Formenbau Kellermann GmbH is a toolmaking operation established 40 years ago, and lately it’s become a sought-after partner to the automotive industry providing complex single- and multiple-component tools for high-quality plastic parts such as intake manifolds, oil modules, air filter housings, and cylinder head covers. Having relocated and expanded twice since its founding, the company is headquartered near Nürnburg, Germany, with a staff of 27.
| One VISI CAD function used intensively at toolmaker Formenbau Kellermann is the ability to convert 3-axis to 5-axis continuous toolpaths, automatically. |
"Pricing pressure, competition from emerging countries and the trend towards ever shorter project terms are challenges that force tool manufacturers to rethink the classical format of single-item production," according to Sabine Kellermann, an engineer and the president of Formenbau Kellermann. "In toolmaking, flexibility and the use of the latest technology is a must. This basic principle is also applicable to Formenbau Kellermann where we have invested heavily in machinery and software so we are ready to adapt to changing market conditions."
| Kellerman technicians use VISI for tool design, and the shop operations that are not directly involved in design are widely standardized to the program. |
The milling and electrical discharge machining (EDM) departments are equipped with two HPM1350 U and HPM 1850 U 5-axis milling centers from Mikron/AgieCharmilles and one 5-axis Huron EX machine. In addition, there is a Mikron HSM 700 milling machine for electrode production, an AGIE 100 wire EDM machine, three vertical eroding machines (Exeron, Hansen), and numerous manually operated machines for additional milling, drilling, and grinding operations.
Process automation is a specialty of Formenbau Kellermann, starting with the tool design. Areas that are not directly involved in the design are also standardized to the greatest possible extent. Components such as pressure plates or guides are uniform in all tools. In the case of die centering, only two to three different sizes are used. In addition, there is an in-house company standard for design, as well as a standard component catalogue.
The CAD/CAM software of choice at Kellerman is VISI from British developer VERO Software. "As a progressive company, we had already invested much earlier in 3D," explained Sabine Kellerman. "Prior to our switch to VISI in 2003, we worked with ICEM DDN, a product that had been on the market for many years but could no longer compete with modern systems."
Vero Software designs, develops, and supplies CAD/CAM/CAE software, specializing in applications for plastic injection molds and progressive dies. More than 24,000 seats have been provided worldwide. Vero has distributors in more than 40 countries, and direct sale efforts in the U.K., U.S., Canada, France, Italy, China, and Japan.
Feature recognition drives CAM consolidation
In 2004, Kellermann’s NC department was equipped with VISI Machining, where the CAM tasks were shared with PowerMILL from Delcam. However, in 2009 the company switched entirely to VISI for all machining activities. "The advantages of a uniform, consistent CAD/CAM system outweighed the benefits of dual products. Typically we deal with short programming times and feature recognition from native CAD data is an important component of our automation strategy," according to Sabine Kellermann.
| Frequently, Kellermann will generate its NC programs as 3-axis operations and convert them using VISI to a 5-axis simultaneous program, for use on the 5-axis Mikron HPM 1350U CNC machine. |
The introduction of 'Compass Technology' for feature recognition means that Formenbau Kellermann can generate 2- and 2.5-axis CNC programs automatically for regular geometries, such as holes or milling grooves, which are common features in tool making —reducing programming time dramatically and eliminating potential positioning errors. In principle, only three steps are necessary for CNC plate programming: Start the feature recognition, run the company-specific Compass based rules and finally, verification of the completed CAM programs. VISI distributor MECADAT GmbH performed the set-up and customized the Compass rules, and on-site assistance was provided to analyze the existing CAM strategies and transfer this knowledge to the rules database.
One function that is used intensively at Kellermann is the ability to automatically convert 3-axis programs to 5-axis continuous toolpaths. "This enables us to reduce expenditures on programming time and still benefit from the advantages of 5-axis machining," reported Sabine Kellermann. "For example, the Mikron HOM 1350U allows for an approach angle from +16° to -120°, whereby the distance between spindle and table is only 30 mm. This approach is applicable for most geometries and we benefit from better surface finish through the use of shorter, more rigid tooling and reduced vibration.
"Automated and standardized processes also require the efficient supply of information,” Kellerman continued. “The possibility of sharing the tool library from VISI was an important milestone for our automated processes. For example, all tooling databases are available to all users across the network and contain information typically seen in expensive tool-management systems such as tool-holders, extensions, collets, cutting tools, including assemblies as well as their individual cutting conditions."
High machine capacity load, and still flexible
"There is rarely something that we cannot mill, and we no longer experience bottlenecks on the CNC machines," Kellermann said. The 5-axis Mikron machining centers are equipped with a palette system that includes three round tables, each of which can be loaded with 1 metric ton of material, and intelligent zero-point clamping systems that ensure highly optimized use of the CNC machinery. Sabine Kellermann also noted the flexibility advantages of a palletized and zero-point clamping system: "A running process can be interrupted at any time, without losing the zero-point,” she said. “This can be particularly useful in case of urgent repairs, or when spotting surfaces must be quickly re-milled, all which effect lead-time and efficiency."
| The ejector side of a complex injection mold machined by Formenbau Kellermann, showing a cavity and sliders. |
For Formenbau Kellermann the benefits of the significantly improved process chain, software automation and advanced CNC machinery can are verified by a recent project for an innovative air-filter housing (inlet and outlet on the same side) for Daimler’s new generation of diesel motors. The automaker’s World Motor OM651 is built into the Mercedes E-Class Cabrio. With great pride, Sabine Kellermann announced, "The consolidation of high-end software and high-end machinery has reduced our lead times by more than 20%.
“Those who stand still have no chance in tool-making, over the long-term,” she concluded. “Automation has reduced our costs now and will continue to do so in the future."