875LF No Clean Lead Free Solder Paste (250 Gram Jar)

875LF No Clean Lead Free Solder Paste (250 Gram Jar)

Temporarily Out Stock
Part #: 875LF
Lead Time: 250 Gram Jar
Manufactured by Qualitek this solder paste uses a unique flux system designed specifically for high temperature lead free alloys. Qualitek alloys are designed as a lead-free alternative for Sn/Pb alloys used in Printed Circuit Board assembly operations.

  • Sn63/Pb37 MP=217-221°C
  • Stencil life > 8 hours
  • Extraordinary tack time
  • Halogen and lead free
  • Speed 25-50mm per second
  • No clean formula
  Specification Test Method
     
Flux Classification ROL0 JSTD-004
     
Copper Mirror No removal of copper film IPC-TM-650 2.3.32
     
Silver Chromate Pass IPC-TM-650 2.3.33
     
Corrosion Pass IPC-TM-650 2.6.15
     
SIR    
JSTD-004 1.54 x 1012ohms IPC-TM-650 2.6.3.3
Bellcore (Telecordia) 2.51 x 1010 ohms Bellcore GR-78-CORE 13.1.3
     
Electromigration Pass Bellcore GR-78-CORE 13.1.4
     
Post Reflow Flux Residue 51% TGA Analysis
     
Metal Loading 88.5% ± 0.5 IPC-TM-650 2.2.20
     
Viscosity    
Brookfield(1), kcps 900+/-10% kcps IPC-TM-650 2.4.34 modified
Malcom (2), poise 1700-2100 IPC-TM-650 2.4.34.3 modified
Thixotropic Index 0.50-0.60  
     
Slump Test    
25 C, 0.63 vertical/horizontal No bridges all spacings IPC-TM-650 2.4.35
150 C, 0.63 vertical/horizontal No bridges all spacings IPC-TM-650 2.4.35
25 C, 0.33 vertical/horizontal No bridges all spacings IPC-TM-650 2.4.35
150 C, 0.33 vertical/horizontal No bridges all spacings IPC-TM-650 2.4.35
     
Solder Ball Test Pass IPC-TM-650 2.4.43
     
Tack    
Initial 143 gm JIS Z 3284
Tack retention @ 24 hr 128 gm JIS Z 3284
Tack retention @ 72 hr 70 gm JIS Z 3284
     
Stencil Life >8 hrs QIT 3.44.5
     
Abandon Time 60 min QIT 3.44.6
Solder Composition
Qualitek Sn/Ag/Cu (Tin/Silver/Cu) Alloys are designed as a lead-free alternative for Sn/Pb alloys for electronics assembly (PCB assembly) operations. The Qualitek Sn/Ag/Cu alloys conform and exceed the impurity requirements of J-Std-006 and all other relevant international standards.

Material Safety Data Sheets (MSDS)
798LF Water Soluble Lead Free Solder Paste MSDS

Typical Analysis
  Sn Ag Cu Pb Sb Bi In As Fe Ni Cd Al Zn Au
LF955-38 Bal. 3.6-4.0 0.5-0.9 0.050
Max
0.050
Max
0.050
Max
0.050
Max
0.010
Max
0.010
Max
0.005
Max
0.001
Max
0.001
Max
0.001
Max
0.002
Max
LF958-35 Bal. 3.3-3.7 0.5-0.9 0.050
Max
0.050
Max
0.050
Max
0.050
Max
0.010
Max
0.010
Max
0.005
Max
0.001
Max
0.001
Max
0.001
Max
0.002
Max
LF965-30 Bal. 2.8-3.2 0.3-0.7 0.050
Max
0.050
Max
0.050
Max
0.050
Max
0.010
Max
0.010
Max
0.005
Max
0.001
Max
0.001
Max
0.001
Max
0.002
Max
LF217 Bal. 3.8-4.2 0.3-0.7 0.050
Max
0.050
Max
0.050
Max
0.050
Max
0.010
Max
0.010
Max
0.005
Max
0.001
Max
0.001
Max
0.001
Max
0.002
Max


