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PPF 800 PRECISION PORTAL MILLING MACHINE 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
PPF 800 PPF 800 The precision portal milling machine was mainly developed for machining flat parts. Due to the compact, stiff portal construction it is very precise and permits high acceleration values and movement speeds of the axes for fast and cost-efficient machining. Both the construction of the machines and the components used are of high quality and thus form the basis for their repeat accuracy and process reliability. The machine is geared to a multiple shifts production, but because of the quick and easy retooling is also well suited for the production of small batch sizes. 04
TECHNICAL DATA Working range Travel x-axis Travel y-axis Travel z-axis Rapid traverse, linear (x-y-z) Acceleration, linear (x-y-z) Repeat accuracy Positioning accuracy 800 mm 480 mm 100 mm 30 m/min 6 m/s² <2 µm ±0.001 mm/100 mm Position measuring system absolute, resolution 0.01µm Clamping range of the vacuum table 610 x 430 mm Max. workpiece thickness 80 mm Main spindle drive HFS 30 Speed range Type of bearing Tool holder Up to 80,000 rpm Hybrid bearing Shrink fit holder Ø 3 mm or Ø 4 mm Collet chuck ER 8 or ER 11 Concentricity of the tool holder <0.001 mm Controller Beckhoff Heidenhain Dimensions Height Height with open lift gate Width Depth Weight Connection data Connection voltage Power consumption TwinCAT 2 TNC 640 (optional) 2000 mm 2630 mm 1320 mm 1590 mm approx. 2200 kg 400 V / 230 V / 50 Hz approx. 4.5 kW Compressed air connection 6 bar 0 3 6 2 n e p o e a g t f i L t 0 0 0 2 260 mm 240 mm 70 mm 27 mm 30 mm 1 mm 1590 1 3 2 0 Workpiece examples 05
FEATURES WORKPIECE CLAMPING – VACUUM TABLE Flat workpieces like foils, plastic slabs or thin parts made of non-ferrous metal or non-magnetic metal can best be machined in a vacuum clamping system. They are easily and securely clamped onto a porous sintered aluminium plate. The plate has neither grooves nor holes, thus ruling out any deformation of the workpieces. The entire 630 x 450 mm machine table is available as clamping surface. Unused areas are closed with cover plates that have been cut to size so that the vacuum pump cannot draw external air. WORKPIECE CLAMPING – ALTERNATIVES Depending on requirements, mechanical single or multiple clamping devices can be used in the same manner as zero point clamping systems and other clamping systems. 06
TOOL SPINDLES Different spindles can be used with the machine. These can be selected as an option, depending on customer requirements. A selection is depicted on page 12. The machine can also be equipped with two spindles, with one of the spindles being set up on an additional z-axis. Only one of the spindles is engaged at any one time during machining. This offers the advantage that workpieces can be machined with two different tools without tool change; alternatively a spare tool can be kept in the second spindle during serial production. GUIDES HARD STONE CONSTRUCTION All axes of the machine are equipped with high-precision profile rail guides, which are pretensioned backlash-free. The machine is driven with ball screws and servo motors. A high positioning and repeat accuracy is supported by absolute position measuring systems with a resolu- tion of 0.01µm. Because of this design configuration of the axes, it is possible to drive the machine with increased acceleration values and to considerably increase productivity. All precision machines by Lehmann are mounted on a substructure of natural hard stone. Apart from the massive base plate, the PPF 800 is equipped with a yoke-shaped mounting bracket for the x/z-axis. 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. 07
CONTROLLER The machine is equipped with a modern 2 ½ D CNC controller with touchscreen. It features an intuitive and structured menu system with dialogue masks. The program 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. For diagnostic and maintenance purposes, it is possible to intervene with the machine via an authorised remote access. Definition of the machine parameters. Menu for manually moving the axes in setup or manual mode. 08
