CAM Engineer's Questions about Design Data
2024/01/05
I: plate and frame
1.99SE and DXP software design, the board frame has GM1 layer and keepout layer, cam engineers will choose one of them as the board frame layer, if the two layers are inconsistent, engineers will propose EQ, especially the fixed screw holes, GM1 layer and keepout layer often appear inconsistent. Occasionally there will be extra 2D lines.
II: Drilling
1. The SLOT slot size of the plate and frame layer or hole level layer (gdd/gd1) is inconsistent with the slot size on the drilling layer.
2. The hole level layer or plate and frame layer is SLOT slot hole shape, but the drilling layer has only one round hole in the center. Careless CAM engineers are easy to ignore slot holes.
3. The plate and frame layer has square slot, and the hole position layer has rectangle/square. However, the drilling layer is oval slot. Some CAM engineers noticed this problem and would propose EQ or make it directly into a square SLOT, while others would ignore the indication that the square weld foot could not be inserted due to the arc shape at the four corners of the slot of the finished board. Therefore, to avoid this problem, delete the oval slot hole in the drilling layer, and retain the indication of the square SLOT slot and hole level layer and the hole attribute (PTH or NPTH) in the plate and frame layer.
Three: the line
1. Multilayer boards must provide layer sequence. Some are named GND,VCC,POWER SIG. These CAM engineers cannot distinguish the sequence of inner layers and will propose EQ.
2. Some 2D lines will cause short circuit on the line layer
3. For holes with connection performance in the inner layer, pads larger than the holes should be designed. For the over-current hole (VIA), it is better to design pads 0.15MM larger than the one side of the hole. The hole of the plug-in is designed to be 0.17MM larger than the one side of the hole. Pads can be set for independent holes or not (CAM engineers will delete independent pads in the inner layer because short circuit is avoided. Unless specifically specified)
4. The outer layer has pads, lines, copper, and D codes. It is best not to be the same. When CAM engineers optimize, they will increase a lot of work and are prone to problems. In particular, the same pad appears to be composed of copper, wire and pad, and the optimization data time will increase several times.
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