Friction testing is a test setup where the friction force is measured over a specified distance. Mechanical properties obtained from a friction test include the static coefficient of friction and the dynamic coefficient of friction.
Testing for the coefficient of friction values includes one or two materials: the specimen material sliding over another “substrate” material or over itself. Films, sheeting, lubricants are common materials where quality control professionals may be interested in studying or comparing the coefficient of friction values of. Perhaps the most common friction test method is ASTM D1894, a testing standard designed to measure the friction of plastic film and sheeting that can also be adapted for other materials. In this method, the friction is simulated by utilizing a stationary sled with a moving plane, or a moving sled with a stationary plane. The fixture used in such testing is the FS-CFT coefficient of friction test fixture linked here.
Material Coatings Friction Testing
Our team worked on designing test equipment for a custom and complex friction test where specimens were coated wires and plastics.
The coefficient of friction values calculated here were to provide information on the static release and the kinetic lubricity of the engineered coatings. Our customer’s coating solutions are engineered for use in medical applications including catheter systems, tipping and welding mandrels, guide wires and pull wires.
The testing objectives provided to ADMET was to quantify (1) the durability and (2) the degradation of materials to the lubricity of the coatings.
Engineered eXpert 7603 with Dual Actuators
The friction testing system was a customized eXpert 7603 single column universal testing machine with ADMET’s advanced MTESTQuattro controller and software. The major modification to the frame was a motor upgrade with the addition of a second actuator to the eXpert 7603. The two actuator design with one load cell on each allowed analyzing the bi-directional wear to the coated wire while a rigid assembly stage with linear rail design minimized friction as the system moved up and down.
Friction Test Fixtures
The fixtures supplied with the system needed to allow testing wires with a wide range of diameters. In order to provide the right solution, ADMET Applications Team ran testing using different fixturing with the customer’s specimens at ADMET.
A pin-style vise grip package was supplied with different sized mini collets with our quick-attach kit to accommodate the different diameter wire specimens. Grip inserts with different surfaces were tested and Polyoxymethylene-coated insert surface was selected based on the in-house verification testing results.
Controller & Software
The software supplied with the equipment was MTESTQuattro’s biaxial configuration. The software was configured to calculate the coefficient of friction values at each logged data point within the desired window. One of the test objectives was to quantify the durability of the coated wires. The test method for this objective was to run degradation testing of the kinetic coefficient of friction over 25 to 50 runs.
ADMET’s highly configurable and customizable load frames with detachable actuators can be used to perform a variety of tests. Our flexible designs and competitive prices mean you can find ADMET systems throughout a broad range of industries such as medical device, metals, plastics, adhesives, and transportation.
Customization points discussed above are solely a summary of an engineered solution designed by ADMET. Our Sales, Engineering, and Applications teams will work with you to ensure the testing solution supplied meets all your testing objectives.
Contact us to see how we can help with your testing needs by clicking here.