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Technical Specification for SMT Laser Steel Mesh Fabrication

Source: Linchuan Precision  Article author:Linchuan Precision  Time:2019-10-08 10:33  Read: 856

The opening method mentioned in this specification is based on the rule of the pad. If the pad is irregular or has a large difference with the normal pad size, the opening mode should be determined depending on the situation.


Steel sheet thickness

A. In the case of PITCH 0.4IC and 0.4 and 0.5BGA, 0.1MM thickness is used.

B. PITCH is 0.5 IC and 0.65BGA with 0.12MM thickness

C. PITCH is 0.65 (including 0.65) or more IC and 0.8 (including 0.8) or more BGA, using 0.15MM thickness

D.0402 component with 0.12MM thickness


The above is for the solder paste laser steel mesh, the red rubber steel mesh is usually used with a thickness of 0.18MM

If the customers in the stencil order remarks have special requirements for thickness, please select the thickness according to customer requirements.


2. Character

In order to facilitate communication with customers, the following characters should be engraved on the steel sheet or frame (except special requirements)

MODEL: (customer model) (ie steel mesh data file name)

SIZE: (steel mesh specification) T: (steel thickness)

DATE: (production date)

NO: (the company's SMT steel mesh number) (customer number)


If there are customer requests for additional characters in the order note, please add as required


3. Component opening method

1. CHIP material components

A. The package is 0201 components, and the inner distance is guaranteed to be no less than 0.23mm and greater than 0.28mm.

B. The package is 0402 components, and the internal distance must not be less than 0.35 and greater than 0.45mm (when the internal distance is less than 0.35mm, it needs to be moved to 0.35mm; when the internal distance is greater than 0.45mm, it needs to be expanded to 0.45mm). Large, can be adjusted to 0.5mm

C. The package is a 0603 component opening (when the internal distance is less than 0.55mm, it needs to be moved outward to 0.6mm and greater than 0.80MM to expand to 0.80mm)

D. The package is 0805, 1206 and above, generally not limited, but the 0805 internal distance is at least 0.7 or more.

E.0805 and above components (excluding diodes) must be treated as anti-tin beads, as shown below


If the 0805 component width is less than 1.0MM and the 1206 width is less than 1.3MM, do not prevent tin beads (except customer requirements)


Or if the document does not have a silk screen layer, the direction of the component and the polarity of the component are not distinguished, and no anti-tin beads are needed. If the customer requests protection, the customer service personnel should be required to screen the layer, and the customer's remarks should be written to prevent tin beads, which is also started from the 0805 component. Defense


2. SOT23 to ensure the quality of the solder hole is 1:1.


3.SOT89 bridge, the bridge width is 0.8-1.0MM


4.SOT252, SOT223 and other high-power transistors, intermediate bridges; 10; word or; well; word frame, or divided into small blocks, depending on the bridge width (pad size)


5. Shaped components

(1) This type of SD card holder, the outer three sides plus 0.2MM, the pin extension 0.15MM

(2). This type of earphone holder requires: pin extension 0.15MM

(3) The requirements of this type of SIM card holder: plus three sides of the fixed foot plus 0.15, pin extension 0.15MM

(4) Such switch requirements: external three-side extension 0.1MML1=L

(5) USB requirements: three sides of the fixed foot plus 0.15, pin extension 0.1MM

(6) Such modules require: long extension 0.15MM, maintaining a safe spacing in the width direction

(7) Such toggle switch requirements: the above two fixed feet, long extension 0.15MM, plus 0.1MM on each side of the width direction, the following two pins, long extension 0.15MM, plus 0.1MM on each side of the width direction

(8) Requirements for such parts: The above parts, the fixed three sides of the fixed foot plus 0.15MM, the lead extension 0.15, the following parts, the width of each side plus 0.1MM, the long extension 0.15MM


The above requirements are subject to availability. If you increase it, you will increase it. If you can't add it, you don't need to add it (for example, the distance from the surrounding components is too small, the pad is already on the edge of the board)


6. IC class (W means wide, L means long)

(1) PITCH=0.8-1.27mm, the width is generally between 45% and 60% of PITCH, depending on the number of pads of the circuit layer, the smaller value of the pad on the circuit layer is smaller, and the line is larger. Take a larger value

(2) PITCH=0.635-0.65mm, W=0.3-0.33MM, L 1:1 and rounded at both ends.

