Medico - FRECON A/S - Mechanical Constructions FRECON A/S - Mechanical Constructions

Close collaboration about the development of new catheter for user-friendly infusion set for Unomedical

Unomedical is part of ConvaTec, a global manufacturer of medico-technical products. Their mission is to “improve the lives of the people we meet …”. FRECON has helped fulfil that mission by designing a new user-friendly catheter for patients with diabetes.

For many diabetes patients, using an infusion set (colloquially called a drip), a small pump that delivers insulin, is part of their daily life. Connecting the drip is not always easy, and there is a risk that the patient may insert the needle incorrectly and, for example, hit a muscle instead of fatty tissue.

Incorrect insertion destroys the functionality
If a patient accidentally inserts the needle incorrectly and hits a muscle instead of fatty tissue, as is recommended, the hole in the tiny and very thin catheter (Ø 0.7 mm), which delivers insulin to the body, may become blocked.

New user-friendly infusion set
This is the reason why Unomedical has developed an infusion set where the infusion device and the set constitute a single sterile unit. For this unit, Unomedical was looking for a catheter that could take into account that the patient might insert the needle incorrectly.

Extensive calculations
Together, Design Specialist FEM/FEA Rasmus Lundby Høyer from FRECON and Unomedical developed a solution to the task, which consisted in modifying the traditional catheter with only one hole at the end.

“Unomedical wanted to introduce slits in the catheter, which is made of soft plastic. We therefore calculated various configurations of these slits and determined which ones would provide the ideal degree of opening on the catheter,” says Rasmus. “We are dealing with very tiny openings with diameters of only 0.7 mm.”

As part of the comprehensive calculations to identify the optimum location of the small slits in the catheter and their size, Rasmus developed a transient calculation model in ANSYS, which consisted of a small block that could simulate a muscle and could be moved up and down to determine when and how the catheter would be deformed or break. This is done by measuring the volume and the area that opens up when the catheter is bent or compressed.

Development of instruction video
Rasmus has also developed and coded a small animation, which simply and precisely illustrates when and how the catheter is deformed in different situations. The customer has subsequently used the video as marketing material at trade fairs.

New market opportunities
With this newly designed solution the customer now has a product that presents brand new market opportunities. “We have enjoyed an excellent collaboration with FRECON,” says Design & Development Engineer, R&D Tobias Stumpe from Unomedical. “They deliver top quality work, and together we have developed a very practical solution, which has just been through the last tests and is ready for the market.”

Unomedical thinks that the new solution, which supports the company’s mission of “improving the lives of the people we meet”, has a great sales potential to customers all over the world.