VFD and Servo Motor in Embroidery Machine
Computerized embroidering machine is the most advanced embroidering machine at present. It can realize traditional manual embroidery with high speed and high efficiency, and meet the requirement of “multi-level, multi-function, unity and perfection” which is out of reach of manual embroidery and it is kind of motor product which can reflect several high and new technologies.
Main composition of embroidery machine system
- Computer control system
- Frame shift system: two sets of stepper motors drive cloth frame to have horizontal and vertical movement in horizontal plane and coordinate with needles moving up and down to make various patterns.
- Spindle system: spindle drives needles to move and use general motor and VFD, slip frequency motor and servo motor.
Working principles of towel embroidery machine
Here we will take towel embroidery machine which uses a large number of servo motors for one single embroidery machine as an example. Generally speaking, towel embroidery machine use three servo motors: main axis, D axis and H axis. Main axis always rotates towards to the same direction and it drives needles move up and down through mechanical cam mechanism. Needles in towel embroidery machine often move up and down above 500 times per minute and above 1000 times per minute in plain embroidery. D axis is used to adjust direction of needles to guarantee gaps which are used to draw lines in needle points direct towards movement direction of needle points (relative to movement of cloth frame). Each time when needle point move once, it will adjust once. H axis is to change color and coil and it uses a location pin to switch between color changing and coiling automatically. When coiling, the axis will guarantee wire feeding direction and gap direction in needle points vertical for convenience of drawing lines. Each time when needles move up and down once, it will move once.
Setting of relevant software
The above is basic setting of parameters. After finishing trial operation of various axes, they can make adjustment according to load status and utilization requirements of various axes to make operation of the whole system more stable and smooth. The built-in automatic inertia estimation function of servo drives can measure load inertia ratio JL/Jm to fill in software. And then fill in response band width B.W. according to use requirements. After selecting matched models of electric motors, software can design a set of most matching increment parameters, and then load them in drives. Among the three axes, the main axis rotates towards to one direction, whose requirements on servo motor are not very high and increment can be adjusted lower; while D axis and H axis should launch and stop with high speed frequency, and increment should be adjusted higher.
Characteristics of servo system
Servo system centres on AC servo motor and control loop adopts high digital speed processor (DSP) which can finish calculation of various complex controls with a high speed and high accuracy. Moreover, it applies some achievements of modern control theories in alternating servo drives and adopts robust control technology to make low speed characteristics of servo motors better, enhance automatic adjustment, design of order smooth function and software analysis and supervision to make alternating servo have higher performance, higher response, higher accuracy and higher reliability in a real sense. The design thought of 5 machines integration, enhancement of communication functions and design of connotation position controller can better serve to construction of control schemes of low costs.
Depending on its competitive price and excellent performance, servo motor will be surely preferred by various embroidery machine production enterprises and will create a new situation of the textile industry.