Solder Connection

Solutions in Soldering Technology

CVP-520 Low Temperature Solder Paste

ALPHA® CVP-520 is designed to enable low temperature surface mount assembly technology. The lead-free alloy in CVP-520 has a melting point below 140°C, and has been successfully used with peak reflow profiles between 155°C and 190°C. The flux residue is clear, colorless, and provides  excellent electrical resistivity, exceeding industry standards. This product enables the elimination of an extra wave or selective wave soldering process when temperature sensitive through hole components are  used in an assembly. Eliminating a wave soldering or selective soldering step can significantly lower the cost of producing an  electronic assembly, increase daily throughput, eliminate the need for managing bar solder and wave soldering flux supplies and eliminate the need for pallets. 

The carefully selected Sn/Bi/Ag alloy in CVP-520 was selected to give the lowest melting point, lowest pasty range during melting and  re-solidification, along with a very fine grain structure, offering maximum resistance to thermal cycle based fatigue. The alloy also yields very low voiding BGA solder joints, even when a traditional SAC alloy sphere is used. The use of Exactalloy™ performs may enable the  elimination of selective wave soldering by providing additional solder  volume when needed. All components used with CVP-520 must be  lead-free to eliminate the formation of tin/lead/bismuth intermetallic which has a melting point under 100ºC.

Key Products Features & Benefits: 

  • Enables elimination of a second or third reflow cycle when temperature sensitive components or connectors are used.
  • Reduces energy consumption in reflow ovens versus standard lead free alloys.        
  • Reduces reflow process cycle time.
  • Delivers 8 Hour stencil life. 
  • Potential eliminations of bar solder, wave soldering flux and energy costs associated with wave soldering.
  • Compatible with all commonly used lead free surface  finishes (Entek HT; Alpha Star Immersion Silver, Immersion Tin, Ni/Au,  SACX HASL, etc.)  
  • Excellent resistance to random solder balling minimizing rework and increasing first time yield. 
  • Low temperature reflow profiles may enable the use of less expensive printed circuit board substrates, when appropriate. 
  • Meets highest IPC 7095 voiding performance (Class III).                
  • Provides excellent electrical reliability properties.
  • Zero halogen (no halogen intentionally added) and halide-free material.                 
  • Compatible with either nitrogen or air reflow.
  • J-STD Classification: ROL0


Product Number : CVP520

Prod. No. 153782
Alpha CVP-520 SnBiAG 500g

Prod. No. 155029
Alpha CVP-520 SnBiAG 10cc 40g


Q - What is colophony and can it cause any health issues?
A - Colophony is a generic term for rosin, this is the sap or sticky substance that derives from pine and spruce trees. Its "stickiness" lends itself to being used in a wide range of products. We have traditionally used this product in fluxes due to these specific properties it can however lead to breathing difficulties and skin sensitivity. Always use fume filtration when soldering and change filters regularly.

Q - What is the difference between rosins and resins?
A - The terms are often used interchangeably, but rosin is a naturally occurring substance, and resin is either a modified rosin or completely synthetic material. Rosins are plant based products and are subject to more natural variation than resins, however resins are commonly used in newer flux formulations due to their more consistent performance.

Q - Do I need to change my printing process when I go to finer printing from size 3 to size 4 paste?
A - Generally when changing from T3 to T4 there is not much difference in printing setup. Depending upon the paste used you may have to make slight adjustments to print parameters such as release speed as aperture fill is greater with finer powders on small apertures but this is just to optimise the print as you would do when changing any paste. It’s by no means certain you will need to do this but it may give you further benefits.

Q - Do I need to change my printing process when I go to Ultra Fine printing from size 4 to size 5 paste?
A - The biggest change will be going to PS5 and its not so much the printing parameters changing but the stencils are invariably a lot thinner and so you need good support and setup such as making sure you have a release distance of 3 mm set (the distance over which release speed is controlled as the stencil acts more like a drum skin) I would also run with the minimum pressure to avoid stencil damage (coining) this is as most PS stencils are <100µm typically 75µm in thickness. It’s not as bad with PS4 as most stencils are in the 100µm or slightly above range and are more robust.

In all cases (can’t really think of an exception) smaller powder sizes go hand in hand with printing smaller features. Smaller features as we approach Area Ratio 0.66 and in some cases people try to/do operate in the region of AR 0.6-0.66 mean that the printing process has to be good, you have to “respect the fundamentals” i.e. board support, calibration of such things as print height, squeegee condition, decent PCB quality, registration etc.

Again more a feature of small apertures rather than the powder size of paste itself you may need to look at what is your maximum ‘abandon’ time with any paste if you run a start stop process and work to it i.e. don’t exceed and use automatic under screen cleaning where needed. Smaller apertures tend to ‘clog’ more readily and so may need a more frequent aperture clean regime.

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