SMT Stencil Printer
What Is SMT Stencil Printer
SMT stencil printing machine is a kind of equipment used to print the printing process in surface mount technology (SMT) of electronic components. In the SMT production line, the SMT stencil printing machine is mainly used to evenly print the solder paste on the pad position of the PCB (Printed Circuit Board) for subsequent electronic component placement. With the SMT stencil printing machine, high-precision and high-efficiency solder paste printing can be realized, ensuring the placement quality and production efficiency of electronic components.
Advantages of SMT Stencil Printer
Consistent branding
Consistent branding is the key to success for many businesses. Using a stencil means that you can add your branding to anything like walls, windows, cars, or shipping materials.
Clear signage
Clear signage plays an important role in safety. Using a stencil to create clear signage can warn of hazardous materials, closed-off areas, or even updated business hours.
Cost-saving
There are services that can create custom stencils for your business, but if you need multiple stencils, they can become cost-prohibitive. Additionally, these are inflexible solutions. If you make any changes to your branding, you have to order an entirely new stencil or reprogram your machine if you have an electronic SMT Stencil Printer.
Time-saving
With a SMT Stencil Printer, you get a consistent and exact cut in minutes. You also cut out the waiting time of ordering a custom stencil when you have a machine available for your business's use.
Why Choose Us
Sales Market
We have a large market share in the USA, Korea, India, Germany, and Turkey, as well as in more than 20 other countries. Our local engineers in India (Delhi, Mumbai, and Daman), Turkey, Egypt, and elsewhere provide great convenience.
Technology Patent
We focus on professional and efficient technology development and innovation. We hold 9 invention patents, 112 practical patents, and 12 software copyrights. Additionally, ETON has invented the fastest automatic pick-and-place machine, capable of a speed of 250,000 CPH.
Our Certificates
We have several important certificates, including the CE certificate, the CCC certificate, and the SIRA certificate. Each of these certificates demonstrates our commitment to quality and safety.
Our Services
ETON offers comprehensive services: pre-sale, on-sale, after-sale, and technical support. Our professional service team has rich experience to ensure we address our customers’ questions. We always strive to provide the best support to you!
Types of SMT Stencil Printer
Framed SMT/PCB stencil
It is supplied as a solder paste-stencil which has been laser-cut and then permanently attached to the frame. When attaching the stencil, use the edge of the net to taut the stencil foil within the frame. Framed stencils are designed for high-volume PCB screen printing. The template additionally processes a smooth opening that can be used with spacings of 16 mils or less. Ideal for stencil printing on high-volume printed circuit boards, using framed surface-mount technology, the stencil is double-bonded to oppose extreme wear and tear.
Frameless SMT stencil
This type of stencil, also called the foil, is a laser-cut stencil designed to work with a reusable stencil frame known as the stencil clamp system. SMT stencil type that does not require permanent adhesion to the frame. Frameless SMT stencils are less expensive than framed stencils. And besides offering advanced quality and great performance, it also saves you money in terms of storage. It has a seamless open wall that can be used for 16mil pitch and below, especially micro BGA, and also has a 24-hour turnaround time standard.
Electroformed SMT stencil
Electroformed SMT stencils or electroformed foils are nickel-based stencils permanently attached to a stencil frame by a mesh rim that stretches the foil within the frame. Electroformed stencils offer one of the best paste release attributes available. As a result, it is used in fine-pitch SMT applications (12 mils to 20 mil pitch) on printed circuit boards. It also applies to flip chips, wafer bumping, and µBGA (6 mils to 12 mil pitch). Additionally, the seamless trapezoidal sidewalls of the SMT stencil improve the solder paste application.
A Common Process for SMT Stencil Printer
Is an additive process, and the manufacturer builds up the stencil by electroforming nickel. It is easier for form smaller apertures with finer pitch on electroformed nickel stencils. The aperture walls are very smooth and mirror-like, allowing good solder paste release as it does not cling to the sides.The electroforming process allows nickel to form around a photo resist template of apertures matching the board design. The processing time is high and the initial cost of manufacturing is also high. However, the cost of the stencil is independent of the number of apertures it contains. Therefore, for stencils with large aperture counts, the electroforming process allows quick turnaround times.
Is a subtractive process, where aperture formation takes place because of chemical etching. Although a relatively low-cost process, the results are rather inferior as the etching forms rough aperture sidewalls.Chemical etching creates apertures into the metal sheet using acid. The manufacturing speed is usually high, and cost of manufacturing low. However, the method is suitable only for forming large openings, and there is a tendency to form sand clock shape on the walls. Chemical etching is unsuitable for forming stencils with fine pitch openings.
