 Dear SMT Assembler, As President of Smart Sonic, I enjoy customer interaction and feedback. As a result, I am often asked, "Why should I use the Smart Sonic Stencil Cleaning Process?" Like the Smart Sonic process, my response has remained the same over the years. The foundation of the Smart Sonic Stencil Cleaning Process is the 440-R SMT Detergent, which has enabled us to provide the same superior process to hundreds of users worldwide since 1990 - the best chemistry, the right machines and the correct waste management. Without 440-R SMT Detergent, Smart Sonic would be "just another stencil cleaner." Since it's introduction, the Smart Sonic Stencil Cleaning Process has been Certified by the California Environmental Protection Agency in 1999 and also Verified by the U.S. EPA's ETV Program*, evaluated by industry experts resulting in two SMT Vision Awards, the Global Technology Award, the Canadian High Technology Award, finalist in the NEPCON West Milton S. Kiver Award for Excellence, and nominated for the President's Green Chemistry Challenge Award. The Smart Sonic Process has been field tested by hundreds of satisfied customers such as Motorola, Intel, H.P., Lucent, Sony, Jabil, and Flextronics... Plus, we guarantee our process to clean any type of solder paste from any fine-pitch stencil! Competitive stencil cleaners have had to change their process several times since 1990 in an attempt to keep up with the ever changing environmental and user safety regulations and new solder paste formulations. None of the current competitive processes have been used for more than a few years, which means that their long-term safety and effectiveness are unknown. The fact that these systems have not been certified certainly makes them suspect. EPA regulations have forced assemblers to change from CFC based processes and are now targeting VOC based systems. Safety regulations have forced assemblers to stop using flammable solvents such as alcohol in stencil cleaner machines because of the fire and explosion hazards. New flux types have forced assemblers to search for new chemistries, new cleaning machines and often, new waste management systems. Assemblers not using the Smart Sonic Stencil Cleaning Process may have gone through 2, 3 or even more stencil cleaning systems since 1990. We have saved our customers thousands of dollars and much aggravation involving stencil cleaning process changes. Smart Sonic is the only stencil cleaning system to withstand the "test of time." Smart Sonic users are the only assemblers that have used the same chemistry, the same machine and the same waste management since 1990. We have saved our customers thousands of dollars and much aggravation involving stencil cleaning process changes. It's a complete and guaranteed process that passed Cal/EPA Certification and completed the U.S. EPA Environmental Technology Verification (ETV) Program* in 1999." There is no risk placed on the buyer. Why would anybody want to buy anything else? If you should have any questions regarding stencil cleaning, please do not hesitate to contact me. I truly enjoy discussing the topic. Sincerely, Bill Schreiber President E-mail: bill@smartsonic.com Tel.: +1-818-610-7900 |
Stencils that are cleaned for storage purposes should be allowed to dry naturally. Natural air-drying conserves energy and frees the machine for additional wash cycles. Automatic drying of every stencil on every cycle wastes time, energy and, if heated, will damage the stencil.
In cases where the stencil is required for production, the fastest and safest way to dry a stencil is with hand-held, low-pressure (15 psi) dry compressed air (the same air used to operate a pick and place machine). The principal is not to "blow" the water off of the stencil; it is to apply the dry air to the surface of the stencil. The dry air absorbs the moisture. It's like seeing alcohol evaporate. You can dry a 29" stencil in approximately 2 minutes. Or, the Model 6000 Stencil Cleaner is available with optional automatic drying using low-pressure and low temperature dry air, which takes 6-8 minutes to dry a stencil.
Heat will damage the stencil and high-pressure air will bend delicate land mass areas between fine-pitch apertures. High-pressure nozzles are also a hazard. If loose, they can become projectiles and cause injury. High-pressure air (air knives) can cause "fugitive" solder balls to become airborne.
Return to TopAll Smart Sonic Stencil Cleaners are designed to clean up to a 29-inch (750mm) stencil. Larger stencil may be cleaned with minor modifications to the machine.
Return to TopNo! Studies have shown that there are two primary factors that can affect the adhesive bond of the screen to the frame and metal etched foil. Heat is the most common cause of adhesive breakdown. The adhesives used to construct the stencil are heat-cured at approximately 160 degrees F (70 C). If a stencil is washed in hot water or dried with hot air, the heat-cured adhesive can weaken and fail. Also, the metals used to construct the stencil (aluminum frame, stainless steel or polyester screen and stainless steel, brass or nickel metal etched foil) will expand and contract which stresses the adhesive bond.
