VERTICAL LATHES IN THE BLACK FOREST, TECHNOLOGY HAS A LONG TRADITION.
PRECISION IS OUR EXCELLENCE. 02
Lehmann Präzision GmbH, a manufacturer of precision machinery in the Black Forest, combines traditional and modern tech- nology. The company emerged from a traditional manufacturing enterprise for precision mechanics. This manufacture continues to be an important mainstay. Today, the company is among the leading suppliers of complex precision assemblies for different sectors of industry and of high-precision machine tools. These are used for a variety of applications, amongst others in the watchmaking industry or in the optical industry. 03
VERTICAL LATHES The turning of disc-shaped small and micro parts is a cumbersome affair because hardly any specific machines are available on the market for this. The new, innovative CNC vertical lathes by Lehmann Präzision GmbH are now opening up a considerable implementation potential while simultaneously providing highest machining precision and quality. The machines meet the highest demands in practical application: - Highest precision, quality and reliability in serial production - Fast workpiece change - Quick retooling for different workpieces - Easy operation - Low maintenance effort - Inexpensive solution The quality of the construction and the components used are uncompromisingly designed for serial production in three- shift operation. However, because of their quick retooling ability, the machines are also well suited for small batch sizes. The modular system permits an optimum customisation of the machines to meet individual customer needs. The range extends from simple 1-axis machines for manual workpiece change to fully automated solutions with 3 axes and workpiece storage and infeed systems. 04
MAIN DIMENSIONS 805 2395 1080 1574 218 800 6 8 2 2 5 8 9 1 4 2 1 1 4 1 9 TECHNICAL DATA Workpiece dimensions (typically) Diameter Thickness Main spindle Size Speed Speed control Concentricity Axial run-out accuracy Infeed guides Travel x-axis Travel y-axis Travel z-axis Repeat accuracy Rapid traverse speed 45 mm 4 mm Ø 100 mm max. 6,000 rpm continuously programmable via CNC < 0.002 mm < 0.002 mm 85 mm 160 mm 60 mm < 0.0015 mm 6 m/min Position measuring system direct, resolution 0.2 µm Machine Weight Mains connection Power consumption Compressed air connection approx. 600 kg 230 V/50 Hz 0.5 kVA 6 bar WORKING x-axis: 85 mm y-axis: 160 mm z-axis: 60 mm In simplified form, the vertical lathes can also be executed with one or two individual axes for pure plunge-cut operations. 05
MACHINING EXAMPLES 06
FEATURES HARD STONE BASE PLATE INFEED GUIDES All precision machines by Lehmann are mounted on a substructure of natural hard stone. The massive base plate rests on a sturdy welded frame. Natural hard stone is absolutely free of distortion, has a low thermal expansion coefficient and excel- lent vibration damping properties. These properties contribute to the high repeat accuracy of machining operations and lead to an outstanding surface quality of the workpieces. The infeed guides are made of chemically nickel-plated grey cast iron and are equipped with high-precision M- and V-rail guides with needle bearing cages, which are pre- tensioned backlash-free. The machine is driven with ball screws and servo motors. A high positioning and repeat accuracy is ensured by absolute position measuring systems with a resolution of 0.2 µm. The infeed guides are protected against soiling by sheet metal covers. TOOL HOLDER Depending on the application, different tool hold- ers are available to chose from. These range from adjustable tool holders for 1-axis machines and tiltable tool holders to multiple holders for tools of specific suppliers. 07
FEATURES MAIN SPINDLE The sturdy spindle is micro-balanced and thus runs vibration-free. This is crucial to ensure a high machining quality and a long service life of the bearings. The spindle is driven by a coupled AC servo motor with high-resolution rotary encoder. Like a CNC axis, it can be accurately positioned for the workpiece change. The spindle is prepared for installation of the work- piece holding devices, which are normally provid- ed by the customer. Owing to the defined interface, the workpiece holding devices can be exchanged in the shortest possible time, so that different parts can be machined on the machine. In addition, the spindle can be supplied with a centre hole with vacuum and compressed air connection. The vacuum serve to support the insertion of the workpieces and to check work- piece presence and position. The compressed air can be used to actuate ejector pins or the finished machined workpiece is blown out directly. The spindle is available in two sizes. 08 SWIVELLING DOWNHOLDER To ensure the workpieces can be machined over their full height at the outside diame- ter, they are positioned accordingly on the workpiece holding device and are held on the spindle during machining by a swivelling downholder. This downholder consists of a pneumatic swivel cylinder with a pivoted mould pressure piece.
FEATURES CONTROLLER The vertical lathes are equipped with a modern CNC controller with touch screen. It features an intuitive and structured menu system with dialogue masks. All masks can be protected by password, allowing the individual machine operators access via an individually set up electronic key. The CNC programs are created directly on the machine or offline on the PC. A handwheel is available for manually moving the axes in set-up mode. For diagnostic and maintenance purposes, it is possible to intervene with the machine via an authorised remote access. MAINTENANCE, SERVICE All components that need to be acces- sible for machine maintenance (elec- tronic components, pneumatic system, etc.) are integrated in the machine in a clearly laid out, easy to maintain manner. 09
FEATURES MINIMUM QUANTITY LUBRICATION The minimum quantity lubrication works according to the Venturi principle. The spray air creates a vacuum, causing the lubricant or coolant to be sucked from the pressureless storage bottle and then sprayed in smallest amounts in the exact position. Alcohol, oil or emulsion can be used. CHIP EXTRACTION Powerful industrial suction devices that are designed for continuous operation are used for chip extraction. The devices can be delivered in an explosion-proof design if required. Chips are extracted directly at the point of machining. During the workpiece change, the suction effect can be interrupted by a bypass valve to prevent light-weight workpieces from being sucked in. 10 MONITORING SYSTEMS Various types of monitoring systems to auto- matically check the presence and position of the workpieces are available (optical systems, vacuum monitoring or others).
