PTH PCB Repair – Choosing an Eyelet

Printed Through Hole (PTH) technology is one of the mounting or assembly techniques used in the Printed Circuit Board (PCB) industry. Just as the design and manufacturing of a through hole PCB is detailed, so is the repair of such as PCB. Many small-sized damaged components are replaced in the repair process. However, one component requires more attention than the others – the PCB eyelet.

What are PCB Eyelets?

Eyelets are small ring or tube like components. In PTH circuit boards, they are placed in drilled clearance holes to repair damaged through hole connections. When it comes to PCB eyelet repair, a specialized eyelet press is used to set the new component into the circuit board.

How to Select an Eyelet

Eyelets come in different specifications. Hence, it is important that you find the right component for the damaged through hole. Here are some points you need to keep in mind when choosing an eyelet.

  • Inside Diameter (ID): The inside diameter of the eyelet should range from 0.075 to 0.500 mm (0.003ʺ to 0.020ʺ). The ID needs to be larger than the diameter of the component lead.
  • Outside Diameter (OD): The OD of the eyelet has to be interfaced with the clearance hole drilled through the circuit board. The clearance should allow the eyelet to be inserted without force. However, it should not measure .125 mm (.005″) more than the OD of the eyelet.
  • Flange Diameter (FD): Eyelets are designed with flanges to help secure new circuits. The flange diameter of the eyelet should be small enough to ensure that it does not interfere with adjacent circuits or lands.
  • Length under Flange (LUF): The length under the eyelet flange should range from 0.63 to 0.890 mm (0.025ʺ to 0.035ʺ). Its length should exceed the thickness of the circuit board.

A Final Point

Ensure that the eyelet meets the required specifications. If the flange is oversized, then it can interfere with adjoining circuits. If the eyelet is too short, then it will protrude out of the circuit board. Due to this, the setting procedure won’t be performed properly.

These are the points that can help you to find the right eyelet for the repair process. In the next post, we shall discuss the remaining steps in PCB eyelet repair. For more information about PCB eyelet, please visit http://www.acceleratedassemblies.com/ or contact the company at (630) 616-6680.