[Design must-see] "Via hole cover oil" and "Via hole opening window"
Regarding the "via opening window" and "via cover oil" (different usage of PAD and VIA), many customers and design engineers often ask what this means when they place orders in the system, which one should I choose for my file? An option? The following is a description of this issue:
I often encounter such problems. The file design is not standard. I ca n’t tell which pad is used. What is the use of via? Sometimes conductive holes are treated with pad attributes, and sometimes keyholes are treated with via attributes. VIA attributes and PAD attribute design is chaotic, which leads to incorrect processing, which is also one of the problems that often complain. For circuit board production factories, when processing CAM data, some processing engineers, because of the irregularity of customer design documents, will be wrong; occasionally, some engineers will help customers modify the documents and correct the irregular design. Experience in processing engineering data, which leads to and encourages customer design irregularities.
I hereby explain that the right thing you did last time does not mean that the file is right! Please all engineers must pay attention to the design standards and specifications. All processing engineers are kindly requested to keep the status quo of customer documents as much as possible, and to handle them according to design specifications and standards as much as possible, not according to experience. Reflect the problem so that you can use it as a reference for design engineers, improve design quality and reduce problems!
This article mainly explains the connection between conductive holes, keyholes, and protel / pads / and geber files. Conductive holes, via keyholes, and pads are prone to several problems:
1. During the conversion process, problems occurred due to non-standard design or unclear design rules for conversion gerber by the design engineer.
When you send a gerber file, the manufacturer can't tell which are the vias and which are the keyholes. The only thing that can be identified is the processing according to the file. There is a window for the solder layer. Dispute point: The via hole I want is covered with oil. Now the window is opened, which may cause a short circuit. When this kind of problem occurs, you need to check the file, because the gerber is a film file. There is no way for the factory to check whether it is a conductive hole or a keyhole. Check whether the gerber file is a solder layer. If there is no window, cover it with oil.
2, pad and via mixed use, causing problems.
When the file is pads or protel, it is sent to the factory, and it is required to cover the hole with oil. Please pay attention to it. You must check carefully whether the plug-in hole (pad) is also useful. , Resulting in inability to weld. Dispute point: The plug-in hole must be sprayed with tin, so how to cover the oil? In the same situation, you still need to check the file first, whether it is a pad design or a via design.
It is sent to the factory when the file is pads or protel. The order request is via hole cover oil, but many customers use pad (plug-in hole) to indicate the conductive hole, which causes the conductive hole to open the window. Maybe what you want is via hole cover oil. At that time, the argument may be: what I want is conductive hole cover oil. Why did you open the window? At this time, you still need to check whether the file design is standard.
In view of this point, it is hereby explained that if it is via, it is processed as via, if it is pad, it is processed as pad. Because no one knows which is the conductive hole and which is the plug-in hole, and via and pad are the only marks. Please know.
3. How to design a hole cover oil in protel or pads?
There is a tenting option in the via attribute in protel. If it is checked, it must be covered with oil, then the transferred gbrber files are all covered with oil. In pads, the files are transferred to the vias to cover them. Oil method: When outputting a soldermask, that is, a solder mask layer, just check the solder mask top-the via below represents all through-hole opening windows, if not checked, the hole is covered with oil.
To sum up: pad is made by pad, its own property is the plug-in hole; via has two options. If the original file is provided, then you can choose when ordering. If the gerber file is provided, you must check whether the gerber file meets the requirements. your requirements!