Module and system for controlling and recording welding data, and welding wire feeder

Description

The invention relates to the acquisition of data related to the feeding process of welding wire consumed in an installation for automated welding, in particular in a welding robot.

BACKGROUND OF THE INVENTION

Installations for automated welding processes such as welding robots need a large quantity of welding wire in order to minimize changeover downtime and maximize productivity. For safety and handling reasons, in modern installations the welding wire is not placed in the immediate proximity of the welding robot, but at a safer distant place where more floor space is available and the pack handling is easier. The welding wire can be supplied in the form of a large bulk pack which can contains from few to several hundreds of kilograms of welding wire. From the bulk pack, the welding wire is delivered to the welding robot by means of a welding wire liner, also called conduit, in which the welding wire is transported with minimized friction.

The welding wire is transported from the bulk pack to the welding torch mounted on the welding robot by means of a feeding system. Usually, the feeding system comprises a driving motor and one or two couples of feeding rolls which are pushing the wire through the welding torch liner into the welding torch. The feeding system ensures that the required amount of welding wire is delivered to the welding torch where it is being melted at a welding arc in order to join two base metal parts.

Even though the feeding system advances the welding wire, they do not keep a record of the actual length of welding wire being fed nor the actual weight of welding wire being deposited over a certain period of time.

BRIEF SUMMARY OF THE INVENTION

The invention provides a module for controlling and recording useful welding data and parameters like actual welding wire usage and wire feed length and time. The module has a sensor with the capability of detecting the welding wire feed motion, a processor for storing data provided by the sensor, and an output device for providing and recording the data. The invention is based on the idea of using a module or device external to the feeding system, for acquiring precise information on the speed and duration with which the welding wire is being advanced. Based on this information, a plurality of other information associated with a precise measurement of the speed and length of the welding wire can be provided as well, such as the entire amount of welding wire consumed in a certain period of time or a certain weld sequence, the length of the welding wire used for a particular welding operation, the amount of welding wire remaining in the bulk pack, the estimated time until the bulk pack containing the welding wire has to be replaced, information on the productivity and the efficiency of the respective welding robot, etc.

According to a preferred embodiment, the sensor comprises a wheel which is adapted for contacting welding wire. Due to the frictional contact between the wheel and the welding wire, the speed of rotation of the wheel precisely corresponds to the speed with which the welding wire is being advanced. This is in particular true if the wheel is not an actively driven wheel used for advancing the welding wire but only a sensor wheel entrained by the welding wire.

In a module in which the wheel is a passive wheel driven by the welding wire, an encoder is preferably provided which senses the rotation of a wheel. The signal of the encoder then is indicative of the speed with which the welding wire advances.

According to an alternative embodiment, the sensor can be a contact-free sensor. A contact-free sensor allows a determination of the speed of the welding wire without any measuring tolerances due to frictional effects.

A contact-free sensor can use one of acoustic waves and electromagnetic waves for sensing a welding wire feed motion. Sensors of these types are well-known and are used for many different applications.

According to a preferred embodiment of the invention, a touch display is provided for allowing an operator to input settings and parameters. The touch display allows adapting the module to the particular welding wire being currently used, for example the amount of welding wire contained in a bulk pack, the material of the welding wire and its diameter.

Preferably, a wire level monitoring module is provided which is adapted for warning an operator if the amount of welding wire remaining in a currently used bulk pack falls below a predefined value. The warning can for example be used to alert the operator that a replacement bulk pack has to be made available within the next hours of operation of the welding robot.

The invention also provides a system for sensing a welding wire feed motion, comprising a module for controlling welding parameters and having a sensor for detecting welding wire feed motion, a processor for storing data provided by the sensor, and an output device for providing the data, and further comprising a welding wire feeder, a module being connected to the welding wire feeder by means of a data connection which is coupled to the output device. The welding wire feeder of the system is an auxiliary feeder or boost feeder which assists a feeding system associated with the welding torch. A boost feeder is particularly advantageous if the distance between the bulk container and the welding torch is quite large, for example more than 20 meters. The boost feeder assists the feeding system associated with the welding torch while the module for controlling welding parameters senses the precise speed and length of the welding wire supplied to the welding torch.

