Bridge Mills for High Speed Machining of Large Parts at a Reduced Cost

In Booth S-338536, Johnford DMC LH Series double-column moving table bridge mills from Absolute Machine Tools Inc. (Lorain, OH) join the expansive lineup of Johnford double column and sliding double column machining centers that bring capacity and affordability to large part machining. The LH series features 110 in (2,800 mm) Y-axis and 122 in (3,100 mm) to 244 in (6,100 mm) X-axis in 39.4 in (1 m) increments. Standard Z-axis travel is 32 in, with 42 in and 60 in options available. These double column machines are created from massive Meehanite® iron castings. The bridge mills have a long base casting with complete support of the table over the full X-axis travel, allowing massive loads to be machined. The Y- and Z-axes hold fixed loads at all times while the X-axis carries the only dynamic load, allowing for tight machining and tight tolerances during high-speed machining operations. Because there is no table overhang, X-axis pitch and yaw are eliminated. The spindle centerline-to-column distance is minimized offering further rigidity.

The machine’s heavily ribbed cast iron construction provides long tool life and part surface finish. The combination of complete surround table guarding with twin screw-type conveyors and a caterpillar conveyor ensures complete chip removal with little manual cleaning. Additionally, Finite Element Analysis (FEA) is used to design each bridge mill, simulating the effects of real world conditions, including vibration, heat, fluid flow and other physical impacts. The DMC-3100LH, 4100LH, 5100LH, and 6100LH all feature rigid box ways in Y and Z and Schneeberger roller ways in X for high load carrying capacity. Heavy duty 35 hp (50 hp opt.) two-speed gearbox driven spindles provide heaving cutting power and torque. The standard 40 tool ATC (60, 80, 120 opt.) provide fast reliable tool changes. The DMC LH Series is available in numerous customizable configurations, including extended Z-axis travels, full automatic 5-face head changing, and full 5-axis. A variety of options are available to tailor the machines to specific applications such as aerospace and mold/die. FANUC, Mitsubishi, Siemens, Heidenhain, and Fagor controls are available based on user preference.

Also on display will be the Nexturn SA-32PYII Swiss lathe, a 32 mm machine that comes standard with an exchangeable rotary synchronous guide bushing that allows changeover from guide bushing to non-guide bushing depending on the application and material. Changing to non-guide bushing mode allows for the use of less expensive non-ground material and greatly reduces remnant length, saving material costs. This lathe features up to 8 total axes (Z1, X1, Y1, Z2, X2, Y2, C1, C2) and up to 25 total tools. Machining capacity is 32 mm on the main and sub-spindle, and 210 mm (8 in) maximum turning length with guide bushing and 60 mm (2.36 in) without the guide bushing. Nexturn Swiss machines use FANUC controls. The machine is built for rigidity, accuracy, reliability, and ease of use. The highly rigid one-piece cast iron machine bed is designed using FEM software. Powerful motors for both turning and milling deliver outstanding machining capability. The use of ultra-precision pre-tensioned ballscrews and LM guides produce high accuracy. High speed positioning of 1,260 ipm reduces cycle times.

Spindles are the heart of this machine. The main spindle is a 10 hp, 8,000 rpm built-in motor spindle. The built-in motor provides outstanding acceleration/deceleration. The full C-axis on both main and sub-spindles with .001 deg position and pneumatic disc brake clamping provide high rigidity for milling operation. The 5 hp integral motor synchronous sub-spindle allows simultaneous front and back working to be performed. Powerful live tools sporting 3 hp and 6,000 rpm on the cross mill unit and 1.3 hp and 5,000 rpm on the backend face tools, provide excellent drilling and milling ability. A wide range of milling, drilling, and tapping can be performed. ER-16 collets for the live tools provide excellent rigidity. Rigid tapping is standard. The synchronous rotary guide bushing features a dual bearing structure with high accuracy. It has strong and accurate bearing support on both ends. The guide bushing is spline shaft driven. The machine can be changed in about 45 minutes to non-guide bushing for short parts, to reduce remnant length, and for use with non-ground bar stock.

Also on display will be the compact, high precision Quicktech S-32 ATM 9-axis twin spindle mill/turn center that combines integral-motor main- and sub-spindles with a 190 deg B-axis milling head and a fast automatic toolchanger to maximize output of small, complex parts. “These compact, versatile machines enable manufacturers to produce precise, complex smaller parts quickly, with the added benefits of the accuracy and consistency that result from processing the parts on a single machine tool,” said Steve Ortner, the president and owner of Absolute Machine Tools. “This machine is ideal for medical applications, for example.” The S-32 ATM has nine axes in total, including two turning spindles and a 190 deg B-axis milling spindle, serviced by a 24-tool (36-tool optional) arm-type automatic changer. Six fixed gang-type ID turning tools at sub-spindle result in a total capacity of 30 tools (42 optional). The machine’s compact 3,750 mm (150 in) x 2,175 mm (87 in) x 2,025 mm (81 in) dimensions (including chip conveyor) promote efficient use of manufacturing floor space.

Both the main spindle and sub-spindle feature 6,000 rpm, 5 hp high-torque integral motors and have 42 mm collet chucks (or 5 in three-jaw hydraulic chucks) with capacity for 30 mm bar stock. The spindles feature a continuous C-axis with a braking system and are fully synchronized for fast and accurate part transfer. The 12,000 rpm, 3 hp, HSK40-T B-axis milling spindle services both turning main and sub-spindles and has a working range of 190 deg (±95 deg from vertical). The B-axis is locked in position by coupling for rigid turning operations. The 24-tool arm-type toolchanger, with an HSK-40T quick change tooling system, produces tool change times of only three seconds. The sub-spindle moves in the X-, Y-, and Z-axes, and in the X-axis can move above and below the centerline to clear the B-axis and enable it to have full tilting capabilities. At the sub-spindle are six gang-type turning tools that allow simultaneous turning operations. Rigid tapping is standard.

The S-32 ATM is built for precision and durability. The main and sub-spindles employ P4 high-precision bearings for stability and heavy cutting ability. The machine frame and all major components are heavy Meehanite cast iron. Large 35 mm Hiwin roller-type linear guideways in all linear axes provide stability and permit heavier machining. Substantial 32 mm ballscrews are double anchored, pre-tensioned and direct coupled to the machine’s servomotors. This mill/turn center is equipped with a Mitsubishi M830S control with a 15 in LCD, and all spindles and axes employ Mitsubishi AC servomotors and amplifiers. Also available is a FANUC OiT-F control with a 15 in LCD and matching FANUC motors and drives. Standard machine features include a bar feeder interface, parts conveyor and catcher, chip conveyor, collet chucks and a 400 psi coolant pump.

Absolute Machine Tools, Inc., 7420 Industrial Parkway, Lorain, OH 44053, 440-960-6911, Fax: 440-960-6918, www.absolutemachine.com.