Bespoke Chamfering

  • Liebherr’s new development: the LCD 300 ChamferCut
  • First stand-alone chamfering solution, using the increasingly popular ChamferCut
    method
  • The new machine enables intuitive guidance and fast set-up times
LCD 300 ChamferCut

LCD 300 ChamferCut

The trend towards quieter, more efficient gear units continues unabated, especially in the vehicle manufacturing industry. This means demands on individual components are increasing: special gears need to have smooth, trim edges. Chamfering helps to avoid workpiece conveyance damage, quench cracks and gear-unit wear caused by sharp edges. Furthermore chamfering makes the assembly process easier and improves finishing process tool service lives, especially honing.

Liebherr now provides a stand-alone chamfering solution, using the increasingly popular ChamferCut method – the LCD 300 ChamferCut. After Liebherr unveiled an integrated, parallel-to-primary-machining gear-hobbing and ChamferCut method chamfering machine designed for the vehicle manufacturing industry for the first time at EMO 2013, the LC 180 ChamferCut, and extended its portfolio in 2014 by adding the LC 300 ChamferCut, the need for a separate LCD 300 unit soon emerged, to complement an existing stock of machinery, to replace existing chamfering machines or to establish new lines. Liebherr has now developed the stand-alone ChamferCut machine to meet these requirements.

Chamfering formation compared: ChamferCut

Chamfering formation compared: ChamferCut

Basic Idea: Quick and Simple

The basic idea behind the terms of reference was unambiguous: “This machine should be simple to operate and as quick as possible”, Dr. Hansjörg Geiser, Head of Gear- Cutting Machine Development and Design Engineering at Liebherr-Verzahntechnik GmbH, explains. Using a separate LCD 300 machine enables gears clamping operations to be geometrically optimized for chamfering purposes. Clamping operations can be performed to maximum rigidity in the gear-cutting machine. Both processes therefore generate optimum results. This technology and fast set-up times enable an LCD 300 ChamferCut machine to perform the same machine-finishing work on the gears as roughly two to three hobbing machines.

The result is a machine with extremely fast set-up times and streamlined workpiece clamping. The operator can easily enter and correct ChamferCut process settings via CNC axes. New software was developed for the user interface. This is based on FETTE ChamferCut tool settings sheets. The operator can get their bearings quickly with the aid of graphics and settings correction examples, intuitive guidance makes machine operation easier.

The machine is loaded automatically in line with the proven ring-loader principle, although the use of robots or gantries is also a possible alternative. This makes incorporation into the automation process flexible, for example via a plastic chain conveyor.

Chamfering formation compared: press deburring

Chamfering formation compared: press deburring

Inexpensive Method Delivering Outstanding Results

Chamfering is growing in popularity compared with press-deburring and tapered-end mills, since this process involves the lowest chamfering costs. The special tools are very durable and simple to regrind. Precision, repeat-accuracy chamfers combined with long service lives speak for the ChamferCut process. So it’s no wonder that ChamferCut chamfering has gained in importance over the last few years. Given the high quality it delivers, chamfering is particularly popular with car and commercial vehicle manufacturers as well as gearbox and engine manufacturers: “Standards in these sectors are naturally very high”, Hansjörg Geiser explains. “The increasingly more compact design of gear units makes high chamfering quality an absolute must, which ChamferCut is particularly good at delivering.”

Total costs per piece (chamfering)

Total costs per piece (chamfering)

Good reasons for deburring using the ChamferCut method:

  • High speed
  • No reduction in hob length
  • Hob and ChamferCut geometries can be selected independently
  • Rigid fixture for hobbing, adjusted fixture for ChamferCut
  • Very small diameters possible (>30mm) with broader applicability
  • High quality and precision chamfer shapes
  • Hassel-free tooth-root chamfering
  • Very long service lives even where dry machining is involved
  • No needle-like cnips
  • Machine settings via CNC axes with simple set-up
  • Lowest chamfering tool costs in comparison
  • Tools are easy to regrind
Source Liebherr-Verzahntechnik GmbH