The printed circuit board design shall consider the aperture size of the welding disc

0.5mm larger than the maximum diameter of the small hole flange of the welding terminal.

The disc is designed to achieve the minimum diameter, which is at least 0.5mm larger than the maximum diameter of the small hole flange of the welding terminal.Test pads must be provided for all nodes as per ANSI / IPC 2221 requirements.A node is an electrical connection point between two or more components.A test pad requires a signal name (node signal name), the x-y axis associated with the reference point of the printed circuit board, and the coordinate position of the test pad (indicating which side of the test pad is on the printed circuit board).Information on the fixtures needs to be provided for the SMT and printing the circuit board assembly layout to facilitate testability in the circuit with the help of "the circuit test fixtures" or commonly known as "nail fixtures". To achieve this end, the need to:

1) The diameter of the test pad specially for detection shall be no less than 0.9mm.

2) Space around the test disc shall be greater than 0.6mm and less than 5mm.If the height of the component is greater than 6. 7mm, the test pad shall be placed beyond 5mm.

3) Do not place any components or test pads within 3mm of the edge of the printed circuit board.

4) The test pad shall be placed in the center of 2.5mm holes in a grid.The use of standard probes and a more reliable fixture was allowed, if possible.

5) Do not rely on the edges of the connector pointer for disc testing.The test probe can easily damage the gilt pointer.

6) Avoid plating holes-exploration on both sides of the printed circuit board.Place the test tip through the hole on the non-component / welding surface of the printed circuit board.