Innovative Sheet Metal Fasteners

Flow Drill Screws, Flow Form Screws

FDS® screws from EJOT and FFS® screws from Arnold have been around for a while.  They offer the benefits of a secure and strong joint from one side between two sheet metals.  A big advantage is that they can join dissimilar materials like aluminium, steel and plastics where spot welding is not possible (they are finding more and more applications in the automotive industry where aluminium and other materials need to be joined).  They also allow the use of thinner sheets without the use of additional hardware to strengthen the joints (this is making them more popular in the whitegoods industries).

The screws form a hole by high pressure and the speed of the screw, the heated material is then threaded and cools around the screw.  The joint is strong, and the unscrewing torque is high.  The thread formed is upto 3 times thicker than the sheet metal.

1. Heating the metal with high end load and high speed screwdriver
2. Penetrating the material
3. Forming of the hole
4. Forming of the screw thread
5. Engagement of the threads
6. Final tightening into the cool thread

Advantages for joining sheet metal:

• No swarf or chips
• Stronger joint, higher screw torque possible
• Higher torque means a larger torque window and less chance of stripping
• Screws can be replaced with standard metric screws
• No additional hardware required to strengthen the joint
• High unscrewing torque and vibration resistance
• Possibility of joining thinner materials
• Possibility to join Aluminium
• Can be accessed from one side
• Possibility to join sheets without pre-drilling (in automated applications)