Summary of the invention
Technical problem to be solved by this invention is to provide a kind of SMT mounting device suction nozzle module that placement pressure is constant that can ensure.
In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of SMT mounting device suction nozzle module, comprise the motor that hollow shaft-like suction nozzle and the driving suction nozzle that is connected with suction nozzle rotate, SMT mounting device is provided with control module and drives suction nozzle module respectively along X to the X driver of, Y-direction and Z-direction movement, Y driver and Z driver, Z driver is connected with described motor, suction nozzle module also comprises the pressure sensor of the placement pressure value for detecting suction nozzle be located on described suction nozzle, and this pressure sensor is also connected with described control module.
Described pressure sensor comprise tubulose along described suction nozzle length direction cover on suction nozzle outside support, be located at bracket outer coil, be positioned at internal stent and two end caps at the magnetic core be fixed on suction nozzle and the both ends open place that is located at support, suction nozzle is through two end caps, one is also provided with elastic component between end cap and suction nozzle wherein, coil comprises a primary coil and is positioned at two secondary coils of primary coil both sides, the motor shaft of described motor can move vertically in motor, motor shaft is connected with suction nozzle, and support installing is on the housing of motor.
Linear bearing is provided with between described two end caps and described suction nozzle.
Described elastic component is be enclosed within the spring on described suction nozzle, and one end of spring is against on described end cap, and the other end is against on the projection of suction nozzle outer setting, and described magnetic core is located on this projection.
Described motor is provided with the angular transducer for detecting described motor shaft corner.
Another technical problem to be solved by this invention is to provide a kind of control method of SMT mounting device suction nozzle module, and it comprises the steps:
(1) in the control module of SMT mounting device, attachment target pressure value is preset;
(2) when mount components, after nozzle pick element to be mounted, move to above pcb board, Z driver drives suction nozzle module moves down, and pressure sensor starts detected pressures value;
(3) when the elements down to be mounted on suction nozzle touches pcb board, pressure sensor inside starts to be subjected to displacement deformation, thus produces the change of the signal of telecommunication, and control module receives the signal of telecommunication that pressure sensor transmits, and be converted into current pressure values, compare with attachment target pressure value;
(4) if when current pressure values is less than attachment target pressure value, suction nozzle continues to press down, until when current pressure values is equal with attachment target pressure value, element is arranged on pcb board by suction nozzle.
The present invention adopts technique scheme, compared with prior art, a kind of pressure sensor that can detect the placement pressure value of suction nozzle is increased in suction nozzle module, the voltage that control module detects according to pressure sensor exports, and can converse force value, and preset attachment target pressure value in the control module, achieve pressure controllable, therefore this suction nozzle module can ensure that placement pressure is constant, ensure that the attachment dynamics of each element is consistent, and not by the distortion of pcb board, the impact of component thickness.
Embodiment
Be illustrated in figure 1 a kind of SMT mounting device suction nozzle module of the present invention, comprise the motor 8 that hollow shaft-like suction nozzle 1 and the driving suction nozzle 1 that is connected with suction nozzle 1 rotate, SMT mounting device is also provided with control module and drives this suction nozzle module respectively along X to the X driver of, Y-direction and Z-direction movement, Y driver and Z driver, Z driver is connected with motor 8, moves up and down in the vertical to drive whole suction nozzle module.As depicted in figs. 1 and 2, this suction nozzle module also comprises the pressure sensor of the placement pressure value for detecting suction nozzle 1 be located on suction nozzle 1, and this pressure sensor is also connected with control module.Be preset with attachment target pressure value in control module, only have component mounter dynamics to reach attachment target pressure value, just can on pcb board installation elements.Operationally, along with pressing down of suction nozzle 1, current pressure values and attachment target pressure value to control module, are compared by control module, see and whether reach attachment target pressure value by pressure sensor by the current pressure values signal transmission that detects.
The motor 8 that this suction nozzle module adopts is servomotor, the motor shaft 10 of motor 8 is connected with suction nozzle 1, motor shaft 10 and suction nozzle 1 integral hollow, negative pressure absorbing can be ensured, motor shaft 10 is wanted to drive suction nozzle 1 to rotate, suction nozzle 1 also can will move along the axis of motor shaft 10 in motor shaft 10, to meet the requirement of picking up material, attachment.In order to realize this function, motor shaft 10 and suction nozzle 1 can be taper fit, and this taper fit ensures that motor shaft 10 can drive suction nozzle 1 to rotate, and suction nozzle 1 can also move along the axis of motor shaft 10.In addition, as shown in Figure 4, between motor shaft 10 and suction nozzle 1, guide pad 11 can also be set, guide pad 11 can lead to the rectilinear movement of suction nozzle 1, and guide pad 11 is arranged on the shaft hole inner wall of motor shaft 10, and the outer wall of suction nozzle 1 is provided with the groove suitable with guide pad 11, by the interaction of guide pad 11 with groove, can not only lead to the movement of suction nozzle 1, when motor shaft 10 rotates, suction nozzle 1 can also be driven to rotate.Guide pad 11 shape can be cylindrical, and the groove on suction nozzle 1 is half slot, or guide pad 11 also can be other shape.The concrete number of guide pad 11 sets as required, at least will arrange one.Be provided with two bearings 7 for support motor axle 10 in the inside of motor 8, this bearing 7 is thrust bearing.Motor 8 is also provided with the angular transducer 9 for detecting motor shaft 10 corner, and detect the corner of suction nozzle 1 when mount components adjusts setting angle for suction nozzle 1, angular transducer 9 and pressure sensor are distributed in the two ends of motor 8.