FEATURES TOOL PROBING SYSTEM The tool probing system is an exchange- able or firmly mounted probing element on the plane surfaces of which the edges of the lathe tools are measured. ADDITIONAL SPINDLE A typical application on the vertical lathe is the decoration of watch parts. A high speed spindle is mounted on the z-axis instead of the tool holder. The décor is created by rotating the workpiece on the main spindle and the single-edget tool in the high speed spindle simultaneously at different, precisely defined rotational speeds. 11
FEATURES AUTOMATED WORKPIECE CHANGE Depending on the requirements, various solu- tions for an automated workpiece change can be offered: - Part infeed from a vibration conveyor pot. The finished parts are collected as bulk material. - Part infeed from pallets. The finished parts are placed back into the pallets in an orderly fashion. ERGONOMICS PACKAGE Machines for manual workpiece change are designed for a seated way of working. The ergonomics package with storage plate, adjustable padded armrests and adjustable footrest ensures comfortable and fatigue-free working. 12
DESIGN EXAMPLES 3-axis vertical lathe with loader. The workpieces are stored in a pallet storage unit. They are automatically placed into the ma- chine with a loading gripper and the finished parts are placed back into the pallets in an orderly fashion in the correct position. 3-axis vertical lathe for manual workpiece change. Equipment - Pallet magazine with workpiece loader - Chip extraction Equipment - Ergonomics package - Chip extraction 13
DESIGN EXAMPLES 3-axis vertical lathe with automatic part infeed for machining balances in the watchmaking industry. Equipment - Workpiece infeed from vibration conveyor pot - Height measurement of the workpieces - Precision scales - Optical monitoring system - Chip extraction 3-axis vertical lathe with automatic workpiece infeed from a pallet magazine. The finished machined parts are placed back in the pallets in an orderly fashion and in the correct position. Equipment - Pallet magazine with workpiece loader - Chip extraction 14
DESIGN EXAMPLES 3-axis vertical lathe with additional spindle. The tool holder for the lathe tool can be quickly and easily replaced with a spindle carrier with a HFS 30 high speed spindle. By means of a single-edged diamond tool, the spindle applies a decorative structure to the workpieces. Equipment - Additional spindle - Chip extraction - Ergonomics package 3-axis vertical lathe for manual workpiece change. Equipment - Ergonomics package - Chip extraction 15
DESIGN EXAMPLES 2-axis vertical lathe for manual workpiece change. The two single axes are used to apply decorative chamfers to the workpieces by means of diamond tools. Equipment - Chip extraction 1-axis vertical lathe with automatic part infeed for profiling of plastic rollers. Equipment - Automatic part infeed from a vibration conveyor pot - Chip extraction 16
DESIGN EXAMPLES 1-axis vertical lathe with automatic part infeed. The air bearing spindle is equipped with a pneumatically actuated collet chuck. The workpieces have a diameter of 2.4 mm and a height of 0.7 mm. Equipment - Automatic part infeed from a vibration conveyor pot - Air bearing spindle with pneumatically actuated collect chuck - Chip extraction - Optical monitoring system 1-axis vertical lathe with automatic part infeed. The machine is the precursor model to the machine depicted above. Equipment - Automatic part infeed from a vibration conveyor pot - Air bearing spindle with pneumatically actuated collect chuck - Chip extraction - Optical monitoring system 17
SPECIAL DESIGNS ALIGNMENT LATHES High-grade optical systems can be produced by stacking individually mounted lenses on top of each other inside a tube with precise inside diameter. It is of crucial importance for the optical quality of the overall system that outside diameter and the plane sur- faces of the lens mounts are arranged exactly parallel or at right angles to the optical axes of the lenses. The vertical CNC precision alignment lathe is used to machine such lens mounts with highest precision in accordance with the optical axes of the lenses. For this purpose, the machine is equipped with inno- vative technology. The adjustment is performed automatically by means of magnetically driven hammers which beat against the parts of the adjust- ment chuck while the spindle is turning. The impact force depends on the size of the centring error. The progress of the adjustment procedure is visualised on a screen. After the adjustment, the adjustment chuck remains magnetically clamped so that the settings are retained during subsequent machining. Technical data Stroke x-axis Stroke z0-axis (machining axis) 600 mm 300 mm Stroke z1-axis (reflected image device) 250 mm Stroke z2-axis (measuring devices) 300 mm Speed main spindle 1,500 rpm Equipment - Hydrostatic bearing main spindle - Plane/calotte or double calotte adjustment chuck - Double lens changer for reflected image device - Manual or motor driven fourfold tool changer - Chip extraction - Blow air - Vacuum connection for vacuum clamping system 18
SPECIAL DESIGNS VERTICAL GRINDING MACHINE The machine is constructed with components from the vertical lathe modular system, but is used for grinding the tooth face on threading dies. Technical data Workpiece sizes Ø 12 - 20 mm, thickness 2 - 5 mm Thread sizes M1 - M6 Infeed guide travels X x Y x Z 370 x 220 x 140 mm Speed range of spindles 6,500 - 80,000 rpm Equipment - Automatic part infeed via vibration conveyor - Camera for position detection of workpieces - Tactile measuring probe for measuring the grinding positions - 2 grinding spindles (1x anti-clockwise rotation, 1x clockwise rotation) - Oscillating motion of the grinding tool during the grinding operation, adjustable stroke and speed - Minimum quantity lubrication - Chip extraction 19