A hydraulic universal testing machine (UTM) applies and controls test force through a hydraulic power pack and cylinder, while a servo controlled UTM uses closed-loop servo control for precise, programmable loading. Hydraulic UTMs suit high-capacity tensile, compression, bend and shear testing of steel, TMT/rebar and fasteners. Servo controlled UTMs suit R&D and laboratory work that needs tight control, complex test profiles and detailed data. Akuracy manufactures both configurations.
Choosing between the two is less about which is better and more about what you test, which standards you follow, and how much control and data your quality process needs.
How each drive system works
A hydraulic UTM generates force with a hydraulic cylinder powered by a power pack. Loading is robust and well proven at high capacities, which is why hydraulic machines are common for heavy tensile and compression work. Control is typically managed through hydraulic valves, with digital or computerized readout depending on the model.
A servo controlled UTM uses closed-loop control, comparing commanded load, displacement or strain against measured feedback many times per second and correcting continuously. This gives smoother loading, programmable test sequences and finer control at low loads and small displacements.
Hydraulic vs servo controlled UTM at a glance
| Aspect | Hydraulic UTM | Servo controlled UTM |
|---|---|---|
| Force generation | Hydraulic power pack and cylinder | Closed-loop servo drive |
| Loading control | Valve-based, manual or digital | Programmable closed-loop control |
| Best suited for | High-capacity QC testing of steel, rebar, fasteners | R&D, laboratories, complex or standards-driven test profiles |
| Data and software | Digital or computerized readout options | Full computer control with detailed curves and reports |
| Maintenance focus | Hydraulic oil, seals and valves | Drive system, electronics and software upkeep |
Choose a hydraulic UTM when
- You test high-strength materials at higher capacities, such as TMT/rebar, structural steel or fasteners.
- Your tests are routine quality-control tensile, compression, bend or shear tests.
- You want a robust, shop-floor-friendly machine with straightforward operation.
Choose a servo controlled UTM when
- You need programmable loading rates, holds or cyclic-style test profiles.
- You work in R&D or a laboratory and rely on precise curves, extensometer data and detailed reports.
- You test a wide range of materials and load levels on one frame.
Frequently asked questions
Is a servo controlled UTM more accurate than a hydraulic UTM?
Both configurations can meet the accuracy class required by common testing standards when correctly built and calibrated. The practical difference is control: servo systems hold programmed rates and profiles more tightly, which matters for research and standards with strict loading requirements.
Can one machine run tensile, compression and bend tests?
Yes. With the right grips, fixtures and accessories, a single UTM frame covers tensile, compression, bend and shear testing. Akuracy supplies manual or hydraulic grips and customized fixtures for applications including rebar couplers and GFRP/FRP.
What capacity should I choose?
Match the frame capacity to the maximum expected breaking load of your specimens, with headroom. Common UTM capacities range from 100 kN up to 2000 kN. Share your material, specimen size and standard with our team and we will recommend a capacity.
Ready to compare configurations for your application? Explore our material testing equipment or talk to an application engineer about your testing requirement.