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Detailed explanation of circuit board manufacturing process and precautions
2021-08-28
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Author:Aure

Detailed explanation of circuit board manufacturing process and precautions

   First-class production comes from first-class design. Shenzhen PCB manufacturers cannot do without the cooperation of your design. Engineers, please design according to the general production process.
  Detailed explanation of relevant design parameters:
   One, via via (commonly known as conductive hole)
  1, minimum aperture: 0.2mm (8mil)
2. The minimum via hole (VIA) aperture is not less than 0.2mm (8mil), and the single side of the pad cannot be less than 6mil (0.153mm), preferably greater than 8mil (0.2mm), it is not limited. This is very important, and the design must be considered .
  3. The via hole (VIA) hole-to-hole spacing (hole edge to hole edge) cannot be less than: 6mil, preferably greater than 8mil. This is very important, and the design must be considered.
  4, the distance between the pad and the outline line is 0.508mm (20mil).
   2. Route
  1. Minimum line spacing: 3mil (0.075mm). The minimum line distance is line-to-line, and the line-to-pad distance is not less than 6mil. From the production point of view, the larger the better, the general rule is 10mil. Of course, if the design is conditional, the larger the better. This is very important. Design Must consider
  2, the minimum line width: 3mil (0.075mm). That is to say, if the line width is less than 6mil, it will not be able to produce (the minimum line width and line spacing of the inner layer of the multilayer circuit board is 8MIL) if the design conditions permit, the larger the design, the better the line width, the better our circuit board factory produces, The higher the yield rate, the general design convention is about 10mil, which is very important, and the design must be considered
  3, the distance between the line and the outline line is 0.508mm (20mil)
   Three, PAD pad (commonly known as plug-in hole (PTH))
  1. The outer ring of the plug-in hole (PTH) pad should not be smaller than 0.2mm (8mil) on one side. Of course, the larger the better, this is very important, and the design must be considered.
  2. The distance between the plug-in hole (PTH) hole and the hole (hole edge to hole edge) cannot be less than: 0.3mm. Of course, the larger the better, this is very important, and the design must be considered.
3. The size of the plug-in hole depends on your component, but it must be larger than your component pin. It is recommended to be larger than at least 0.2mm or above, which means that the component pin of 0.6, you must design at least 0.8 to prevent processing Tolerance makes it difficult to insert.
  4, the distance between the pad and the outline line is 0.508mm (20mil).
  Four, solder mask
  1. The plug-in hole opens the window, and the single side of the SMD window cannot be less than 0.1mm (4mil).
   5. Characters (the design of the characters directly affects the production, and the clarity of the characters is very relevant to the character design).
1. The character width should not be less than 0.153mm (6mil), the character height should not be less than 0.811mm (32mil), and the ratio of width to height is preferably 5, that is, the character width is 0.2mm and the character height is 1mm. kind.
   Six. Non-metalized slot holes, the minimum spacing of the slot holes is not less than 1.6mm, otherwise it will greatly increase the difficulty of milling.
   Seven, imposition
1. There are no gaps and gaps in the imposition. The gap of the gaps should not be less than 1.6 (board thickness 1.6) mm, otherwise it will greatly increase the difficulty of milling. The size of the imposition work board will vary depending on the equipment. , The gap of about 0.5mm for gapless imposition cannot be less than 5mm.
   Related matters needing attention
   1. The original document about PADS design
  1. In the double-sided circuit board file PADS, the hole attribute should be through hole attribute (Through), blind and buried hole attribute (Partial) cannot be selected, and the drilling file cannot be generated, which will lead to missed holes.
  2. When designing slots in PADS, please do not add them together with components, because GERBER cannot be generated normally. To avoid leaks, please add slots in DrillDrawing.
  3. PADS is laid with copper, and the circuit board manufacturer uses Hatch to lay copper. After the customer's original file is moved, it must be re-coppered and stored (copper with Flood) to avoid short circuits.


Detailed explanation of circuit board manufacturing process and precautions

   2. Documents about PROTEL99SE and DXP design
   1. The solder mask of the circuit board manufacturer is based on the Soldermask layer. If the solder paste layer (Paste layer) needs to be made, and the multilayer (Multilayer) solder mask cannot generate GERBER, please move to the solder mask layer.
  2. Please do not lock the contour line in Protel99SE, it will not generate GERBER normally.
  3. Do not select the KEEPOUT option in the DXP file, it will screen outline lines and other components, and GERBER cannot be generated.
  4, please pay attention to the front and back design of these two kinds of files. In principle, the top layer should be straight and the bottom layer should be reversed. The circuit board manufacturer superimposes the board from the top to the bottom. Pay special attention to single-chip boards, and don't mirror them at will! Maybe it's the opposite of doing it.
  three. Other matters needing attention
   1. The shape (such as circuit board frame, slot, V-CUT) must be placed on the KEEPOUT layer or the mechanical layer, and not on other layers, such as silk screen layer and circuit layer. All slots or holes that need to be mechanically formed should be placed on one layer as much as possible to avoid leaks or holes.
2. If the shape of the mechanical layer and the KEEPOUT layer are inconsistent, please make special instructions. In addition, the shape should be given an effective shape. If there is an inner groove, the line segment of the outer shape of the board at the intersection with the inner groove needs to be deleted to avoid leakage inside the gong. Slots, slots and holes designed in the mechanical layer and the KEEPOUT layer are generally made without copper holes (copper is required when making film). If you need to process them into metal holes, please make special notes.
  3. Designed with three kinds of software, please pay special attention to whether the buttons need to be exposed to copper.
  4. Please make a special note when placing an order for the golden finger circuit board.
   5. If you want to make metalized slots, the safest way is to put together multiple pads. This way, there must be no mistakes.
  6. For the GERBER file, please check whether the file has a few layers. Generally, the manufacturer will make it directly according to the GERBER file.
  7. Under normal circumstances, gerber uses the following naming methods:
  Component surface circuit: gtl component surface solder mask: gts
  Component surface character: gto welding surface line: gbl
   Welding surface solder mask: gbs Welding surface character: gbo
  Appearance: gko Split hole diagram: gdd
  Drilling: drll