Flexibility and surface quality

Flexibility is important to LARO-NC Technik GmbH. “You never know what comes next,” says Elmar Müller, managing director of the 30-person company, located in Illmensee, in southern Germany. “We need machines that provide not only consistently good quality and productivity, but also machines that we can flexibly apply for 5-axis machining operations.”

To help meet Müller’s machinery goals, LARO-NC uses three Handtmann machines in production with a fourth – the second HBZ Trunnion – scheduled for installation soon. For LARO, the Handtmann machines are machining centers that fulfill the requirements of quality, productivity, and flexibility.

LARO manufactures small to large components; with individual parts, tools, models, and test equipment prototypes making up its core business. The company also offers contract manufacturing of complex workpieces in a wide range of materials including aluminum, steel, tool steel, titanium, bronze, copper, glass-fiber reinforced polymer, and carbon-fiber reinforced polymer.

Often, the chip removal rate is more than 90%. For this reason, LARO relies on “flexibly applicable HSC high speed cutting machining centers,” and has been using machines of Handtmann A-Punkt Automation GmbH in Baienfurt since their start in 2001, says Production Manager Markus Meschenmoser.

LARO and Handtmann have a long customer-supplier relationship: The Handtmann UBZ NT universal machining center delivered in 2001 was one of the first machines in LARO’s facilities. At that time Müller was looking for a machine constructor that could provide good service and found Handtmann.

Flexibility in material choice has been equally important: the machine to be purchased had to be able to machine aluminum and finish steel. Recently, panels for aeronautics have been machined on the UBZ NT.

In 2009, LARO began manufacturing on a UBZ HP 300/200 with pallet automation. With three pallets (3m x 2m) the machine’s use is primarily for machining large workpieces, unmanned, for several hours. LARO’s criteria were chip removal rate, flexibility (material: aluminum and steel), a large tool magazine (250 slots in total), and the pallet system.

“Automation is getting more and more important,” Müller states. “The ultimate goal is that machines run 24 hours and that we are able to set-up in advance for weekends and nights. This is decisive criteria where manufacturers stand out from each other.”
 

Choosing machines

The current equipment in the southern German facility is comprised of nine machines, and when adding machines, the company follows a defined purchasing strategy with clear selection criteria recorded and evaluated in a matrix. Highest weighting is on a machine’s ability with different materials. For future orders, Müller says the machinery has to provide solutions for a huge variety of requirements but also specialized enough to deliver premium quality. Further selection criteria for the machines are good ergonomics with good accessibility and setup possibilities, high surface quality without steps, and reliability for 5-axis simultaneous machining of complex workpieces in different materials. Reaction time and quality of service are also important.

LARO gave all manufacturers in the selection process a complicated test part to mill. Workpieces need to leave the machine in optimum condition without needing any manual reworking. CNC programs, detailed milling strategies including cutting data, and tools were provided by LARO. Surface quality and machining time are the typical decisive factors within this process.

Weighing all of these factors, LARO decided to purchase a HBZ Trunnion 80 5-axis HPC horizontal machining center, the smallest machine of the Handtmann HBZ Trunnion series and the first horizontal machining center for LARO. Besides the selection criteria of the LARO-purchase-matrix, the Handtmann HBZ Trunnion 80 demonstrated convincing surface quality, and advantages of high machine rigidity, easy operation, and above-average acceleration of 60m/min. The 18,000rpm spindle with 31kW and 200Nm motor plays an important role, according to Meschenmoser, because the spindle power can be used fully due to the machine’s rigidity. With the universal spindle, the center is able to machine workpieces of various materials up to 850mm x 630mm. The large amount of chips that result from high-speed cutting does not influence the machining process since it is a horizontal machining center, and the chip conveyor is large enough to easily clear chips out of the workzone. LARO uses the HBZ Trunnion 80 for 5-axis machining of aluminum and steel, primarily complex parts with deep pockets.

Company officials evaluated the total cost of ownership of Handtmann’s HBZ Trunnion 80 very positively based on the supplier providing training, service, and other measures for long-term machine availability.
 

Flexible, accurate

Handtmann’s latest project is a HBZ Trunnion 160, the largest machine of the series, with pallet automation. Long run-time, easy operation, the ability to handle workpieces of different materials with maximum diameter up to 1,700mm and a maximum height of 1,000mm, plus the high-speed spindle were the convincing arguments.

The machines are multi-purpose centers for 5-axis horizontal machining of aluminum, steel, titanium, and other common materials. High power and performance on a small footprint, a broad repertoire of insertable spindles, and a very rigid machine design provide productivity and process stability.

High workpiece accuracy comes from the double clamping and drive system of the X-axis with upper and lower guidance, wear-free direct drives in the A- and C-axis, and linear axes that are independent of the workpiece weight. Application are primarily milling and mill-turning of structural parts for aerospace and automotive, as well as mold- and-die, tool making, machine construction, and energy technologies. Maximum table load ranges from 1.2t on the HBZ TR 80 to 2.8t on the HBZ TR 160. Available controllers are either the Siemens 840D SL or Heidenhain TNC640.

LARO needed 5-axis machining centers for a variety of workpiece materials, sizes, weights, and complex parts with machine uptime of 96%, and the HBZ Trunnion Handtmann A-Punkt fulfills these requirements.

Technical functionality, coverage of the variety of requirements, long-term reliability, and service were decisive factors for LARO adding an additional Handtmann HBZ Trunnion machine. Now, LARO will have four Handtmann machines in production this year: two universal machining centers, the UBZ NT and UBZ HP 300/200 with pallet automation system; and two horizontal machining centers from the HBZ Trunnion series, the HBZ TR 80 and HBZ TR 160.

Handtmann CNC Technologies Inc.
www.handtmanncnc.com

LARO-NC
www.laro-nc.de