Medical Device Link.

Originally Published EMDM September 2003

Testing Equipment News

A line of high-potential testers for electronic products and components features a user-friendly interface for easy setup. Supplied by QuadTech (Maynard, MA, USA), the Sentry Plus series testers have a large LCD that indicates programmed test conditions, as well as the output voltage and leakage at the test connection to the device. The units use both visual and audible fail indicators and require resetting after a failure and before making another measurement. Other features include a pause mode with operator prompts and a ground continuity test with displayed results. The units also have front and rear panel connections. In addition to fast device discharge and rapid shutdown on fail, the Sentry Plus design includes a ground fault interruption circuit. This safety feature is designed to shut down the unit in case an operator comes in contact with the output.

The Sentry 50 ground bond tester can be used with the devices for high-current testing of the ground connection on an electrical product. When used together, the two instruments provide complete product testing at the push of a button. 

The equipment can run one or more stand-alone continuity tests with programmable pass-fail limits. Measured results can be displayed over the range of 0.1 to 5 ž. Remote start input and pass-fail outputs ensure that the units adapt quickly to most production test environments. 

Machine vision system rapidly reads data on caps’ circumference

A new sensor used with a machine vision system can read data matrix and alphanumeric codes on the circumference of medicine bottle caps. A single camera is able to cover 360° of a cap’s side surface using a specially designed lens and light source. Introduced by Vitronic GmbH (Wiesbaden, Germany), the vision system reads the caps in motion at speeds of 18 m/min, reaching a throughput of five bottles per second. During the production cycle, each bottle is identified by a seven-digit code on the first line and a three-digit code on the second line. 

In one pharmaceutical application in which the vision system is used, the bottles are marked after being filled and are placed in the sterilization chamber. As sterilization begins, the vision system verifies the chamber contents to ensure that different batches have not been mixed together. This verification is necessary, because the labels are applied to the bottles later in the process. 
To make the characters readable by the vision system, Vitronic has developed a grey-scale correlation process. In contrast with standard OCR algorithms, the matching process does not rely on image binarization. This technology reportedly increases performance when there are variations in brightness and other impediments. The camera uses a special lens that views the entire circumference of the cap. The image resolution is approximately 0.01 mm. 

Vitronic’s vision systems include complete process documentation, with all steps and system changes automatically entered in an audit trail.

Systems perform tests on surgical needles

Two needle-testing systems perform puncture and bend tests on straight and curved surgical needles. Available from Instron (Canton, MA, USA), the testers ensure that needles are sharp enough to puncture tissue with minimal force yet strong enough not to bend excessively during use. Designed to provide accurate low-force testing, the systems are suitable for quality control and R&D applications. 

The puncture test system includes a special fixture to align curved needles with the test membrane. During the test, a torsional drive rotates the needle through an arc to maintain a constant entrance angle to the membrane. Force on the anvil is used to calculate bend properties. A setup fixture is provided for alignment of different size needles: 1¼2- and 3¼8-circle needles of various radii and wire sizes can be tested. The membrane holder rotates to allow each puncture to be done on a fresh test area. 

Production-line leak tester developed for medical products

A compact pressure decay–type leak tester offers a low-cost alternative for automatic testing. The M-1045 medical tester provides quality assurance and statistical process control data for such products as diagnostic and analytical equipment, filters, and IV systems. Supplied by Intertech Development Co. (Skokie, IL, USA), the microprocessor-controlled system monitors test pressures up to 100 psig. It controls fill and bypass and stabilize times automatically, and reports the results on a vacuum-fluorescent display.

While operating in “normal” test mode, real-time pressure changes, pressure drop due to leakage, date and time of test, and type of fault are displayed. No operator judgment is required. Lighted indicators on the front panel show amber for “test-in-progress,” green for “accept,” and red for “reject.” The instrument can also convert pressure drop data to display actual leak rate in standard cubic centimeters per meter. 

Test results reflect transducer accuracy of 0.05 psig, with transducer sensitivity and repeatability at 0.005 psig. The transducer operates in self-check mode and a seal check feature monitors fixture integrity. Calibration is simple and automatic, initiated by a single keystroke on the touch pad. The unit automatically stores data for the last 100 tests. Stored test data can be recalled for display, printing, or downloading.

Equipment tests catheter- and stent-delivery products

Data gathered during testing of catheter- and stent-delivery products can have a direct impact on a manufacturer’s product design. And, in turn, this information will affect how end-users such as interventional cardiologists or radiologists employ these types of products. Realizing the value of accurately measuring performance criteria, Machine Solutions Inc. (Flagstaff, AZ, USA) recently introduced its Interventional Device Tracking Equipment (IDTE) at the MD&M East 2003 trade show.

A personal computer controls the IDTE, which has an adjustable PFA track that enables both 2- and 3-D testing. “The track can be configured to simulate the different parts of a patient’s anatomy,” says James P. Kasprzyk, the company’s director of global marketing. Typical configurations mimic the aortic arch for coronary procedures, or the superficial femoral artery or iliac branches for peripheral applications. Stepper motors push catheters through the tortuous path that is submersed in water maintained at body temperature.

A data-collection feature samples up to 100 data points per centimeter of the product being tested. The information is saved in a spreadsheet format for further analysis. It can be used in US FDA submissions, pre-clinical-trial testing, marketing literature, competitive product testing, or product design calculations. 

The IDTE measures catheter characteristics including push efficiency, guidewire movement, device crossability, trackability force, catheter flexibility, and device lubricity. Stents can be tested for device lubricity, expansion force, and retention force.

Torque tester holds samples up to 8 in. in diameter

A motorized torque test stand is capable of testing up to 100 lb-in. of torque. The Model TSTM by Mark-10 Corp. (Hicksville, NY, USA) is suited for materials testing, bottle-cap testing, fastener testing, and related applications. The rotary table has tapped holes on its surface for fixture mounting, and a dial on its side for angle measurement. It can accommodate test samples or fixtures of up to 8 in. diam. 

The sensor bracket is part of a lockable slide mechanism for ease of engagement with the test sample. Adjustable mechanical stops allow repetitive testing. The remote console contains an adjustable speed control for the internal motor. A knob for manual position control is also provided. The modular design allows the stand to be used as a component of larger or automated systems. 

Leak detector incorporates blockage test

Developed for manual or semiautomatic test benches, a leak detector features four test programmes and fast fill system. The F535 from Ateq (Les Clayes-sous-Bois, France) features easy setup and has a choice of front or rear output connections and three measurement ranges. A front-mounted quick connector for calibrated leaks and a clear high-resolution light-emitting diode enhance operator convenience. Other features include a leak/flow calibrator and a four-line liquid crystal diaplay. The detector incorporates a blockage test that detects defective blocked parts. The F535 has a full range of options including two pneumatic outputs for control of sealing connectors, autocalibration, and temperature compensation. 

Benchtop leak testers can accommodate elastic or rigid medical products

Benchtop electropneumatic equipment is suitable for air-pressure decay leak testing of elastic or rigid products. The P-Test leak testers from Tecnoideal S.r.l. (Mirandola, MO, Italy) can be used for routine tests in production departments and also for validation and destructive tests in quality assurance and R&D departments. New features include automatic pressure adjustment, and pressure drop or flow measurement. The company also designs and produces custom automated systems for the assembly and testing of medical tubing sets.

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