The data connection between the module and the welding wire feeder can be an electric cable or can also comprise a wireless transmission device based on Bluetooth, Wi-Fi (WLAN) or a similar data transmission standard.

The invention also provides a welding wire feeder comprising a motor, a feeding wheel driven by the motor and adapted for advancing welding wire, a control which controls the operation of the motor, an operator interface adapted for allowing an operator to input data which being used by the control, and for making available to an operator data indicative of a welding process in which the welding wire provided by the welding wire feeder is being used. This welding wire feeder incorporates the task of sensing the welding wire speed into the auxiliary or boost feeder and can, based on this information, provide to an operator different data associated with the welding process.

The operator interface can preferably be a touch display which allows inputting different data in a very convenient manner.

The feeding wheel can be mounted in a replaceable manner to the welding wire feeder. Preferably, a quick connection coupling or a similar device is used for mounting the feeding wheel so that it can, in case of need, be very easily replaced against a different feeding wheel, for example for adapting a welding wire feeder to a different type of welding wire.

According to a preferred embodiment, an electrical data interface is provided via which data collected by the welding wire feeder can be transferred to an external device. The electrical data interface can be a USB port, an electrical plug connection, an Ethernet port, a Bluetooth port, a Wi-Fi port or a similar interface which allows transferring the data to for example an external computer. The port can also be used for providing a software update to the welding wire feeder.

The invention further provides a method for operating a welding wire feeder having a motor, a feeding wheel driven by the motor, a control of the motor operation, an operator interface adapted for allowing an operator to input data which is being used by the control, with the method comprising the steps of counting the length of welding wire supplied from the bulk container in use, and of providing an operator with information on the quantity of welding wire remaining in the bulk container in use and the welding wire already paid out from the bulk container in use. Hitherto, an operator had to frequently manually inspect the bulk pack residual content in order to assess how much welding wire was still available inside the bulk container, and the risk of suddenly running out of wire could cause sudden and unwanted interruptions of production. With the invention, the operator can now accurately determine the residual quantity welding wire inside the bulk container and this information can help him better plan the welding wire inventory levels and to optimize the pack replacement procedures, with significant reduction of changeover downtime.

According to a preferred embodiment, the control allows the operator to accurately assess the actual length of the welding wire being paid out and the residual length of welding wire still inside the bulk container, through a sequence of steps which involve the input of all relevant parameters, such like the type of welding wire, the size of the bulk container and the diameter of the wire.

In a preferred embodiment a setting procedure allows a calibration of the module based on the actual wire diameter being used, for a more precise measurement of the wire length and all related parameters: for obvious reasons the setting of parameters can only be theoretically based on the average values of a particular wire diameter, however, the international Welding Industry Standards and Norms like ISO and AWS, and all the existing welding applications, contemplate the possibility for wire diameters to range from a minimum to a maximum (normally +/−2%). Since the collected data strictly depend on the actual wire mass and diameter, the possibility to calibrate the module on the actual diameter of the welding wire in use can further increase the accuracy of the data collected. This more precise information can be particularly useful when assessing the exact amount of welding wire deposited in a limited weld sequence in order to determine with maximum accuracy the costs to weld a certain part or component.

According to a preferred embodiment, the control of the welding wire feeder calculates and makes available to an operator, important production data like the effective run time of the welding wire feeder, the actual arc-on welding time, the number of welded meters and the actual amount of wire deposited into the welded part in a selected period of time which can range from a single welding sequence to a much longer production cycle of days, weeks or months. Such information can be particularly useful to calculate the actual cost of a weld sequence or to help measure the robot productivity levels.

