DE3334066A1 - MICROPROCESSOR CONTROLLED ULTRASONIC WELDING APPARATUS - Google Patents

Description

Description:

The invention relates to a microprocessor-controlled ultrasonic welding apparatus, its work sequence and monitoring of the operating status by a microprocessor be performed. In particular, the invention relates to an ultrasonic welding apparatus with a plurality of actuating or Actuators independently controlled in terms of certain parameters by a single microprocessor will.

The use of ultrasonic energy for welding plastics, for inserting, clipping, deep drawing and removing the gate for thermoplastic parts and for heat sealing thermoplastic fabrics and films is well known. An ultrasonic welding apparatus for performing these operations is for example in the U.S. Patent 3,790,057. The basic ultrasonic welder has operating elements such as double palm buttons for operating the device, a power supply to convert the mains voltage into a high-frequency electrical signal, a piezoelectric converter for converting the high-frequency electrical signal into high-frequency mechanical energy as well as a pneumatic one or compressed air device on which the transducer and a tool or horn on the end of the transducer for a given Holds period of time in forced engagement with a workpiece to be welded. The combination of pneumatic The system and converter are usually referred to as actuators or actuators.

Ultrasonic welding apparatus of the type described above have an adjustable control device to to set a certain welding time and to adhere to this time to carry out the welding work or the welding process. The welding time is the time in which high frequency mechanical energy, i.e. ultrasonic energy from the horn or horn is transmitted to the workpiece. the

Dwell time is the length of time that pressure is on the Workpiece is exercised by the horn radiator after the end of the welding time. Most of the gadgets show a release or triggering device which scans when a predetermined engagement force between the horn antenna and the workpiece is present and if the welding time is predetermined as a function of the achieved Engagement force begins.

IQ is also known to have several ultrasonic welding machines to unite into one group to make multiple welds to be carried out on the same workpiece. Usually several individual units of the type described above are used connected to each other in cycle sequence for independent operation.

According to the invention, a ultrasonic welding apparatus with multiple actuators controlled by a single microprocessor. It also includes functions such as tapping of voltages and self-diagnosis carried out with the help of the program equipment of the microprocessor. It deals is a complete and expandable modular system, controlled by a single microprocessor will »The facility can have any number of power supply modules and actuating converter units be added, which is controlled by a single main control module, the additional child control modules controls as needed.

The object of the invention is therefore to provide a microprocessor-controlled ultrasonic welding machine. The ultrasonic welding machine should also diagnose itself. It is further provided that the instantaneous voltage, which is tapped from the individual power supply devices for the transducers and horn radiators, and that the individual peak voltage values tapped are stored until the subsequent welding process.

The invention is explained in more detail below. All features and measures contained in the description can be used by essential to the invention. The drawings show:

1 shows the power supply modules and a control module together with several actuating elements.

2 shows an electrical block diagram of the microprocessor circuit contained in the control module.

In the figures, particularly in Fig. 1, a table is shown on which four actuators or actuators 10 are attached with support devices or beams. The individual actuators each have a partial visible converter 12, such as the converter or converter, which is described in US Pat. No. 3,524,085 and converts high-frequency electrical energy into mechanical energy. An ultrasonic horn or ultrasonic horn radiator 14 is at the output of the transducer in an antinode region coupled to the longitudinal oscillation of the energy that passes through the transducer. The horn antenna is dimensioned so that its The resonance frequency is half the wavelength of the fundamental frequency of the system. Usually horn and transducer dimensioned so that their resonance frequency is in the range between 10 and 100 kHz, especially at a frequency of 20 or 40 kHz.

The individual actuators each have a pneumatic one or compressed air mover which causes the horn and transducer to be different from that shown Move the upper position down to the workpieces W1 and W2 to be welded. The work pieces are on one corresponding anvil 15 arranged. The individual actuators 10 also each include an adjustable release or trigger device, which has the effect of a predetermined welding pressure between the front surface of the

Scan the horns and the workpieces, e.g. according to the US-PS 3 493 457. If a certain welding pressure is tapped? a trigger switch signal is generated, which the The welding and dwell time of the system starts, as explained in more detail below. The actuators described of general design are commercially available items sold by the Branson Sonic Power Company, Danbury, Connecticut.

