Torque, also called moment or moment of force, is the tendency of a force to rotate an object about an axis or pivot. Torque is rotational force. Twisting the female to male fitting, to remove or replace the connection, is an example of applying torque. The amount of torque developed is proportional to the force applied and to how far from the center of the rotation the force is applied.
When making manufacturing decisions for medical device applications and other material testing applications it is important to know the product’s torque and angle capacity. How easy or difficult it is to twist a cover, connector, or switch is important to the practitioner using the product. Biopsy needles are inserted and then twisted to remove a sample. If the value of force needed to insert the needle was not calculated precisely, it could effect the practitioner’s ablity to retrieve a proper sample. If a conical fitting was not tightened to it’s full torque capacity, there may be liquid leakage, air leakage, stress cracking, and/or separation.
ADMET suggests the following systems to perform a range of static and fatigue torsion tests.
eXpert 3610 Biaxial or Horizontal eXpert 81T 20 Nm Torsion Testers
- Vertical or Horizontal orientation
- Tabletop Torsion Testers// 0.1Nm to 500Nm(4,500 in-lb)
- Floor standing Torsion Testers //to 11,000 Nm (100,000 in-lb)
- Employ a linear slide design to allow:
- maximum torsional stiffness
- minimal axial friction
- A reaction torque transducer is attached to a movable tail stock mounted on a linear slide
- Interchangeable torque transducers available
- Linear slide dimensions sized to accommodate specimen lengths
- The tail stock can be left free floating or clamped during testing
- Most systems have unlimited rotation in the clockwise and counter clockwise directions
- Ability to apply axial forces through a dead weight pulley system or optional linear actuator
- Optional linear displacement transducer to measure tailstock movement
- Speed range – determined by customer input. Torsion fatigue testing systems are capable of performing sine, square or sawtooth waveform amplitude control to 20 Hz
- Data export capability – .csv, ascii delimited, .jpg, bitmap image
- FULLY Customizable-The length of the test bed, servo motor, and gearing is modified to accommodate varying specimen lengths, capacities and test speeds.
Grips and Fixtures
eXpert 81T Torsion Testers can be equipped with collets, chucks and drive sockets to hold and twist your specimens.
- ADMET will also machine custom adapters to accommodate unusual shapes and sizes
- Environmental baths with heating and cooling systems meet aerospace and medical device test requirements.
ASTM and ISO Torsion Test Standards
ISO 594/1and /2-1986 describes the dimensions, testing profile, and parameters for testing conical fittings with a 6% (luer) taper for hypodermic syringes, needles, and certain other medical equipment, such as transfusion and infusion sets. This standard covers rigid and semi-rigid materials for guaging and performance.
- Several of the mechanical tests in section 5, figures 4+5, require torque testing. In ISO 594-1, an axial force of 27.5N(5lbs) is applied for 5 seconds while applying 0.1Nm torque load to an angle of 90 degrees.
Recommended system for sections 5.2.1, 188.8.131.52, 5.5.1 is an ADMET eXpert 81T Torsion Tester with MTESTQuattro Torsion PC Based controller or with an eP Torque digital controller, dead weight pulley, and grips.
ASTM F1541– External Skeletal Fixation Devices This test method has many different annexes for testing Fixator connectors, joints, rings, pins, sub-assemblies and constructs.
- 81T Torsion Tester or
- eXpert 7600 single column testing frame or
- eXpert 3600 Biaxial or Triaxial Tester.
- MTESTQuattro Torsion, MTESTQuattro, or MTESTQuattro Integrated. Depending on which annexes you would like to perform.
- Request a quote
ASTM A938-07 – the torsional strength of wire.
Recommended system 81T Torsion Tester, 12Nm, MTESTQuattro Torsion, Collet Chuck, 5c Collet, Dead Weight Pulley System