  Sn/Ag/Cu Sn63/Pb37
Melting Point, °C 217-221 183 E
Hardness, Brinell 15HB 14HB
Coefficient of Thermal Expansion Pure Sn=23.5 24.7
Tensile Strength, psi 4312 4442
Density, g/cc 7.39 8.42
Electrical Resistivity , (µohm-cm) 13.0 14.5
Electrical Conductivity, %IACS 16.6 11.9
 
 Sn/Ag/CuSn63/Pb37
Yield Strength, psi 3724 3950
Total Elongation,% 27 48
Joint Shear Strength, at
0.1mm/min 20 C
27 23
Joint Shear Strength, at
0.1mm/min 100 C
17 14
Creep Strength, N/mm2 at
0.1mm/min 20 C
13.0 3.3
Creep Strength, N/mm2 at
0.1mm/min 100 C
5 1
Thermal Conductivity, W/m.K 58.7 50.9


Particle Size
Sn/Ag/Cu alloys are available in Type 2 (75-45µm), 3(45-25µm), 4(38-20µm), and 5 (25-15µm) J-STD-005 powder distribution. Solder powder distribution is measured utilizing laser diffraction, optical analysis and sieve analysis. Careful control of solder powder manufacturing processes ensures the particles’ shape are 95% spherical minimum (aspect ratio < 1.5) and that the alloy contains a typical maximum oxide level of 80 ppm.

Classification of Solder Powders by Particle Size
Powder Type Fines Majority Coarse Typical Mesh
 <10%>80%>90%<1%0% 
12075-150 150160100/200
22045-75 7580200/325
32025-45 4550325/500
420 20-383840400/635
515 15-252530500
65 5-151520 


Metal Loading
Typical metal loading for SMT stencil printing application is 88-89%. Compared to typical Sn63/Sn62 solder pastes manufactured with 90% by weight metal loading, DSP 875 Lead Free provides as much as 10-12% higher metal volume than Sn63/Sn62. This increased in volume of DSP 875 promotes better wetting and spreading of Sn/Ag/Cu lead-free alloy.

Solder Paste
Qualitek has developed a unique flux system designed specifically for high temperature lead free alloys. It provides the fluxing activity levels that promote thermal stability and prevents thermal degradation when reflowing under air atmosphere (normal). Since use of nitrogen is not required, DSP 875LF Lead Free Solder paste will provide excellent cost savings.

In addition, DSP 875LF Lead Free paste exhibits super low spattering, superior joint strength, excellent wettability, extraordinary print definition and tack life. The post soldering residues of DSP 875LF are non-conductive, non-corrosive and highly insulated.

Main Features
  • Halogen-Free
  • Super low flux spattering
  • Low Voiding
  • Superior Hot Slump
  • Extended stencil life
  • Long tack time
  • Excellent wettability

PRINTING

SMT Stencils
Use of chemical etched/electroformed SMT stencil is preferred however DSP 875LF has been used successfully with chemical etch, electroformed, and laser cut stencils.

Squeegee
     Blades:    Metal (stainless steel) squeegee blades angled from 45-60° give the best print definition for PCB assembly. Metal(nickel) squeegee blades angled from 45-60° give the best performance. 90 durometer polyurethane may also be used.
     Pressure:    Pressure should be adjusted at the point where the paste leaves a relatively clean SMT stencil after each print pass. Typical pressure setting 0.6-1.5lb per linear inch of blade.
     Speed:    Normal print speeds are 1.0-2.5 (25-50mm) per second. As print speeds increase pressure will need to be increased. Although slower print speeds are desirable, Qualitek 875 lead free solder paste is capable of printing up to 6 inch per second.