Pressure sensor is based on LVDT (Linear Variable Differential Transformer) principle, belong to the kind of displacement transducer, it is made up of parts such as a primary coil, two secondary coils, magnetic core 4, coil rack, support 3, end cap, linear bearings.As depicted in figs. 1 and 2, support 3 is tubulose, both ends open inner hollow, and support 3 covers on the outside of suction nozzle 1 along suction nozzle 1 length direction.End cap is provided with two, is respectively the upper end cover 2-1 being located at support 3 upper end open place and the bottom end cover 2-2 being positioned at support 3 lower ending opening place, and suction nozzle 1 is through upper end cover 2-1 and bottom end cover 2-2.Linear bearing is located at upper end cover 2-1 respectively, between bottom end cover 2-2 and suction nozzle 1, suction nozzle 1 is supported on two linear bearings.The upper end of the support 3 of pressure sensor is fixedly connected with the housing of motor 8, and upper end cover 2-1 also inserts in the housing of motor 8.Between upper end cover 2-1 and suction nozzle 1, be also provided with elastic component, the effect of elastic component makes suction nozzle 1 terminate laggard horizontal reset in mount components.That magnetic core 4 is positioned at support 3 inside and be fixed on suction nozzle 1, coil 5 is located at the outside of support 3, coil 5 comprises a primary coil and is positioned at two secondary coils of primary coil both sides, and as depicted in figs. 1 and 2, two secondary coils lay respectively at the upper and lower sides of primary coil.Magnetic core 4 is with the aligned in position of the primary coil of centre in an initial condition, when magnetic core 4 is moved to both sides secondary coil by centre, the difference of two secondary coil output voltages and magnetic core 4 be moved into linear relationship.
Elastic component in pressure sensor is the spring 6 be enclosed within suction nozzle 1, and one end of this spring 6 is against on upper end cover 2-1, and the other end is against on the projection of suction nozzle 1 outer setting, and magnetic core 4 is fixedly mounted on this projection.
The operation principle of pressure sensor is as follows:
Alternating magnetic field symmetrical is vertically produced, the magnetic flux density therefore on coil central axe and just there is a kind of functional relation between magnetic core 4 position after primary coil (primary coil) applies high-frequency ac ripple.By rational layout designs, after two secondary coils (secondary coil) differential, the secondary linear with magnetic core 4 displacement can be obtained and export: Es=E1-E2, as shown in Figure 3.
When magnetic core 4 is positioned at center, the output of pressure sensor is 0, and therefore, can facilitate calibration 0, this structure only gets an one direction simultaneously, and namely forward moves, and displacement is less, is therefore very easy to obtain the very high linearity and precision.
Read output voltage Es by control module, can judge current displacement S, according to F=k × S, control module can calculate current force value F, and wherein k is spring rate.
Such as when element touches pcb board, need certain pressure to be adjacent to, be 5N as chosen target pressure value, Displacement-deformation when pressure sensor receives 5N pressure is 0.35mm, and exports as 15mv, therefore exports according to the voltage detected, control module can converse current pressure values, testing result is not by the distortion of PCB, the impact of component thickness, and precision is high, pressure controllable.
The feature of above-mentioned pressure sensor:
1.LVDT dynamic characteristic is good, can be used for high speed on-line checkingi, automatically measures, automatically control;
2.LVDT is very responsive for the axial motion of magnetic core 4, and very blunt to radial motion;
3. reliability is very good, impact resistance 150g/11ms, vibration frequency 2kHz acceleration 20g; Volume is little, and price is low, and the ratio of performance to price is high; Having very high is market application and promotional value.
The control method of SMT mounting device suction nozzle module of the present invention, it comprises following step:
(1) in the control module of SMT mounting device, attachment target pressure value is preset;
(2) when mount components, after suction nozzle 1 picks up element to be mounted, move to above pcb board, Z driver drives suction nozzle module to move down again, and pressure sensor also starts detected pressures value;
(3) when the elements down to be mounted on suction nozzle 1 touches pcb board, pressure sensor inside starts to be subjected to displacement deformation, thus produces the change of the signal of telecommunication, and control module receives the signal of telecommunication that pressure sensor transmits, and be converted into current pressure values, compare with attachment target pressure value;
(4) if when current pressure values is less than attachment target pressure value, suction nozzle 1 continues to press down, until when current pressure values is equal with attachment target pressure value, element is arranged on pcb board by suction nozzle 1.
This control method is by receiving the pressure signal of pressure sensor, using the placement pressure value of suction nozzle module as judge whether can the foundation of installation elements, not by the distortion of pcb board, the impact of component thickness, all associate without any with the distortion of pcb board, component thickness, thus ensure that the constant of suction nozzle module placement pressure.
Above by reference to the accompanying drawings to invention has been exemplary description; obvious specific implementation of the present invention is not subject to the restrictions described above; as long as have employed the improvement of the various unsubstantialities that method of the present invention is conceived and technical scheme is carried out; or design of the present invention and technical scheme directly applied to other occasion, all within protection scope of the present invention without to improve.