Wednesday, 6 January 2016

Friction "Pinch" testing of Hydrophilic Coatings on Catheters

These days angioplasty, is an endovascular procedure to widen narrowed or obstructed arteries or veins, is almost considered a routine procedure, yet the technology behind it is exacting and subject to rigorous quality and performance control. In this procedure an empty, collapsed balloon, known as a balloon catheter, is passed over a wire into the narrowed locations and then inflated to a fixed size. The balloon forces expansion of the narrowing within the artery or vein and the surrounding muscular wall, opening up the blood vessel for improved flow, and the balloon is then deflated and withdrawn. A stent may, or may not, be inserted at the time of ballooning to ensure the vessel remains open.

Not only are the stents themselves, and the wire used in their construction, tested for tensile strength, compressive strength and stiffness properties, so too are the balloon catheters used to deliver the stent into the body. In recent times, more attention is being paid to the frictional properties of the hydrophilic coating of the catheter’s outer surface must be qualified, known and controlled. At Tinius Olsen we have developed a test system which accurately measures, and records, the frictional forces developed between the catheter and a known surface finish applied at a given and controlled “Pinch” force. The pinch force and surface finish provide the known parameters for each test, so any variation in the measured friction forces is derived from the variation in the catheter surface. 

The test is a cyclic test where the catheter specimen is repeatedly subjected to the pinch force against the known surface finish as shown in the clip Click Here . The test is conducted within a saline solution environment which is heated to, and maintained at, body temperature. 

The output from the Tinius Olsen system includes specific results; friction force, time, and the position of the catheter as its cycles through the test process. It also produces test graphs that show the catheter’s performance. It is these results and graphs which qualify the quality and capability of the catheter’s surface coating.

Tinius Olsen systems can be configured to test the mechanical quality and performance of a wide range of medical devices subjecting them to tensile, compression, bending, shear, torsional, impact and hardness tests.

Monday, 4 January 2016

Two New Fantastic Products in Automation of Tension Compression Materials Testing

Hope to see you at Control exhibition in Stuttgart Germany April this year because we are launching two new fantastic products in automation of tension compression materials testing, it will all be live on our booth Hall 1 # 1327 check this clip for a preview of the event

Tuesday, 17 November 2015

Micro Flex Bend Test On Cell Phone Components

A Tinius Olsen testing machine can be used to test the performance and strength of the very “BIG” say a piece 40mm diameter reinforcing bar ripping it apart under a tensile load of 889,644 N (90 metric tons force) or the very “small” say micro electronic and electrical components, forces less than 5 N . Testing electronic components requires small attachments which are fitted to the tension compression materials testing machine to hold the material under test and apply the required force. Recently we supplied a tension compression system which included a micro flex bend attachment to facilitate bend tests on flexible membranes used in mobile and cell phones.

The unit pictured part 99-1004733-330-034 is a variable span (can be adjusted by the user) 3 point flexural bend attachment with a span up to 30mm and points of contact diameter 3mm.

Pictured here with a 5N load cell (Force measuring device) mounted on the testing machine through which the loading force is applied and measured.

The same Tinius Olsen system can be used to perform tests on components in tensile, peel and shear by simply changing the specimen support attachments and selecting the predefined test method from the library of methods in the Tinius Horizon materials testing software. Equally by adding a temperature chamber tests can be performed not just at ambient but at low and elevated temperatures allowing for performance comparison under differing conditions.