pcb design considerations

- Aug 10, 2016-

one. Overlapping pads

Pads (except the pad surface mount outside) overlap, that is overlap hole is placed in the borehole drilling because of the multi-pilot in a

Cause broken drill bit, wire damage.

two. Abuse patterned layer

1. violation of conventional design, such as a design element in the BOTTOM surface layer welding surface design TOP, resulting in a positive file editing

The opposite error.

2. PCB board if required within the milling groove, or use KEEPOUT LAYER BOARD LAYER layer shown, should not be used

It level, to avoid false or no milling milling.

three. Hole

If there are holes in the plate-shaped, with KEEPOUT layer draw a hole the same size as the area can be filled. Hole length / width ratio

Cases should be ≥2: 1, the width should be> 1.0mm, otherwise, in the processing of drilling Hole drilled easily broken, resulting in processing difficulties.

four. Place characters

1. Character cover pad SMD solder pieces, the welding element of continuity testing and PCB inconvenience.

2. Character design is too small, causing difficulties for screen printing, so that the character is not clear enough.

Fives. Sided pad aperture settings

1. Sided pads are generally not drilled, drilling should be labeled if its aperture should be designed to be zero. If the design of the value, so that the production

When raw drilling data, drilled holes will be in its place, it will affect the appearance ranging from the board, while the board scrapped.

2. To one side of the pad drilling is necessary to make a special label

six. Videos pads filled with blocks

In the design of the line through the DRC painting pad with a filler block, but the process is not enough, so the class can not pad

Data generated directly solder, when the solder resist, the filling block area will be covered with the solder resist, causing the device difficult welding.

Seven. Design stuff too much or filler block filled with hairlines

1. Generating gerber data have to be lost, gerber data is incomplete.

2. Because when the block is filled plot data processing is to draw a line, and therefore the amount of light generated by a large plot data, by

Plus the data processing difficult.

Eight. Surface mount device pad is too short

This is for continuity testing, too dense for surface mount devices, the spacing between its feet relatively small, the pad is quite

Fine, installation and testing should be up and down (right and left) staggered position, such as pad design is too short, while not affecting component placement, but will

Probes not open the wrong place.

nine. A large area of the grid spacing is too small

Composed of a large area between the grid lines with the edge of the line is too small (less than 0.30mm), during the printing process can cause a short circuit.

ten. A large area of copper foil too close to the distance from the outer frame

A large area of copper foil frame should ensure that at least more than 0.20mm pitch, because when milling shape of a milling onto copper foil is likely to cause

Alice and flux caused by off problems.

eleven. Shape frame design is not clear

Some customers KEEP LAYER, BOARD LAYER, TOP OVER LAYER designed so that the contour line and

These outline do not coincide, resulting in difficult to judge which one is the appearance of the molding line.

twelve. Line placement

The connection between the two pads, do not draw off, if you want to add lines to broad-brush Do not repeat placed directly change

WIDTH can change lines, so the line when modifying easy to modify.


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