The architecture of the electric control is of the âopen typeâ. The frequency converter âVector typeâ individual
Rotating die holder Interchangeable
BEST MACHINERY SRL
WIRE DRAWING MACHINE
BEST MACHINERY drawing machines are suitable for drawing metallic steel wire in the entire carbon content range, stainless steel and special alloys of wire drawing materials. The speed of the wire drawing is continuous from zero to the maximum permissible speed for each application. The mechanical ratios are calculated to allow an ample choice of wire drawing diagrams and of section reductions based on the materials drawn. The area reduction at each block is free (usually in the range 5 – 35%) The number of blocks used can be freely chosen (from 1 to 10) and any intermediate block can be skipped. MACHINE MAIN BODY - FOUNDATIONS The MONOLITHIC STRUCTURE is built in electro-welded steel and contains all the components, including motors on adjustable skids. The electrical equipment and controldesk (when provided) are the only separated components. The main body of the machine is wired up, partially run-in at the factory and requires no particular foundations. The machine shall just be positioned on a flat floor with appropriate load capacity, without any bolting screws. MACHINE CONFIGURATION The machine is of the straight-through type, with tilted blocks and speed control by sensingarm. It is made in one or more sections, in order to fit the dimensions of the truck or container for transportation. FIRST or LAST BLOCK DESIGN (AS OPTION) The block is designed to accumulate the wire on the capstan and pay it off from the top. The wire is guided from the top of the block through an idle flyer with adjustable torque to the wire deflecting pulley sited on a steel column and from there to the inlet of the die-box of block No. 2 or in the spooler from the last block. The wire is accumulated on the block with a pre-set number of wire laps. The flyer at the top of the block operates same as a dancer-arm, controlling the speed of the block in order to maintain constant the pre-set quantity of wire. When the first block is stopped due to a snarl on the pay-off, all the other blocks continue to run and the wire accumulated on the block is paid-out. The flyer accompanies the wire and rotates backward, counting electronically the number of laps of wire paid-out. As soon as the wire tangle is eliminated, the operator restarts the first block and the wire is accumulated again until the pre-set value. If the number of laps of wire remaining on the block is reduced to a minimum (pre-set value), the machine is stopped automatically. For the last block the system it’s at reverse.
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DRAWING CAPSTANS These are made of high resistance forged steel, tempered and induction hardened at 60 HRC minimum. The thickness of the capstan is studied to maximize the heat transmission. The lower part of the capstan surface is coated by black ceramic or other specific materials at the necessary height to increase the wear resistance very much and is polished in order to guarantee the smooth climbing of the wire in such quantity to guarantee the best cooling effect. Inside, if request, it’s nickel coated for corrosion protection. Capstans profile is tapered with the right angle according to the product to be drawn. MAIN BLOCK CASE The block case is made of welded steel, is self-contained and can be slipped out of the machine bed. It contains: Block cooling ducts (water and air), Bearing mounts, sealing, block shaft, Gearbox, Mechanical transmission. TRANSMISSION A multiple "V" belt TRANSMISSION connects the electrical motor to the gearbox, which operates the drawing capstan. GEAR BOXES All the blocks are equipped with standard gearboxes (this means available on stock at any moment) with high efficiency helical steel gears with rectified profile, in oil bath. Gears are sized for average life of 80,000 hours MOTORS A.C. motors IP55 of suitable power, fed at variable frequency by vector type inverters individually drive all the blocks. The motors, which are servo-ventilated, are installed vertically on hinged belt tensioning skids for easier maintenance and space saving. DANCER AND SENSING-ARMS The continuous control of block and wire back-pull upstream of each die, is achieved by regulating the movement of intermediate dancers or sensing-arms, which are controlled by a pneumatic cylinder and whose function is the synchronization of the speed between the capstans. A progressive proximity switch, faced to a circular cam integral with each dancer or sensing-arm, produces an electric signal proportional to the deviation of the dancer from its central position. This signal, processed by the electronic control equipment, sets the blocks relative speed depending on the arm position. Deflecting rolls are made of induction hardened steel. The support of dancer arms will have a steel protection to prevent damages to the electric and air connections in case of wire breaks. All the rolls and sheaves in contact with the wire are coated by Tungsten Carbide for a longer wear prevention.
