1, the hole used as little as possible
Once the selected hole, be sure to handle it with the surrounding entities of the gap, easily overlooked, especially in the middle layers and vias are not connected to the line and via the gap, if it is automatic routing, in "the number of vias minimized "(Via Minimiz8tion) sub-menu, select" on "key to automatically resolve. (2) the need for greater carrying capacity, the greater the required hole size, such as power and ground connection used with other layers of vias should be larger.
2, screen printing layer (Overlay)
To facilitate installation and maintenance of the circuit, in the printing plate on the upper and lower surface of the printing needs logo and text code, such as, for example, component label and the nominal values, components, and manufacturers outside the profile shape of the sign, production date, and so on. Many beginners silkscreen of the content, text symbols only pay attention to put a tidy appearance, ignoring the actual effect of the system out of the printed circuit board manufacturer. They designed the Indian board, the character is not blocked by components of the flux penetrated region was wiped on credit, as well as the components play in the adjacent components on the label, so all of the designs will be great to assembly and maintenance inconvenience. Silkscreen character layout correct principle is: "no ambiguity, they must attack, nice."
3, SMD specificity
Protel package database has a large number of SMD package, the surface of the welding device. In addition to small size of these devices outside of the single most important feature is the distribution of per-pin hole. Therefore, the use of such devices where the surface to define the device to avoid "missing pin (Missing Plns)". In addition, these components of the text where the surface marked only with the component placement.
4, grid-like area filled with
Fill the grid-like area (External Plane) and fill areas (Fill) as the name of both, as network-like filling area is to be processed into large area of ??copper mesh, filling area is only intact copper foil. Beginner on the computer design process often can not see the difference between the two, in essence, as long as you enlarge the surface after a glance. It is usually not easy to see as the difference between the two, so do not pay attention when using more distinction between the two, to emphasize the former in the circuit characteristics have a stronger role in high-frequency interference suppression for to be done a large area filled places, especially to some of the region as a shield area, partition or high current power cord is particularly suitable. The latter are used for the general end of the line or turning areas that require a small area filled place.
5, pad (Pad)
Pad is the most contact with the PCB design is the most important concept, but for beginners it is easy to overlook the choice of and amendments in the design fits in a circular pad. Choose the type of component pad into account the element to the shape, size, layout of forms, vibration and heat conditions, the force direction and other factors. Protel library in the package are given a series of different size and shape of the pad, such as round, square, octagonal, square and round pads for positioning, etc., but sometimes this is not enough, you need to edit their own. For example, fever and a larger force, the current large pad can be designed as a "teardrop-shaped" in the familiar TV line output transformer pin PCB pad design, many manufacturers is using this form. In general, self-editing pad when talking about other than the addition to the above, but also consider the following principles: (1) the length of the shape is inconsistent with the pad width to consider the connection side of a specific size differences can not be too large; (2 ) need to lead the component alignment angle between the asymmetry of the length of time the pad is often used more efficiently; (3) the size of the hole component pad thickness, respectively, according to editors to determine the component leads, in principle, is the size of the hole diameter than the pin large 0.2-0.4 mm.
6, various types of film (Mask)
These films are not only essential to the process PcB production process, but it is a necessary condition for welding components. Press the "film" position and its role, the "film" can be divided into component surface (or solder side) flux membrane (TOp or Bottom and the component surface (or solder side) solder mask (TOp or BottomPaste Mask) two type the name suggests, flux is applied to the pad on the film, to improve solderability performance of a membrane, which is in the green pad on the board slightly larger than the light-colored spots on each. solder mask, the opposite, in order to the board made to adapt the form of wave soldering, etc., requiring non-pad on the board at the tin foil does not stick, so all parts of the outside pad should be coated with paint, used to prevent these parts on the tin. can be seen, these two films is a complementary relationship. this discussion, it is not difficult to determine the menu, similar to the "solder Mask En1argement" and other projects set up.