Solder Connection

Solutions in Soldering Technology

OM-340 Lead-Free Solder Paste

ALPHA® OM-340 is a lead-free, no-clean solder paste designed for a broad range of applications. OM-340 provides best in class low defect rate for Head in Pillow defects combined with excellent first pass yield on ICT/pin testing. OM-340 also yields excellent  print capability performance across various board designs and, particularly, with ultra fine  feature repeatability and high “through-put” applications.

Outstanding reflow process window delivers superior soldering on CuOSP with excellent coalescence on a broad range of deposit sizes,  excellent random solder ball resistance and mid-chip solder ball  performance. OM-340 is formulated to deliver excellent visual  joint cosmetics and best in class in circuit pin test yields.  Additionally, OM-340’s capability of IPC Class III for voiding and ROL0 IPC classifications ensures maximum long-term product reliability.

Key Products Features & Benefits:

  • Maximizes reflow yield for lead-free processing,  allowing full alloy coalescence at circular dimensions as small as 200μm  (8 mil) with 100μm (4 mil) thick stencils.     
  • Excellent print consistency with high process capability index across all board designs.     
  • Print speeds of up to 150mm/sec (6”/sec), enabling a fast print cycle time and a high throughput. 
  • Wide reflow profile window with good solderability on various board / component finishes. 
  • Excellent solder and flux cosmetics after reflow soldering.                
  • Best in class low defect rate for Head in Pillow.
  • Best in class in circuit pin test yield.                
  • Reduction in random solderballing levels, minimizing rework and increasing first time yield.
  • Meets highest IPC 7095 voiding performance classification of Class III.                
  • Excellent reliability properties, halide-free material.                
  • Compatible with either nitrogen or air reflow.                
  • Zero halogen (No halogen intentionally added to the formulation). 
  • J-STD Classification - ROL0           


Product Number : OM340

Prod. No. 152800
Alpha OM-340 SAC305 500g


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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