ENGEL demonstrates it can deliver BIG with precision, flexibility and speed to accommodate a partner’s rapid response to producing nest-and-tub packaging for vaccine vials.
All-electric, high-performance machines by ENGEL combine efficiency with precision. The decisive factor prompting Röchling Medical to invest in eight e-motion machines was the overall package, including digitalisation. In the production of nest-and-tub systems, the two largest machines, each with a clamping force of 5000 kN, impress with self-regulating temperature control processes.
Nest-and-tub systems provide packaging for liquid pharmaceuticals in the form of vials or prefilled syringes. COVID-19 has led to a massive increase in global demand, as vaccine vials are also offered in this packaging form. For Röchling Medical at its Brensbach, Germany site, nest-and-tub systems are a new application which demands flexibility from injection moulding production. Focused on vials, five sizes of nest inserts are currently produced at Röchling on two new all-electric ENGEL e-motion injection moulding machines. The same applies to the standardised tubs for all nest sizes, which require the highest clamping force of 5000 kN across the entire range of parts. To set up the moulds flexibly, the two machines intended for this application were ordered in size 500 and designed identically. “In the near future, the two 5000 kN machines will be in action 24/7 for nest-and-tub production,” says Marco Treuner, Technical Project Manager at Röchling Medical.
Extra features boost efficiency in the cleanroom
The nest-and-tub packaging dimensions are standardised to accommodate different filling and sterilisation systems by different suppliers. Throughout the filling and production process, vials remain in the nest, thus avoiding falling over or colliding with each other. The vials are well protected in the nest’s honeycomb structure. For 50 mL tubs, there are 16 vials per nest. The lower the filling quantity, the more vials there is room for in a package, and the more honeycombs the nest inserts have. POM is used for this demanding component geometry. This economical material reliably withstands cleaning and sterilisation before the filling process. But due to its pronounced shrinkage during cooling, POM places high demands on the stability and repeatability of the injection moulding process. Added to this is the mould design, which has many long, closely spaced cores. “We need very rigid mould mounting platens and particularly small centring diameters to avoid overmoulding, even with the very large platens of the e-motion 500,” says Treuner. The e-motion machines come with highly rigid platens as standard. ENGEL designed the platens with a particularly small centring diameter of 80 mm specifically for the nest-and-tub application at Röchling.
The two e-motion 500 injection moulding machines in cleanroom design (easy-to-clean surfaces, closed lubrication systems and some more features reducing particle emissions) are equipped with a linear robot from the viper series and GMP-compliant belt conveyors — both of which ENGEL developed and produced. In addition, tailored solutions for Röchling make the large machines even more efficient than their standard counterparts. The cable ducts are enclosed, smaller cable bundles are routed in hoses, and the control cabinets have their own heat exchangers to prevent air turbulence at this point. Because the nest components are too unstable to stack when they are taken off the mould, additional U-shaped belt conveyors were installed above the clamping unit as a post-cooling section. Only 15 minutes after part removal, the viper robot picks up the components from the post-cooling conveyor and cycles them out via the larger belt conveyors for stacking in boxes.
Smart temperature control
Constant temperature control is crucial for the dimensional accuracy of the demanding POM parts. Treuner explains: “We have to ensure repeatable quality as early as possible in the production process.” Quality controls (QC) occur several times at the Brensbach plant and at the customer’s site. If the customer is in the US — as is the case with the current order — sufficient time elapses between production and QC, and the recrystallisation process (shrinkage) is finished by then. At Röchling, part ageing is simulated in parallel over 6 months using a heat-ageing process.
For precisely repeatable temperature control, Röchling Medical took a step toward digitalisation. Both machines use iQ flow control — ENGEL’s smart temperature control assistant. Equipped with six e-flomo temperature control water manifolds and six temperature control devices from the ENGEL e-temp series, the system relies on the software to control and regulate itself over the entire production batch, keeping the conditions constant. The temperature difference acts as a control variable for dynamic individual circuit temperature control.
In the ENGEL solution, the injection moulding machines and the temperature control devices communicate with each other via OPC UA. In this way, iQ flow control can adapt the pump speed in the temperature control devices to the actual demand. This interaction combines temperature stability with high productivity and energy efficiency. “We can already see, in the short time after the start-up, that the pumps are running at just under 30% output instead of constantly at 100%,” reports Treuner. The decisive factor for the investment in iQ flow control was the POM material (it requires a very stable process to receive a constantly high product quality and dimensional accuracy), yet the company is benefitting from the significant energy savings. The energy consumption displays of the e-motion machines support the processor in systematic energy management.
Medical machines take priority
The two 500 models form part of the comprehensive package. All eight new e-motion machines with clamping forces of 1600, 2800 and 5000 kN are used for pharmaceutical packaging, diagnostics and medical technology cleanroom applications. In addition to the nest-and-tub systems, Röchling Medical also uses ENGEL machines to produce racks for pipette tips and microtiter plates. As a competence centre for injection moulding technology, the Brensbach plant combines injection moulding production, assembly and mould making. All-electric drive technology is the factory standard to avoid oil in the cleanroom. In addition, fast machine motion is crucial: the nest parts have cycle times of up to 40 seconds, and the tubs require a cycle time of 10 seconds.
Triggered by COVID-19, the two 5000 kN machines were subject to enormous time pressure. “We adjusted our processes at the beginning of the pandemic and prioritised medical machines in all plants,” says Holger Kast, sales engineer at ENGEL Deutschland’s Stuttgart site. “For the Röchling project, we also accelerated order processing and postponed the red tape.”
Getting the machines operational as quickly as possible was aided by ENGEL who delivered them in two parts, at no extra charge. “Our airlock is too small for a fully assembled 5000 kN machine,” explains Treuner. “If we had to open up the cleanroom to take in the machines, this would have involved a production stoppage of a week.” This would have affected several because there are more than 10 production cells in the large cGMP cleanroom.
Finally, by getting the complete production system from one single source means all components are perfectly matched to one another. “In ENGEL, we have a central point of contact, and we communicate directly,” says Lehmann. “Right from the outset, the entire production cell was perfectly planned, and all the components were precisely tuned. ENGEL made it easy for us. When it comes to complex production cells, there are few companies who can achieve that at speed.”