Print Definition
DSP 875LF provides excellent print definition characterized by brick-like prints. Good release is seen on 12-9 mil apertures with prints speeds in the range of 1.0-6.0 inch per second (25mm-150mm). Refer to data sheet

Open & Abandon Time
Tests have proven that DSP 875LF will perform during continuous printing for up to 8 hrs. Field test have shown that an abandon time of at least 1 hr is possible, resulting in a perfect 1st pass print on resumption of printing.

Paste Application
Solder paste should be taken out of the refrigerator at least 3 to 6 hours prior to use. This will give the paste enough time to come to thermal equilibrium with the environment. Also, any fresh jar of paste should be gently mixed for at least one minute with a spatula. Be sure not to mix the paste too vigorously, as this will degrade the paste’s viscosity characteristics and introduce entrapped air into the paste. The purpose of the mixing is to insure that the paste is smooth and consistent. If paste is supplied in cartridges pre-mixing is not necessary due to the shear action produced from the dispensing.

Reflow
Best results have been acheived when DSP 875LF is reflowed in a forced air convection oven with a minimum of 8 zones (top&bottom), however reflow is possible with a 4 zone oven (top & bottom). Refer to data sheet

CLEANING
DSP 875LF is a no clean formulation therefore the residues do not need to be removed for typical applications. If residue removal is desired, the use of Everkleen 1005 Buffered Saponifier with a 5-15% concentration in hot 60 °C (140 °F) will aid in residue removal.

Storage & Shelf Life
It is recommended that lead free solder paste be stored at a temperature of between 35-50 °F (2-10 °C) to minimize solvent evaporation, flux separation, and chemical activity. If room temperature storage is necessary it should be maintain between 68-77 °F (20-25 °C).

Shelf life
Unopened Container (35-50 °F/2-10 °C) 6 months (from DOM)
Unopened Container (68-77 °F/20-25 °C) 3 months (from DOM)
Opened Container (68-77 °F/20-25 °C) 24 hours

Reusing Solder Paste
This is not normally recommended, because it typically generates more problems than it is worth. If you do decide to reuse lead free solder paste, these pointers may be helpful. First, Qualitek recommends putting any used paste in an empty jar, so any fresh paste will not become contaminated. This paste should be tightly sealed and refrigerated. Then, the paste may be reused at a later date, provided that the paste has not separated or thickened significantly compared to its original properties. If you have success in printing the reused paste, the paste is acceptable for use. If significant printing problems occur, discard the paste. You also may want to mix 50% “used” and 50% new to get maximum utility of the paste. This will keep the paste relatively fresh while consuming the used paste.

Working Environment
Solder paste performs best when used in a controlled environment. Maintaining ambient temperature of between 68-77 °F (20-25 °C) at a relative humidity of 40-65% will ensure consistent performance and maximum life of paste.

Cleaning Misprint Boards
If you should have a misprinted circuit board, the paste may be cleaned off manually with alcohol (IPA).

Stencil Cleaning
Periodic cleaning of the SMT stencil during production is recommended to prevent any paste from being deposited in unwanted areas of the circuit board. Without stencil cleaning, solder balling will increase. We recommend a periodic dry wipe (every 5 to 10 printed circuit boards) with an occasional wet wipe (every 15 to 25 printed circuit boards). When running fine pitch boards, the cleaning may need to become more frequent. The wet wipes should be performed with either alcohol or a stencil cleaner. Qualitek SK-11 stencil cleaner is designed for this purpose. When cleaning the stencil at the end of a job, the cleaning should be more thorough. If you have stencil cleaning equipment Qualitek SK- 44 Stencil Cleaner Saponifier is highly recommended for stencil cleaning purposes.

Disposal
DSP 875LF should be stored in a sealed container and disposed of in accordance with state & local authority requirements.

Packaging
DEK Proflow Cassette   800 gm
6 oz Jar   250-500 gm
6 oz Cartridge   500-700 gm
12 oz Cartridge   1000-1400gm

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