IQ The actuators can be adjusted with respect to the vertical stroke and the angle of the workpieces in order to adapt them to the outline and dimensions of the workpieces. They can also be used on turntables or with multiple horns as required. In another modification, a single compressed air system can be used to drive multiple converters.

The power supply units and control panels are in slide-in units remotely arranged cabinet 20 housed. A drawer contains a control panel 16 and one or more Power supply units 28 »Further plug-in units with power supply units 28 can be added, with all power supply units 28 being through the same Control panel 16 controlled i ^ ground. The switching or Control panel 16 includes a microprocessor, an adjustable dwell time control 26, a memory mode switch 24, a power switch 18 and subsequent displays 22 to ο

The control panel 16 has a microprocessor, an adjustable one Dwell time controller 26, a memory mode switch 24, a power switch 18 and flow indicators 22 on.

The on / off switch 18 on the control panel 16 switches the system a. A series of seven displays 22 indicate the operational status of the apparatus for diagnostic purposes. The memory mode switch 24 serves in combination

e.

hang with a voltage display on each power supply unit 28 Storage of the peak voltage fed to the actuator 10, as will be explained in more detail below.

The dwell time controller 26, shown as a digital roller switch, is set by the operator on a predetermined dwell time set, which is common to all actuators 10 and measured from the point in time on which the last power supply module 28 its welding

£ Q clock completed. Effect at the end of the specified dwell time all actuators 10 via their compressed air devices that the horn radiators 14 lift off the workpieces, whereby the operator remove the welded product and insert new workpieces to be welded can. While the controls are shown as digital switches, it will be apparent that other controls as well how potentiometers can be used.

A mains or power supply part 28 is assigned to each actuating element 10. In every rack in the facility there is a rectifier and a regulator for pre-adjusting the mains voltage. The individual mains or power supply components contain a power supply circuit that converts the pre-adjusted mains voltage into a high voltage and converts high-frequency electrical signal that controls a corresponding converter 12. An LED bar display 30, which is divided into twenty segments, shows the instantaneous voltage produced by a particular power supply is delivered to the associated transducer 12 to the welding voltage through the relevant transducer-horn unit to monitor. Two setting members 32,34 are provided on the module 28 to set the upper and lower voltage levels of a voltage cut-out range. As explained in more detail below, a voltage range alarm display 38 is applied when voltage is outside the predetermined range by a power supply unit 28 Actuator 10 is released. The power supplies 28 further

sen also an adjustable welding time control 40, on which a predetermined welding time can be set, in which the associated converter 12 with welding voltage is supplied by the corresponding power supply unit. If the transducer g 12 is acted upon, and a horn 14 coupled to it if it is in contact with a workpiece, the welding process takes place. There is also an overload warning indicator 36 an alarm signal when the electricity supply is through Overvoltage is overloaded, or if the resonant circuit of the ^ q Power supply moves to a frequency that is outside of the normal working frequency range. A typical overload circuit is described in U.S. Patent 3,946,280.

Part of the microprocessor circuit housed in the control panel 16 is shown schematically in FIG. In a preferred embodiment, the microprocessor is 50 is a model 8039 manufactured by Intel Corporation. The microprocessor 50 controls together the crystal-controlled deflection generator 51 and an internal clock generator all logic and clock functions, which are from the program are controlled in the program memory 58. The operating program is stored in a read-only memory (PROM) or preferably stored in erasable read only memory (EPROM) such as the Model 2716 from Intel Corporation. Of the Microprocessor 50 is with various display and control parts via a parallel interface 52 and a serial interface 54 connected = an input-output logic decoding circuit 56 completes the control circuit. A busbar driver is provided to control the power supply interface attached to each power supply unit 28. Address and data signals go back and forth between the control modules via busbars. Although certain manufactured by Intel Corporation Components have been listed, other microprocessors and the associated circuitry of Intel or other manufacturers can be used.

