Schütte SC 32 CNC

A multi-spindle automatic (MSA) has multiple spindles (typically 4, 6, or 8) arranged in a circular drum. Bar stock is fed through each spindle. As the drum indexes (rotates one station), each spindle moves to a new cutting station where different tools machine it simultaneously. On a 6-spindle machine: Spindle 1 is rough turning, Spindle 2 is finish turning, Spindle 3 is drilling, Spindle 4 is threading, Spindle 5 is back-working, and Spindle 6 ejects the finished part — all happening at the same time. The cycle time equals only the slowest station's machining time, not the sum of all stations.

Traditional cam-driven multi-spindle automatics use a rotating camshaft to drive all tool movements at each station — the cam profile determines the feed rate, stroke, and timing of every tool motion. Changing parts requires physically changing the cam profiles — a skilled setup that takes 4–8 hours or more. CNC multi-spindles replace the mechanical cams with servo-driven axes controlled by a CNC program — changing parts requires only reprogramming the CNC and adjusting tooling, typically 1–2 hours. CNC also enables infinite flexibility in feed rates, dwell times, and motion sequences that cam profiles cannot easily accommodate.

The SC 32 CNC handles bar stock from approximately 3 mm to 32 mm diameter. Compatible materials include: free-cutting steel (11SMnPb30, 1215), alloy steel (4140, 4340), stainless steel (303, 304, 17-4PH), aluminum alloys (6061, 7075), brass (CW614N free-cutting brass), copper alloys, and titanium at reduced cutting parameters. Free-cutting materials (steel with sulfur additions, lead-free alternatives, free-cutting brass) are strongly preferred for multi-spindle work because their chip-breaking characteristics prevent chip jams in the multi-station environment where chips cannot be easily removed mid-cycle.

Back-working is machining operations on the rear face of the part (the face that was gripped by the bar collet) after the part is parted off from the bar. Without back-working, the rear face is unfinished and a secondary operation is required. The SC 32 optional back-working unit is a separate spindle that grips the parted-off part as it falls from the drum and performs additional operations (center drilling, reaming, threading, facing) on the back end before the part exits the machine. Back-working enables truly complete single-cycle part production — every operation done in one machine pass.

Production rate depends on part complexity and the slowest station's cycle time. For simple turned parts (3-4 operations): cycle times of 3–8 seconds are achievable, producing 450–1,200 parts/hour. For complex parts with 6 operations including threading and drilling: cycle times of 8–20 seconds, producing 180–450 parts/hour. Compared to a single-spindle lathe running the same complex part at 25–60 second cycles (60–144 parts/hour), the SC 32's productivity advantage is 3–6x, which directly translates to lower labor cost per part in high-volume production.