Oxyfuel tutorials and training

When to change consumables? Why does it cut badly?

Oxyfuel consumables have a very long service life. Given their constructive and technological simplicity, they can last for months.

However, it may happen that the cut is not the best. In these cases, the flame must be observed, it will probably not be perfectly perpendicular to the sheet but will be inclined in one direction. This is determined by the presence of dirt or molten material in the nozzle.

There is a kit that includes a brush and a very thin file, the brush is for roughly removing the dirt from the tip and the file to remove any residues inside the holes from where the gas is expelled.


What maintenance should I do? And when?

Before starting the cutting operation, with the machine in safety mode:

• Check that there are no signs of burns or discolouration on the spare parts of the torch and on the oxygen and gas-carrying tubes, if so, replace them;
• Replace the gas tube according to the regulations in force, checking the manufacturing date shown on it;
• Check that the connections are tight;
• When necessary, empty the scraps collection drawers;
• Accurate control of the torch cables and general control of the cables;
• Top up lubrication oil;
• Clean the guides of the X, Y and Z axes;
• Clean the racks of the X and Y axes;
• Clean the Z axis recirculating screw;
• General cleaning of the machine with a damp cloth.


What consumables should I fit? Where do I buy them?

The consumables in an oxy-fuel torch are made up of two parts, tip plus lid. They can be purchased directly from Promotec by contacting the assistance service. We always emphasize to our customers the importance of using original or in any case good quality consumables to increase the cutting capacity and the lifetime of the cutting system.

Buying from Promotec means getting the right product quickly.

To understand which are the right consumables, just consult the laser cutting tables, they contain the product codes to communicate to Promotec, or alternatively, contact us to help you choose the right consumables.
Consumables vary in relation to the thickness of the sheet. Each consumable is suitable to cut a certain material with a certain thickness.


What are the correct cutting parameters? Can I go faster?

In the manuals is available an indication on which parameters to set, they are also easy to find online. Leafing through them you can easily understand which cutting parameters to set so that the operation is performed in the best way.

Generally, if you follow the indicated parameters, you won’t encounter any problems. In some cases, however, the status of the consumables or the large differences in temperatures during the cutting operation may require a slight variation of the parameters. Before performing the cut, a flame heats the sheet metal to very high temperatures.

This factor means that for the first cuts and for large thicknesses, the speed must be slightly lower; once the sheet is hot, the speed can be slightly increased. In case of need and doubts Promotec can guide you to find the optimal set of cutting parameters according to your necessities.


If I increase the oxygen pressure, can I go faster?

Many assume that if you raise the oxygen pressure, you can also increase the speed of movement since the breakthrough will be faster. It is an absolutely wrong concept.

The speed with which the flame penetrates the sheet along its entire thickness is not a function of the pressure of the sheet but a function of the oxidizing action of oxygen on the iron that composes the metal.

The time required for the oxidation of iron does not vary much if the pressure of oxygen increases; the temperature instead plays a major role: the higher it is, the less time it takes for oxygen to oxidize the iron and break through the material.

It is therefore understood that the speed must tend to be lower when the metal block is still cold. Once some cuts have been made and the metal will be much hotter, it will be possible to increase the speed a little. However, there is about 50 mm / min difference between start and end, therefore, it is not much worth trying to increase the speed to increase productivity.