Flexibility continues to be the primary standard for manufacturers and machine shops that support automotive manufacturing programs — not incidentally because dimensional accuracy and surface quality standards have become so uniformly stringent. To achieve their own goals, then, the suppliers need options from the CNC machines they adopt.
Heller Machine Tools is offering a new horizontal machining module, a compact design for 4- and 5-axis set-ups, but multiple standard equipment details and spindle drive options. The concept allows the operator to adapt set-ups and sequences cost-effectively while maintaining high-accuracy machining — in particular, the developer noted, “for flexible series production in automotive applications.”
Heller MC20 machines may be deployed as stand-alone machines, converted for parallel processes, or arranged and programmed for series production.
Heller reported that it has secured an order for an initial 65 MC20 machines to produces transmission cases, converter housings and valve bodies for a North American automotive OEM. The modular design allows the machines to be scaled to meet individual requirements.
All the machines for the project will be assembled at Heller’s Troy, Mich., headquarters.
The MC20 machining module is designed to offer optimal performance settings for any program task, in terms of dynamics, machining accuracy, and chip disposal. It is equally adaptable for wet or MQL machining, so it may be used to machine materials from aluminum to iron and alloy steels.
The work area presents an X stroke of 800 mm, Z stroke of 800 + 200 mm loading stroke, and a Y stroke of 750 mm. Workpieces move in the Z axis as the tool moves in X and Y, in a vertical Y slide and X traversing column. A system tool magazine directly above the main spindle carries HSK 63 or 100.
The X axis carries the traversing column, which is designed for high dynamics and excellent process rigidity and stability. “This design offers excellent conditions for machining processes with high performance requirements,” Heller noted. “The Y axis is designed as a vertical slide in cast construction. The bridge-type Z axis is equipped with 1 or optionally 2 drives.” The A axis is designed as swivel traverse in L-form or in optional U-form.
According to Heller Machine Tools v.p.-Sales Vince Trampus, “The MC20 modules are a product of Heller’s experience in designing machines that can be adapted to provide the lowest possible cost per piece in a range of production machining applications. Heller matches machine speed and torque to material, provides easy access to work areas and tools, and creates a bed and frame that provide optimum rigidity even in heavy cutting over years of operation.”
The main, direct, liquid-cooled spindle drives deliver power at the spindle for optimal milling characteristics and the ability to achieve fine boring quality. Four different spindle drive options are available to best handle a wide range of different work materials.
As for process control, the MC20 is outfitted with Heller’s temperature compensation program, (“especially critical for MQL machining,” it emphasized) so that part temperature is measured in the work area and spindle offsets are adjusted automatically during the machining cycle.
All linear axes are driven by digitally controlled synchronized AC motors that are fully enclosed. Idle time is said to be minimized by drive systems designed for high rapid traverse and acceleration rates.
Absolute measuring scales mounted on all linear axes give direct path measurement and contribute to the MC20’s high accuracy. Specially installed guarding ensures fault-free operation of the recirculating ball-screw drives and measuring system and protects them against chip and coolant contamination. The linear measuring system is purged by air pressure.
To control heat growth and minimize temperature influence on accuracy, the mounting faces for the axis drive motors are optionally available as water-cooled flanges on the machine base and the column.
Depending on the machine size, the tool spindles may be equipped with the following HSK-A63 or HSK-A100 hollow-shaft taper and are mounted directly into the housing with pre-loaded precision spindle bearings. Lifetime lubrication is provided for the bearings.
