Solder Composition
Sn63 alloy is the conventional eutectic solder used in most electronic assemblies. The Sn63 alloy conforms and exceeds the impurity requirements of J-Std-006 and all other relevant international standards.
Material Safety Data Sheets (MSDS)
XP692 No-Clean Solder Paste MSDS
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Typical Analysis
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| Sn |
Pb |
Cu |
Ag |
Sb |
Bi |
In |
As |
Fe |
Ni |
Cd |
Al |
Zn |
Au |
62.5- 63.5 |
Bal. |
0.030 Max |
0.020 Max |
0.050 Max |
0.050 Max |
0.050 Max |
0.010 Max |
0.010 Max |
0.050 Max |
0.010 Max |
0.010 Max |
0.010 Max |
0.020 Max |
| |
Sn63 |
| Melting Point, °C |
183 E |
| Hardness, Brinell |
14HB |
| Coefficient of Thermal Expansion |
24.7 |
| Tensile Strength, psi |
4442 |
| Density, g/cc |
8.42 |
| Electrical Resistivity , (µohmcm) |
14.5 |
| Electrical Conductivity, 104/ohm-cm |
6.9 |
|
|
| | Sn63 |
| Yield Strength, psi |
3950 |
| Total Elongation,% |
48 |
Joint Shear Strength, at 0.1mm/min 20 C |
23 |
Joint Shear Strength, at 0.1mm/min 100 C |
14 |
Creep Strength, N/mm2 at 0.1mm/min 20 C |
3.3 |
Creep Strength, N/mm2 at 0.1mm/min 20 C |
1 |
| Thermal Conductivity, W/m.K |
50.9 |
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Particle Size
Sn63 alloy is 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% | |
| 1 | 20 | 75-150 | | 150 | 160 | 100/200 |
| 2 | 20 | 45-75 | | 75 | 80 | 200/325 |
| 3 | 20 | 25-45 | | 45 | 50 | 325/500 |
| 4 | 20 | | 20-38 | 38 | 40 | 400/635 |
| 5 | 15 | | 15-25 | 25 | 30 | 500 |
| 6 | 5 | | 5-15 | 15 | 20 | |
Metal Loading
Typical metal loading for stencil printing application is 89.0-90.2 %.
Solder Paste
Qualitek XP692 is a new generation no clean solder paste for surface mount and other electronic assembly applications (PCB Assembly). XP692 provides features such as fine pitch capability (<16 mil), high-speed printing, and probable residues. In addition, XP692 Lead Free paste exhibits excellent wettability, extraordinary print definition and tack life. The post soldering residues of XP692 are non-conductive, non-corrosive and highly insulated.
Main Features
- Low residues
- Extended stencil life
- Long tack time
- Excellent wettability
- Soft, non-tacky post solder residue
PRINTING
SMT Stencils
Use of chemical etched/electroformed stencil is preferred for printed circuit board assembly however XP692 has been used successfully with chemical etch, electroformed, and laser cut stencils.
Squeegee
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Blades: |
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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.
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Pressure: |
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Pressure should be adjusted at the point where the no clean solder paste leaves a relatively clean SMT stencil after each print pass.
Typical pressure setting 0.6-1.5lb per linear inch of blade.
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Speed: |
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Normal print speeds are 1.0-2.5 (25-50mm) per second. As print speeds increase pressure will need to be increased. XP692 paste is capable of printing up to 6 in/sec.
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Print Definition
XP692 provides excellent print definition characterized by brick-like prints. Good release is seen on 12-9 mil apertures. Tack values are high even after extended open time in both normal and high humidity environments.
Refer to data sheet
Open & Abandon Time
Tests have proven that XP692 will perform during continuous printing for up to 10 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
No Clean 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 destroy 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 the no-clean 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 XP692 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
XP692 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 no clean 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 68-77F (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) 1 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 no clean 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
No clean 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) or Qualitek SMT stencil cleaner, SK-11. If you have a more elaborate board cleaner, the paste may be easily removed with use of a 5% saponifier solution in hot DI water. Qualitek SK-44 saponifier could be used in this process.
Stencil Cleaning
Periodic cleaning of the SMT stencil during production is recommended to prevent any paste from being deposited in unwanted areas of the board. Without stencil cleaning, solder balling will increase. We recommend a periodic dry wipe (every 5 to 10 boards) with an occasional wet wipe (every 15 to 25 printed circuit boards). When running fine pitch circuit 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
XP692 should be stored in a sealed container and disposed of in accordance with state & local authority requirements.
Packaging
| DEK Proflow Cassette |
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800 gm |
| 6 oz Jar |
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250-500 gm |
| 6 oz Cartridge |
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500-700 gm |
| 12 oz Cartridge |
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1000-1400gm |