Before the welding apparatus begins to work, the dwell time is set on the dwell time control 26. Each Power supply is then set by setting the weld timing controls 40 as well as by adjusting the maximum voltage level 32 and the minimum voltage level 34 are adjusted to to create a certain voltage range section. Then the individual power supplies are connected via an analog multiplexer 62 and an analog-to-digital converter 64 are connected to the microprocessor 50. Due to the erasable fixed

IQ value memory (EPROM) 58, the welding time signals are tapped through the serial interface 54, and the voltage level signals tapped from the individual power supply units are sent through the multiplexer 62 and the analog-digital converter 64 in order to be processed by the microprocessor 50.

An electrical cable connects the circuit in the cabinet 20 with the individual actuators 10. If that Welding is to begin, there is an actuation or trigger signal via the parallel interface 42 at the input of the microprocessor 50. In the case of a manually loaded circuit arrangement, the operator must at the same time Depress the double palm keys (not shown) to operate the welding machine and the microprocessor control. The operator cannot take a hand off the switch buttons until all trigger switches give a signal to the microprocessor. If one or both hands are lifted prematurely, the facility is interrupted. In the case of an automatic workpiece feed, an actuation or trigger signal is sent to the microprocessor, that the workpiece "is ready for welding. In another arrangement, a pre-trigger signal is sent to the microprocessor released before the horn has achieved a certain engagement force with the workpiece.

When the actuation signal is applied, the microprocessor 50 generates under the control of the stored in EPROM 58

no.

Program a signal for the solenoid control, which sends a corresponding signal to the solenoid driver in the Compressed air device of the individual actuators 10 delivers, in response to the solenoid control or drive signals each horn 14 is forcibly engaged with the workpiece W1. Is the specified engagement or pressure force is reached between the horn and the workpiece W1, so trigger switching signals are from the actuators transferred to the parallel cut surface 52. When the actuation signal and all signals from the trigger switch are present the individual power supplies 28 are acted upon as a function of the respective trigger switching signal, which also the assigned converter 12 is controlled. When activated of a corresponding power supply unit, the welding time period of this power supply unit is measured. At the end of this welding time period this particular power supply unit 28 is switched off. The measurement of the dwell time period starts at the end of the last one Viewing period. Caused at the end of the dwell period another signal from microprocessor 50 to solenoid controller 60 that all actuators 10 are horns 14 lift off the workpiece W1.

During the welding cycle, the microprocessor 50 monitors the current voltage level of the individual power supply units 28.

The voltage level signals are present on the microprocessor 50 multiplexer 62 and analog-to-digital converter 64 from each power supply 28. A visual indication of the current one monitored voltage value is on the corresponding "bar graph 30 to see. When the switch 24 is in the save mode, the maximum voltage on the display 30 saved until the next welding cycle begins. If a voltage level is outside the specified voltage range measured, then a signal is generated by the serial interface 54, the corresponding Voltage alarm indicator 38 illuminates. Several program sequence indicators light up during the welding cycle 22 like the seven shown lamps according to the program

/ 12.

command in sequence and deliver a diagnosis of the system. For example, a first lamp lights up when the actuation signal is applied, a second lamp when the solenoid is activated, a third when a power supply is activated, a fourth when all trigger switches are closed, a fifth at the beginning of the dwell time, a sixth on At the end of the dwell time and a seventh, if a fault occurs in the system, an overload warning 36 or a cutout alarm display 38 are activated. IQ If there is an incomplete welding cycle, the last illuminated lamp 22 in the sequence remains illuminated in order to facilitate troubleshooting and diagnosis of the fault in the system.

The workflow is as follows: The dwell time control 26 and the individual welding timers 40 are set to specific values, and the memory mode switch 24 is set to save or not to save. The controls for the maximum and minimum voltage levels 32 and 34 are set. The double palm buttons are at the same time depressed or an automatic actuation signal for the microprocessor 50 is generated. Then the solenoid control 60 applied, the horn radiators moving down to the workpiece. When the trigger switch in each actuator generates a trigger signal for a certain engagement force between the horn and the workpiece, the data is received by the microprocessor 50 and processed.

