Tech Talk Blog

Rulon XL is a new alloyed polymer with excellent wear compared to even other Rulon materials. Rulon XL is compatible with soft mating surfaces such as stainless steel and aluminum, has a very low coefficient of friction and good chemical resistance with the exception being alkalis. The polymer also exhibits excellent resistance to deformation making it a good choice for bearings or seals. Rulon XL has a PV rating of 10,000 with a P of 1200 psi and a V or 400 sfpm. It is the best Rulon choice for vacuum service and also works well in steam or other wetted environments. Available in rod, sheet, tube or skived tape. Contact Tri Star at www.tstar.com for more information.

New TriSteel PE material utilizes the outstanding wear properties of PEEK, combined with the PTFE low friction additive, make this product unique in thin wall metal backed products. The PEEK liner has excellent resistance to chemicals and when combined with a stainless steel shell material it is perfect for applications in chemical pumps, valves or environments where temperature is critical. TriStar’s TriSteel PE bearing is available in inch and metric sizes as sleeve, flange and thrust bearings. Ask the Experts or visit www.tstar.com for more information.

Recent studies have proven beyond question that the surface finish of the mating hardware when using composite bearings will make or break the performance. In a rotary test, the 8rms mating surface finish had a wear rating of 1, at 16rms it increased to 1.4, 32 rms 2.2 and at 63 rms 5.3. It was also noted in the test that the method of finishing also influenced the bearing wear. Roller burnished surfaces performed the best with ground and polished next best. Turned finishes or mill finishes, even at 16rms, tended to have faster wear than the other finishing techniques.

And if that wasn’t enough for you – head over to the Video Learning Center and pick up a few more nuggets of information.

Determining the effects of aging on a package/product in real time is a lengthy process that would severely delay market introduction of new products. Therefore, a standardized test methodology was developed to accurately evaluate the environmental effect of storage on a package/product during its expected usable shelf life. Accelerated aging, which subjects samples to elevated temperatures for specific periods of time, is used to simulate the effects of real-time aging and provides data which allows the manufacturer to accurately predict the effect of real-time aging on his package/product. A product can be released to market based upon successful accelerated aging of the package/product that simulates the period claimed for product expiration. (1 year, 2 years, etc.) Concurrent with the accelerated aging process, the manufacturer should still conduct real-time studies in order to substantiate the data generated during the accelerated aging process.

• Standard Test Method: ASTM F1980; Accelerated Aging of Sterile Medical Device Packages

Methodology: Accelerated aging techniques are based on the assumptions that the chemical reactions involved in the deterioration of materials follow the Arrhenius reaction rate function. This function states that a 10° C increase or decrease in the temperature of a homogenous process, results in approximately a two times or ½ time change in the rate of a chemical reaction.
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Definition of variables:
AAR     : Accelerated Aging Rate
AATD   : Accelerated Aging Time Duration
DRTA   : Desired Real Time Aging
AAT     : Accelerated Aging Temperature
AT       : Ambient Temperature
Q10     : Accelerated Aging Factor
Q10 = 2 – industry standard
Q10 = 1.8 – more conservative option

Equations:
Step 1. AAR = Q10^ ((AAT – AT) /10)
Step 2. AATD = DRTA / AAR

Example: Time duration calculation for accelerated aging of a medical product:
One year shelf study at 55° C, where ambient temperature is 22° C and Q10= 2

Equation Sample Data
AAR = Q10 ^ ((AAT –AT) /10)
AAR = 2 ^ ((55 – 22 / 10) = 9.85
DRTA = 1 year x 365 = 365 days
AATD = DRTA / AAR
AATD = 365 / 9.85 = 38 days
NOTE: 55° C and Q10 =2 are the most commonly used factors for medical devices and medical packaging components.
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