Standard Operating Procedure - silanex.com · Standard Operating Procedure Thermally Conductive Adhesive:Product Name ... Thermally conductive adhesives ST0903 and S100 are epoxy
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1 Notes 1.1 Product Features
Thermally conductive adhesives ST0903 and S100 are epoxy glue which realizes adhesion by the chemical reaction between epoxide resin and the firming agent.
Significant amount of metal is mixed with the resin to achieve high heat-conducting property and low heat capacity.
Main features: High heat-conducting property and low heat capacity.
An adhesive material with ultra-high bonding strength; It is perfect to achieve adhesion between different material without applying any mechanical part.
ST0903 and S100 polymerized at room temperature or below. This low-temperature curing characteristic prevents
heat sensitive components from thermal damage during assembly process. Cured ST0903 and S100 are electrically insulated which improves the safety class of the products.
ST0903 and S100 are in paste and suitable for automatic dispenser, manual operation and stencil printing.
1.2 Important Reminders 1.2.1 Operating temperature
Thermally conductive adhesives are very susceptible to heat. It is important to follow below storage and operation guideline.
Storage temperature (in unopened original packaging):
Storage temperature Storage life
25℃ avoid light 1 month
-2℃ avoid light 12 months
Visual check
Detection of deteriorated product.
1) Color of glue is not consistent. 2) Bubbles are observed when the glue is squeezed out from the mixing tube.
3) Bubbles are observed inside the hardened glue or the glue has poor adhesion.
Transportation temperature (in unopened original packaging):
Transportation temperature Storage life
50℃ avoid light 14 days
25℃ avoid light 30 days
Please keep open packaging adhesive away from light and heat.
Operating temperature:
Operate the adhesive glue at room temperature (25℃). It could be difficult to squeeze out the adhesive if temperature is too low.
1) Viscosity of the adhesive increases if the room temperature is too high. It is recommended to put the squeezed adhesive aside for 30 minutes before using.
2) Viscosity of the adhesive decreases if the room temperature is too low. It is recommended to slightly heat up the adhesive to reduce the viscosity before using.
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Curing temperature Longer curing time is needed if too much adhesive glue is applied. Following data is just for reference:
Curing temperature Surface drying time Curing time
25℃ 3-5 hours 36 hours
40℃ 1-3 hours 24 hours
60℃ 30 min 4 hours
80℃ 15 min 1 hour
100℃ 10 min 45 min
1) Never apply the adhesive twice. Aging test must be run after the adhesive glue is completely hardened to avoid the LED from peeling-off due to thermal stress.
2) It is suggested to apply the adhesive glue by stencil printing or automation process at production to maintain consistent adhesive glue amount and thickness.
3) It is strongly recommended to apply heat for sample test curing at the first time to ensure a completely hardened adhesive glue.
Warning: Poor bonding and LED peeling-off will occur if the curing temperature or curing time is not sufficient.
1.2.2 External factors
Wires / Optics
Solutions:
Change the production processes to firstly attach LED on the heat sink with adhesive glue. Do not connect any wire and ensure no mechanical force is applied to the LED before the adhesive glue is hardened (surface drying).
Utilize a fixture to hold the LED position if necessary. Use soft wires.
Do not apply screws on the LED (especially before the adhesive is hardened) Use recommended stencil design to ensure right adhesive glue is applied.
Speed up curing by heat.
1.2.3 Surface contaminations
Solutions: Check the contact surfaces of both the LED and the heat sink to ensure no oily substances and/or solder flux is left on
the surface. Do not apply adhesive on any oily surface. Clean the surface with alcohol if oily contamination is found.
Apply the adhesive glue on gloss surfaces only. Polish the rugged area if it is found on the heat sink surface.
Do not apply adhesive glue on an heat sink with rugged surface and dust.
Oily substances could seriously impact on the curing of the adhesive glue and result in system failure.
Wires and optics may easily lift the LED from heat sink if the assembling is done before
the adhesive glue is hardened. This may cause LED overheating and system failure.
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2.1.4 Stencil Cleaning
To clean the cured adhesive glue, please drop acetone onto the hardened adhesive glue and apply for 5 minutes.
Then clean the stencil with microfiber cloth which contains acetone.
How to deal with surplus adhesive 1) Rub the stencil with microfiber cloth which contains alcohol or toluene until it is clean.
2) A mixing tube can be reused twice if it is not blocked by hardened adhesive. 3) A used mixing tube can be frozen immediately after use.
Do not reuse the mixing tube more than one time.
2.2 Automatic Dispenser and Chip Mounter Operations
Silanex’s adhesive glues are suitable for automatic assembly production operations. The setup normally includes an automatic dispenser and chip mounter.
Please contact us for further discussion if it is required.
Step 2
Real Product Finish
After cleaning Before cleaning
Please clean the stencil with microfiber cloth which contains alcohol or acetone after use.
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3 Disassembly 3.1 Notes on Disassembly
3.1.1 The adhesive glue printing area should be 2mm smaller on each side of the LED substrate to allow easy disassembly.
3.1.2 Keep the whole disassembly away from any flame.
3.2 Disassembly Steps
Bake the heat sink for 5-10 minutes at 100℃
After
Remove the heat sink from the oven and carefully remove the LED
with a flat-bladed screwdriver
Put the heat sink on a workbench and apply appropriate amount of acetone around the LED substrate and heat
sink surface.
Before
1 2
3 4
Remarks:
If adhesive had overflowed, firstly apply appropriate amount of acetone around the edge of LED substrate and apply for 5-10 minutes, then remove the overflowed adhesive before step 1
If the LED is still not removable, once again apply the acetone and further remove the overflowed adhesive Clean the heat sink surface thoroughly before re-attach LED onto the heat sink according to 2.1.3