Boring mill

This article explains the machine, for the location in Styria see boring mill (municipality of Mariazell) .

Small boring mill (right) with a boring bar supported by a quill (lower left corner, not in the picture) and guided through a workpiece (center)

A boring mill is a machine tool that is used in general mechanical engineering . The more correct designation is horizontal boring and milling machine .

Normal size boring mill. Left boring mill (section of the stand / tower), right partly machined larger cast part on the clamping field

Boring mills are universal machines that are preferably used for machining large machine parts. As a rule, they work in a horizontal direction. The main headstock is attached to a stationary or movable stand, depending on the design, so that it can be moved vertically. This headstock contains the entire drive and feed unit for the retractable and extendable main spindle, in which standardized tool holders ( e.g. Morse taper ) are used to fasten the tools commonly used on other milling machines as well as especially boring tools and boring bars, around which the machine table or clamping field is fastened To machine workpiece . Modern boring mills today usually have a ( CNC ) control and regularly also rotating and sliding clamping tables and often an automatic tool changer with its own tool magazine. Often a second large stand with a quill , which can also be set up, is part of the machine to clamp a boring bar between the spindle and quill through the workpiece. A prerequisite for this special boring work, however, is a design with a movable clamping table, since the spindle must no longer change its position after setting up.

Due to their open design, boring mills can be used very flexibly and universally, especially for very large workpieces up to over 100 tons, and accordingly they are regularly among the largest machine tools in mechanical engineering . Machines with a construction height of over 10 meters, a spindle diameter of 200 mm and clamping fields of over 100 square meters are not unusual for boring mills.

Designs

• A table boring mill has a horizontal bed on which a transversely movable turntable moves. At one end of the bed is the stand on which the headstock moves vertically, at the other end there can be a support with a bearing (steady rest) for boring bars.
• A boring mill with a cross table [or cross boring mill ] has two horizontal beds connected to form a T. A turntable moves on the transverse bed. A column with a vertically movable headstock moves on the longitudinal bed.
• A plate boring mill is mainly used for large workpieces. It has a transverse bed on which a stand with a headstock or an extendable support sleeve moves. A clamping plate is firmly attached to the machine's concrete foundation so that the workpiece does not move. A turntable can be used as an alternative or in addition to the clamping plate.

See also

• Boring mill lathe

Individual evidence

1. ↑ Řasa, Gabriel: Strojírenská technology . tape 3/1 , p. 92-100 .