NL8503353A - Electronic system controlling welding or reflow-soldering - has programmed microprocessor to select, apply and control energy, temp. and weld-solder electrode pressure - Google Patents

Abstract

The system is for electronically controlling the temp. of and the energy supplied to a welding or soldering electrode, partic. for reflow soldering when the components to be connected have the required amts. of solder previously applied thereto. It comprises at least one electrode, a dc or ac supply unit, and a control unit with a programmed micro-processor to control the electrode in accordance with a required energy, temp. vs time curve at a given electrode pressure, either continuously or in steps. The relevant parameters are controlled within close limits and the measured data stored in a memory. The measured and stored curve may be produced as a print-out.

Description

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Device for electronically controlling and controlling the temperature and energy flow of a soldering or welding electrode.

The invention relates to a device for electronically controlling and controlling the temperature of and the amount of energy supplied to a soldering or welding electrode, in particular in reflov soldering, in which the parts to be connected are previously of the required amount of solder are provided.

In practice, soldering and welding electrodes are known in which a certain amount of energy, depending on the application, is supplied to the electrode.

10 Control of this amount of energy is only possible by adjusting the absorption capacity of the electrode.

It is not possible to accurately control the amount of heat supplied over time. Step-like temperature curves for heating solder brackets are customary here. It has been found that temperature shocks hereby occur which are detrimental to the sensitive components in electronic circuits.

Accurately controlling the amount of heat supplied to the electrode becomes increasingly important in soldering connections in increasingly miniaturized electronic circuits and components to prevent damage to these parts.

The object of the invention is to provide a device in the field of precision soldering or welding in microelectronic circuits, wherein the desired temperature and the amount of energy supplied to the electrode tip can be accurately controlled.

To this end, such a device is designed in such a way that it comprises at least one soldering or welding electrode 30 and is provided with a direct or alternating current unit and a control unit with a programmed microprocessor to adjust the soldering or welding electrode in time according to a desired or required energy. -, temperature, time curve under a certain soldering or welding electrode pressure 35, whether or not to be controlled stepwise within narrow limits, to check yj -J ü ^ Ö ö * s - 2 - and to store the measurement data in the memory.

The device according to the invention therefore comprises a heating system of the soldering or welding electrode monitored by a central microprocessor, controlled in accordance with a desired or required curve.

According to a further elaboration of the invention, the energy, temperature, time curve and the solder or welding electrode pressure can be built up in steps of one or more of the N available tables in this respect in the RAM memory of the microprocessor. N will be between 1 and 100.

The advantage of this is that any desired energy, temperature, time curve can be generated to the electrode tip in a simple manner.

Furthermore, according to the invention it can be provided that the temperature deviations from the set point by the programmable energy setting per table are very small and can be limited to about 5 ° C. The advantage of this is that the quality of the solder or shaft connections can be guaranteed.

For a further practical use of the device according to the invention it can be provided that an outprint of the supplied and measured energy, temperature, time curve at the electrode tip can be obtained.

The advantage of this is that a written measurement for quality control is obtained for both the manufacturer and the customer.

The invention will now be further elucidated on the basis of an exemplary embodiment, shown in the drawing, in which both the "hardware" and the "software" are indicated. In the drawing: Fig. 1 shows an overview of the soldering or welding device 35 according to the invention; Fig. 2 shows an IC soldered with the device according to the invention; Fig. 3 is a diagram of the device according to the invention; Fig. 4 a flow chart of the program for the 8 5 ö 3 3 S 3 - 3 - • V_; ·> · • h · '·' 'mir.

soldering or welding device for electronically controlling and controlling the temperature profile of a soldering or welding electrode; Fig. 5 shows a "hardware" set-up of the solder or 5 welding device; and FIG. 6 is a temperature-time curve for an electrode tip.

Fig. 1 shows a possible arrangement of the device according to the invention, comprising a soldering unit 1 with an electrode tip 2, a transformer unit 3 and a control unit 4, provided with an LED display 5 for input data, and controls touch controls 6.