The second factor is long exposure to moisture. Adhesives are hygroscopic (absorb moisture). Long cleaning cycles or soaking times will cause the adhesive to swell and weaken.
The Smart Sonic process cleans without heat and wash cycle times are less than 2 minutes. Stencils are cleaned safely and fast.
Return to TopWet solder paste will clean in 1 - 2 minutes, depending on the flux type. Drying can be accomplished naturally, or expedited by using hand-held low-pressure dry compressed air (approximately 2 minutes). The total cycle time to wash, rinse and dry a stencil, when using hand-held dry air is approximately 3 - 4 minutes.
Return to TopNo! Many stencil manufactures recommend the Smart Sonic Stencil Cleaning Process not only because it cleans better than other stencil cleaners, but also because it will not damage the stencil.
High temperatures and high pressures are what cause stencil damage. Hot wash water or hot drying air will breakdown the glue on a stencil and cause distortion due to expansion and contraction. High-pressure sprays and high-pressure air knives will bend the delicate land mass areas between fine-pitch apertures.
Return to TopOther stencil cleaners require that the user buy the machine from one vendor, the chemistry from another and the waste management system from still another. No one vendor is expert on the complete process and the user is expected to take total responsibility. When the process fails, the different vendors blame each other and the user is stuck in the middle with little recourse.
Smart Sonic provides the complete process and guarantees the performance. The Smart Sonic Stencil Cleaning Process has been field tested since 1990 by well over 1,000 users. The process works, it is safe and it is economical.
Return to TopSmart Sonic is the most widely used stencil cleaning process in North America. Over 1,000 systems have been installed worldwide. Customers include: Intel, Motorola, Jabil, Sony, Flextronics, Temic, Nokia, For a complete list of companies, visit the Smart Sonic Web Site: www.smartsonic.com/users.html
Return to TopThe Models 1500 and 1550 will use approximately 2 gallons (7.5 liters) of 440-R SMT Detergent per month. The Model 6000 will use about 4 gallons (19 liters) per month.
The energy required to operate the machines is very low because 440-R SMT Detergent is not heated, the ultrasonic generator has a very low amp draw and the cleaning cycles are very short.
When using an optional evaporator to manage the wastewater, energy consumption is very low because wastewater is evaporated at a rate of 4 - 6 gallons per hour. Therefore, an evaporator servicing a Model 1500 or 1550 will only be operating approximately 10 - 12 hours per month (20 - 30 hours per month for a Model 6000).
Return to TopUltrasonic technology is capable of delivering the 440-R SMT Detergent into fine-pitch apertures where spray systems cannot penetrate. High-pressure spray systems are known to bend delicate land mass areas between fine-pitch apertures. In addition, spray systems will "broadcast" the solder paste throughout the cleaning chamber causing solder ball contamination of misprinted PCBs.
Return to TopThe most important factor of any cleaning process is always the chemistry. Smart Sonic's 440-R SMT Detergent is the "backbone" of the cleaning process. Without 440-R SMT Detergent, ultrasonic stencil cleaners will not clean as well.
Smart Sonic introduced the first ultrasonic stencil cleaning process in 1990. We have more experience in ultrasonic stencil cleaning than all other competitors combined.
Return to TopYes. Misprinted substrates clean in much the same manner as fine-pitch stencils. Solder paste from within vias will also clean well.
Return to TopPopulated misprinted PCBs should never be cleaned in a "spray" style stencil cleaner. The solder balls from side "B" will broadcast throughout the wash chamber and contaminate the components on side "A".
A Smart Sonic Ultrasonic Stencil Cleaner does not spray or circulate the wash solution. The PCB can be oriented with the paste side down. When using an ultrasonic stencil cleaner, the solder paste from side "B" falls freely away from the board by gravity. Components on side "A" are less likely to become contaminated with solder balls when using ultrasonics.
