Series Production with Flexible Machines
ANGER transfer centres combine the advantages of machining centres and transfer lines
ANGER MACHINING has made a name for itself as a pioneer of series technology for CNC-controlled series machining systems. These so-called transfer centres, considered a combination of a machining centre and a transfer line, are impressive due to their high-output, yet flexible, series production. Examples include two HCXchange 2000 machines, controlled by a FANUC Series 31i CNC, delivered to the automotive supplier Magna.
ANGER MACHINING GmbH, based in Traun, Austria, is a manufacturer of high-speed machining systems. With its series concept developed in 1984, the company has set new productivity standards and gained a successful standing in the world market. Roland Haas (Dipl.-Ing.), Head Engineer at ANGER, explains in a nutshell what makes this technology special: "We have implemented the concept of a transfer line in a single machine." The work piece is loaded in a clamping device and then moved lightning fast from one stationary spindle to the next. The chip-to-chip times are extremely short, ideally only 0.3 seconds. The work pieces to be machined can be moved linearly and rotationally in all spatial axes and thus machined from six sides.
In Focus: Reducing down times
All the tools are picked up by special machining spindles and multi-spindle heads mounted on up to four sides of the machining area of the centre. On these high-production machines, down times caused by tool changes are a thing of the past. On the flexible ANGER machines, tool changes are carried out in parallel during the machining time. This results in shorter cycle times and high output on a much smaller footprint – compared to traditional machining centres.
In roughly 20 to 40 stations, the machine handles all required machining tasks – and does so with utmost precision, he tool remains in the exact same position in the tool holder. As clamping only has to be performed once, this reduces clamping and manual positioning errors. As a result, ANGER transfer centres can achieve process reliable position tolerances of 0.015mm, with diameter tolerances of IT 5 and roundness values of up to 0.001mm.
The small weights moved help reduce wear and tear on system components and enable extremely dynamic traversing characteristics with machining speeds of up to 90 m/min and 1 g acceleration. The highest level of rigidity is provided by the machine beds fortified with vibration-reducing steel-reinforced concrete, which depending upon the machine specifications can weigh up to 25 metric tonnes.
From eyewear to the automobile industry
ANGER transfer centres are the ideal choice especially where unit numbers from 150,000 to 500,000 per annum of the same work piece or with a similar design are required. In the company's early history, ANGER delivered its high-performance machines primarily to the eyewear industry. They were able to reduce down times thanks to machining with several tools, and thus offered an efficient method for fully-automatic milling of eyewear frames from plastic blocks.
After machining in this market was displaced by ever-increasing quality of injection mould technology, ANGER delivered its machines to the growing market of mobile telephones, where, for example, they milled magnesium frames for Ericsson cell phones. The focus then very quickly shifted from the cell phone industry in the direction of the automobile industry, where similar unit quantities of the same work pieces were required. In the beginning, these included above all shafts and cube-shaped components made of aluminium. In the meantime, with the introduction of the machine models ANGER HCS and HCP, the range of applications was expanded to ABS cylinders and many other small, complex components.
HCX Machines: Even larger traversed paths and higher rigidity
The ANGER machines also continued to evolve. Out of the HCP series grew the HCX model, which indeed retained the proven basic principle with stationary spindles and a moving work piece, but the technology was completely reengineered. The most obvious innovation is the flange frame on which the machining spindle units are freely mounted and can be easily rearranged.
Roland Haas reports: "For the HCX, we carried out a complete mechatronic development and used the full spectrum of virtual simulation." First of all, the developers calculated and compared the various travelling columns with box-in-box group mounts, whereby they opted for the latter solution. With various partners, they developed the concept further. Supported by a mechatronic simulation system, they optimised the various components in several development iterations. Roland Haas explains in more detail: "We improved the rigidity in decisive areas, whilst reducing material where mass is moved. And we simulated and optimised the control behaviour of all the axes. Only after all simulations were set up in green was the HCX prototype built." For the series, ANGER finally optimised its new machines with respect to service life, as well as ease of assembly and maintenance-friendliness.
In addition, the machine engineer introduced a CAM system with which immediately after receiving an order, the subsequent machining process can be simulated. "This enables us to design the spindles in a way that is guaranteed collision-free", explains Roland Haas. After all, ANGER works as a general contractor. This means it not only delivers the machine but also the entire machining process with a pre-determined cycle time. The project is handed over to the customer turnkey ready with the CNC program, statistical quality certificate and automation.
In 2014, the next milestone in the company's history was established with the market launch of the ANGER FLXBL. These machines are flexible, standardised, modular transfer centres, designed for the machining of precision parts in medium-to-large volume production. The ANGER FLXBL can be easily and quickly reconfigured, and a great variety of work pieces of various volumes thus can be machined in several sequential product life cycles. Thanks to its flexibility, for the system operator this means the greatest possible protection of his investment, coupled with the advantages of the proven transfer centre technology.