HYDRAULIC METAL CUTOFF MACHINE

      MODEL  Q43-1600

 

3.  Main Technical Data and specs

Max shearing force: 160 KN

Max pressing force: 25 KN

System pressure: 22MPa

Max span of cutter: 320 mm

Work length of cutter: 700 mm

Nos of cutoff per minute: 6 – 10

Motor type: Y180M-4

Power: 18.5 KW

Speed: 1470 rpm

Pump type: 80YCY14-1B

Flow rate: 80ml/rev

Max pressure: 31.5MPa

Electrolyte valve: 4WEH25G60/6AW220RNZ5LT

 

 

 

3.2 Cutoff specs

Round steel: Ø 55 mm

Square steel: 50 x 50 mm

Angle steel: 45 x 45x60 mm

Channel steel: 100 x 60 x 16 mm

Steel plate: 30 x 350 mm

Note: with lever enlargement device on this machine, the shearing force at different points of cutter is different. The list shows a max section size when material, with a tensile strength not bigger than 450Mpa, is at the root of cutter and under a system pressure of 25MPa.

 

1. 4.     Electric system

Mains power source: AC 380V, 3 Phase, 50Hz

Consists of 2 circuits: control circuit for motor and that for motions.

4.1   An asynchronous motor Y-type, 380V 3 phase (model Y180M-4 power 18.5KW, 1470 rpm) to drive a high pressure axial piston pump. Its start and stop are by pushing buttons via a AC contactor. A fuse breaker is available for overload protection.

4.2   The control circuit for motions is switched to a 220V supply gained from a step down transformer. Buttons and proximity switches are used to operate cutting off, pressing and return. Control electricals are inside the power cabinet on the side of the tank. A control panel is available on the top of the machine with all buttons on top of the machine to operate each motion.

4.3   Major electric elements

Button SB3:  Start pump

SB2:  Stop pump

          SA:   Switch over between STEP and AUTO modes

   Button SB4:  Shearing & pressing

   Time relay KT:  Control time delay, motor Y-∆

   Proximity switch SQ1: Send out signal in sensing cutoff and pressing movements reach position.

   Proximity switch SQ2: Send out signal in sensing it returns to end

4.4   Electric principle

4.4.1    The auto switch QF operates to switch on or off the power supply.

4.4.2    Start and stop of the motor

When switching on the power, the indicator light becomes luminous. Push the button SB3 and the normal open contacts 3-4 of AC contactor KM1, normal closed contacts 3 – 21 of the time relay and normal closed contacts 21-23 of KM2 will get powered. And the coils of KM1 and KM3 get on, too. KM1 and KM3 are closed. The motor is started in star mode. The time relay delays about 3-5 seconds as KT1 preset. Now the normal closed contacts 3-21 get open while normal open contacts 3-22 get closed. The KM2 coil gets on while KM3 coil off. Thus AC contactor KM2 gets closed and KM3 is open. The motor is connected in a delta mode. And the motor runs regularly. Push SB2 to disconnect the contactor and the motor stops.

 

4.4.3 When the motor starts up, turn SA to STEP to operate the machine in step mode, i.e. pushing SB2 once will perform one step motion. If you turn SA to AUTO, the machine will do shearing, return, pressing and open continuously.

 

1. 5.     Hydraulic system

Please see Hydraulic Schematics.

Consists of oil tank, pump unit, valve unit and hydraulic piping. Its working pressure is set normally at 21MPa and max pressure should not be above 25MPa.

5.1   The oil tank is a steel weldment. On the front face there is a repair opening for convenience in cleaning. There is a oil leveler and thermometer (Type YWZ-150T), air filter (Type EF8-120, a port to fill oil and filtering device) on its top face. Also filter fleece is available for rough filtering.

5.2   Pump unit consists of motor-pump combination made up of motor type Y180M-4 and axial piston style pump type 80YCY14-1B with a nominal pressure 31.5MPa and a flow rate 80 ml/rev. It stands on the tank surface. It takes in oil by way of self suction and acts as a power source.

5.3   Valve unit consists of special valves, including electrolyte change valve and overflow valve. They are center of the system.

5.4   Hydraulic piping system connects between the power source and executive units, passing over energy. High pressure steel pipes are available for all fixed piping while high pressure rubber pipes for movable piping.

5.5   Major hydraulic elements

5.5.1    High pressure axial piston style pump type 80YCY14-1B with a displacement 80 ml/r and nominal pressure 31.5MPa. It distributes oil through distributor disc and its body rotates. It features a  static hydraulic balance between slide shoes, variables and distributor disks. It supplies for the system a high pressure work oil. Please see PUMP STRUCTURE.

→ High pressure oil flows into the bottom cavity (d) of the variation body 302 via passages (a),(b),(c) →  Then into passage (f) and servo piston (312) via (e) → When a push is produced, the oil gets into top cavity (g) and pushes the variation piston (301) to move downward. Now the pump increases flow. → When the push at the bottom of the servo piston gets greater than the spring push force, the servo piston will move upwards to close the passage (h) while get the oil in the (g) cavity to flow pass passage (i). → Now it dumps. With the variation piston moving upwards, the flow is decreasing.

