Why Zero‑point Drift Occurs After Potting Robot Torque Sensors? Protective Adhesives May Also Affect Accuracy

Zero‑point shift, increased temperature drift or altered output curves after potting robot torque sensors and tactile sensors are not always caused by chip damage. Modulus, curing shrinkage, thermal expansion, potting thickness of encapsulant, as well as contact mode with sensitive areas, may generate extra mechanical loads.

Torque Sensor Potting

For ordinary PCBs, the priority is robust protection.

For torque sensors, the requirement is protection with minimal interference to measurement.

How to Judge Different Zero‑point Drift Phenomena

Phenomenon	Suspected Root Cause	Recommended Verification
Immediate zero‑point change right after potting	Curing shrinkage / mechanical constraint	Zero‑point reading before and after potting
Significant drift upon temperature rise	Thermal expansion stress	Temperature‑zero‑point curve
Incomplete recovery after cooling	Residual stress	Thermal cycle test
More obvious drift with thicker adhesive	Excessive structural coupling	Different potting thickness
Noticeable variation among batches	Process consistency	Adhesive dosage / curing condition
Drift after medium exposure	Material compatibility	Immersion test

Why Low‑stress Property Outweighs High Strength

Torque sensors measure tiny mechanical variations. If the protective material forms a high‑modulus shell after curing, extra constraint will be imposed on the deformation of sensitive structures. Hence evaluation criteria differ greatly from adhesives for magnet steel bonding.

	Magnet Steel Structural Bonding	Torque Sensor Protection
High shear strength	High priority	Normally not the primary factor
Low modulus	Secondary (design‑dependent)	High priority
Curing shrinkage	Concerned	Critical concern
Temperature drift impact	Indirect	Direct verification required
Moisture‑proof & insulation	Required	Required
Structural load‑bearing	Required	Interference shall be avoided

FSGEL 3200

Torque Sensor Potting

FSGEL 3200 is a one‑component fluoro‑silicone gel for protection of sensors and power modules. It features medium‑resistance encapsulation, insulation and protection for sensitive components. In robot‑related applications, FSGEL 3200 serves low‑stress flexible cushioning and precision electronics protection for torque / tactile sensors.

Industry Pitfall

The most common mistake: only conducting waterproof test without sensor performance test. Passing IP waterproof rating merely proves sealing performance.

For torque sensors, the following items shall be tracked sequentially: Zero‑point before potting → Zero‑point after potting → Zero‑point after curing → Zero‑point after thermal cycling → Zero‑point after aging.

Scenario‑based Adaptation

Scenario	Is Low‑stress Gel Recommended?
Torque sensor	Yes
Tactile sensor	Yes
MEMS sensitive component	Yes
Pressure‑sensitive element	Yes
Magnet steel structural fixation	No
Load‑bearing housing bonding	No