Working quality obtained by laser cutting is determined by the shape and dimension precision as well as by cut quality. The work piece shape and dimensions' accuracy are determined by the characteristics of the coordinate working table as well as by the control unit quality as in the case of CNC laser cutting machine.

The cut quality refers to the cut geometry, the cut surface quality and physical and chemical characteristics of the material in the surface cut layer. The cut geometry comprises the following: cut width, cut sides' inclination and rounding out of the cut edges. The surface quality includes the accessed roughness, waviness and deviation of the shape - surface error. The physical and chemical properties of the material in the surface cut layer refer to the surface layer formed in the laser cutting process due to the heat effect of the laser beam upon the work piece material.

The cut width is an essential characteristic of the laser cutting process giving it advantage over other sheet cutting procedures. The cut width of metals is small, it ranges 0,1÷0,3 mm with steel sheets’ cutting. The cut sides' inclination also determines the cutting quality. The cutting of material by means of the focused laser beam is characterized by narrowing of the cut. Its size depends on many factors, primarily on the focal distance of the focusing lenses as well as on defocalization, in addition to the properties of the work piece material and the laser beam’s polarization.

In order to determine quantitatively the cut sides' inclination the cut sides' inclination tolerance (u) and the cut sides' inclination angle (β) are used. The cut edges at the laser beam entrance side are rounded out due to the Gauss distribution of radiation intensity over the laser beam cross-section. The edges’ rounding-out is very small. The cut edge rounding radius ranges from 0,5 mm to 0,2 mm with steel sheets cutting. The round increases along with a rise in sheet thickness.

The laser cut surface reveals a specific form of unevenness. Observation of the cut surface can reveal two zones: the upper one in the area of the laser beam entrance side and the lower one, in the area of the laser beam exit side. The former is a finely worked surface with proper grooves whose mutual distance is 0,1÷0,2 mm while the latter has a rougher surface characterized by the deposits of both molten metal and slag. That is why it is determined to measure roughness of the cut surface at the distance of one third of sheet thickness from the upper cut edge.

The laser cutting is a high-temperature process causing a noticeable yet small heat damage of the material surrounding the cut zone, that is an insignificant change of the basic properties of the work piece material. The shape of the changes upon the materials induced by the laser radiation can be of various forms. The changes may involve the crystal structure as micro and macro cracks of the material on its surface or as zones molten together or evaporated. Since the laser cutting is actually the thermal way of cutting then the structure of the material changes in the cut zone. Changes of hardness in the surface cut layer are due to the fact that the work piece material is heated to high temperatures exceeding the critical transformation points with the onrush of the laser beam.

After the passing-through of the laser beam the process of self-cooling occurs causing a rapid cooling of the heated surface layer. In most cases the laser thin sheet cutting is successful in removing material from the cut zone with no dross produced. In sheets of greater thickness and some kinds of materials deposits of the molten metal dross appear along the exit cut edge. The cutting speed change along with the material thickness change for a variety of laser power at the assist gas pressure of 70 kPa.

The cutting speed rapidly decreases when material of greater thickness are cut. The cutting speed can also increase along with the laser power. However, it has to be remembered that the laser almost always works with an optimal radiation power.