印制电路板dfm通用技术要求General specification for printed circuit board DFM.docx

1、印制电路板dfm通用技术要求General specification for printed circuit board DFM印制电路板dfm通用技术要求（General specification for printed circuit board DFM）General specification for printed circuit board DFMThis standard specifies the general requirements for design for manufacturing single sided printed circuit board, inc

2、luding materials, dimensions and tolerances, printed wires and pads, metal holes, holes, mounting holes, coating, coating, character and mark. As designers of printed boards, design a single, double sided (Single/Double, sided, board) reference:1 General requirements1.1. This standard serves as a ge

3、neral requirement for PCB design, specifications for PCB design and manufacturing, and effective communication between CAD and CAM.1.2 we shall give priority to the design drawings and documents as the basis for production in the process of documentation.2 PCB material2.1 substratePCB substrate is u

4、sually made of epoxy glass cloth covered with copper plate, that is FR4. (including single panel)2.2 copper foilA) more than 99.9% of electrolytic copper;B) double plate surface copper foil thickness more than 35 m (1OZ); special requirements, specified in the drawings or documents.3, PCB structure,

5、 size and tolerance3.1 structure(a) the design elements that constitute the PCB shall be described in the design drawings. The appearance shall be uniformly expressed by Mechanical 1, layer (priority) or Keep out layer. If used in the design document at the same time, the general keep out layer is u

6、sed for shielding without opening, and mechanical 1 is used to represent the forming.(b) in the design drawings for opening long SLOT holes or hollow out, with Mechanical 1 layer draw the corresponding shape can.3.2 plate thickness toleranceFinished plate thickness0.41.0mm1.12.0mm2.13.0mmtolerance+

7、0.13MM+ 0.18mm+ 0.2mm3.3 dimensional tolerancesPCB the overall dimensions shall comply with the requirements of the design drawings. When the drawings are not specified, the overall dimension tolerance is + 0.2mm. (except for V-CUT products)3.4 flatness (warpage) tolerancesThe flatness of PCB shall

8、be in accordance with the design drawings. When the drawings are not specified, follow the followingFinished plate thickness0.41.0mm1.03.0mmWarpageSMT = 0.7%; SMT = 1.3%SMT = 0.7%; SMT = 1%4 printed wiring and pads4.1 layoutA) the layout, line width and line spacing of printed wires and pads shall b

9、e specified in accordance with the design drawings. But we will have the following treatment: appropriate according to process requirements for line width, PAD ring width compensation, single panel general, we will try to increase PAD, in order to strengthen the reliability of customer welding.(b) w

10、hen the design line spacing is not up to the technical requirements (too closely affecting performance and Manufacturability), we shall adjust the design specifications according to the pre system design.C) we advise customers to design single and double boards in principle. The diameter of through

11、hole (VIA) is more than 0.3mm, the outer diameter is more than 0.7mm, the distance between lines is 8mil, and the line width is above 8mil. To minimize the production cycle, reduce manufacturing difficulties.D) our minimum drilling tool is 0.3, the product is about 0.15mm. The minimum line spacing i

12、s 6mil. The minimum line width is 6mil. (but the manufacturing cycle is longer and the cost is higher)4.2 wire width toleranceInternal control standard for width tolerance of printed wiring is + 15%4.3 mesh processing(a) in order to avoid foaming and heating of copper surface when wave soldering occ

13、urs, the PCB plate is bent due to thermal stress, and the large copper surface is recommended to be laid in a grid form.B) the grid spacing is larger than 10mil (less than 8mil), the grid width is greater than or equal to 10mil (less than 8mil).4.4 heat shield (Thermal pad) processingOn the ground o

14、f large area (electric), often with components of the legs are connected to the connecting legs, both electrical properties and process requirements, made of cross flower pad (heat insulation plate), the possibility of resulting weld point due to excessive heat in the welding section is greatly redu

15、ced.5 aperture (HOLE)5.1 definition of metallization (PHT) and non metallization (NPTH)A) our company defaults to the non-metallic hole as follows:When the client sets up the Kong Fei metallization property in the Protel99se advanced properties (plated tab removed from the Advanced menu), we default

16、 to a non-metallic hole.When the customer directly uses the keep, out, layer or mechanical 1 layers of arc to indicate the drilling (no more separate holes) in the design document, we will accept the non-metallic hole as the default.When the customer placed the word NPTH near the hole, we are respon

