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STIRRI VS UHF™ is a no-clean solder paste and tacky flux designed for stencil applications. It belongs to the rosin chemical family and meets regulatory standards like REACH (Europe). With excellent printability and a halogen-free formulation, it ensures efficient and high-quality soldering results.

Product Type: Solder Paste

Application Area: Stencil

Features: Excellent Printability

Chemical Family: Rosins

Technical Data Sheet

Knowde Enhanced TDS

Identification & Functionality

Chemical Family
Product Type

Features & Benefits

Labeling Claims
Ready-to-Use Product Features
Keynotes
  • Rosin-based low-activity ROL0 (No-clean)
  • World-class printability, instant activity response
  • Halide & Halogen-free (EN14582) - ZERO!
  • Ultra-Low voiding. Clear residue. Optimal viscosity. REACH-complaint
  • Superior dispensing or stencil printing
  • Sharp definition at high-speeds
  • Low solder balling and graping. Long stencil life
  • Easy to clean using IPA, solvents, water-based saponifiers, vapor degreaser or ultrasonic devices

Applications & Uses

Application Area

Properties

Typical Properties
ValueUnitsTest Method / Conditions
Stencil Life (at 30 - 70% R/H & 20 - 25°C)max. 12hours-

Regulatory & Compliance

Certifications & Compliance

Technical Details & Test Data

Viscosity
PRINT jar/cartridge DISPENSE syringe Tacky flux Tack force (g/cm)
120-190 100-150 40-65 35-45

* Malcom @ 10 RPM @ 25°C x10³ g/cm/s

Printer Operations

Stencil printer does not require any specific optimization, should be fully adjustable based on standard in-house process requirements, including high-speed printers

Print Speed: 20-200 mm/sec (add pressure for speed)
Squeegee Pressure: 70-540 g/cm of blade (add for speed)
Stencil Vac/Wipe: Every 10-25 prints or as necessary

Automated and vacuum cleaning systems for both stencil and misprinted boards. Manual cleaning using Isopropyl alcohol (IPA), co-solvents and/or ultrasonic scrubbers, vapor degreaser.

Test Results
IPC-TM-650 Test Value Result
Corrosion 2.6.15 L: No corrosion PASS
Copper Mirror 2.3.32 L: No breakthrough PASS
ECM (No-clean) 2.6.14.1 <1 decade drop PASS
Quantitive Halides 2.3.28.1 L: <0.05% PASS
SIR Test (No-clean) 2.6.3.7 ≥100 MΩ PASS
Printing

Optimal print definition for fine pitch applications. Long stencil life of this product virtually eliminates waste of solder paste. For mesh/size determination refer to the Pitch Requirements chart below:

 

Size (micron) Type Value
75 - 45 μm T2 24 mil +
45 - 25 μm T3 16 - 24 mil
38 - 20 μm T4 12 - 16 mil
25 - 15 μm T5 < 12 mil
20 - 5 μm T6 < 8 mil
Sample Reflow Profile

STIRRI MT HF™ (No-clean Solder Paste & Tacky Paste Flux) - Sample Reflow Profile - 1

Mt° Profile-A can be used as a starting point for the leaded process optimization with Sn60, Sn62, Sn63 alloys. A cooldown rate of 2-4°C/sec is ideal for the formation of fine grain structure without risking damage to thermally sensitive components.

STIRRI MT HF™ (No-clean Solder Paste & Tacky Paste Flux) - Sample Reflow Profile - 2

Mt° Profile-B is an alternative approach to solder Sn60, Sn62, Sn63 utilizing a soak of up to two minutes at 155°C may help to minimize voiding in leaded BGA, LGA & QFN assembles. This will allow more time for solvent components of the solder paste to outgas prior to reflow.

STIRRI V3™ (No-clean Solder Paste & Tacky Paste Flux) - Availability - 1

LF Profile as a starting point for lead-free process optimization using SAC305/SAC307 alloys. A cool down rate of 2-4°C/sec is ideal for the formation of fine grain structure without risking damage to thermally sensitive components.

STIRRI V3™ (No-clean Solder Paste & Tacky Paste Flux) - Availability - 2

LT Profile as a starting point for low-temperature process optimization using Sn/Bi alloys. To achieve better results with voiding or reduce tombstoning, consider using a longer soaking zone.

Packaging & Availability

Availability

STIRRI-VS-HF™ - available in many alloys including high reliability solder: Sn42Bi58, Sn42Bi57.6Ag0.4, Sn42Bi57Ag1, Sn96.5Ag3.5, Sn96.5Ag3.0Cu0.5, Sn99Ag0.3Cu0.7, Sn99.3Cu0.7, Sn100c, Sn100cv, LF-C2

Packaging Information

Options with various viscosity and metal load for stencil printing and dispensing applications:

  • Printing: Jars, 1/4 NPT nozzle cartridges
  • Dispensing: Syringes, ProFlow cassettes

Storage & Handling

Shelf Life, Storage, and Handling

Refrigerated storage at 5-7°C will prolong the solder paste shelf life to no less than 6 months. Solder Paste should be allowed to reach ambient temperature, normalize for about 6-8 hours before use. Tacky flux has 24 months shelf life stored in room temperature. Refrigeration won't extend shelf life. Normalize for 4-6 hours if stored refrigerated. Paste/flux in syringes and cartridges should be kept vertically, dispensing tip pointing down.

Note :NEVER FREEZE SOLDER PASTE / FLUX!