When cleaning populated misprints, frequencies should be kept at 40 KHz or higher (the lower the frequency, the more aggressive the cleaning action) and ultrasonic power should be kept at a minimum. Because of the efficiency of 440-R SMT Detergent, Smart Sonic does not need to use high-powered ultrasonic energy. Research indicates that ultrasonic power should be kept lower than 10 watts per liter of wash solution. Because of the superior cleaning efficiency of 440-R SMT Detergent, Smart Sonic systems are able to clean effectively at less than 10 watts per liter of wash solution! Assuring the utmost safety for populated assemblies. [Total power of ultrasonic energy (watts) / Total capacity of wash tank solution (liters) = Total watts/liter]
Return to TopWhen ultrasonics was first developed in the 1950s, the technology was very crude and uncontrollable and the PCBs were very cumbersome and delicate. The two technologies were not compatible. Delicate wire bonds would break because of the low (20-25 kHz) and constant frequencies that were used. The lower the frequency, the more aggressive the ultrasonic cleaning action.
Today's ultrasonic systems are the most controllable precision cleaning technology available. The user can control virtually every parameter. In addition, today's PCBs are very compact and durable. The two technologies are now very compatible. Many Smart Sonic customers clean double-sided misprints with their ultrasonic stencil cleaner.
When cleaning populated misprints, frequencies should be kept at 40 KHz or higher (the lower the frequency, the more aggressive the cleaning action) and ultrasonic power should be kept at a minimum. Because of the efficiency of 440-R SMT Detergent, Smart Sonic does not need to use high-powered ultrasonic energy. Research indicates that ultrasonic power should be approximately 10 watts per liter of wash solution. Smart Sonic systems are able to clean effectively at less than 10 watts per liter of wash solution! Assuring the utmost safety for populated assemblies.[Total power of ultrasonic energy (watts) / Total capacity of wash tank solution (liters) = Total watts/liter]
Contact Smart Sonic for copies of published papers on this subject.
Return to TopNo! With Smart Sonic's 440-R SMT Detergent, you will be able to clean any type of solder paste in the same machine at the same time.
Other stencil cleaners use chemistries that only selectively clean a few types of solder paste. They may clean RMA well but fail when attempting to clean no-clean or lead-free. (Alcohol is a good example of a selective or "vertical" type of chemistry).
Return to TopIt is estimated that up to 72% of all solder defects are a result of the screen printing operation. Thus, having a clean and accurate stencil is a major concern. An SMT stencil that has maintained good structural integrity and has zero contamination within the apertures will produce a better and more consistent print, which reduces incidence of misprints and downtime.
Return to TopYes and no. They are similar in that they all use ultrasonic cavitation as the mechanical scrubbing action. However, some require very high ultrasonic power because of the poor cleaning characteristics of the chemistry used. It has been demonstrated that high power ultrasonics can damage populated PCBs. The cleaning efficiency of 440-R SMT Detergent allows Smart Sonic to use the lowest effective ultrasonic power in the industry, assuring safety when cleaning populated misprints yet effectively cleaning stencils better than any other process. Without the proper chemistry, all ultrasonic stencil cleaners are similar. Some may have a few more "bells and whistles", some may be better engineered ergonomically or for ease of use, but they all use ultrasonic cavitation as the mechanical scrubbing action.
Return to TopSmart Sonic has been manufacturing ultrasonic stencil cleaners since 1990. We have made the mistake years ago that new competitors are just now experiencing. A 29" stencil is only contaminated a maximum of 25-26 inches from one end. Therefore only 26 inches of the stencil requires immersion. The remaining 3 - 4 inches remains outside of the wash solution and serves as a convenient "handle." Otherwise, the user would need to wear gloves or the stencil would need to be placed into a basket.
Systems that totally immerse a 29" stencil need to be made taller to accommodate the additional 4 inches. This additional height makes it more difficult to load and unload. If the stencil is totally immersed, the user will need to load the stencil into a basket. Now, the user will need to lift the weight of the stencil and basket. The basket handles will be above the stencil which means the user will need to use a step ladder to clear the top of the machine.
OSHA frowns on an operator lifting anything above their shoulders. Therefore an automatic hoist may be required. If a step is used, OSHA may require a handicap ramp installation. A ramp will occupy 3 times the floor space as the cleaner.
Buy making the tank only as large as the required cleaning area, the system is more efficient, uses less wash solution and therefore generates less wastewater.
This is just one of the many advantages that Smart Sonic has gained from years of experience.
