Medical Device Maker Measures With Vision
The AERx is a handheld aerosol dispenser that is used by patients for self-administration of consistent dosages of medication delivered to the lungs in fine-particle aerosol form. The system includes electronic controls to determine how much active pharmaceutical material is dispensed. The active substance is contained in a sleeve-like plastic disposable pouch called a dosage form (DF).
The reliability of the entire system depends on the dimensional and performance characteristics of the DFs containing the medicine. So it was critical that Aradigm come up with a system for measuring the plastic pouches that was not only extremely reliable, but also fast enough for 100% inspection without slowing down production.
"If the dimensions of the DFs are not correct, we risk delivering an incorrect dosage to the patient," says Bikash Chatterjee, Aradigm vice president for manufacturing. "In all likelihood, however, the inaccuracy would prevent Food and Drug Administration (FDA) approval of the device. The critical issue was maintaining accuracy and throughput."
The company found that it was able to meet the DF inspection requirements with the Quick Vision (QV) 3D CNC vision measuring machine, supplied by Mitutoyo America Corp. (Aurora, IL).
Aradigm initially evaluated a number of coordinate measuring machines (CMMs) for the job, and quickly came to the conclusion that a noncontact system was required. The DFs are made of flexible web materials that deform when measured by contact-based systems. In addition, the DFs would be used in human clinical trials and therefore had to be handled throughout in a clean environment. FDA standards require that they be free of any potential contamination or damage that could be generated by a CMM contact system.
Aradigm purchased two QV systems to meet its inspection needs--a QV 606 system for incoming plastic material inspection and a smaller QV 202 machine used for inspection of the manufactured DFs.
Each DF is a pouch that measures 0.433 by 1.5 by 0.012 inch. The DFs, made from plastic web materials, are cut into strips of 10 each and are placed on a fixture for inspection by the QV 202 machine. The system is programmed by Aradigm to inspect six strips at a time, measuring seven different attributes on each DF, with tolerances of + or - 0.005 inch. The system collates the data and records it in a system file, while flagging reject data for the operator. Total processing time for six strips is about one minute.
By enabling fast, accurate 100% inspection of the DFs, the QV system enables Aradigm to maintain high quality of product during its clinical trials. The system also enables Aradigm to detect defects early in the manufacturing process, the company says. This avoids wasted time and money on defective product and enables early correction of problems.
Mitutoyo America Corp.
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- The vision measurement system enables accurate inspection of plastic pouches used in medical devices without deforming the material and without the potential contamination of a contact system.
- Total inspection time for six strips of 10 pouches each is about one minute, eliminating production bottlenecks.
- The system enables problem detection early in the manufacturing process, saving time and money.