wolfcraft GmbH successfully applies combination of multicomponent and gas assisted moliding technologies from Witmann Battenfeld GmbH for power tools components manufacturing
Five years have now passed since wolfcraft GmbH manufacturing a wide range of do-it-yourself tools decided to relocate its plastics processing sector from the “extended workbench” to in-house manufacturing by mastering molding of plastics articles and installing Witmann Battenfeld equipment. wolfcraft currently has more than 12 machines with clamping forces ranging from 60 to 160 tons, all from Witmann Battenfeld which produce 18.5 million individual parts a year with the proportion of plastics components is continuously increasing. Recently wolfcraft faced a challenge of manufacturing of ergonomic plastic sanding tool handle which must also be light and have the desired soft-touch effect making it possible to work fast and without fatigue. The manufacturing possibilities were discussed in the product development process by a team of experts consisting of mold makers, product developers, designers, injection molding operators and application engineers from wolfcraft and Witmann Battenfeld. The question of required production equipment was raised at the early stage. After extensive tests carried out at WITMANN BATTENFELD’s technical lab, a combined process solution was chosen, integrating WITMANN BATTENFELD’s COMBIMOULD multi-component technology with the patented AIRMOULD® gas injection technology, also developed by WITMANN BATTENFELD. In order to do so the multicomponent machine was delivered recently, an HM MK 160/750H/130V with an integrated servo-electric rotary unit and AIRMOULD® equipment for gas injection technology. The handle is produced as follows. At the first station the basic PP body is molded. Via an AIRMOULD® injection unit incorporated in the mold, gas is injected into the melt to form the cavity inside the part and keep the previously injected melt in contact with the cavity wall. Components from the AIRMOULD® modular system are used for this: a DE 12 compressor unit and a monomodule with a manual programming device. After the hollow part has been formed, the mold is opened. A rotary unit then turns the preform into the second position, and the mold is once again closed. Now the second component is injected onto the hollow part. Here, deformation of the hollow part must be avoided. This is achieved by optimal positioning of the injection points and a special mold technology in combination with AIRMOULD®. The HM MK 160/750H/130V is equipped with an adjustable, servo-electric rotary unit offering the advantages of fast, precise rotations and low height. This rotary unit, which can be adapted to match the size of the machine, is available for 2-, 3-, and 4-station systems. The second injection unit for the soft component is arranged in a vertical position next to the standard horizontal aggregate. This allows injection of the second component into the mold parting line. With the use of hot runner systems, injection points in different positions are also possible. In order to target such injection points, the vertical unit can be freely moved along its linear guides and thus adjusted to the individual requirements of the mold. Where parts removal by a robot is desired, a robot can be mounted above the moving platen. The high precision HM MK with its extensive range of options is the right package deal for any multi-component technology opening up a wide range of design options.
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