The sawing machine system’s servo position control module employs position control combined with sampling interpolation and foresight control to determine the closing position of the feeding cylinder, thereby stopping it at the target position. (Specific control details are omitted.)
Controlling the feed slide to move precisely 0.1 mm by simply turning it “on” and “off” is nearly impossible due to electromagnetic mechanical hysteresis and motion inertia.
To ensure minimum feeding length and accuracy, the rear pliers first retracts the feed slide to the LK position and then moves it forward to the predicted position LT to close the feed solenoid valve.
The rear clamp is engaged once the feed cylinder stops moving.
Sawing machine classification
(1) Circular sawing machine
Circular sawing machines can be classified into fully automatic and semi-automatic machines.
The saw blade of a circular saw machine rotates while being fed into the material being cut.
Circular sawing machines can be further categorized into three types based on the feeding direction of the saw blade:
- Horizontal sawing machine (horizontal feed)
- Vertical sawing machine (vertical feed)
- Pendulum sawing machine (swing feed at one point)
There are also various specialized circular saw machines available, such as a head saw machine used for cutting large castings, and a sawing and drilling machine used for rail cutting and drilling.
(2) Band sawing machine
The annular saw band is tensioned between two saw wheels, and the saw wheel drives it for cutting.
Band sawing machines are available in vertical and horizontal configurations.
The vertical band sawing machine has a vertically arranged saw frame, and the workpiece is moved during cutting to cut curved contours of sheets and formed parts. The saw band can be replaced with a shackle or a belt for repairing or grinding.
The horizontal band saw blade’s saw frame is horizontally or slanted and fed in a vertical direction or in a direction that oscillates around a point. The saw band is typically twisted by 40° to keep the saw teeth perpendicular to the workpiece.
The horizontal type is divided into three types: scissors type, double-column, and single-column band sawing machine. It can be divided into manual and automatic types based on the use condition. It can also be divided into semi-automatic (manual feeding) and fully automatic (automatic feeding and cutting) types according to the automatic program using the controller.
(3) Bow sawing machine
The saw blade attached to the saw bow moves back and forth and guides the saw frame around a fixed point.
The machine is compact and has a simple design, but it has a low efficiency rate.
The saw blade can move in two ways: a straight line and an arc.
During the arc motion, the saw bow swings slightly around a point. This method allows for each saw tooth to cut a large amount of material, facilitates chip removal, and increases efficiency. As a result, most new bow sawing machines utilize this technique.
Mechanical structure
The main components of the sawing machine are:
- Sitting at the bottom
- Bed, column
- Saw beam and transmission
- Guiding device
- Workpiece clamping
- Tensioning device
- Feed rack
- Hydraulic drive system
- Electrical control system
- Lubrication and cooling system
(1) Base
The base is a box-shaped structure that is welded together using steel plates. Both the bed and the column are fixed onto it.
The interior of the base has ample space. On the front left side, there is an electric button control box, while the electric switchboard box is on the right side. In the middle, there is a hydraulic oil tank made of welded steel plates. The chamber also houses a hydraulic pump station and hydraulic pipelines. On the right side, there is a cooling cutting fluid tank and a water pump.
(2) Frame
The frame, fixed to the base, is made of cast iron.
The column is made up of a large and a small cylinder. The large round column acts as a guide rail for the saw frame, supporting the lifting movement of the saw beam up and down, ensuring precise guidance. The small cylinder serves an auxiliary role, ensuring the normal cutting of the saw blade.
In the center, there is a clamp vise and a manual feeding mechanism. The front of the vise is connected to a worktable to receive the finished product. The clamping device on the left side is a clamping screw passing through the inner hole of the hydraulic clamping cylinder rod, enabling the movement of the left jaw left and right by rotating the hand wheel or pressing the button.
(3) Saw beam and transmission mechanism
This machine is constructed by cutting and welding thick steel plates, which provides it with strong rigidity.
The worm wheel box is located on the right rear side, and the worm wheel inside the box is fixed to the driving wheel on the saw beam. These two components rotate synchronously, and the passive wheel and saw blade tensioning position are located on the left side.
The saw blade’s rotary motion is powered by the main motor, pulley, and worm wheel, which are then transmitted to the driving wheel through a two-stage shifting process. The driving wheel and saw blade, in turn, drive the driven wheel. The saw blade has a total of three running speeds.
(4) Saw blade guiding device
The saw beam support plate’s guiding device comprises left and right guiding arms and guiding heads.
Both the left and right guide arms can be moved along the dovetail (or the right guide arm can be fixed on the column sleeve). The distance between the two guide arms is adjusted to be approximately 40 mm wider than the workpiece size.
