Many plastic items consist of both blow-molded and injection-molded components that have been welded together. Not only does this require multiple machines and production steps, but the parts may also fail at the weld points. Spanish research center ASCAMM’s new EBIT technology, however, combines the two plastic injection techniques in one process, to efficiently create weld-free parts.
In extrusion blow-molding, hollow plastic items are created by putting molten plastic into a hollow tube, then inflating that tube with air. Injection molding, on the other hand, is used to create solid plastic parts, by injecting molten plastic into a mold.
The EBIT (Extrusion Blow molding Injection molding Technology) process is based around an existing extrusion blow-molding platform, to which a satellite injection unit has been attached. A control system incorporating intelligent embedded systems and mechatronics is used to combine the two techniques. Although the technical details are confidential, the “closing force” of the blow unit is reportedly used to define how much plastic can be injected.
According to ASCAMM, EBIT “allows the manufacturing of hollow parts with complex geometry and integrated bindings,” carrying out in one step what would otherwise take at least three. This is said to result in estimated cost savings of 25 to 35% per item.
EBIT was originally designed for use in the automotive sector, particularly for air intake parts such as pipes, filters, ducts and resonators. These are typically hollow, but incorporate external protrusions such as supports and joints. The technology has indeed already been licensed to a Spanish automotive company, although ASCAMM’s Jose Carlos Pérez told us that licensees in other industries are still being sought – a “well-known company that manufactures fridges” has apparently expressed interest.