17、sible for the non - metallization of the hole.When the customer explicitly calls for the corresponding aperture non - metallization (NPTH) in the design notice, they are processed according to the customers requirements.(b) in addition to the above conditions, the components, holes, mounting holes,

18、and through holes shall be metallized.5.2 hole size and tolerance(a) the PCB element holes and mounting holes in the design drawings assume the final product aperture size. The aperture tolerance is usually + 3mil (0.08mm);B) the through hole (that is VIA hole) we usually control it as follows: the

19、negative tolerance is not required, and the positive tolerance is less than + 3mil (0.08mm).5.3 thicknessThe average thickness of the copper plated layer of metallized hole is not less than 20 m, and the thinnest is no less than 18 mu m.5.4 hole roughnessPTH hole wall roughness is controlled in less

20、 than 32um5.5 PIN hole problemA) our CNC milling machine positioning pin is 0.9mm minimum, and the positioning of the three PIN holes should be triangular.(b) when the customer has no special requirement and the design bore bore is less than 0.9mm, we will add the PIN hole at the appropriate positio

21、n of the blank wireless channel or the big copper surface in the board.Design of 5.6 SLOT hole (slot)A) it is recommended that the SLOT hole be drawn with Mechanical 1 layer (Keep, out, layer). It can also be expressed as a continuous hole, but the holes should be of the same size and the center of

22、the hole is on the same horizontal line.B) our smallest slot knife is 0.65mm.C) when the SLOT hole is used to shield and avoid creepage between the high and low pressure, it is suggested that the diameter is above 1.2mm to facilitate processing.6 solder layer6.1 coating parts and defectsA) the solde

23、r coating shall be applied to the PCB surface except the solder pads, MARK points, test points, etc.(b) if a customer uses a disk represented by FILL or TRACK, a corresponding size graph must be drawn on the solder resist (Solder, mask) layer to indicate the presence of tin at the site. (I strongly

24、recommend that there be no non PAD form before design)(c) if the solder needs to be cooled on a large copper sheet or sprayed on an online bar, a corresponding size pattern must also be painted on the mask (Solder) layer to indicate the presence of tin.6.2 adhesionThe adhesion of the solder resist i

25、s required by level 2 of IPC-A-600F in the United states.6.3 thicknessThe thickness of the solder resist conforms to the following table:Line surfaceLine cornerSubstrate surfaceMore than 10 mMore than 8 m2030 mu m7 characters and etch marks7.1 basic requirementsA) the characters of PCB should be des

26、igned by word height 30mil, word width 5MIL, character spacing 4mil or more, so as not to affect the differentiability of text.B) etching (metal) characters should not be bridged with wires and to ensure adequate electrical clearance. General design according to word height 30mil, word width 7mil ab

27、ove design.(c) when the customer characters are not clearly defined, our company will adjust the proportion of characters according to the technical requirements of our company.D) when there is no clear customer, we will in the silk printing layer is the proper position of our printed trademark, mat

28、erial number and cycle according to the requirements of our technology.7.2 PADSMT processing on textDisc (PAD) can be a silkscreen logo, in order to avoid. When the customer has the design of PADSMT, our company will do proper movement processing, the principle is that it does not affect the identit

29、y of its identification and device.The concept of 8 layers and the processing of MARK pointsLayer designEight1 double panel, we default to the top (ie Top, layer) for the face, topoverlay screen layer characters are positive.8.2, single panel to top (Top, layer) painted circuit layer (Signal layer),

30、 it means that the line is facing the face.8.3, single panel to the bottom (Top, layer) painted circuit layer (Signal layer), that the layer is a perspective line.Design of MARK points8.4 when the customer has a surface mount (SMT) for the board file, it should be placed MARK at the point of Mark, a

31、nd the circle diameter is 1.0mm.8.5 when the customer has no special requirements, we put an arc of F1.5mm on the Solder Mask layer to represent the flux free to enhance the identifiability.8.6 when the customer is a splicing board file surface patch process side did not put MARK, our general in the

32、 process of edge position of the diagonal median plus a MARK point; when the customer is a splicing board file has no surface patch technology, is generally required to communicate with the customer need to add MARK.9 about V-CUT (cut V groove)9.1 V cut panels do not leave a gap between the board and the board. However, attention should be paid to the distance between the conductor and the center line of the V cut. Generally, the conductor spacing on both sides of the V-CUT