INTRODUCTION

Packaging manufacturing equipment is expensive. The purchase of machinery is a very important chapter within their budgets for metal companies. Therefore it is convenient to study the investments very well, it is preferable to spend a little more but acquire a good, reliable and long life equipment.

The machines have to be taken care of, maintained properly and trying to introduce in them successive improvements, so that they evolve, whenever possible, at the same time as the respective technologies.

Among the most expensive equipment, are the electric welders of the lateral seam of bodies. Therefore all the work that is done updating them, and increasing their productivity, will always be the main things we can do in our factory. It will directly affect the economic results.

We will now describe a series of improvements, which certain packaging manufacturers have introduced in welding machines, which have been very widespread for a few dozen years, but which, because of their quality, are still used. We refer to the FBB and ABM models manufactured by the Swiss firm Soudronic.

 

WELDER FBB 400

This welder, the first reference of this model, has proven a long life in the manufacture of round containers, at a welding speed of 50 m / min, which allows a production of 400 containers / min for the typical format of ½ Kgr. Its designation with the number 400 is due to the fact that it works with an electrical current of 400 Hz of frequency, which is achieved by means of a rotary frequency converter.

It is possible to transform its initial version, to increase its speed. Basically the modification consists of changing the power supply of the frequency converter of the 50Hz machine. at 60 Hz. The precise changes on the equipment are:

–          Add a frequency inverter to feed the electric current to 60 HJz ..
–          Change the capacitor plate adapting it to this situation.
–          Increase the cadence of the machine, changing pulleys and belt.
–          Increasing the speed of the welding wire, replacing the variator v2

With all this we will work at an output frequency in the 470 Hz converter, at a welding speed of 57 m / min, with a point length of 1.01 mm, which means even improving the quality of the welding point, because initially The machine works at a point length of 1.04 mm.

The following table shows the starting situation and the end of the different basic parameters of the equipment.

As it is clear from these data, these changes are intended for machines located in the European market, where the frequency of supply of the electric current is 50 Hz.

This modification was made on machines that worked the format of ½ Kgr (RO 73 x 110), arriving to work at a speed of 500 containers / min. After some time of activity it was seen that it was convenient to also adapt the kinematics of the FBB 500 model, since the original was too weak. That is, change the box of the suction cups and the intermediary box. Without this modification, these boxes of FBB 400 are used at their maximum capacity and deteriorate rapidly. With the boxes of the FBB 500 the results are positive.

The same modification was carried out on machines prepared for the format of 1 Kg. (RO 99 x 119), which increased the speed from 400 containers / min to 460. The results were satisfactory, without needing to resort to the change of the boxes, although if it is done it contributes a bigger reliability in the good functioning of the welder.

 

WELDER FBB 500

This machine is a more modern and faster version than the FBB 400 and works originally at a frequency of 500 Hz in the welding current. In this state it is possible to work at 500 containers / min for the ½ Kg format. To improve its performance, it is possible to act in several stages on this machine.

1st stage: Without introducing any modification, but simply adjusting the speed variators of the welder, the welding speed can be increased from 57 to 60 m / min. This way you can get from 500 to 525 containers / min. Under these conditions, the length of the welding point goes from 0.95 to 1 mm.

2nd stage: Reducing the stroke of the movement of the suction cups of the body feeder, by modifying the warehouse and controlling the suction cups. This makes it possible to increase the welding speed to 63 m / min. With this, 550 containers / min can be obtained with a weld point length of 1.05 mm. We are always talking about the ½ Kg format.

3rd stage : Incorporating more profound modifications, with the aim of reaching 600 containers / min. For this, in addition to the modifications indicated in the other two stages, it is necessary to add others that allow the increase of the frequency of the welding current. In fact, if the frequency is not increased and maintained at 500 Hz, when it is brought to the welding speed of 69 m / min, necessary to reach 600 containers / min, we would obtain a point length of 1.15 mm, this already it is not acceptable, especially if an internal protection system of the solder is used by means of liquid rebarnizado. Therefore it will be necessary to increase the frequency to approximately 550 Hz, which will allow a point length of 1.05 mm. This frequency of 550 Hz is near the maximum limit of the machine FBB 500, because it generates a high heating of the weld by the energy issued, due to the current loop.

There are two ways to increase the frequency, the first by increasing the frequency of the original rotary converter of the machine, by means of the use of a frequency inverter, and the second by changing this converter by another static one of greater frequency than the original.

If the manufacturing line, where the FBB 500 welder is mounted, is equipped with an electrostatic powder application installation for the internal protection of the weld, the point length can be increased up to 1.15 mm without significant loss of quality, what could be dispensed with changing the frequency in the welder.

 

WELDING MACHINE ABM 400

Soudronic ABM machines are very robust machines, designed to work with containers of high heights. They had great acceptance, and are still widely used.

The increase in performance of this machine has also been achieved by increasing the frequency of the current. The modification consists in implanting in the equipment a frequency inverter, and changing the capacitor stage to increase the output frequency of the welding current from 400 to 470 Hz.

In this way it is possible to increase the speed substantially in the manufacture of containers of high height. For example, for the RO 99 x 174 format, it went from 275 to 320 containers / min.

In order to take full advantage of the increase in the cadence, it was necessary to equip the feeding chains with cushioned fingers, to suppress the marks on the back of the tubes, because the increase in speed caused this defect when the fingers impacted. Primitives on the edge of metal.