Regarding the point of "window opening through hole" and "oil cover through hole" (PAD and VIA usage distinction), many customers and design engineers often ask what this means when placing an order in the system, which option should I choose for my file? This problem is explained as follows:
Sometimes the conductive hole is processed by PAD attribute, and sometimes the key hole is processed by VIA attribute. The design of via attribute and pad attribute is confused, leading to wrong processing, which is also one of the problems frequently complained about. And for the circuit board production factory, in the processing of CAM data, some processing film engineers, because the customer design documents are not standardized, and the mistake; Occasionally some engineers help customers modify the documents, the non-standard design to do right, with their own experience to deal with the engineering data, which leads to and contributes to the customer's design non-standard.
This is to clarify: the last done right, does not mean the document is right! All engineers must pay attention to design standards and specifications. Please all the film processing engineers, as far as possible to keep the current situation of customer documents, as far as possible to do according to the design specifications and standards, not according to experience processing. Reflect the problem, so that you can design engineers do a reference, improve the quality of design and reduce the occurrence of problems!
This article focuses on conductive holes, keyholes, and the connection between protel /pads/ and geber files. Conductive hole, via keyhole, pad especially prone to several problems:
1. In the conversion process of via, problems are caused by non-standard design or unclear gerber setting rules for conversion by design engineers.
When you send a gerber file, the manufacturer can't tell which are the holes and which are the key holes. The only thing that can be identified is the processing according to the file, where the welding layer is where there is a window. Contention: I want to cover the hole oil, now open the window, may lead to short circuit. In case of such problems, you need to check the documents, because the gerber is the film file, the factory has no way to check whether it is conductive hole or keyhole, and check whether the gerber file is conducive to welding layer. If there is one, open the window, if not, cover the oil.
2. pad mixed with via, resulting in problems.
When the files are pads or protel sent to the factory, it is required to pass through the hole cover oil. Please note that you need to carefully check whether the pad is also used for via, otherwise green oil will be found on the pad hole, which will cause no welding. Contention: Plug-in hole must be the above to spray tin, how to cover the oil? In the same case, you need to check the file first, whether it is designed by pad or via.
When the files are pads or protel sent to the factory, the order requirement is to cover the holes with oil, but many customers use pads (plug-in holes) to represent the conductive holes, thus causing the conductive holes to open the Windows. Maybe what you want is the through hole cover oil, and then the argument may be: What I want is the conductive hole cover oil, why open the window? At this time, we still need to check whether the file design is standard.
In view of this point, it is hereby stated that if it is via, it should be processed by via; if it is pad, it should be processed by pad. Please note that no one will know which is the conductive hole and which is the plug-in hole, and via and pad are the only identifiers.
3. How to design orifice cover oil in protel or pads?
There is a tenting option in the via attribute in protel. If you tick it, it must be covering oil. Then the gbrber file transferred out is all covering oil; In pads, you need to pass through the hole (via) to cover oil to transfer files: when exporting soldermask, solder layer, just check the via below, which means all pass through the hole to open the window. If you do not check, pass through the hole to cover oil.
To sum up: pad according to pad, its own property is the plug-in hole; via has two options, if the original file is provided, then you can choose when placing the order, if the gerber file is provided, be sure to check whether the gerber file meets your requirements!