Viewpoints: High-Efficiency Production in the Smallest Spaces
By Kevin Heise
Liebherr Automation Systems Co.
The integration of an automation system facilitates higher productivity as well as streamlined management of equipment and workpieces by utilizing machines effectively and keeping distances short. Small-batch manufacturers are driven by one key issue: how to decouple the work tasks of operating personnel from machine operation times? Decoupling a machine’s setup and operation from the cycle time required for machining a workpiece offers major potential for increasing utilization and reducing unit costs in the long term.
Long setup times, especially for small batches, considerably reduce productivity; it is especially costly if the employee needs more time to set up than the machine needs for machining. It is here that automation systems come into play.
Complex, linear automation solutions are not suitable for every company: there is no space or the capital investment is simply too high. But smaller installations can move into high-efficiency production with one or two machines—delivering utilization of more than 90%.
Adding a compact automation solution can make investing in an additional machine completely unnecessary in certain cases. This solution is clearly more effective than marginal increases in productivity that could result, for example, from optimizing CNC programs or the tools of machines that are manually fed or partly automated. One or two machining centers can be docked to the system.
For batch size 1 and above, a compact workpiece handling solution unleashes considerable efficiency potential. The operator can use the machine’s running time to perform other production tasks; setup costs thus don’t enter into the machine costs/hour equation. Such a system is designed for workpiece weights of up to 800 kg or 1,500 kg and dimensions up to 1,300 mm. The formula is simple: Optimum machine utilization and reduced staffing requirements result in decreased unit costs—up to 20%. So as a rule, the investment pays for itself in less than two years. Moreover, the system improves delivery capability and facilitates rapid, flexible responses to changes in customer demand.
A cost-effective entry-level solution for users with very small batch sizes (batch size 1 and above) or small batch manufacturers with 20–30 employees, or tool and diemakers, who manufacture individual components with very long running and setup times, as well as very substantial cutting capacity, can benefit from a cost-effective entry-level solution.
Such a solution can also be designed to integrate existing machinery, accommodating older machines at relatively low cost. Liebherr tests this in advance, based on the existing production and machine layout. There are usually several small mechanical adjustments needed to establish accessibility. Machining parameters like CNC programs and tool data remain in the normal machine environment and are linked in an uncomplicated way to the RLS via a Profibus interface.
There is a positive relationship between basic investment and storage volume. Given its compact dimensions and high storage density, a compact circular storage solution is also suitable for end users, who can’t accommodate a linear system. Up to 24 storage locations on a minimal footprint ensure sufficient work-in-progress to bypass an entire third shift.
The important factor of future reliability is therefore added to the flexibility of the basic design—an issue where similar systems on the market have their limitations. Components must be pre-configured to integrate any number of machine contours. If needed, the users can add storage modules to permit the docking of a second machine in various positions—depending on which location space is available.
The design of the system will permit the user to access the automation engineering easily. An integrated setup station is located directly next to the operating side of the machine; the short distances resulting from it create space and reduce stress for the operator.
Software, which also facilitates integrated job planning, should be modular, open and intuitive to use with a drag-and-drop via the graphic user interface, and Production Control Software (PCS) should be suitable for use by a broad range of machine manufacturers. NC control of workpiece machining and tool management still functions using the usual control system directly at the machining center. ME
This article was first published in the December 2013 edition of Manufacturing Engineering magazine. Click here for PDF.
Published Date : 12/1/2013