Return to TopYes! However, cleaning adhesives is not quite as easy as cleaning solder paste. Wash cycle times are usually 2-3 minutes and most adhesives require warm wash water (95 degrees F, 35 degrees C).
Ultrasonic scrubbing (cavitation) is a pulling action caused by the implosion of millions of microscopic vapor bubbles. This pulling action is very affective in cleaning particulate matter (such as solder balls in solder paste). The particulates actually help carry the paste away from the stencil.
Adhesives, on the other hand, are soft, elastic and without particulate matter. Ultrasonic cleaning of adhesives is like "pulling on a rubber band". Contact Smart Sonic for a copy of the recommended protocol for cleaning adhesives with a Smart Sonic Stencil Cleaner.
Return to TopYes! This is an excellent application. The only variables are that the wash water should be approximately 120 degrees F (46 degrees C) and the detergent will "load" with flux during the cleaning process. If oven radiators or large quantities of pallets are being cleaned, a filter recirculator system may be required to help keep the wash solution fresh. Smart Sonic is the only ultrasonic stencil cleaner recommended by Permali for cleaning Durostone pallets.
Return to TopWhen cleaning no-clean, RMA and lead-free solder pastes, the Models 1500 and 1550 will use approximately 2 gallons of 440-R SMT Detergent per month. The Model 6000 will use approximately 4 gallons per month.
Because 440-R SMT Detergent does not react with the solder paste and is not consumed during the cleaning process, the amount of chemistry used to clean solder paste is very predictable.
When cleaning post solder flux residue or SMD Adhesives, the amount of 440-R SMT Detergent used will depend on the amount of contaminant cleaned. If large flux contaminated items are cleaned, such as oven radiators, a filter recirculator system installed on the wash tank will remove excess flux and prolong the life of the chemistry.
Return to Top440-R SMT Detergent does not react with the solder paste and is not consumed during the cleaning process. The only reason the chemistry need be changed is for preventative maintenance purposes. An ultrasonic bath is a "standing pool of water." As with any standing water, if left long enough, it may begin to develop odors. Because 440-R SMT Detergent is so economical, the fastest and cheapest way to maintenance the wash water is to change it regularly. When cleaning solder paste, we recommend that the wash water be emptied and replaced with fresh solution once per month.
Because 440-R SMT Detergent does not react with the solder paste and is not consumed during the cleaning process, the amount of chemistry used to clean solder paste is very predictable.
When cleaning no-clean, RMA and lead-free, the Models 1500 and 1550 will use approximately 2 gallons of 440-R SMT Detergent per month. The ErgoSonic and Model 6000 will use approximately 3 and 4 gallons per month respectively (based on changing the wash water every four weeks).
When cleaning post solder flux residue or SMD Adhesives, the amount of 440-R SMT Detergent used will depend on the amount of contaminant cleaned. If large post-solder flux contaminated items are cleaned, such as pallets and oven radiators, a filter recirculator system installed on the wash tank will remove excess flux and prolong the life of the chemistry.
Return to TopYes. However, the EPA Certification and performance guarantees are based exclusively on the use of 440-R SMT Detergent. If another chemistry is used, the Smart Sonic machine will only perform as well as some other stencil cleaners.
Return to TopThe waste solder paste simply falls to the bottom of the wash tank by gravity. Models 1500 and 1550 Series have shallow tanks where the waste solder paste may be easily accessed by wiping the tank bottom after draining the wash solution. An optional removable tray (Quick Kleen Liner) is available to capture the solder paste. The Quick Kleen Liner is removed from the tank bottom, wiped clean and replaced.
The Model 6000 and ErgoSonic incorporate a "Sparge" system that flushes the tank bottom with water, forcing the waste solder paste out a drain outlet and then captured in a gravity trap (Quick Kleen Trap). The solder paste is removed from the trap by simply unscrewing the plastic container. The container is wiped clean and replaced.
The waste solder paste can be recycled via a dross process or dehydrated and melted in a wave solder pot.
Return to TopThe Smart Sonic process is better than "closed-looped." The process is "closed from the environment." Traditional closed-loop systems eventually have spent solvent for disposal. Solvents are always environmentally problematic.
A Smart Sonic process does not add any additional hazardous waste streams. The non-hazardous liquid is evaporated to atmosphere. The waste solder paste is recycled via existing protocols. The only waste product is the dehydrated detergent residue from the 440-R SMT Detergent (approximately 4 - 5 lbs. per month).
