Technical and economic indicators of the machine efficiency Indicators: energy intensity, intensity, degree of automation, the competitiveness.
Modern machines with numerical control, replacing conventional machines, thanks. speed, accuracy, manufacturability and reliability. At medium volume and mass production of the machines very quickly pay for itself.
If you take the machining centers, automation degree is very high, and it is possible in a single clamping of the part to the final product, thanks a lot axis machining and application timing of the auxiliary tool for lathe-milling machines
Patient effect is achieved by the processing of the machine with numerical control of technically complex parts, with lots of machined surfaces, the contours of which contain curved portions and elements of straight lines and planes that are not parallel to the coordinate axes of the machine.
Electromechanical 3-axis milling machines
Milling machines move in three axes, by means of an Electromechanical or electrohydraulic actuator. Machines have different types of engines. In milling machinesas the main drive asynchronous motors are used (in these cases a gearbox) or DC motors.
it is believed that the improved scheme is to use a motor-spindles, which govern speed stepless, wide range.
the axis Drive system 3 axis milling machines with numerical control , also Electromechanical. To transmit the torque of the motor shaft, to the actuator , use a short kinematic chain, where the main acts ballscrews, ball screw. The latest generation of machine tools have motors that are directly connected with the Executive mechanism.
3-axis milling machines use contour CNC system, which enable you to create complex trajectories. When buying machines, the secondary axis, are considered optional, they will be managed as the same stand, and plug-in (synchronization packet).
electro-hydraulic 3-axis milling machines
3-axis machines with electro-hydraulic drive for the main movement using an Electromechanical circuit. Hydraulic devices are used for the traffic flow, movement of the headstock and the console. Working from a discrete engines. As a rule, for high-precision milling machine, one impulse engine, table milling machine, moves up to 0.005 mm. Design provides, on the one hand, high precision, and with another — gives the chance to regulate the speed of movement over a wide range, these machines are considered to be highly accurate and are more expensive than simple equivalents.
Kinematic structure of machine — the Foundation of a layout.
Milling machines with numerical program can handle-and three-dimensional surfaces of complex-shaped parts. By design, CNC machines comparable with universal machines and in addition have the ability to automatically process the item at the specified control program.
Milling machines with SPU have the following divisions:
- the Arrangement of the spindle;
- the number of coordinates of movements of the milling table or the headstock;
- the number used in the processing tools (odnostoronnee and mnohostranne);
According to the method of clamping tools in the spindle (manually or automatically).
layout milling machines divided into four groups:
- vertical milling machine with cross table (652ОФ3, МА655Ф3, etc.);
- milling (6Р13Ф3, 6Р13РФ3, etc.);
- milling (6М610Ф3-1, etc.);
- versatile tool.
In vertical milling machines with cross table (Fig. a) the table moves in the longitudinal (X-axis) and transverse (axis Y) horizontal directions, and milling grandmother — in vertical direction (Z-axis).
knee-type milling machines (Fig. b) the table moves in three axes (X,Y, and Z), and grandmother still.
In the longitudinal-milling machines with movable cross member (Fig.4) the table moves along the X-axis headstock — Y-axis and cross — axis Z. the longitudinal-milling machines with a fixed cross-member (Fig. d) the table moves along the X-axis and headstock — Y and Z.
wide universal tool milling machines (Fig. d) the table moves in X and Y, and headstock — z
Milling machines mainly equipped with the rectangular contour control.
Difference of 3 axis milling machines 4 and 5 are axial in that it does not have these axes, 4 coordinate machine 4 axis is a-axis in 5 coordinate is used, rotating the cradle and he already has an axis A and B. it is Noticed that the simpler the layout of the machine, where the X-axis is performed by moving on the table and Have Z moves the spindle Assembly, the stiffness on these machines anymore, and they are used to rough-in mechanical operations.
are Distinguished guides to the path of movement of the nodes in: guides rectilinear and circular motion. The shape of the cross section : dovetail, rectangular, round.
A) rolling Guides
rolling Guides consist of support elements: rail-carriage, linear bearing shaft or rail-rail flat-separator.
Consider a set of rail-carriage.
Rail. All the seats here are polished and are hardened and raceway serving to move the rolling elements.
the Carriage guide is:
- solids of revolution
- End caps
Under divided depending on body rolling:
1) Ball-rolling guides
2) the Roller rolling guides. Apply under high loads on CNC machines
Videos unlike balls provide greater stiffness to guide its durability and load capacity.
the Advantages of rolling guides:
low friction coefficient.
high-Precision movement and positioning.
the Disadvantages of slides:
counteract Bad races.
the Main producers of rolling guides:
B) sliding Guides
sliding Guides and rolling guides, perform the same function.
In appearance of friction slip them into:
- Hydrostatic lubricating layer is formed by the flow of high pressure oil in special pockets.
Hydrostatic sliding guides
Hydrodynamic bearings are well proven at high speeds. In these guides used by the hydrodynamic effect, the effect of floating of the movable node. The design has V-bevels and when you move in narrowing these gaps is grease.
- Aerostatic guides for oil is served, compressed air. Structurally similar to hydrostatic guides. The disadvantages include a small load capacity.
Oil for the guides comply with DIN 51 502 and ISO 6743-13. Advantages of slides:
- the Stiffness
the Small gap
Large loading capacity
the Reliability and durability of work.
Manufacturers of slides:SCHNEEBERGER GmbH (Germany)
ZITEC Industrietechnik GmbH (Germany)
item Industrietechnik GmbH
KAMMERER Gewindetechnik GmbH (Germany).
- the Stiffness
Spindle units of the machine
the Main design criteria. The design of the spindle unit and its determining factors
Spindle milling machine provides secure fastening bars the cutting tool. Mechanism spindle millingtank ensures it stability significant racially radial stress, прекрасныйзапаспрочностиработыпри heavy operation.
Conditional division on execution:
nizkobonitetnyh (to 2500 rpm). Often used for transmission of high torque and speed from the engine to the COP. On the spindle there is one gear or many pairs of gears.>
high-speed (2000~24000) rpm, belt drive or direct transmission of torque from the engine. Uses various gear or transmission clutch backlash-free are necessary.
Ultrasociality 15000~70 000 Rev/min. is often presented in the form of motorspindles, i.e. with vstroennye windings and sensors
According to the method of tool change:
manual (strevel, bolt, collet)
automatic (strevell and grapple)
design Features shaftand milling machine
This is a hollow elongated shaft, made of high-alloy steel. The front part is machined and polished on the inside under the cone (Morse, ISO, BT, HSK etc) necessary for rigid mounting of the mandrel in the machine spindle. Fixing the mandrel with the cutting tool is provided by external forces and can be either manual(by operator) and automatic.
Valdostanodes nedvizhimostyu, moving parts, bearing, node clip/release, cooling, blowing, flow Sozh, governing nuts, balancermember and the Analysis of unsuccessful solutions in spindle units.