Avoid the Pain of Pinched Fingers

We heard from many of our customers about pinched fingers when changing grip faces. And we all know how much that can hurt. So, we developed a safety guard for our pneumatic side acting grips that virtually eliminates finger pinching.

These guards also have graduation marks that help with specimen alignment. The v-notch on the center of the guards locates the center of the clamping faces and is ideal for testing wire or round stock. You can adjust the guards laterally, which allows just enough space to insert the specimen, but not your fingers. And no matter the size of your specimen - or your fingers - these guards are available for different clamping faces.

We uploaded a "How To" video showing a lab operator using the safety guards. Take a look! Read more

Plastics Testing Challenge 5: Testing in Non-Ambient Conditions

Most plastic products are expected to be used in various environments and conditions, some of which include cold and hot temperatures. Mechanical properties of plastics are influenced by temperature which makes it very important for designers to consider the plastic’s performance over the temperature range a given product is expected to perform in. While environmental chambers are available to simulate both cold and hot temperatures, it is challenging to identify the appropriate extensometers and fixtures to use at these extreme temperatures.

Solution: The majority of our basic standard clip-on style extensometers are designed to work within a temperature range of -100 to 200° C (-148 to 392° F), which covers a vast range of the testing needs. However, there are some applications that have higher temperature requirements, and for these applications, we recommend our high-temperature clip-on extensometers, which can be used in temperatures as high as 540° C (1004° F).

Tip: Video extensometers, such as the AVE, can also satisfy requirements for a variety of hot and cold applications. The AVE can mount to the outside door of most Instron® environmental chambers, allowing it to measure strain through the viewing window while not subjecting it to the various temperature extremes. Read more

Plastics Testing Challenge 4: System Compliance

System compliance and stiffness can impact results. When significantly high forces are expected, systems with inadequate frame stiffness are susceptible to absorbing energy from a specimen during testing and transferring it back into the specimen, which results in premature failure. At lower forces, compliance or elastic ‘give’ becomes more of an issue. When compliance is not corrected or dealt with appropriately, load and extension data may not be entirely representative of the material being tested.

Solution: When stiffness is important, using an appropriate testing system is critical. Stiffer testing frames will reduce system compliance. For overall compliance consider grips, fixtures, and adaptors.

Tip: The most effective way of eliminating the effect of compliance on test results is by using a strain measuring device, such as an extensometer, which can be attached directly to the specimen. Read more

Plastics Testing Challenge 3: Strain Measurements from Modulus to Break

Challenge 3: Strain Measurements from Modulus to Break
When testing various plastics it can be difficult to select an extensometer that is capable of accurately measuring modulus and strain at break. This is true for extensometers where accuracy is inversely proportional to travel and the strain at break is 50% or higher, which is common for many thermoplastics.

Solution: For operators that remove the extensometer at yield or test materials that strain less than 50%, a traditional clip-on style extensometer is highly recommended. For operators testing higher elongation materials to failure, we have two recommendations:
1. For non-contacting measurement, the video extensometer is an excellent choice.
2. For contacting solutions, we recommend an automatic contacting extensometer where the measuring arms are counterbalanced and operate on a nearly frictionless linear guidance system. Read more

Plastics Testing Challenge 2: Thin Films

Challenge 2: Thin Films
One of the most common plastics test is tensile testing of thin films. Two common challenges are often encountered including instances when specimens fail at the grip and uneven stress distributions.

Both issues are strongly influenced by the grip type, type of jaw face, and specimen alignment. When the appropriate configuration is not utilized, repeatability and reproducibility of results will deteriorate and vary.

Solution: To minimize or eliminate specimen failures at the gripping point, it is important to accurately position the specimens vertically in the tensile grips. Our new pneumatic side acting grips have an optional alignment device, ensuring that each specimen is installed in a precise vertical position, and oriented along the centerline of the load string.

Tip: Specimen preparation is an extremely important factor to consider when evaluating the repeatability of results. Specimens with nicks, cuts, and non-parallel edges will impact repeatability. Read more

Mo and Jo Cycle the Boston Marathon

Mo and Jo are ready to go the distance in the Boston Marathon. Tell us your marathon testing stories.

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Pounding the Pavement

Do your athletic shoes rebound the way you expect? Extreme sports activities, such as basketball, skateboarding or even running the Boston Marathon, are placing more challenging demands on today’s athletic shoes. These activities can result in impact forces at more than 10 times one’s bodyweight.

Shoe designers investigate the impact and rebound performance of different materials and structures. In addition to normal, daily uses, our customers are under pressure to develop new designs of sports shoes with advanced air cushioning, gel-filled capsules, or complex sole structures that offer superior technical performance.

ASTM F1614 "Standard Test Method for Shock Attenuating Properties of Materials Systems for Athletic Footwear” includes evaluating the energy returned by a shoe during impact, the amount of cushioning provided by different shoe and sole designs, and the long-term fatigue behavior of the shoe. Read more how our ElectroPuls™ Systems test to ASTM F1614.

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