Two sides of cleanroom molding

Cleanroommolding has more variations than most of us generally think. TwoGerman molders that produce laboratory equipment and medical productsillustrate how companies that actually have much in common canadopt significantly different design strategies for cleanroommolding. More interesting still, both strategies work well.

Although Brand GmbH of Wertheim-am-Main produces a wide rangeof products, its major focus is precision laboratory disposablessuch as optically precise cuvettes and pipette and dispenser tipsfor handling volumes measured in nanoliters. Quality levels areobviously high in this market and are made all the more challengingby the precision these small sizes demand. Brand has been a leaderin laboratory equipment for more than 50 years because, as TechnicalDirector Peter Mahler says, "There's always a market forgood products." He is being modest: Brand's quality standardsare considerably higher than "good."

The Frör Group of Erlangen had been known until slightlymore than a year ago primarily as a molder of bottle crates andtoys. Realizing it had the competency to expand into such higher-value-addedareas as food contact and technical medical products, Frörbegan what has proven to be a rewarding move into cleanroom production.Managing Director Joachim Lehmann says, "We reengineeredour whole production system from scratch. In the final analysis,part quality could be a question of life or death for patients."For reference, Frör works to tolerances as small as 5 µm.

Similar, Yet Different

Both Brand and Frör believe in automation to maintainclose quality control and consistency, as well as track everycomponent. Both companies, though perhaps Brand a bit more, makefrequent mold changes due to their broad product lines. Each hasnoncleanroom injection machines and, in line with their full customersupport, each offers a wide range of finishing, assembly, andpackaging services.

Interestingly, both companies also use the same brand and modelof injection molding machine in their cleanrooms: Krauss-MaffeiC Series systems. Brand's K-M machines range from 660 to 1500kN (73 to 165 tons) in the cleanroom and up to 2000 kN (220 tons)outside. Frör's C Series machines range from 150 to 8000kN (16 to 880 tons). Both Brand and Frör worked closely withcleanroom specialists in Krauss-Maffei's technical support groupin the design and function of their facilities. Notwithstandingall that similarity, there is a very significant divergence.

Inside or Out?

Frör's injection molding machines are just outside itsClass 10,000 cleanroom, which is a laminar flow tent. Brand'sinjection machines are inside a fixed-wall cleanroom that is alsoClass 10,000 (see photos). Both Mahler of Brand and Lehmann ofFrör are pleased with how these respective solutions meettheir critical productivity and quality standards.

Mahler says the machines that operate in the cleanroom havean excellent record of productivity with no contamination fromhydraulic systems, tiebars, or platen guides. Brand employs considerabledownstream automation to ensure consistency and invests in high-performanceequipment and in-depth staff training, especially for cleanroomstaff. Since production operates around the clock with minimalmanual intervention, the ability of the K-M machine controls toautomate the process and to ensure repeatability were key factorsin their selection.

Frör opted for the laminar flow tent with the injectionmachines outside. However, parts are conveyed from the mold intothe cleanroom packing area through closed chutes that form partof the cleanroom system. This solution, says Lehmann, is verycost effective. Frör decided not to use an outside engineeringfirm to create its cleanroom, instead relying on the internalstaff, which worked with K-M engineers on the design. "Wewere able to draw on their experience with other cleanroom projects,"notes Lehmann. For him, compactness of the injection machineswas a positive factor. It meant more room for the automated handlingsystems and other equipment. He is also positive about maintenanceand mold changing taking place outside the tent.

Both Brand and Frör have systems that work for them now,and are designed to fit their overall plans and environment. Thereare off-the-shelf solutions for portable and single-machine cleanrooms,Krauss-Maffei notes, but to best suit the products and the company,a cleanroom installation demands customization.