Is also a subtractive process, where aperture formation takes place as a laser beam removes unwanted material from the stencil foil, usually stainless steel. Laser cutting helps form stencils with high quality and with a high degree of precision. Unlike the other two methods, laser cutting allows making the openings trapezoidal rather than vertical, thereby allowing good solder pasterelease.Laser cutting helps achieve more consistent results, and the greater accuracy of the process allows creation of apertures with very fine pitch at reasonable costs. The relatively low manufacturing speed is its only disadvantage.
SMT Stencil Printer Fabrication Process
Stencil material selection
The stencil fabrication process begins with selecting the optimal material such as stainless steel, nickel, or polyimide based on the application requirements, printing environment, and budget. This choice influences durability, chemical resistance, paste release characteristics, and cost considerations.
Design file preparation
The SMT Stencil Printer layout data defines the circuit pad geometries and positions. This data must be formatted into stencil-cutting tool instructions that specify the locations and dimensions of each aperture opening to be formed. Additional features like fiducial registration markings, tooling holes for alignment, and the outer stencil frame dimensions are added to the design file as well.
Laser cutting
A CNC laser cutting system uses the digital stencil design file to precisely remove or vaporize sections of the stencil material where apertures are required. A pulsed UV laser is commonly used, allowing complicated patterns and fine features to be formed with tight tolerances thanks to the laser's accuracy. The melted material is vacuumed away during cutting.
Post-processing
While laser cutting defines the aperture opening locations, additional steps refine the cut edges and impart key characteristics. A secondary lower-power laser pass around the apertures creates the optimal inward draft angle to aid paste release. Chemical etching smooths edges.
Framing
The finished SMT Stencil Printer foil then undergoes a framing process where it is stretched across and attached to a rigid frame for rigidity and ease of handling. This also allows securing the stencil onto stencil printers.
Final quality control
Before shipment, quality checks validate critical parameters like aperture opening dimensions, placement accuracy, and total SMT Stencil Printer thickness match specifications. This step picks any defects in the fabrication process before the stencil reaches the customer.
Manual printing
In the PCBA manufacturing process, manual printing is carried out by holding the squeegee of the solder paste printing machine, which is only suitable for products with low precision requirements and early use with high equipment investment costs.
Semi-automatic printing
Offline SMT printing machine needs to manually pick and place each printed PCB, mainly for mechanical positioning.
Fully automatic printing
In-line operation, the solder paste printing machine can automatically pick up and deliver the printed PCB, and has a post-printing visual alignment system and 2D/3D inspection function. And the solder paste printing machine has more options in various printing parameters. The more advanced SMT printing machine also has functions such as automatic erection of steel plates.
Influencing Factors of SMT Stencil Printing Machine
Manufacturing process
The best process is electropolishing after laser cutting. Chemical etching and electroforming will have errors, such as lamination, exposure, development, etc., and electroforming will also be affected by the unevenness of the substrate.
Material selection
The screen frame must be able to withstand a certain program relay and have good flatness; the stencil is best to use a polyester mesh because it can maintain tension and stability for a long time; and the steel sheet is preferably 304, which is more conducive to solder paste rolling than the mirror surface.
Opening design
The design of the steel mesh opening has the greatest impact on the quality of the steel mesh. The design of the opening should take into account the manufacturing process, width-to-thickness ratio, area ratio, experience value, etc.
The integrity of the production data
The more complete the data, the better. When there are several data coexisting, it is necessary to emphasize which one is the standard. In addition, the steel mesh made according to the data file can minimize the occurrence of errors.
Use of printing method
The correct printing method can maintain the quality of the steel mesh and increase its life. On the contrary, improper printing methods, such as excessive pressure, uneven steel mesh or PCB during printing, etc., will cause the steel mesh to be damaged to varying degrees.
Cleaning method
Solder paste is particularly easy to solidify. If the solder paste or tin powder on the steel mesh is not cleaned in time, it will block the opening of the steel mesh, and reprinting will cause difficulties and errors. Therefore, after the steel mesh is taken off the machine or the solder paste is not printed on the printer for 1 hour, it must be cleaned in time.
Storage conditions
Different materials have different storage environments. Steel meshes should also be stored in specific storage places and cannot be placed randomly. This can protect the steel mesh from accidental damage. At the same time, steel meshes must never be stacked together at will. This is not beautiful and not good, and it may also bend the mesh frame.
What Are the Specific Requirements for Using SMTStencil Printer
The first piece needs to be confirmed by the technician, and mass produced after being qualified;
Every 30 printed boards need to be inspected by an inspector, and then sent to the placement machine after being qualified;
After the operation of the SMT Stencil Printer is completed, remove the screen and clean it, shut it down according to the operating instructions, and clean the work surface.