Fig. 2 shows in detail how, for example, an IC, filled with 7, with its connection points 8 is soldered to the connection points 9 of the printed circuit board 10. The soldering unit 1 can be positioned very precisely, so that a corresponding precise positioning of the solder joints is obtained.

FIG. 3 shows the interaction of the microprocessor with the transformer and the printer for controlling and controlling the solder or welding electrode temperature.

This is thus a method of processing data and information using "software", which makes it possible to obtain an optimum end result by means of a technical process.

Fig. 4 shows the flow chart for programming the microprocessor for electronically controlling and controlling the temperature trend of a solder or welding electrode tip. In the relevant blocks of the flow chart, the following activities are carried out in conjunction with the touch keys 6 on the control unit 4.

Block 1; This block contains all the input data required for the program 35, which is required to enable efficient control, monitoring and execution of data. These data also include the N tables concerning the energy control for the welding process and the energy, temperature and timing control for the soldering process.

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Block. 2; In this block, the choice is made between soldering or welding.

Block 3: In the welding process, only a time control for the energy supply according to a specific curve is realized.

Block 4: In this block a check is made of the realized welding curve, whereby it is determined whether the welding process has been completed or should be continued according to another additional welding curve, after which again blocks 3 and 4 are run through again.

Block 5: In this block a table N is selected for the connection to be soldered.

Block 6: Here the chosen table N from block 5 is generated in an energy, temperature, time curve at the electrode tip.

Block 7; With the help of a sensor at the soldering or welding electrode tip, feedback is given as to whether the desired process has been carried out within the specified limits.

After internal comparison, an additional process can be performed, so that the desired process can be approached very accurately.

Fig. 5 shows the further construction of the soldering or welding device. The power source is modularly constructed from a number of standard printed circuit boards, which are mounted in a cabinet. The solder generator will consist of at least: - cabinet with 5V power supply and busboard; - processor card with 6809 processor; - Plk card for display and keyboard; - timer card for the output transformer and for reading the temperature control; - ΡΙΆ card for entries and exits; - temperature measurement print; 35 - starting point for the output transformer; - output transformer with cabinet; - set of EPROMS.

A welding or soldering process can be carried out, for which the following controls are necessary: 8503353 - 5 - ♦ "i. ·" - during welding a time control of the energy to the electrode; - during soldering a time control and regulation of the temperature.

At least thirty different programs are available for both welding and soldering, each of which can be pre-programmed with the keyboard and can be quickly called up during operation of the device. Each program can be used independently, or two or more programs can be linked in succession in order to compile a profile.

Parameters to be used: - soldering: energy (phase cut - 0 - 100% soldering time - G - 1G.G00 msec.

15 soldering temperature - G - 60G ° C

pressure - N

preheating temperature - 0 - 6G0 ° C

soldering time - 0 - 10,000 msec, cooling time - 0 - 10,000 msec.

20 lift-off temperature - 0 - 600 ° C

- welding: energy (phase cut I - 0 - 100% pressure - 0 - 10,000 msec, prepress time - 0 - 10,000 msec, up-slop time - 0 - 10,000 msec.

25 welding time - 0 - 10,000 msec.

down slop time - 0 - 10,000 msec, cool down time - 0 - 10,000 msec, rest time - 0 - 10,000 msec.

The welding / soldering head is driven by a 4-phase stepper motor. This requires an additional "hardware", namely: motor control point, timer point and set of EPROMs.

The welding / soldering head is powered by a pneumatic cylinder. The start command is given with a 35 foot pedal. An additional output relay is required for this.

By replacing the output transformer and the output unit with a programmable switching power supply, it is possible to use the power source for those applications where only DC voltage can be applied.

40 This requires extra: PIA card, DA converter and 830 3 3 o 3

Hr '-¾ - 6 - switching power supply.

It is possible to measure up to four thermocouples simultaneously and use one of the four temperatures or one calculated temperature from the measured temperature as a reference for the output control. This requires extra: timer print and a number of temperature measuring points.