The guiding device is used to change the mounting angle of the saw blade, ensuring that the saw blade is perpendicular to the table.
To ensure cutting precision and reduce saw blade vibration, a pair of guide wheels (rolling bearings) and wear-resistant guide blocks are installed on the left and right guide arms. Additionally, guide blocks made of wear-resistant alloy are placed on the back of the saw blade.
(5) Clamping mechanism
The right vise is fixed on the bed, and the clamping screw passes through the inner hole of the hydraulic clamping cylinder. The left vise is attached to the left and right guide rail using a screw and is connected when the left vise is 10-30 mm away from the workpiece.
To clamp or release the workpiece, press the control panel to operate the clamp.
(6) Tensioning device
The tensioning device is composed of a skateboard seat, a skateboard, and a ball screw.
To tension the saw blade, use a torque wrench to rotate it in a clockwise direction until the blade is tightened and ready for use.
If the sawing machine is not in use for an extended period, release the tension on the saw blade by rotating the torque wrench counterclockwise.
Working principle
The hydraulic transmission system comprises a hydraulic circuit consisting of pumps, valves, cylinders, fuel tanks, pipelines, and other auxiliary components. Under electrical control, it completes the lifting of the saw beam and the clamping of the workpiece. The speed control valve enables stepless speed regulation of the feed speed to fulfill the sawing needs of workpieces made of different materials.
The electrical control system comprises a control circuit that includes an electrical box, a control box, a junction box, a travel switch, an electromagnet, etc. It is used to control the rotation of the saw blade, the lifting of the saw beam, and the clamping of the workpiece to allow for operation according to certain working procedures to achieve a normal cutting cycle.
Before running, the lubrication system must be refueled according to the lubrication parts of the machine (wire brush shaft, worm gear box, active bearing housing, worm bearing, lifting cylinder upper and lower shaft, movable vise sliding surface clamping screw).
The worm gear and the worm in the worm gear box are lubricated with #30 oil, which is injected from the oil plug hole in the upper part of the worm gear box. The box is equipped with an oil mark, and when the saw beam is at the lowest position, the oil level should be between the upper and lower limits of the oil mark.
After one month of use, the oil in the worm gear box should be changed, and thereafter, it should be changed every 3-6 months. The lower part of the box is fitted with a drain plug.
The motor, mounted on the worm gear box, is driven by the saw blade via the pulley. The triangular belt drives the worm and worm wheel in the box, causing the driving wheel to rotate, which in turn drives the saw blade wound around the active/passive rim to perform the cutting and turning motion.
The hydraulic circulation system responsible for the saw blade feed motion consists of a lift cylinder and a speed control valve, which regulate the speed of the saw beam descent to control the saw blade feed (steplessly adjustable).
The saw blade rotates in the direction of the saw blade where it chips and is cooled by a coolant pump, which removes chips from the saw teeth.
The cutting fluid tank, located on the right side of the base, cools the coolant, which is directly driven by the water pump.
To start the oil pump motor and the gear pump, press the stop button and turn it clockwise. The oil enters the pipeline via the filter, and the relief valve adjusts the system’s working pressure to meet the necessary requirements.
If the button is not pressed, all motors will stop working.
To clamp the workpiece, press the clamp button, and the solenoid valve will operate, allowing hydraulic oil to enter the left side of the clamp cylinder, while the right hydraulic oil returns to the oil tank. As a result, the left clamp will clamp onto the workpiece.
By pressing the work button, the saw beam will descend. The hydraulic oil will enter the lift cylinder through the solenoid valve and fill the rod cavity. The rodless chamber hydraulic oil will pass through the electromagnetic valve and the one-way speed control valve before returning to the oil tank.
Pressing the down button will lower the saw beam, and the solenoid valve will operate to allow hydraulic pressure into the lift cylinder’s rod cavity. The rodless chamber oil will be returned to the oil tank via the electromagnetic valve.
To raise the saw beam, press the up button, and the hydraulic oil will enter the rodless cavity of the lift cylinder through the solenoid valve. The rod cavity oil will pass through the solenoid valve and return to the oil tank.
To loosen the workpiece, press the clamp button. The hydraulic oil will enter the right side of the clamping cylinder via the solenoid valve, and the left hydraulic oil will be able to return to the oil tank via the solenoid valve, causing the left jaw to move to the left, releasing the workpiece.
The system’s analog input and output module has a wide range of significance for monitoring the sawing process. For example, the sawing machine can adjust its speed adaptively by increasing the feedback of the saw blade deformation.
A servo valve has been added to optimize the speed and position control of the sawing process.
The system’s management functions make managing materials and workpieces more convenient.
The system’s Chinese interface and real-time graphical status display make the operation more user-friendly and intuitive.
