®
Technical Data Sheet
EP256HA Solder Paste
No-Clean
Product Description
EP256HA is a no-clean, air or nitrogen reflowable solder paste specifically designed to provide maximum print charac-
teristics and solderability on lead-free parts using leaded solder paste. EP256HA has been designed for applications that
require the ultimate activity with respect to difficult to solder to components and board surface metalizations. EP256HA is
also capable of stencil printing after downtimes of up to 90 minutes with an effective first print down to 20 mils. EP256HA
is a solder paste formula that maintains its activity and printing characteristics for up to 8 hours without any shear thinning.
Performance Characteristics:
■
Excellent solderability on difficult to
solder to components, i.e., PdAg
■
High activity on all substrates,
including OSPs
■
Capable of 90-minute break times in
printing
Standard Applications:
For stencil printing: 90% Metal
■
Excellent printing characteristics to
0.4mm (16 mil) pitch with Type 3
powder
■
High print speeds to 150 mm/sec
(6 in/sec)
■
Stable tack over 8+ hours
■
Stencil life: 8+ hours (process
dependent)
■
Scrap is reduced due to less paste
dry out
■
Classified as ROL0 per J-STD-004
■
Compliant to Bellcore GR-78
RoHS Compliance
Kester does not determine any applicable Restriction of Hazardous Substances (RoHS) exemptions for our lead
containing products at the user level.
Physical Properties
Data given for Sn63Pb37, 90% metal, -325+500
mesh)
Initial Tackiness (typical):
37 grams
Tested to Kester Method 1W-QC-3-04
Solder Ball Test:
Pass
Wetting Test:
Pass
Viscosity (typical):
1600 poise
Slump Test:
Pass
Tested to J-STD-005, IPC-TM-650, Method
2.4.43
Tested to J-STD-005, IPC-TM-650, Method
2.4.45
Malcom Viscometer @ 10rpm and 25°C
Tested to J-STD-005, IPC-TM-650, Method
2.4.35
Reliability Properties
Copper Mirror Corrosion:
Low
Corrosion Test:
Low
Tested to J-STD-004, IPC-TM-650, Method
2.3.32
Tested to J-STD-004, IPC-TM-650, Method
2.6.15
Silver Chromate:
Pass
Tested to J-STD-004, IPC-TM-650, Method
2.3.33
Fluorides by Spot Test:
Pass
Tested to J-STD-004, IPC-TM-650, Method
2.3.35.1
Chloride and Bromides:
None
Detected
Tested to J-STD-004, IPC-TM-650, Method
2.3.35
Surface Insulation Resistance (SIR):
Pass
Tested to J-STD-004, IPC-TM-650, Method
2.6.3.3
Global Headquarters: 800 West Thorndale Avenue, Itasca, IL USA 60143
■
Phone: +1 800.2.KESTER
■
Fax: +1 630.616.4044
Asia-Pacific Headquarters: 61 Ubi Avenue 1 #06-01 UB Point, Singapore 408941
■
Phone: +65 6.449.1133
■
Fax: +65 6.242.9036
European Headquarters: Ganghofer Strasse 45, 82216 Gernlinden, Germany
■
Phone: +49 (0) 8142 4785 0
■
Fax: +49 (0) 8142 4785 61
Asia Manufacturing: Hengqiao Road, Wujiang Economic Development Zone
■
Suzhou, Jiangsu Province, China 215200
■
Phone: +86 512.82060807
■
Fax: +86 512.8206 0808
■
Website: www.kester.com
■
Application Notes
Availability
®
EP256HA is commonly available in the Sn63Pb37 and Sn62Pb36Ag02 alloys. Type 3 powder mesh is recommended, but
different powder particle size distributions are available for standard and fine pitch applications. For specific packaging
information, see Kester’s Solder Paste Chart for available sizes. The appropriate combination depends on process vari-
ables and the specific application.
Printing Parameters
Squeegee Blade
Squeegee Speed
Stencil Material
Temperature/Humidity
Stainless Steel or 80-90 Durometer Polyurethane
Capable to a maximum speed of 200 mm/sec (8 in/sec)
Stainless Steel, Molybdenum, Nickel Plated or Brass
Optimal ranges are 21-25°C (70-77°F) and 35-65% RH
Kester Reflow Profile
Alloy: Sn63Pb37 or Sn62Pb36Ag02
240
220
200
180
Recommended Reflow Profile
The recommended reflow profile for EP256HA made with either
the Sn63Pb37 or Sn62Pb36Ag02 is shown here. This profile is
simply a guideline. Since EP256HA is a highly active solder paste,
it can solder effectively over a wide range of profiles. EP256HA is
capable of reflowing at the 235°C peak temperatures required for
fully collapsing lead-free SAC BGA’s for maximum reliability, and
remains easy to clean after these high temperature profiles. Your
optimal profile may be different from the one shown based on your
oven, board and mix of defects. Contact Kester Technical Support if
you need additional profiling advice.
Peak Temp.
210-230 C
Temperature (C)
160
140
120
100
80
60
40
20
0
0
30
60
90
120
150
180
210
240
270
300
330
<1.8 C/Sec
(120 sec. max.)
30-60 sec. typical
Soaking Zone
(90 sec. max)
45-75 sec. typical
Reflow Zone
Time to Peak Temperature
3.5-5.0 min. typical
5.5 min max
Time (sec.)
Cleaning
EP256HA is a no-clean formula. The residues don’t need to be removed for typical applications. Although EP256HA is
designed for no-clean applications, its residues can be easily removed using automated cleaning equipment (in-line or
batch) with a variety of readily available cleaning agents. Call Kester Technical Support for details.
Storage, Handling and Shelf Life
Refrigeration is the recommended optimum storage condition for solder paste to maintain consistent viscosity, reflow char-
acteristics and overall performance. EP256HA should be stabilized at room temperature prior to printing. EP256HA should
be kept at standard refrigeration conditions, 0-10°C (32-50°F). Contact Kester Technical Support if you require additional
advice with regard storage and handling of this material. Shelf life is 6 months from the date of manufacture when handled
properly when held at 0-10°C (32-50°F).
Health and Safety
This product, during handling or use, may be hazardous to your health or the environment. Read the Safety Data Sheet
and warning label before using this product.
Global Headquarters: 800 West Thorndale Avenue, Itasca, IL USA 60143
■
Phone: +1 800.2.KESTER
■
Fax: +1 630.616.4044
Asia-Pacific Headquarters: 61 Ubi Avenue 1 #06-01 UB Point, Singapore 408941
■
Phone: +65 6.449.1133
■
Fax: +65 6.242.9036
European Headquarters: Ganghofer Strasse 45, 82216 Gernlinden, Germany
■
Phone: +49 (0) 8142 4785 0
■
Fax: +49 (0) 8142 4785 61
Asia Manufacturing: Hengqiao Road, Wujiang Economic Development Zone
■
Suzhou, Jiangsu Province, China 215200
■
Phone: +86 512.82060807
■
Fax: +86 512.8206 0808
■
Website: www.kester.com
■