these fasteners eliminate parts, processes and associated overhead as well as the energy required to produce, ship, process and install these extra and less performant solutions.
The value proposition for TAPTITE PRO® fasteners is easily understood as explained above. POWERLOK® II™ thread-locking fasteners also offer a compelling value proposition as these fasteners eliminate the need for additional physical locking features such as lock washers, lock nuts and/ or chemical locking features such as adhesives and patches.
TAPTITE PRO® thread-forming fasteners and POWERLOK® II™ thread-locking fasteners both help to streamline the assembly process, simplify procurement, eliminate expensive parts and provide improved resistance to vibrational loosening compared to existing alternative approaches. This is on top of the excellent grounding performance proven in the Element testing.
If you or your colleagues are in the process of designing products that need to be assembled, particularly those where grounding is critical, TAPTITE PRO® thread-forming fasteners and POWERLOK® II™ thread-locking fasteners should be part of your design playbook.
For a copy of the complete report, please contact us at firstname.lastname@example.org.
i. FORD WORLDWIDE FASTENER STANDARD WD 957 2018 12 17 - MECHANICAL AND PERFORMANCE REQUIREMENTS OF (090) THREAD ROLLING SCREWS
WITH INDUCTION HARDENED POINTS FOR USE AS GROUNDING SCREWS OR GENERAL USE
ii. AT&T-TP-76416 ISSUE 5.1. NOVEMBER 2015 - GROUNDING AND BONDING REQUIREMENTS FOR NETWORK FACILITIES
REPORT NUMBER: EWA106759P
27485 George Merrelli Drive
Warren, MI 48092
P: 586 754 9000