A new micro-injection module from press maker Arburg GmbH + Co. KG uses two screws — one for melting the material and one for injection. Other alternatives use a combination of a screw and a piston for injection.
Micromolding can involve shot weights of less than 1 gram. One problem with these tiny parts is too long of a dwell time in the injection unit. Also, the displacement distance of the screw is extremely short because of the small injection volume.
Arburg's module uses two screws that “share” the preparation, dosing and injection of the resin. First, a servo electrically driven screw pre-plasticizing section is installed at a 45-degree angle to the horizontal injection unit. The molten material is then transported to the injection unit.
The injection screw, with a diameter of only 8 millimeters, is fitted with a non-return valve.
A Selogica control system runs the press, ensuring that newly dosed material is always available for every shot, which keeps material dwell times short, Arburg said.
Tel. 860-667-6500, fax 860-667-6524, e-mail [email protected].