Successful validation of iQ weight control with ENGEL support

The Intrafix® Safeset infusion device is a million-selling product of the renowned medical technology company B. Braun. An essential component of this device is the roller clamp housing, which enables particularly fine adjustment of the flow rate. This precision component requires a stable manufacturing process with particularly high repeatability. For this reason, this housing is produced on all-electric ENGEL injection molding machines from the e-mac series with the help of the digital assistance system iQ weight control.

ENGEL's iQ weight control assistance system is a software-based production tool that adjusts process parameters in real time during the injection molding cycle. This ensures consistent quality of the roller clamp housing. The injection pressure is compared with a reference curve, and deviations in injection volume and viscosity are detected in fractions of a second. Switchover point and holding pressure are automatically adjusted for each shot. This has significantly reduced the need of manual adjustments to the injection molding process by the machine operator.

For medical products that are not documented by full production monitoring or subsequent individual testing of each component, process planning, and the production phase must be comprehensively validated in advance. Since B. Braun's roller clamp housings are used internationally, validation according to EN-ISO and MDR for Europe, as well as FDA regulations for the USA, was required. The main challenge for B. Braun and ENGEL was the dynamic process control using iQ weight control, which, unlike the existing rigid injection molding process, would have significantly increased the complexity of validation.

This is where ENGEL was able to make a decisive difference: ‘For us, it was important that the process window is not reduced by iQ weight control. We didn't have to adapt our process to iQ weight control. We just used it to adjust the process within the predefined limits,’ explains Andreas Wettlaufer-Ganz, Team Leader of Project/Process Support at B.Braun in Melsungen. “Our system adapts 100% to the product, and nothing needs to be changed in the actual process,” says Norman Buls, medical specialist at the ENGEL facility in Hanover, highlighting this important advantage once again.

The validation process in Melsungen consists of four steps to ensure that the process consistently meets the required results.

• First, the limits of the process are determined in DOE (Design of Experience) in a 20-point statistical experimental plan. Based on this, limit values are defined as worst-case combinations that still allow good parts within the tolerance to be produced. These values are saved in the CC300 control unit of the e-mac injection molding machine.

• The IQ (Installation Qualification) was carried out at the beginning of production - still without the assistance system - and was therefore no longer necessary when iQ weight control was implemented.

• In Operational Qualification (OQ), the defined process limits are checked to ensure that parts that meet the specifications are produced with the worst-case settings.

• In Performance Qualification (PQ), the process is tested over a longer period, with product samples being taken and checked for quality according to the specifications.

This extensive project had to be prepared accordingly, in particular to better estimate the achievable benefits in relation to the effort. Before the actual validation process, B. Braun carried out its own tests – both with and without iQ weight control. ENGEL examined the influence of iQ weight control on consistent component weight. The results of these preliminary tests showed that the use of the digital assistance system would be worthwhile: The measured deviation with the assistance system was noticeably improved compared to production without support.

‘We can clearly speak of a successful integration of iQ weight control,’ as Norman Buls states. “ENGEL's assistance systems are beneficial for us, which is why we will continue to consider the company in future procurement discussions,” confirms Andreas Wettlaufer-Ganz.