5.5.2 Electrolyte change valve: Type HWEH25G60B/EW220, nominal pressure 31.5MPa, flow rate 25 litre/min. A leading valve operates it and it in turn controls the main oil circuit to diverse its flow.

It consists of valve body (1), core (2), reset spring (3) and leading valve with elecro-magnet. The core (2) can stay in middle or at starting position, thanks to the spring force. Spring cavity connects to T cavity (leading valve) and let the oil go from the passage (7) into the leading valve (4). When the magnet gets on, valve(4) changes to have the oil push the core (2) to move. And thus all ports act as slide valves to change oil flow. Vise versa, when the magnet gets off, the core will come back to its mid position. The oil inside the spring cavity comes out of the outer port Y or inner passage T via the leading valve.

Please see its structure drawing.

 

5.5.3    High pressure overflow valve type YF-B20H4, with a set pressure range from 16 to 32MPa, serves to adjust system pressure and keep a stable and constant pressure like a safety valve.

5.5.4    One-way valve type S25A32 locating at the outlet port of the pump is used to keep a backup pressure to warranty the core is sure to diverse.

5.6       Hydraulic principle

Pressing and cutoff: → Push the button CUTOFF and the magnets YV1 & YV3 will get on. The electrolyte valve changes to let oil flow from valve 9 and 10 to the rear cavities of cutoff and pressing cylinders. The two cylinders act in order to achieve shearing and pressing.

Return: → Press heavily the button STOP and it will perform its 2^nd function “return”. → YV2 gets on and solenoid valve changes to let the oil go from valve 9 & 10 to the rear cavities of cutoff and pressing cylinders. → The 2 cylinders return respectively.

 

1. 6.     Installation & Test

6.1   Installation

6.1.1    Foundation should be done as per the foundation drawing prior to the arrival of the machine. It is not as important for the machine produces no heavy vibration in operation. A floor of concrete 189mm deep is just OK. In outdoors, a ceiling is necessary to safeguard the electric apparatus.

6.1.2    Place the machine into position as per the foundation drawing.  Level the machine. And then place the tank on the foundation. Clean oil pipes and fittings. While the oil pipes are laid according to the hydraulic schematics, please not forget put in seal rings.

6.1.3    Hook up the wires according to the wiring diagram and also secure all connections.

6.1.4    Make sure all mechanical, electrical and hydraulic connections and joints correct and reliable. Now Hook in the mains power source into the power cabinet.

 

6.2   Adjustment & test

6.2.1 Preparation work before test

6.2.1.1  Double check and make sure all connections are correct and secured according to the electric schematics. No loose connections are allowed.

6.2.1.2         Fill in the oil tank with clean filtered oil. The amount would be 80% of the total volume approximately. YB-N46# to be recommended for use in summer while N32# for winter.

6.2.1.3         Fill some lead oil into the oil port of the high pressure pump. And lube all lube points with 20# machine oil.

6.2.1.4         Operators need to read this manual carefully and have an overall knowledge of structure and functions of each unit. They will be prohibited to start the machine unless they have got known with the working principle of electrical and hydraulic systems.

6.2.2  No load test

6.2.2.1 Switch on the mains power and unscrew the overflow valve handle to let the system overflow safely.

6.2.2.2 Switch on the mains power and start the motor. And then stop it right away to see if it is running in same direction as indicated in the label on the pump.

6.2.2.3         Start pump for no-load operation for 3-5 minutes and make sure everything is OK. Now set the pressure for overflow valve so that a stable and reliable overflow is ensured under a system pressure 8MPa. A lower pressure is preferred during test.

6.2.2.4         Now do in STEP mode first shearing, pressing and return operation as hydraulic and electric working principles.

 

6.3   On-load test

6.3.1     Get ready the material for cutoff test. Gradually set the system pressure to 21MPa. Tighten the hold-down nut on the overflow valve handle.

6.3.2    Put a few metals with different specs at varied positions on the cutter in order. Now do the shearing operation.

6.4   Adjustment of cutoff stroke, system pressure and clearance between blades

6.4.1    Adjust the cutoff stroke

On the work side of the machine, there are proximity switches that are set already before ex-works. To readjust, just move the 2 proximity switches so that the cylinder stroke can be reset and it can do more within a same time. An optimum distance between the switch probe and the cutter rack sensor should be 3-5mm.

6.4.2    Reset the system pressure

Turning the overflow valve handle can alter the system pressure. It is up in clockwise while down in counter-clockwise. A lower pressure is enough for cutting off light and thin material. And high pressure for thick material. However the max will not be above 24MPa.

6.4.3    Readjustment of blade clearance

Normally wear of guide board, friction ring and bushes will make blade clearance become bigger. It’s necessary to re-adjust according to different materials to be cutoff. Regularly we recommend a clearance of 0.20 – 0,60mm that would suit all materials. For thin metals, take a smaller clearance.