EXAMPLES OF PRACTICAL APPLICATIONS 1 An application-specific menu for workpiece carrier definition can be drawn up at the customer’s request. This menu is used to define the type and number of workpiece carriers on the machine table. 2 If defective parts were found on the workpiece panel during the intermediate check, the machine should not machine these. The defective parts are marked directly on the workpiece panel. 3 The selected menu can be used to select or deselect workpieces for machining; these parts will then not be machined. All machine functions can be manually actuated via the controller. It is possible to display all the important operating data of the machine. 09
OPTIONS All machines are basically of a modular design and can thus be customised to meet the respective application needs. Apart from options such as thread cutting unit, electronic measuring sensors and the automated workpiece infeed, the following is offered. CHIP EXTRACTION The chips generated during machining are extracted as they are arising. A powerful industrial vacuum cleaner that is designed for continuous operation is used for this; the device can be delivered in an explosion-proof design if required. CAMERA SYSTEM The entire workpiece pallet or each individual workpiece can be located in x and y direction by means of a camera system. In accordance with the values measured, the coordinate system is automatically correctly positioned and aligned for machining via an offset. Camera system 10
OPTIONS TOOL CHANGER If it is equipped with an appropriate spindle, the machine can be supplemented with a tool changer. Up to 20 HSK 25 tools are stored on a slide and are changed fully automatically. The time for a tool change is 6 seconds. TOOL LENGTH MEASUREMENT The length of the tools can be directly measured in the machine and processed in the controller. During production, tools can be checked for tool breakage or undue wear. The measurement can optionally be performed with a tactile or contactless system. 11
OPTIONS HIGH SPEED SPINDLES STANDARD SPINDLES Depending on the system, different standard spindle types are offered. Lehmann has developed both ball bearing and air bearing spindles. All spindles are designed for serial production. On account of their design, all spindles exhibit a high degree of concentricity due to the particu- lar stiffness of the bearing, thus ensuring a highly precise machining of the workpieces. The spindles are integrated in the machines’ cooling circuit, thus preventing an uncon- trolled change in length. This has a positive effect on tool life, repeatability and thus surface quality. Ball bearing spindles with a diameter of 30 mm, 38 mm or also 60 mm and 80 mm. Air bearing spindles with a diameter of 60 mm, 80 mm and 100 mm. SPINDLE OPTIONS - Different drive concepts (synchronous, asynchronous motor) - Automatic tool changer with HSK 25 - Special tool holders - Tool holders with shrink fit system - Integrated balancing system - Tool preparation space HFS 30 HFS 38 HFS 60 12 HFS 80 AWW HFS 80 WS
OPTIONS STROKES Owing to its modular design, the machine can as an option also be constructed with different strokes: Strokes (mm) Outside dimensions (mm) X 800 1200 1600 Y 480 750 1000 Z 100 150 200 Width 1320 1800 2500 Depth 1590 2200 3000 Height 2000 2100 2200 PPF 800 PPF 1200 PPF 1600 PPF 1600 > PPF 1200 > PPF 800 > 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. 13
DESIGN EXAMPLE Precision portal milling machine PPF 800 for milling out different annular parts from plastic foil. Equipment - Stroke X x Y x Z = 800 x 480 x 100 mm - 2 high speed spindles HFS 30 - Tool length measuring system - Camera system for identification of pass marks on the workpieces - Chip extraction 14
DESIGN EXAMPLE Precision portal milling machine PPF 1600 for milling finest rod lenses for screen masks. The machine operates inside an enclosed temperature-controlled room and therefore has no casing. Equipment - Stroke X x Y x Z = 1600 x 1000 x 200 mm - Air bearing y-axis with a running accuracy of less than 2 µm on 1000 mm - Air bearing high speed spindle HFS 80 HSK 25 with semi-automatic tool change - Pivoting spindle holder - Contactless tool length measuring system - Vacuum system for workpiece fixation - Minimum quantity lubrication - Chip extraction 15
GERMANY Lehmann Präzision GmbH Weilerstraße 27 78739 Hardt Phone: +49 7422 95800 Fax: +49 7422 958020 vertrieb@lehmann-praezision.de www.lehmann-praezision.de SWITZERLAND Lehmann Präzisionstechnik GmbH Ruppertsmoosstrasse 25 8583 Donzhausen Phone: +41 71 570 5372 verkauf@lehmann-praezision.ch www.lehmann-praezision.ch