BRIEF DESCRIPTION OF THE DRAWINGS

Invention will now be described with reference to the enclosed drawings. In the drawings,

FIG. 1 shows an installation for automated welding in which a system according to the invention is being employed,

FIG. 2 shows a front view of a welding wire feeder used in the installation of FIG. 1,

FIG. 3 shows a side view of the welding wire feeder of FIG. 2,

FIGS. 4 to 21 show the touch display used in the welding wire feeder of FIG. 2, with different information being displayed on the touch screen,

FIG. 22 shows a different embodiment of an installation for automated welding,

FIG. 23 shows in a perspective view a module for acquiring the welding wire speed as used in the installation of FIG. 22, and

FIG. 24 shows a rear view of the module of FIG. 23.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an installation for automated welding which comprises a welding torch 10 which is here mounted on a welding robot 12. Associated with the welding robot is a main feeder 14 for feeding welding wire to welding torch 10. The welding wire is taken from a welding wire supply 16. Welding wire supply 16 is here a bulk container which contains a significant quantity of welding wire.

In view of its weight and further in view of considerations such as accessibility, available space etc., welding wire supply 16 is arranged at a distance from welding torch 10. Welding wire 18 from welding wire supply 16 is guided towards main feeder 16 and welding torch 10 by means of a wire guide 20. Wire guide 20 can be any device which allows to reliably guide the welding wire from welding wire supply 16 towards welding torch 10. Preferably, wire guide 20 is formed from a plurality of interconnected bodies which each support a couple of rolls. The rolls guide the welding wire 18 in the interior of the bodies with low friction while at the same time ensuring that the wire guide 20 can follow the movements of welding torch 10.

At a suitable location between welding wire supply 16 and main feeder 14 and preferably close to welding wire supply 16, an auxiliary welding wire feeder (also referred to as “booster feeder”) 22 is arranged. The purpose of auxiliary welding wire feeder 22 is to provide a pushing effect on welding wire 16 for pushing the welding wire towards main feeder 14, or to at least assist the advancing motion of the welding wire provided by main feeder 14.

Welding wire feeder 22 (please refer to FIGS. 2 and 3) comprises a schematically shown motor 24 which is operatively connected to a feeding wheel 26. Associated with feeding wheel 26 is a pressing wheel 28. The welding wire passes between feeding wheel 26 and pressing wheel 28 so that the welding wire is advanced according to the speed of feeding wheel 26 when the latter is driven by motor 24.

Further provided as part of welding wire feeder 22 is a control 30 which controls the operation of motor 24.

Welding wire feeder 22 also comprises an operator interface 32 which here takes the form of a touch display. An operator can input certain parameters into control 30 by means of operator interface 32, and the welding wire feeder 22 can make available to an operator certain data via operator interface 32.

Welding wire feeder 32 also comprises an electrical data interface 34 which is here formed as an insertion slot for a USB stick or a connecting cable of the USB standard. Electrical data interface 34 allows retrieving data stored in a processor of control 30 so as to externally process the data with dedicated computer software. The data interface can also be used for updating the software (operating system) used by welding wire feeder 22.

Operator interface 32 can display a plurality of different screens by means of which certain parameters can be requested from an operator, and by means of which operational data can be shown to an operator.

FIG. 4 shows a screen of operator interface 32 which is the main menu. This screen allows selecting an automatic feeding mode, a manual feed mode, to change settings in the system, and to change to a data exchange mode.

FIG. 5 shows a screen of operator interface 32 which with certain system settings can be made. One of the settings is the length of the liner (please see FIG. 6) as the length of the guiding liner between the welding wire container 16 and the welding torch has an influence on the friction occurring within the entire system and consequently on the amount of feeding force necessary for transporting welding wire 18 within guiding liner 20. Control 30 can either automatically adapt or make suggestions on the amount of assistance provided by welding wire feeder 22, depending on the length of the liner.

As shown in FIG. 7, operator interface 32 can also request information on the number of curves which are present between welding wire container 16 and welding torch 10, as the number of curves also has an influence on the friction occurring within the entire system.

FIG. 8 shows a screen in which an operator finally confirms that the parameters previously inputted are correct.

