Precision PCB Fabrication, High-Frequency PCB, High-Speed PCB, Standard PCB, Multilayer PCB and PCB Assembly.
The most reliable PCB & PCBA custom service factory.
So we need to learn from the Soviet design experience -- build good products under existing production conditions. Including the printed circuit board layer, thickness, aperture, line width line distance, copper thickness and other basic parameters requirements; It also includes special requirements for plate type, surface treatment, special machining, etc. Generally, when PCB is processed, it is divided into sample processing for testing and batch product processing for final molding. For designers, what has practical significance and needs to be strictly observed is the process requirements of batch product processing.
For manufacturing related process requirements, line width, line spacing and aperture are basically important. That is, how much line width and how much hole can the processing plant handle. If the line width in the design does not meet the requirements, too thin words can not be processed correctly. Line width line spacing also affects whether the text on the screen printing layer is clear. And if the aperture is too small, there is no corresponding bit support. The bit size corresponding to the aperture also affects the tolerance of mechanical holes, mounting holes and other types of plate shear.
Line width Line spacing and aperture rule setting precautions
In PCB design, batch processing can support line width and line spacing of 4mil. That is, the cabling width must be greater than 4mil, and the spacing between the two lines must be greater than 4mil.Of course, it's just the limit of the line width and the line distance. In practical work, the line width needs to be defined as different values according to the design requirements. For example, the definition of power supply network is wider, and the definition of signal line is thinner. These different requirements can define different network line width values in the rule, and then set the rule application priority according to the importance. Also, for line Clearance, the Rules page Design-Rules-Electrical Clearance defines the safe Electrical Clearance between different networks, including line Clearance. There is another special case. For components with high density pins, the spacing between pads within the device is usually very small, such as 6mil. Although it meets the manufacturing requirements of line width or spacing greater than 4mil, it may not meet regular design requirements for PCB design.
If the safe spacing setting for the entire PCB is 8mil, then the pad spacing of the component clearly violates the rule setting. Will always be highlighted green during rule checking or online editing to show violations. This violation obviously doesn't need to be dealt with and we should fix the rule Settings to eliminate the green highlighting. In the original approach, different safe spacing rules were defined separ
ately for the device in the Query language and set to high priority. In the new version, this problem can be solved by simply checking the option to Ignore the Pad spacing within the package. As shown in the figure below.
It's easy to check with this option. Instead of using the Query InComponent('U1'), set the safe spacing to 6mil and spacing priority, through hole (VIA) aperture not less than 0.3mm(12mil), pad unilateral not less than 6mil(0.153mm), greater than 8mil(0.2mm) is not limited (see Figure 3) this point is very important, must be considered in design.Through hole (VIA) the hole to hole spacing (hole edge to hole edge) should not be less than :6mil > 8mil this point is very important, must be considered in the design. Distance from pad to contour line 0.508mm(20mil).
Welding plate
The size of the plug hole depends on your component, but it must be larger than your component pin. It is recommended that the plug pin be larger than 0.2mm or less, that is to say, 0.6 of the component pin. You should design it as 0.8 at least, in case the machining tolerance causes difficulty to insert. The single side of the outer ring of the plug hole (PTH) pad should not be less than 0.2mm(8mil). Of course, the larger the better (as shown in FIG.2 pad). This point is very important and must be considered in the design.
Plug hole (PTH) hole to hole spacing (hole edge to hole edge) should not be less than: 0.3mm of course, the larger the better (as marked in FIG.3) this point is very important, must be considered in the design.
Distance from pad to contour line 0.508mm(20mil).
The welding
Plug-in hole window, SMD window opening side should not be less than 0.1mm(4mil).
character
The character word width cannot be less than 0.153mm(6mil), and the character height cannot be less than 0.811mm(32mil). The relation between width and height ratio is 5, that is to say, the word width is 0.2mm and the word height is 1mm.
Nonmetallic notch
The spacing of the slot is not less than 1.6mm, otherwise it will greatly increase the difficulty of milling.
puzzle
There is no gap, and there is a gap, there is a gap, the gap should not be less than 1.6 mm (thickness of 1.6) mm, otherwise it will greatly increase the difficulty of milling side of the plate, the size of the plate is not the same depending on the equipment, the gap of no gap, about 0.5mm process edge can not be less than 5mm.