Return to TopNo. The Smart Sonic wastewater can be filtered in the same manner as other aqueous stencil cleaner wastewater. However, when using filtration, there is always an effluent left over for disposal. Most users prefer not to discharge an effluent to drain because of the associated liabilities. i.e. The EPA regulations state that if there is a hazardous contamination of the drain system (lead) and the source of the contamination cannot be identified, all generators of lead wastewater within a 50-mile radius will share in the cleanup of the contamination.
When using evaporation, there is absolutely no liquid hazardous waste for disposal and nothing goes to drain. Evaporators cost less than their ion exchange or reverse osmosis filtration counterparts. Using evaporation is an advantage that Smart Sonic has because of the non-hazardous 440-R SMT Detergent. Other systems cannot evaporate their wastewater because the cleaning chemistry contains hazardous ingredients such as ethyl ether or VOCs.
Return to TopNo. The Smart Sonic Stencil Cleaning Process is closed from the environment when using an evaporator. A drain line strainer is provided to capture any fugitive solder balls that may be discharged with the wastewater in order to protect the transfer pump. However, the wastewater is discharged to the evaporator - nothing goes to drain. Therefore, because all waste material only ends up in the evaporator, special filters are not necessary. The non-hazardous liquid is safely evaporated to atmosphere and all solid material precipitates out for solid disposal.
By eliminating the need for filters, maintenance is reduced and the cost of replacement filter media is eliminated.
Return to TopEnvironmental regulations are constantly changing. A stencil cleaner that is legal today might not be legal in the near future. In the early 1990s, virtually everyone was cleaning with CFC solvents. Today's regulations disallow CFCs. Many companies have purchased equipment to utilize other solvents, such as alcohol or terpenes. Today's regulations have restricted the use of these solvents, because of VOC (volatile organic compound) emissions and/or fire, explosion and safety hazards placed upon the user, resulting in additional process changes and equipment purchases.
A California EPA Certified Process and U.S. EPA Verified Process provides the user with specific information relevant to environmental safety, user safety and process efficacy.
Return to TopSmart Sonic's 440-R SMT Detergent was the first stencil cleaning chemistry to be CAS Certified in 1997. However, CAS Certification certifies only the chemistry from its original container. It does not take into account the resulting waste stream. Stencil cleaning has been identified as the most hazardous process confronting an SMT assembler because of the lead from the solder paste and because of some of the hazardous chemistries associated with cleaning raw solder paste. Just because a chemistry is CAS Certified does not mean that the process is environmentally safe. Only California EPA Certification and U.S. EPA Verification encompass the entire cleaning process and waste streams.
Return to TopYes, The Smart Sonic Stencil Cleaning Process has received more industry awards than any other cleaning process. This is important because experts within the industry have evaluated the process and have acknowledged its advantages and merits.
Awards include:
Warranty: All Smart Sonic Stencil Cleaners are backed by the best warranty in the industry. The ultrasonic transducers are unconditionally guaranteed not to crack, depolarize, deteriorate or become detached from the radiating surface for ten years. The Ultrasonic Generator is guaranteed to be free from defects in workmanship and materials for a period of two years and the remainder of the Smart Sonic Stencil Cleaner is guaranteed for one year. All guarantees include parts and labor, f.o.b. Smart Sonic.
Plus, when using Smart Sonic's 440-R SMT Detergent, all Smart Sonic Stencil Cleaners are guaranteed to clean any type of solder paste from any fine-pitch stencil!
Return to TopSmart Sonic Stencil Cleaners are very easy to maintain:
Wastewater Evaporators:
EZ-0Factory service is available. However, the Smart Sonic systems are designed so local personnel can perform service, a tremendous post warranty advantage. Machine designs are very simple and straightforward. Complete electrical, plumbing, mechanical and layout schematics are provided with every Operations Manual. Free unlimited technical support is available to all Smart Sonic customers.
Return to Top* Information on the performance characteristics of this technology can be found at www.epa.gov/etv, or call Smart Sonic at 1(818) 610-7900 for a copy of the ETV verification report. Use of the ETV® Name or Logo does not imply approval or certification of this product nor does it make any explicit or implied warranties or guarantees as to the product performance.