True Mill-turn Machining

July 22, 2008
Stama’s MT Technology delivers true mill-turn operations with a series of machines built on vertical machining center foundations. What this means is that main vertical spindles run all tooling, both rotating and static. The ...

Stama’s MT Technology delivers true mill-turn operations with a series of machines built on vertical machining center foundations.

What this means is that main vertical spindles run all tooling, both rotating and static. The spindles are extremely strong with high torque and can securely hold a stationary turning tool in position.

The machines are capable of highprecision six-sided complete turning, milling and drilling of parts out of raw barstock or semifinished blanks to potentially reduce machining times by as much as 70 percent.

According to Stama (www.stama-amerca.com), milling from barstock eliminates the need to saw off unmachined parts and pre-milling block-shaped blanks.

The company offers its machines in several configurations that range from a singlespindle model with a 2-axis turning/ swiveling unit and NC turntable to those with dual spindles and dual turning/swiveling units.

For small to medium batch sizes, Stama offers its M Variant System 7 models. These models have one main milling spindle and mill and drill from barstock that is moved into the work area through a 2-axis turning/swiveling spindle. When it is ready for sixth-side machining, the part transfers to an NC turntable equipped with jaw clamping. There also is an optional pivoting NC tailstock that is available to handle long, slim workpieces.

The company’s MT System 7 model machines feature one main milling spindle and two turning/swiveling spindles for combining milling, drilling and turning. Eleven NC axes and tool magazines that accommodate 42 tools to 180 tools allow shops to machine different part features and to transition from one type of material to the next for fully automated production.

For job sizes of one thousand to one million parts, Stama configures an MT machine with two independent traveling columns on a common machine bed. Each traveling column is a separate system with a milling spindle, large standard tool magazine and turning/swiveling unit with integrated turning spindle.

In typical operation, the machine can perform 5-sided machining by milling, drilling and turning in one chucking at the first traveling column. After that, the turning spindle swivels 90 degrees to allow the second turning/swiveling unit to grip the part while the milling spindle performs a cut-off operation.

After part cut off, the second turning spindle moves to its position below the second traveling column, where the part is finished and ejected onto a conveyor belt. While this is happening, the first traveling column starts to machine the next part.

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