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Available Technology

Automotive, Manufacturing

Flow Drilling for Joining Stronger Materials

Inventors: Laine Mears, Brandt Ruszkiewicz, Jamie Skovron

Market Overview

This technology allows for the coupling of high strength and dissimilar materials, particular for lightweighting designs. An effort to reduce fuel consumption has led automakers to use new high strength materials and fastening methods, making these into $110 Billion dollar markets by 2021. Driven by regulatory standards, this push has led to increased use of flow drill screws (FDS) in one-sided joining processes. However, current methods are limited in use by material stackup stiffness, strength, and fasteners. Clemson University researchers have developed a technique that allows for the joining of stackups that cannot currently be joined by FDS, and can do so in a faster manner than current methods for common stackups.
Laine Mears
Brandt Ruszkiewicz
Jamie Skovron


Manufacturing, Automotive

Technical Summary:

FDS is a slow process compared to many other joining processes, and is limited by the 8Nm torque limit of the commonly used and lightweight M5 fastener. By applying electricity from the left to right ends of both sheets when two aluminum sheets are being joined, or from the bottom in an aluminum on steel stack, process time is reduced. Current is initially applied during the finding process, and ultimately leads to an 18% decrease in installation torque and a 32% reduction in process time due to a pre-process starting temperature of 128 °C. Not only does this process retain one-sided accessibility, but this addition of electricity allows the M5 fastener to penetrate a commonly used, stronger material such as Boron Steel, which it would otherwise fail to be able to.


  • Applied electric current creates ability to join thicker and stronger material stackups
  • Reduced process time and installation torque results in increased manufacturing efficiency
  • Existing machines in production lines can be modified for this technology now and when new materials emerge

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Technology Overview

State of Development

Validated Prototype

Patent Type



Automotive, Manufacturing

Serial Number


CURF Reference No.



Laine Mears, Brandt Ruszkiewicz, Jamie Skovron

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