(3) PITCH=0.5mm, W=0.24mm, if L is less than 1.5MM, then the extension is 0.1MM, and the ends are rounded.

(4) PITCH=0.4mm, W=0.19mm, L is extended by 0.1MM and rounded at both ends.

(5) PITCH=0.3mm, W=0.16MM, L extension 0.1MM, and rounded at both ends (if the length is <0.8mm, the length is extended outward by 0.15mm).


Above (0.65-1.27), if L<1mm, the length needs to be extended to 0.1mm.



7.BGA class

PITCH=0.4mm, open 0.23m

PITCH=0.45mm, open 0.26mm

PITCH=0.5mm, open 0.3mm

PITCH=0.65mm, open 0.35mm

PITCH=0.8mm, open 0.45mm

PITCH=1.0mm, open 0.55mm

PITCH=1.27mm, open 0.65mm


If the aperture on the line is too far from the data, please contact customer service.


0.4 0.5IC grounding pad, open to square hole according to 60-70% of the pad. If the square hole is larger than 1.5, please bridge, the width of the frame is 0.3MM minimum, whether it is a cross or a field or a well, see the pad size. However, if the ground pad is originally small, such as 1.0MM or so, then do not shrink


#Plastic mesh opening method


 0402 component width is 0.26mm, length is 0.15mm

0603 component width is 0.28mm, length is 0.20mm

0805 component width is 0.32mm, length is 0.20m

1206 component wide open 0.5-0.6mm (or 30%-35% of open pad pitch)

1206 or more components are 35% wide and 0.2mm long.

When the gap of 0603 component is greater than 0.75mm, the width is 0.32mm

When the 0805 component gap is greater than 0.95mm, the width is 0.35mm

Diode width is 35-40% of the internal distance, plus 0.25mm


In addition to the diode, if you can't judge which component, you can open about 30% of the internal distance, the internal distance is too small, see the situation


# MARK point

1, MARK points generally have printed surface, non-printing surface half-cut, through-hole, determined by the customer's printing equipment, generally non-printing surface half-cut, diagonal two, generally four (see customer requirements)

2. The glue net is convenient for alignment when not in automatic printing. Use the through hole to make the positioning hole. If the customer requests MK as the positioning hole, please do as required.

3. If you choose MARK, if there is no MARK on the board, you will not make a choice. If the customer requests that the through hole be replaced, please follow the customer's request.


#Layout method: If the single-sided PCB, the PCB length is centered on the steel mesh (ie, long to long centered), if multi-faced, the pattern length is centered on the steel mesh. (In both cases, ensure that the PCB frame does not exceed the frame)


If the above is electrolytic polishing, reduce 0.04MM when turning LMD, and make the center line. If it is not polished, please reduce 0.03MM, but do not do the center line.


When you switch to TCM, you must remember the mirror phase. (If the pad is a line instead of a D code, turn the pad into D code when processing the file, otherwise the software will cause a leak.)


Turn the pads of the two overlapping parts into one. After selecting the pads, press


The requirements are written:&ldquo; completely made according to the document, there is no mirror phase, no anti-tin beads, but the IC is still modified according to the specifications, the large pad still needs to be bridged.


If the file has only one layer of patch and no silkscreen, GTP (TP) is displayed. The default is positive, not mirrored, and the layer name shows GBP (BP). For the reverse side, the mirror phase is required. If there is no layer name, directly Production, no mirror


After that, the front and back sides are judged by the silk screen characters. If the silk screen is positive, it is front, not mirror, and the silk screen is reverse, then the mirror phase, no matter the layer name.


Chip material components, if there are through holes in the components, no matter how large, our company does not avoid hole processing, IC grounding, electrolytic capacitors, large-effect transistors, if there are 0.5 or more through holes on the pad, then avoid the hole treatment, If you have special requirements, please see the instructions.

Last article:Technical specification for steel mesh fabrication
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Linchuan Precision specializes in the production and development of SMT steel mesh
serving over 3,000 customers in 7 years
producing over 200,000 high-quality steel meshes.
Service hotline:0755-29749682/18928403435
Shenzhen Linchuan Precision Technology Co., Ltd.
Tel:0755-29749682  18928403435
E-mail:xjx.smt@163.com
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Company Address: 2/F, Block C, Fengrun Building, Huafeng Second Industrial Park, Gushu, Xixiang, Bao'an District, Shenzhen
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