SMT gasket

This is a patch of conductive silicone foam that can be attached to a PCB using the SMT process.
It has good electrical conductivity and excellent elasticity after reflow soldering and can be used as an EMI shielding ground or as an alternative to mechanical antenna shrapnel.
At the same time, when the whole machine is subjected to external impact force, the product has a buffering function to avoid damage to other components by the impact force.

We independently developed a highly conductive PI film, which is the first in China. The total thickness can be 0.018mm, the surface resistance can be within 0.03Ω (the actual measurement is around 0.01Ω), and 3 related patents have been extended.

NO	Patent Name
1	Electromagnetic shielding material based on polyimide film
2	High temperature resistant double-sided conductive electromagnetic shielding material
3	High temperature resistant high elastic conductive electromagnetic shielding material

SMT Gasket Specification:

Item	Unit	Properties	Method
Color	---	Silver	Visual
Size	mm	Customizable	---
EMI SE	dB	＞75	ASTM D4935-99
Resistance	Ω/Sq	≤0.03	ASTM F390
Salt Spray	Ω/Sq	＜0.06	ASTM B117-03
Temp. & Humi.	Ω/Sq	＜0.05	GB/T 2423.3-2006
Operating temp.	℃	-40~280	---
Hardness	Durometer	＜50	ASTM D 2240
Compression	%	40	ASTM D3574
Compression Set	%	<8	---
Welding strength	N	14-16	GB/T 13936-2014
Operating freq.	---	10MHz ~ 10GHz	---
RoHS & Halogen	---	Pb, Cd, Hg, Cr+6, PBBs, PBDEs, Br, CI	IEC 62321
Flame retardancy	---	94V0	UL94-2013

Specification of tinned SMT Gasket

Item		Method	Properties
Material		-	Silicone rubber & conductive PI (Au-Sn / Cu plated)
Color		Visual	Silver, Gold
Size		Digital calipers	Customizable
Heat resistance		GB	Max.400℃
Operating temp.		GB	-40 ~ +280℃
Corrosion resistance	Material	HIOKI 3540 mΩ HITEST ER	Max.0.1Ω
	Temp. & Humi. (85℃ / 85%RH)		Max.0.1Ω
	Salt Spray		Max.0.1Ω
	Heat Shock		Max.0.1Ω
Welding strength		Push-pull test	Min. 1500gf / cm
Compression Set		Press 40% at 70℃ 22h	Min.95%
Resilience		Press 20% at 25℃ 40%RH	Max.1.0kgf
Flame retardancy		UL 94	UL 94-V0 equivalence
RoHS & Halogen		Pb, Cd, Hg, Cr+6, PBBs, PBDEs, Br, CI	N.D.

Specification of Gold plated SMT Gasket

Item	Method	Result
Surface Resistance	HIOKI 3540 mΩ HITEST ER	Pass
Heat resistance	85℃ & 96hr	Pass
Cold resistance	-40℃ & 96hr	Pass
Temp. & Humi	85℃ & 85%, 96hr	Pass
Thermal Shock	70℃ & 60min / -40℃ & 60min (30 cycles)	Pass
Salt Spray	Spray 5% NaCl, 1.0kgf / cm spray pressure, 35 ℃ for 48 hours, stand for 16 hours.	Pass
Compression Set	Press 40% (70℃ 22hr)	Pass

Reliability test of SMT Gasket

Product	SMT Gasket	Metal spring Gasket	Conductive cloth Gasket
Material	Silicone rubber	Metal	Resin
Operation	SMT	SMT	Manual Operation
Bonding	Welding	Welding	Adhesive
Conduction	⭐⭐⭐	⭐⭐	⭐
Performance	⭐⭐⭐	⭐⭐	⭐
Contact area	Wide	Narrow	Narrow
Size	Customizable	Limit	Customizable
Reliability	Better	Easy to break	Easy to fall off
Installation time	Less	Less	More

Comparison of advantages of SMT Gasket, Metal spring Gasket, Conductive cloth Gasket

Reflow temperature curve setting:

SMT Gasket reflow soldering temperature curve

Reflow temperature curve setting of SMT Gasket

1. Preheating zone. It is suggested that 150 ℃ should be used, the heating rate should be 1 ~ 1.5 ℃ / s, and the time should be 100 ~ 120s.

2. Activation zone. For different fluxes, the activation temperature is different. The heating rate is recommended to be 0.3 ℃ / s, and the final heating temperature is about 180 ℃. The recommended time is 90 ~ 120s.

3. Fast heating zone. The heating rate is recommended to be about 2 ℃ / s, and the time is recommended to be 15 ~ 20 s.

4. Reflux zone. It is recommended to refer to the data provided by the solder paste manufacturer for the selection of the peak temperature and overall reflux zone time. Different types of solder have different requirements for reflow temperature. The peak temperature is generally 240 ~ 250 ℃. The time of the whole reflux zone is recommended to be 40 ~ 80s. The residence time at the peak temperature is generally less than 10s.

5. Cooling zone. It is suggested that the temperature change rate should be consistent with that in the rapid heating zone, and it is suggested to set it at 1 ~ 3 ℃ / s.