Gerresheimer Regensburg: New generation of lancing devices for blood sugar measurement

On behalf of a leading diagnostics company, Gerresheimer Regensburg has developed the lancing devices for a blood sugar measurement system which contains a band with test fields for 50 tests instead of individual test strips. The new 5th generation lancing device can be docked onto the measurement device, benefiting the patient by combining the functions of pricking and measurement in a single device unit. From the development process emerges a lancing device which is smaller, faster, quieter and more robust and enables one-handed operation without having to reach around.

Gerresheimer Regensburg GmbH had demanding challenges to overcome in developing the lancing device. In comparison with its predecessor model, this device was supposed to receive a smaller magazine while retaining the same number of lancets. The operation was largely to follow the tried-and-true scheme, but offer the patient more convenience while requiring less force and effort and generating less noise. But above all, operation also had to be possible in a combined state, meaning that the lancing device and measurement device really form a unit.

The lancing device is made of 19 plastic parts as well as three steel springs -springs purchased from other suppliers. There is also the magazine, with its six individual lancets, the magazine drum and an enclosing locking sleeve. A replaceable cap is also supplied for making pricks at alternative locations such as the ball of the thumb. The size of the lancet magazine for the new generation of lancing devices was reduced by nearly one half, while retaining the same size and number of lancets. Since the number of components remained the same, this meant that tolerances and wall thicknesses had to be especially low without jeopardizing function and component stability. It was no longer possible to snap fit the components like it was with the preceding model. Instead, assembly had to be done with laser welding. Play between the individual components was optimized in order to enable operation required as little force as possible in spite of the small dimensions. It was also necessary to identify the sources of noise in the device and reduce sound development there in a targeted manner.

In order to meet these complex requirements, Gerresheimer Regensburg GmbH launched a comprehensive feasibility study. In the process, a moldflow analysis was conducted for each and every plastic part. Additionally, the tension in components under mechanical load was determined using finite element analysis to guarantee fatigue resistance. Functional problems which occurred during the development phase were analyzed and rectified through the use of computer tomography. A variety of acoustic simulations were conducted to detect noise peaks and their cause so as to reduce volume development. More than 20 concepts in total were compiled and tested in the scope of a market study with diabetics.

Both the device and magazine are manufactured at the plant in Pfreimd using a fully-automated line in an ISO class 8 (100,000) clean room. The devices are then assembled at the plant in Horšovský Týn. Mold making and automation engineering for the project was entirely handled by Gerresheimer Werkzeug- und Automatisierungstechnik GmbH. 19 molds were built with 8 cavities for the individual parts of the lancing devices and three tools were made with 16, 32 and 64 cavities for the three components of the lancet magazine. A particular challenge was the 16 cavity mold for producing the drum. It required the creation of resilient supporting geometries and interior shafts with friction-optimized surfaces for the lancets.

More Information: www.gerresheimer.com

Medtec, 23.-25. March 2010, Stuttgart, 4/434