How No-Clean Solder Paste Helps in Speeding Up the Assembly Process

The assembly process can be tedious and time-consuming, but you can improve it with the right materials and solutions, like the no-clean solder paste. It is practical for reflow and ultra-fine feature printing applications, but unlike conventional liquid fluxes or pastes, the no-clean variant may speed up the process of soldering for higher throughput. Cleanable solder paste material prints and reflows Type 5 and Type 4 powder to meet the requirements of processes in ultra-fine applications. The best formulations of a no-clean flux has a sufficient reflow process window to provide reliable soldering on CuOSP, with superb coalescence on various deposit sizes. Moreover, they display excellent mid-chip and random solder ball resistance.

No-clean solder paste ensures good print volume deposit, which can be repeated numerous times without fail. This way, it provides value to your soldering process when it reduces the risk of defects, which typically come from variability in the print process. The printing performance is considered excellent, but in case of residue after the reflow, it can easily be removed or cleaned with relevant cleaners or nPB-based solvents.

A no-clean flux can add a level of safety to manufacturers and workers involved in the soldering and assembly process, as it contains no halogen or lead. It is also designed for Type 5 and Type 4 powders. Cleanable solder paste provides longer stencil life, as it ensures consistent results to reduce paste dry-out and variations in the print performance. High tack force life guarantees higher pick-and-place yields and proper self-alignment, and the wide reflow profile window makes the product useful in soldering high-density and complex PWB assemblies in N₂ environments with high ramp rates, and a soak profile as high as 170° Celsius to 180° Celsius.

There are many other benefits to using a no-clean solder paste, including better coalescence and enhanced wetting performance, and excellent flux residue and solder joint cosmetics. The formulation complies with TOSCA, halogen-free requirements, EINECS, and RoHS, so it is considered environmentally friendly and safe.

Features and Applications of Lead-Free Solder Bar

Going lead-free may be the best in certain applications where safety and reliability are prioritized, and when the assembly process can be compatible with it. The lead-free solder bar is one of the most flexible products, particularly if it is developed and formulated by an established and reputable company that provides soldering solutions. This way, you can be confident in using technologically advanced solder products that offer high throughput applications and high reliability. Here are some of the important things to learn about lead-free solder bars:

• The composition – Leading lead-free solder bar can be made of Sn95.5Ag4Cu0.5 or Sn96.5Ag3Cu0.5, with replenishment alloys being Sn96.5Ag3.5Cu0, Sn96Ag4Cu, and Sn97Ag3Cu0, all of which are lead-free alloys that are safe replacements for the Sn63 alloy. Replenishment alloys stabilize on the reduction of copper content during wave soldering, depending on the conditions of the process.
  
  
• It removes impurities – The alloying process in high-quality lead-free solder bars eliminate oxides and other impurities that can affect the quality of the joints. Alloy conditioning helps reduce dross generation, too.
  
  
• Increase yield – A good lead-free solder bar ensures the best in class yield that may surpass the quality of performance of Sn/Cu-based materials. Faster wetting helps speed up the manufacturing process and solderability for higher throughput and increased productivity. Excellent drainage minimizes the chances of bridging, unlike when you use certain types of Sn/Cu alloys. This way, it delivers dependable performance across various flux technologies.
  
  
• Helpful to electronic assemblers going lead-free – Lead-free solder bar works with lead-free surface mount and wave soldering applications.
  
  
• Recommended temperatures – You need to make sure that the solder pot temperature is within the range of 491 to 509° Fahrenheit (255° to 265° Celsius). The manufacturer should be able to provide a guide to help you select the right solder bar for your application.

Is Solder Dross Recyclable?

Solder dross is made up of layers of impurities and oxidized metal that collect on the solder’s surface and it is typically produced during the selective or wave soldering process. It is technically leftover solder that still has over 90 percent of metal in it, with drossing rate dependent on agitation, alloy type, and temperature. Instead of letting all the remaining metal go to waste, smart electronic assembly companies turn to solder dross recycling, which refines the recycled material into a new solder bar.

Solder dross recycling services are safe and environmentally friendly, and they allow you to meet legislative and environmental requirements of your city or state. Moreover, they enable you to maximize returns on solder dross, paste waste, and scraps. Reputable manufacturers of solder dross offer these services as a part of their commitment to be responsible for the environment, with recycling facilities located in key areas around the world. With their help, metal waste streams are responsibly and efficiently recycled into highly pure raw materials, which can be reused once more. They serve a wide array of markets including computers, telecommunications, automotive, power supply, semiconductor packaging, IT, photovoltaic, medical and military, television and displays, and LED.

The benefits of solder dross recycling apply to your business, too. The process itself is simple, as you only need to get in touch with an appropriate solder manufacturer that offers the service and make arrangements for pick-up. So, it should not have to disrupt your daily operations. Some recycling companies offer flexible custom programs that will suit your unique requirements, too.

                

When considering solder dross recycling, be sure to pick a reputable and dependable company that has a good track record. Check if they have a minimum weight requirement for pickup. Some companies can recycle any amount of dross you may have generated for the time being. Also check if they can provide you with the vessels, and make sure that there are no additional fees.

Emerging Applications for Low Melting Point Solders

Electronic assembly requires the use of proper solders to establish electrical circuits and connections. Low melting point solders are fairly new and have the potential to be a low-cost way to establish reliable and strong joints. Low melting point solders are suitable for surface mount technology processes and they deliver high-quality joints while reducing operational costs, as they reduce the need for additional materials, labor, and energy. Using the material in through-hole steps can replace two critical SMT steps and the wave soldering process, resulting in more value for electronics manufacturers.

A lead-free alloy in a good solder material provides a lower melting point while exhibiting temperature resistance in advanced thermal cycling tests. Using low melting point solders can create value to your company and assembly process once it is established in your electronic assembly procedure. SAC alloys used to be the main alloys used in large-scale electronic manufacturing when lead-free standards were initially implemented. However, some manufacturers have begun looking into innovative alloy alternatives for their SMT processes, as lead-free soldering continues to thrive in the industry.

A low melting point of 138°C enables peak reflow temperatures between 170 to 180°C. The SnBiAg alloy system in the solder paste meets those parameters for reflow and melting point. Some lead-free alloys in certain products may have a lower melting point, but the resistance is good against accelerated thermal cycling tests in consumer electronics. This way, low temperature SMT processes help eliminate the wave soldering step, which is often a part of mixed technology assemblies.

Low melting point solders can be practical as you implement an SMT-only assembly process to ensure higher and streamlined throughput. It lets you switch to a low-temperature processing that can enhance secondary soldering, a process that will enable you to rework certain components, like RF shields that must be soldered separately. Low temperature alloys may also be used as an alternative to mercury in certain applications, so you can ensure the safety of your workers.