The benefits of automated data acquisition become apparent to this manufacturer of synthetic skin, which found improved accuracy and time savings
When thinking of something you don't want to break or tear when stretched, rubber bands, bungee cords, fishing lines, cables, your pants, maybe even muscles come to mind.
But definitely not your skin.
The elasticity and strength of our skin is something we all take for granted.
But not Bio Med Sciences, which since 1987 has produced a patented synthetic skin formulation which combines the properties of silicone and polytetrafluoroethylene (commonly known as Teflon) and is used for biomedical applications.
In producing its formulation, Bio Med developed a simple system that increases productivity and accuracy during the quality control testing of its formulation. The elasticity and strength of the formulation, named Silon-IPN, is critical, since Bio Med has developed it for a wide variety of commercial applications including the healing and treatment of wounds and burns.
These commercial applications include temporary skin replacement (a dressing substance for promoting moist wound healing and pain reduction for patients), silicone elastomer sheeting - a soft and durable material used with pressure garments worn during the care of wounds to promote healing and patient comfort and reduce keloids (scar tissue) and hypertrophic scaring - and silicone thermoplastic splinting, a material which combines a therapeutic surface of silicone with a mouldable orthotic material to manage burn scars and scar treatment. Initially, Bio Med performed quality control strength and elasticity testing manually.
The manual pendulum-type measuring system, which involved manually transcribing force load and elongation measurements on paper and then typing them into a Access database, proved to be time consuming and error-prone. Mark Dillon, a materials engineer and the president of Bio Med, designed an automated quality control testing system to ensure quality and consistency in manufacturing.
In designing the system, Dillon sought measuring tools that would allow automation and a software program to serve as a communication interface between his measuring instruments and his database.
Dillon preferred to maintain his data in Access since he had already developed an Access-based reporting system.
To determine the strength characteristics of the manufactured Silon materials, the breaking point force and elongation of the materials are measured as samples are pulled on a tension tester.
To accomplish this, the samples are placed on a tension and compression testing machine with a force gauge mounted on it.
The samples are then stretched to the breaking point.
The breaking point measurements, including the force applied and elongation, are then transmitted automatically to a PC running Access 7.0 in Windows 95.
These maximum tension strength values are then compared to quality control values in the database.
The automation of the quality control testing is possible since both the tension and compression testing machine and the force gauge have RS232 output.
Both devices are connected directly to two different serial ports on the PC.
The readings are filtered and sent to the Access database using the SoftwareWedge for Windows standard version (WinWedge) data acquisition software.
WinWedge serves as the communication interface between the two measuring devices and the Access database.
The Wedge communicates with each device independently and directs the data to the appropriate fields in the database.
Dillon found that by automating the quality control strength testing, the process takes half as much time as the manual process.
He noted: "The data entry used to take as much time as the actual testing and analysis". "WinWedge has saved us a lot of time and improved our accuracy to 100%." Additionally, Dillon recently began developing strength profiles by graphing the force load data continuously over time in Excel.
The elongation can also be calculated since the samples are pulled at a constant rate (distance = rate x time).
WinWedge is supplied and supported in the UK, Ireland, Denmark, Germany and America by Adept Scientific.