FIG. 9 shows a screen with which an operator can provide to the welding wire feeder 22 specific information on the welding wire supply. The first important parameter is the type of wire, for example aluminum wire or copper wire. The material and the resultant resistance to bending have an influence on the level of friction within guiding liner 20. The same applies with respect to the wire diameter; a thicker wire results in more friction.

Another important parameter is the weight of the pack, meaning the weight of the wire contained in welding wire container 16. Providing the weight of the pack in combination with the diameter and the type of the wire allows control 30 to calculate the length of welding wire contained in the particular pack. This also allows control 30 to inform an operator if the welding wire contained in welding wire pack 16 is most completely consumed. To this end, the settings allow an operator to indicate at what remaining percentage of the original amount of welding wire a low level alarm shall be provided. An operator can for example decide that he shall be warned if there is only 5% of welding wire left (please see FIG. 10).

An operator can also define a maximum manual speed (please see FIG. 11) or a maximum auto speed (please see FIG. 12) which shall be provided by welding wire feeder 22. Still further, an operator can manually adjust the boost (meaning, the drive force which welding wire feeder 22 provides an addition to the action of main wire feeder 14) if the feed assistance calculated by control 30 does not meet the expectation of the operator. As an example, an operator can indicate what percentage of the maximum driving power of the motor shall be provided (please see FIG. 13).

In the manual feed mode (please see FIG. 14), operator interface 32 shows a screen in which the operator can manually operate welding wire feeder 22 by telling the feeder in which way to feed the welding wire, with which boost and with which speed.

The screen shown in FIG. 15 allows an operator to make basic settings such as time and date.

FIG. 16 shows a screen which is shown by operator interface 32 during an automatic mode of welding wire feeder 22. The screen here shows essential parameters such as the boosts set and the actual boost, the feeding speed, the currently available amount of welding wire (in this example approximately ⅝of the original amount) and the level at which a low wire alarm will be triggered (here approximately ⅛ of the original amount).

Welding wire feeder 22 can also be used for collecting and making available to an operator certain data associated with the welding process. An example is shown in the screens of FIGS. 17 and 18 where general data relating to a certain welding robot and collected over a certain time of operation is made available to an operator. This allows analyzing the performance of the particular welding robot and, if a plurality of welding robots is being used in parallel, to compare their operation.

It is also possible to analyze individual welding processes or a welding process of certain parts. An example is shown in FIGS. 19 and 20 which show slides providing information on specific parts welded by welding robot 10 to which welding wire is fed by welding wire feeder 22. Welding wire feeder 22 calculates or counts the amount of welding wire advanced towards welding torch 10 based on the number of rotations of feeding wheel 26. To this end, control 30 takes from a lookup table the true feeding wheel circumference which varies depending from the diameter of welding wire 18.

Feeding wheel 26 as a groove (usually a V-groove) which ensures that the welding wire is properly guided at the feeding wheel. The smaller the wire diameter, the deeper the wire sits within the groove thereby reducing the actual length by which the welding wire is advanced per rotation of feeding wheel 26.

Furthermore, control 30 is provided with information as to how many meters of welding wire correspond to the amount of for example one kilogram, based on the diameter of the welding wire and the material. Based on the values provided by the operator, control 30 very precisely knows how much welding wire is available within the respective welding wire container 16.

It is furthermore possible to calibrate the welding wire feeder to the actual diameter of the welding wire in use. FIG. 21 shows a screen with which the date in the look-up table in control 30 can be modified if an operator, after a certain period of time, makes a determination as to the actual diameter of the welding wire contained in the currently used container. Such deviation can be made with a precision scale and the information as to how many meters of welding wire have been withdrawn. The length of the consumed welding wire allows calculating how many kilograms should have been withdrawn. Any difference to the actual loss of weight of the pack must be due to the welding wire having a diameter which differs from the nominal value.

The operator can input this delta so as to increase the accuracy of the data provided by the welding wire feeder for the rest of the welding wire pack.

If the welding wire feeder is being reset for a fresh pack, the inputted diameter correction is reset as the deviation in diameter usually differs from pack to pack.

In addition to the screen explained so far, a screen saver can be provided.

It is now explained how the welding wire feeder is being used.

