Portal machine

Type of CNC machines, in which the working spindle or the aggregates support is mounted on a crossbar (portal), which is supported on two sides.

Portal machines generally have a higher rigidity than cantilever machines because of the two-sided support, and are therefore mostly used for editing workpieces with large dimensions, for high cutting rates or for processing with very high feed rates and the resulting extreme acceleration and brake values. Another application is the low-cost sector in order to built a machine with acceptable stiffness with minimized material costs.

Versions:

Standing portal

A fixed portal carries the processing aggregates. An axis (usually X) is realized by moving the working table, the other axis (usually Y) by moving the aggregates support along the portal. Less often, machines with fixed tables and a separate Y-axis on the aggregates support are used. Standing portals are often used in applications where alternating field processing shall take place as efficiently as possible, because one table can always be moved out of the machine and thus, the operator is not restricted by the processing movements.

Moving portal, Gantry machine

The portal is mounted movable along the fixed machine table and in 'real' gantry machines driven by synchronized motors on both sides. For cost reasons, partly also a central motor is used, which moves both sides of the portal mechanically synchronized. Some very low-cost machines, which by their construction are gantry machines, only have a unilateral drive. This creates a minimal deviation between driven and non-driven side. For most applications of woodworking that is relevant.

Since the mid-2000s, a support mounted on prism guide is used intensively in cantilever machines to improve the stiffness at the end of the cantilever. Thus, the illusion arises that they are moving gantries.

Alternative terms

Images

Schweres Standportal mit bewegl. Tischen
MAKA
Fahrportal, Antrieb nur einseitig
MORBIDELLI
Auslegermaschine mit zusätzlicher Stützung
WEEKE