Solder paste dispensing is often used to attach later-stage components to PCBs that have already been populated with devices but this also requires multiple reflow stages to arrive at the final product. Typical examples of this are RF shield metal cap attachment on a mobile phone motherboard and discrete device attachment on a package substrate.
Nordson ASYMTEK's in-line, SMEMA-compatible and batch dispensers are fully programmable, single-point dispensing platforms that easily adapt to most production requirements for accuracy, speed and process carrier design.
A range of field-proven auger valves allows for a wide selection of paste materials. Nordson ASYMTEK's Heli-Flow™ Series Pump with closed-loop velocity control delivers consistent dot volume.
Non-contact laser height sensing or low-force height sensing delivers accurate and consistent dispense height control for excellent dot repeatability and consistent solder paste line widths. Improved designs of the latest generation of platforms from Nordson ASYMTEK contribute to the dispensing consistency and accuracy over the entire wet dispense area.
Other solder paste dispensing applications include:
- Solder paste rework after screen printing to address designs that are difficult to screen print
- Soldering rework for component replacement
- R&D testing, before a solder printing stencil is designed
- High-mix, low-volume production, as a lower-cost alternative to solder screen printing
To ensure a successful solder paste dispensing process, keep these facts in mind:
- Solder paste with 84 to 86% metal by weight is most ideal for dispensing
- Dots smaller than 300 microns typically require solder paste type 5 or type 6 and a 28 to 30 gauge needle
- Controlling the dispense gap is very important for achieving consistent dot size or line width. If substrates are warped, additional process controls like frequent height sensing, will be required
Nordson ASYMTEK offers systems that are capable of dispensing solder paste in a wide range of operations including production, labs and R&D, and on many surfaces, including recesses.
These systems can be configured with the DV-8000 auger valve or the piezo-driven SV-100 Slider Valve™ depending on your specific solder paste application. Choose the platform that best meets your production requirements – from batch (like the Spectrum™ S-820) to inline systems (Spectrum™ II S2-910).
To read more about solder paste dispensing:
Advancements in Solder Paste Dispensing
D. Ashley, S. Adamson (SMT Magazine, July 2008) (PDF 500 KB)
Formulation Considerations for Automated Dispensing of Lead Free Solder Paste
A. Lewis (2003) (PDF 254 KB)