These V6 cylinder heads were produced in quantities of 210,000 parts per year on an automated production system consisting of 16 HMCs. A given automotive industry manufacturer would have myriad options for setting up such a system, and Makino support personnel frequently play a critical role in helping customers find the right one.
One "Automotive Day" presentation explored the pros and cons of two common options: parallel and serial production. The former involves a series of machines performing the same operations simultaneously. This offers flexibility advantages because it is easy to reconfigure, and it’s reliable because there are multiple process streams. However, costs can be quite high, in part due to the need to duplicate tooling. In contrast, the latter is akin to an assembly line—a series of machines each performs one operation to complete the part. While this option offers can provide lower costs, maintenance or a problem on a single production resource can shut down the whole system, and it lacks the flexibility of the parallel strategy. Makino application engineers Makino application engineers can also set up hybrid systems that combine the best features of both approaches.
This demonstration showcased the possibilities of combining a vertical and horizontal machine into an automated machining cell. In this particular example, a pedestal-mounted Fanuc R1000 robot arm uses a quick-change gripper to load three unique fixtures into a PS65 VMC (left) and a51nx HMC (right), which perform op 10 (VMC) op 20 and op 30 (HMC) operations on a V-twin-style cylinder block.
Status information on the machine and robot alike are available at a glance with the company’s robot cell controllers. Here, the robot interface screen of the controller used for the HMC-VMC cell demonstration displays all communication between the robot and the machines. Among other functionality, the system also controls auxiliary functions such as continuous pressure hydraulic fixture control, part wash-off, and more.
The cell also made use of a continuous pressure hydraulic (CHP) system, which the company highlighted as a key accessory for automated production. Integrated with the CNC and fixtures, the system uses hydraulic pressure to ensure the proper clamping force for the application. It also facilitates part-seating capability to ensure workpieces are loaded correctly before machining begins, as well as coolant-flushing to remove debris from fixtures.
Another demonstration highlighted Makino’s process monitoring and data management software, MPmax. The system is designed to improve manufacturing intelligence by providing at-a-glance information on machine status, alarms, probe date, spindle and axis movement and more. It also features remote monitoring and e-mail and text notification capabilities. According to the company, close examination of data provided by the software can reveal production trends and provide plant managers with the insight they need to identify and remedy workflow inefficiencies.
Recognizing that even the most sophisticated production system begins with reliable machine tools, Makino used this “naked” NX-Series HMC to showcase notable aspects of its approach to manufacturing. The bed is a one-piece casting, and the structure is fully supported on three points to simplify installation and improve rigidity. To ensure quality, the company installs fake ballscrews during machining to accurately represent all the forces that will be present when fully assembled. For the same reason, it uses a weight to simulate the force of the yet-to-be-installed automatic toolchanger while machining the lower guides. Other notable elements include the use of cylindrical roller guides to improve rigidity, load capacity and precision; a cooling system that circulates controlled-temperature oil through the ballscrews, spindles, bearings and table; standard, direct-drive rotary tables with inertia active control; dual-side support for the ATC arm; and single-panel way covers for reliability and chip evacuation.
A “stepped” design for the two X-axis guides under the NX-Series machines’ column improves rigidity by directing cutting forces into the casting.
The tapered cone bushings that link the pallet to the machine table are hydraulically controlled via four independent pressure switches. The system secures the pallet with a total force of 4.5 tons (a51nx)/ 9.4 tons (a61nx). When pallets are changed, the cones emit jets of air to prevent chips from entering the taper.