The welding time periods begin when the trigger switching signals are applied of the corresponding power supplies 28, which are acted upon in order to excite the individual transducers 12, the in turn emit ultrasonic energy to the horn radiators 14 connected to them for welding the workpieces. At the At the end of a welding period, the corresponding network

part 28 switched off. Are all the residence time intervals of the Power supply 28 terminated, then the dwell period begins. At the end of the dwell period, after welding the Workpieces, there is a signal from the microprocessor 50 to the solenoid control 60, which causes the compressed air device in each actuator all horn radiators 14 lifts off the workpieces.

The instantaneous voltage of the individual power supply units is during each welding cycle is measured and made visible on the corresponding display 30. Runs the one selected by switch 24 Storage mode, then the peak value of the applied voltage of the individual power supply units 28 in the corresponding Display 30 saved until the next welding cycle.

The overload circuit is part of the power supply unit. If an overload condition occurs, the overload warning indicator lights up 36 on the corresponding power supply unit 28.

When the actual voltage level from a power supply unit 28 is smaller or larger than the minimum level or the maximum level of the voltage cut-out area, the corresponding voltage warning indicator 38 lights up. As above as described, the program sequence indicators 22 also light up simultaneously with the operation of the device.

After a workpiece is welded and neither the voltage cutout warning display nor the overload warning display

SO is applied, the apparatus is extinguished, the welded workpiece is removed and new workpieces to be welded inserted. When the double hand plate buttons are pressed or when an actuation signal is applied, begins the next welding cycle.

In addition to the embodiment described above, others are possible without departing from the scope of the invention.

Claims (5)

333 / .066 Claims j Ι »Microprocessor-controlled ultrasonic welding machine, marked by: several actuators (10) each with a converter (12) and a compressed air device, which moves the converter (12) to the workpieces (W1, W2) to be welded and allows it to lift off again,
several power supply units (28), each of which is connected to an actuating element (10) in order to selectively act on an associated transducer (12), a triggering device (52) which generates a first signal at the beginning of the welding cycle, trigger switch (FIG. 2 , 52), which has a second Si £ 5 gnal «triggered by the individual actuators (10) when a certain switching state occurs for the start of the welding cycle, adjustable welding time controls (40), which are assigned to each sharpening part (28) and generate a welding time signal for each power supply unit (28) Dwell time controls (26) which generate a signal for a certain welding time of the actuators (10) and
a microprocessor (50) connected to the actuators (10), power supply units (28), a release device (52), trigger switch (52), adjustable welding time controls (40) and adjustable dwell time controls (26), ums a. depending on the presence of the first signal, a signal to trigger the compressed air device to create, b, depending on the concerns of the first and second Signal to generate a signal which is applied to the power supplies (28) to selectively a generate high-frequency electrical signal for each transducer (12), χ * · c, a signal to switch off a corresponding power supply unit (28) to produce after the corresponding welding time, d. to generate a signal to switch off the compressed air system after the end of the welding time / e. control the signal sequence of steps a-d, 2. A microprocessor-controlled ultrasonic welding apparatus according to claim 1, characterized in that voltage indicators (30) sense and display the voltage output by the individual power supply units (28) during the welding cycle to corresponding transducers (12) and
that the microprocessor (50) with the voltage displays (30) is coupled to effect this indication. 3. Microprocessor-controlled ultrasonic welding apparatus according to claim 2, characterized in that a memory (58) causes the display (30) to save the peak value during each welding cycle. 4. Microprocessor-controlled ultrasonic welding apparatus according to claim 2, characterized in that Devices for setting the voltage level (32, 34) set the specified voltage level which is supplied by the individual power supply units (28) during the welding cycle are generated and that the microprocessor (50) generates a signal when the voltage is greater or less than the predetermined Voltage level. 5. Microprocessor-controlled ultrasonic welding apparatus according to claim 1, characterized by: a diagnostic device (22) which the operating state of the welding apparatus (10,12,14) as a function of signals from the microprocessor (50). Microprocessor-controlled ultrasonic welding apparatus according to claim S, characterized in that the diagnostic device (22) has several displays which are acted upon in a specific sequence depending on the operating state of the welding apparatus (10, 12, 14).