By using an additional temperature circuit and an additional output relay, it is possible to connect a constantly heated table to the power source. Additional requirements are required for this: thermocouple measuring point and output relay point.

A soldering table can look like this: (N-table i.

SOLDERING TABLE: 1 15 After pressing a number <1. .75> the relevant table can be changed.

<EXTER> 'ENERGY: 0%' (0 .. 100%) <~> 'APPROACH: 0 C' (0 .. 999 C) <*> 'TEMP: 0 C' (0 .. 999 C) 20 < *> 'SOLDER: 0.00 s' (0 .. 99.99 s) <~> 'HOLD TIME: 0.00 s' (0 .. 99.99 s).

<~> 'LIET-OFF: 0 C' (0 .. 999 C) <*> 'PRESSURE: 0 st' (0 .. 5000 st) <*> 'Speed P: 200 Hz' (200 .. 3750 Hz ) 25 <">" Pos. Z0: 0 pcs '(0 .. 5000 pcs) <*>' Speed Z0: 200 Hz '(200 .. 3750 Hz) <~>' Pos. Z0: 0 pcs' (0 .. 5000 pcs) <*> 'Speed Z0: 200 Hz' (200 ... 3750 Hz) <“> 'NEXT PROG: 0' (0 .. 75) 30 The soldering cycle looks like as follows: SOLDERING CYCLE:

After pressing the foot pedal:

Message "COMPANY"

The "Z motor" moves to the Z0 position.

35 After reaching the Z0 position, the CONTROL time starts.

If the foot control is released during the CONTROL time, the CORRECTION time will start.

8503353

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Mi · mi - 7 - SOLDERING PROCESS:

The "Z motor" goes to the Zl position, the "balance motor" also goes to the set position (PRESSURE).

Soldering starts after the soldering pressure has been reached.

The soldering temperature is visible on the display during soldering and cooling.

After soldering, the soldering bracket remains in place until it has cooled to an entered temperature, then an entered period of time begins.

When a next soldering table is called (NEXT PROG <> 0), the soldering process starts again.

After the soldering process has ended, the WZ motor "and the" balance motor "return to the starting positions.

Message "COMPANY" is canceled.

After reaching the starting position, the message 'End of solder program' is given until the foot pedal is released.

20 If the foot pedal is released during the soldering cycle, full reset will immediately follow.

The soldering cycle starts at the front again.

The temperature-time curve for an electrode tip may look as shown in Fig. 6. The temperature is plotted on the vertical axis and the time on the horizontal axis, so that the curve indicates the temperature that the electrode tip assumes during a soldering cycle.

As can be seen from the above, the soldering or welding device can be programmed so that after 3Q enough any desired soldering or welding program can be efficiently performed.

8503353

Claims (7)

1. Apparatus for electronically controlling and controlling the temperature and amount of energy supplied to a soldering or welding electrode, especially at. reflow soldering, in which the parts to be connected are pre-supplied with the required amount of solder, characterized in that the device comprises at least one soldering or welding electrode, and is provided with a direct or alternating current unit and a control unit with a 10 programmed microprocessor to control the soldering or welding electrode in time according to a desired or required energy, temperature, time curve under a certain soldering or welding electrode pressure, step by step or not, within narrow limits, and to check the measurement data in memory store. 2. Device as claimed in claim 1, characterized in that the energy, temperature, time curve and the solder or welding electrode pressure can be built up stepwise from one or more of the N tables available in this respect in the RAM memory of the microprocessor. 3. Device according to claim 2, characterized in that N is between 1 and 100. Device according to any one of the preceding claims, characterized in that the temperature deviations from the set point due to the programmable energy setting per table are very small. 5. Device according to claim 4, characterized in that the temperature deviations are limited to almost 5 ° C. 6. Device according to any one of the preceding claims, characterized in that an outprint of the energy, temperature and time curve supplied and measured at the electrode tip can be obtained. 7. Device as described and / or shown in the drawing. 3333353