When handling the solder paste with SMT Stencil Printer, you should wear rubber gloves or disposable gloves. If the solder paste is accidentally adhered to the skin, it should be cleaned with alcohol or hand sanitizer immediately, and then rinsed with plenty of water;
After the operation, the remaining solder paste, the used SMT Stencil Printer screen wipe paper and disposable gloves shall be treated uniformly in accordance with the relevant provisions of environmental laws and regulations;
Clean the equipment, tooling, and tools before use, especially the environmental protection status of the site before processing lead-free products.
During the operation of SMT Stencil Printer, the body is strictly prohibited to reach into the machine;
The longest time from printing the solder paste on the substrate to entering the reflow soldering is no more than 4 hours;
Check the integrity of the squeegee before operating the SMT Stencil Printer.
How to Maintain SMT Stencil Printer
Develop a maintenance plan
Developing a maintenance plan is the first step to ensure that the conveyor system is properly maintained. The plan should specify the frequency of inspections and maintenance and the tasks that need to be performed. Depending on the workload of the SMT stencil printer, maintenance frequency may be daily, weekly, or monthly.
Regular cleaning
The conveyor belt should be kept clean to prevent material buildup and reduce friction, which can damage the conveyor belt and cause increased wear. Regular cleaning should include removing debris, dust, and dirt from the conveyor belt, rollers, and other components. We recommend air/wipe cleaning when contaminants are dry on the conveyor belt. In sanitary environments, full washdown and sanitation guidelines are recommended.
Belt inspection
Tension-free belts make smooth operation of dynamic SMT stencil printers very simple and require little maintenance. The conveyor belt should be inspected regularly to detect any problems. Look for signs of wear, damage, belt elongation, and misalignment. Resolve any problems immediately to prevent further damage.
Inspection of SMT Stencil Printer components
SMT stencil printer components should be inspected regularly to detect wear and damage. This includes belts, rollers, bearings, motors, gearboxes, and other components. Any damaged components should be replaced promptly to prevent further damage to the system.
Proper loading
Properly loading the conveyor system will help reduce tension on the conveyor belt. Make sure the load is evenly distributed across the width of the conveyor belt and avoid overloading the conveyor belt.
Electrical connections
Electrical connections should be checked regularly to ensure they are tight. Loose connections can cause arcing, which can damage the electrical components of the conveyor system.
The SMT Stencil Printer consists of a template with a window for printing graphics, a squeegee that fills the openings of the template with solder paste, and a printing table that clamps the printed circuit board. The materials used are solder paste and printed circuit boards. When printing, you should first align the template window with the land pattern on the PCB. After positioning, put a sufficient amount of solder paste to print. While applying pressure to the squeegee, move it from left to right to make the solder paste roll. The solder paste is filled into the opening of the template.
Graphic alignment
It is essential to align the PCBA substrate and the stencil before printing, so that the PCB board pads and the stencil openings can overlap to ensure the quality of solder paste printing.
Scraper material
In the actual SMT patch processing, the scraper material is mostly steel scraper, which is convenient for solder paste forming and stripping.
Squeegee angle
The smaller the angle between the squeegee and the stencil in the solder paste printing process, the greater the downward pressure, and it is easy to inject the solder paste into the mesh hole, but too much pressure may cause the solder paste to be squeezed to the stencil the bottom surface, causing the solder paste to stick. In the actual SMT processing, the angle between the scraper and the steel mesh is generally 45° to 60°. Generally, automatic and semi-automatic printing machines use more angles of 60°.
Stencil cleaner
The stencil also needs to be cleaned. Generally, IPA and alcohol solvent are used for cleaning. Be careful not to use a solvent containing chlorine, otherwise it will destroy the composition of the solder paste and affect the processing quality.
Printing speed
Since the speed of the scraper is inversely proportional to the viscosity of the solder paste, the speed is slower when the high-density graphics are used.
Shenzhen ETON Automation Equipment Co.,Ltd. is a leading manufacturing and process solution provider focusing on R&D, production, sales, and service of SMT high-speed pick and place machines and SMT peripheral automation equipment. ETON has SMT high-speed pick and places machine division, precision solder paste stencil printer division, high-speed precision dispensing equipment division, and SMT peripheral automation equipment, division. ETON obtains a number of intellectual property technologies, including 9 invention patents, 112 practical patents, 12 software copyrights..
Our Certificate
CE certificate,CCC ce rtificate,SIRA certificate
Video
FAQ
We're well-known as one of the leading smt stencil printer manufacturers and suppliers in China. If you're going to buy high quality smt stencil printer with competitive price, welcome to get quotation from our factory.
smt stencil printing supporting, PCB Full Auto Stencil Printer, smt stencil printing standard