At the beginning of a welding operation when a fresh pack 16 is provided, the operator resets the counter within welding wire feeder 22. Based on the length of welding wire advanced towards torch 10, control 30 can therefore continuously show to an operator interface 32 how much welding wire remains in the container, and can also indicate (for example by changing the wire level indication from green to red) that an amount of welding wire remains which is below a certain level.

Setting the level at which a low level alarm is triggered, to a desired level allows adapting welding wire feeder 22 to the particular circumstances where it is being used. If welding wire feeder 22 is used in a large plant where there are hundreds of robots, it is impossible to place a backup wire container on every station. In order to prevent that a pack runs empty while there is no forklift available for promptly delivering a new pack, the low level warning can be set to a level which is high enough for an operator to order a forklift to bring a new pack within for example the next eight hours or even the next day, depending on how the alarm is set.

When a new pack is loaded, it is sufficient to click on a symbol for a new pack on operator interface 32 so as to reset the current counting and to restart.

Based on the feeding information gathered in control 30, valuable additional information can be provided to an operator. This information can comprise the actual production time of the welding robot, the actual time during which the robot is in stand-by but not welding, the total length of welding wire used in a specific welding robot, the length of welding wire used for producing a specific component, the downtime of the welding robot, the time it took to weld a certain part, how many welds were necessary in a particular sequence, how much wire has in fact been deposited, etc.

This information allows a very convenient calculation of the costs of welding a particular part or a number of parts. By indicating the working hours and comparing them with the actual run time of the welding wire feeder, robot efficiency and productivity can be very easily determined. This can be checked on a weekly, monthly or yearly basis and can be compared with other robots in the same plant.

It can also be checked how long the welding robot was down during a specific period of time, for example to double-check with the number of hours which were charged by a repair team doing some maintenance on the robot.

In case the performance of two competitive welding wires is to be compared, the data supplied by the welding wire feeder regarding robot productivity will provide a reliable hint as to which welding wire performs best.

Furthermore, the productivity level can allow a plant manager to concentrate on the robots with the worst performance and analyze the reasons for the bad performance (defective parts, bad maintenance, etc.).

Welding wire feeder 22 can also help analyzing operating costs, in particular for energy, in case of comparison with a welding wire feeder of a different type (for example electrically driven as compared to pneumatically driven).

In the embodiment described so far, feeding wheel 26 can be considered as part of a sensor for detecting welding wire feed motion. It is however also possible to use a separate module for detecting and counting the feed motion of welding wire 18. Such embodiment is shown in FIG. 22 in which a module 40 for controlling welding parameters is being used adjacent to welding torch 40, with module 40 being formed separate from welding wire feeder 22.

Module 40 (please see FIGS. 23 and 24) comprises a sensor for detecting welding wire feed motion and is here in the form of an encoder 42. Encoder 42 is connected to a wheel 44 which is passively driven by the welding wire which is guided through module 40. In order to ensure that there is no slip between the welding wire and wheel 44, a pressing wheel 46 is provided which maintains a sufficient frictional contact between the welding wire and wheel 44.

The number of revolutions of wheel 44 as counted by encoder 42 is sent to control 30 of welding wire feeder 22 via a data connection. The data connection can be an electric cable which can be integrated into guiding liner 20 and can for example use the USB standard, or can be a wireless transmission using an Ethernet protocol, Bluetooth, Wi-Fi (WLAN) or a similar standard. All functions provided by welding wire feeder 22 based on the information provided by module 40 are the same as described above for the first embodiment.

The measuring accuracy of the second embodiment is slightly higher than for the first embodiment as there is no slip between the welding wire and the wheel which “counts” the feeding process. In the first embodiment, it cannot always be prevented that there is some slip between the feeding wheel and the welding wire.

As an alternative to a mechanical sensing as is done in module 40 shown in

FIGS. 22 to 24, module 40 could employ a contact-free sensor which uses for example acoustic waves or electromagnetic waves for sensing the welding wire feed motion. Such sensor could also be incorporated into welding wire feeder 22.