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ROTATING DIE BOXES The die boxes made of normalized alloy cast iron, are adjustable in two planes for a better control of the diameter of the waps . The back section of the die-box contains the lubricant powder, the front section contains the motorized rotating part suitable to install pressure dies. Turbulent water flow against the die for a more efficient heat exchange. A frontal locking nut, easy to release for quick die replacement, keeps the die in the right position. VIBRATION DAMPERS The vibration dampers are installed at the exit of each die box. The dampers are designed as fingers that touch the wire coming out from the die in order to stop any possible vibrations that could influence the quality of the wire surface. WIRE COOLING: An high turbulence water flow is provided inside the block. The internal surface of the capstan is very smooth and optionally nickel coated to reduce the deposit of calcareous scale and rust prevention. Air flow tangential to the capstan around 360 ° is provided to increase the cooling effect by means of electric blowers (available as option). SAFETY GUARDS The machine is provided with steel-sheets safety guards with balanced opening, each guard is provided with a big protected crash-resistant glass window in correspondence with the diebox and capstan. There is mechanical and electric locking during machine operation. The access to the soap box is protected by a hinged lid and steel shields to prevent operator to be hurt in case of wire break, but, in any case, it is possible to fit the soap box without open the guards. The internal lighting system, (Neon tubes or LED tubes are protected by shootproof acrylic shields and wire-mesh) will be located on the front side of the safety covers in order to allow the clear vision of the area of die-box an capstan. From safety cover it is not possible to approach the die-boxes, it is possible only when the safety cover is open. DUST PREVENTION The machine is provided with a centralized duct for dust extraction integrated in the frame, to be connected to the OPTIONAL dust extraction and filtering system that could be provided on request.
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ELECTRICAL EQUIPMENT The architecture of the electric control is of the “open type”. The frequency converter ”Vector type” individually powers each three-phase motor servo ventilated, which drives a block of the drawing machine. Such inverters are mounted inside the electrical cabinet and have the function to transform A.C. network power into D.C., and then back to A.C. at a set frequency to feed the motors and to vary the frequency in order to obtain a controlled speed. The speed is controlled step less from zero to the maximum. The stability and synchronism of each motor is achieved through an elaborate electronic system that manages the reference speed in operation from the data supplied by the speedsetting potentiometer, the encoders at each motor and by the sensing arm position transducer. The arm position transducer can control all the functioning within and beyond the range of dies. The power components, electric-electronic controls and auxiliary equipment are housed in steel, modular, servo-ventilated and protected cabinets, the cooling of the inside air is performed by a air-conditioning unit or water exchanger. Electronic system for wire-break checking is provided at each block. Special safety sequences automatically inhibit all operations not involved in the specific operation in progress. The network indicator instruments, together with the general conditions of the machine and the main switch are located on the door of the 1st cabinet. All the sequences are controlled by means of a powerful PLC (by SIEMENS). The electromechanical and auxiliary components are all from first class international manufacturers, available in almost all the countries. Project and execution are in accordance with international safety standards and all our electric cabinet are certified. CONTROL DESK The set-up and operation of the machine is performed by a control desk with the following: stop, reset and emergency pushbuttons LCD display and keyboard to set up and visualize all the operating parameters such as: A.C. motors amps, machine speed, total production in length and time, occurred faults, die diagrams calculation, etc. Selectors for machine set-up. Controls for optional devices
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ON BOARD CONTROLS It is provided a control panel at each block, comprising of start, stop, emergency, forward and reverse jog push-buttons, forward and backward sensing-arm position selector, back pull adjustment knob and pressure gauge, hand wheel for regulation of cooling water flow to both dies and capstans ON BOARD WATER PIPING Separate piping to feed fresh water to the dies and capstans. A cutoff solenoid valve is provided to stop the cooling water to the capstans when the machine stops or runs at low speed during jog operation, to avoid under cooling of the capstans. The drain-pipe is integrated in the frame structure to collect the exhaust water from the dies and capstans. Suitable glass windows allow the visual check at each block of the quantity of drain water from the cooling system of dies and capstans. ON BOARD ELECTRIC WIRING The machine is completely pre-wired to the terminal box. The Customer has to connect the cabinet to the terminal box, the A.C. power cables to the motors and the cabinet to the mains.
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