TMA(Thermomechanical Analysis)principle and application

TMA, whose full name is Thermo Mechanical Analysis, is a testing method used to study the changes in dimensions of materials with temperature, time, or load during temperature changes. TMA serves as a "thermal expansion and contraction physical examination" for materials. What can TMA test?
TMA can be used to test important parameters of many materials, especially suitable for thermoplastics, thermosetting resins, films, rubbers, adhesives, foam materials, etc. The main testing items include:
Coefficient of thermal expansion (CTE)
Measure the rate of linear dimensional change of a material during heating or cooling.
For example, if the thermal expansion and contraction of the glass and metal frame of a mobile phone differ significantly, it is prone to cracking!
Glass transition temperature (Tg)
Determine the critical temperature at which the polymer transitions from a "hard and brittle state" to a "soft state".
For plastics, glues, and composite materials, this temperature is crucial.
Softening point / Melting behavior
It helps to understand when the material starts to "collapse", deform, or flow.
Creep behavior Simulate whether the material will slowly deform under high temperature and continuous pressure, and evaluate its long-term thermal stability. How is TMA tested?
The working principle of the TMA tester is actually quite "sophisticated":

Place the sample in the heating furnace;
Apply a very small pressure or load to the sample;
During the heating or cooling process, record the dimensional changes of the sample (such as elongation, compression, or bending)
Finally, output a curve representing "displacement vs. temperature".

Purpose of TMA testing In the fields of material research and development, product design, and quality control, TMA testing plays a crucial role:

When developing new materials → determine whether the thermal properties of the material meet the design requirements
When selecting encapsulation or bonding materials → assess thermal expansion compatibility to avoid thermal cracking
During aging or reliability analysis, assess whether the material will deform under long-term high temperature conditions
During quality anomaly analysis, identify the true cause of thermal stress failure

TMA Test Instance

Thermal stress issue between PCB board and encapsulation adhesive In the electronics industry, if the CTE (Coefficient of Thermal Expansion) difference between PCB boards and encapsulation adhesives is too significant, stress concentration may occur during repeated heating and cooling processes, ultimately leading to delamination and cracking, severely affecting product reliability.
Through TMA (Thermal Mechanical Analysis) testing, we can identify these thermal performance mismatches in advance and promptly replace materials or optimize structural designs.