Printed Circuit Boards SMT Stencils

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Shipped: 8th-October-2024

1 General Description
SMT stencil in our house, framed or frameless are 100% laser cut. The thickness of stainless steel foil ranges from 0.05mm to 0.4mm, with size 300mm x 300mm to 600mm x 600mm. They are fabricated per IPC 7525A using supplied Gerber data, squeegee area locating in the center.Fiducial marks are half carved on the back side to suit for the SMT machine. It’s packed with KK carton (hard card) and usually 2 stencils are packed for shipment.

2 Features and Benefits
1.) The data file is used directly to produce and reduce the error rate;
2.) The opening accuracy of SMT template is very high: the whole process error is ≤ ±4 μ m;
3.) The opening of SMT template has geometric figure, which is advantageous to the printing and forming of tin paste;
4.) Quick and on-time delivery;
5.) Diversified shipping method;
6.) No MOQ, low cost for prototypes and small runs quantity

3. Applications
SMD package such as PLCC,QFP,0402,0201,BGA,Flip Chip.

4. Manufacturing Essentials
1) Aluminium Frame
2) Laser cut
3) PCB locate in the middle of squeegee area.
4) Stainless Steel Shim: In general a standard thickness of 5 mils. For microBGA step down in the area to 4mils. For fine pitch QFP reduce the paste apertures by 10%-15% at centre.
5) Reduction for fine pitch components
6) Engraving is required
7) Electro Polishing

5. Available Thickness of Stainless Steel Foils
0.05mm, 0.06mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.25mm, 0.3mm, 0.4mm

6. Aluminum Frame Size
The size of the aluminum frame is chosen based on the customer's printing machine. For fully automatic printers, the options are 736×736mm, 584×584mm, 550mm×650mm, or 550mm×600mm. For semi-automatic printers, the options are 370mm×470mm or 420mm×520mm.
Although stencil is custom-made product, there are also some sizes which are in common use. For example, 300mm x 300mm, 520mm x 420mm, 600mm x 600mm

7. Aperture Design for SMT Stencil

Component Type	Pitch	Soldering Width	Soldering Length	Opening Width	Opening Length	Shim Thickness
PLCC	1.27mm	0.65mm	2.00mm	0.60mm	1.95mm	0.15-0.25mm
QFP	0.635mm	0.35mm	1.50mm	0.32mm	1.45mm	0.15-0.18mm
QFP	0.50mm	0.254-0.33mm	1.25mm	0.22-0.25mm	1.20mm	0.12-0.15mm
QFP	0.40mm	0.25mm	1.25mm	0.20mm	1.20mm	0.10-0.12mm
QFP	0.30mm	0.20mm	1.00mm	0.15mm	0.95mm	0.07-0.12mm
0402		0.50mm	0.65mm	0.45mm	0.60mm	0.12-0.15mm
0201		0.25mm	0.40mm	0.23mm	0.35mm	0.07-0.12mm
BGA	1.27mm	0.80mm		0.75mm	0.75mm	0.15-0.20mm
BGA	1.00mm	0.38mm		0.35mm	0.35mm	0.10-0.12mm
BGA	0.50mm	0.30mm		0.28mm	0.28mm	0.07-0.12mm
Flip Chip	0.25mm	0.12mm	0.12mm	0.12mm	0.12mm	0.08-0.10mm
Flip Chip	0.20mm	0.10mm	0.10mm	0.10mm	0.10mm	0.05-0.10mm

8. Tags:
Printed Cirucit Board SMT stenicls
Latest Stencil Laser Technology from Bicheng
Laser Cut SMT Stencils

Prototype SMT Stencils
Stainless steel SMT Stencil
Frameless SMT Stencils
Framed SMT stencils

SMT stencil with home plate aperture
home plate stencil
adhesive-paste printing stencil

9. General terminology
1). SMT Stencil
The stencil used in SMT printing machines serves to accurately apply a precise amount of solder paste (or other materials) to the correct positions on the PCB.

2). Step Stencil
A step stencil is a type of template designed to address the varying thickness requirements of solder paste (or other materials) in surface mount technology. It differs from a standard stencil in that it features localized thinning or thickening.

3). Glue Stencil
This type of stencil is suitable for PCBs that already have protrusions such as SMT components and DIP pins. The bottom surface of the stencil features grooves to avoid these protrusions when in contact with the PCB surface. Glue is printed onto the PCB through the printing holes using a special squeegee.

4). Squeegee Side
The side of the SMT stencil that comes into contact with the squeegee during the printing process.

5).PCB Side
The side of the SMT stencil that comes into contact with the PCB during the printing process.

6). Fiducial Mark
Fiducials are circular points, typically around 1mm in diameter, used by automatic printers for positioning. They have a color contrast with their surroundings. By locating two or more of these points on the stencil, the relative position between the SMT stencil and the PCB can be determined, ensuring that the openings of the stencil align accurately with the printed positions on the PCB.

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