Analysis of the influence of cutting parameters on surface roughness in laser cutting of tungsten alloy using control charts

Rad predstavlja analizu utjecaja parametara rezanja na hrapavost površine tijekom CO2 rezanja laserom legure volframa uporabom nitrogena kao pomoćnog plina, zasnovanu na kontrolnim kartama izrađenim pristupom statističke kontrole procesa. Zavisna varijabla je hrapavost površine, dok su neovisne varijable snaga lasera i brzina rezanja. Kontrolna karta koja se koristi u ovom radu je karta promjenjivih srednjih vrijednosti, koja potrebne srednje vrijednosti i raspone uzoraka proračunava uporabom tri uzastopne pojedinačne mjerne vrijednosti. Uporabom kriterija koji se često koriste u metodama statističke kontrole podataka za provjeru da li je situacija "izvan kontrole" može se zaključiti da povećanje brzine rezanja vodi k pogoršanju kontrole procesa s manjom uporabljenom snagom lasera.The paper presents analysis of the influence of cutting parameters on surface roughness during CO2 laser cutting process of tungsten alloy by using nitrogen as assist gas, based on control charts made by statistical process control (SPC) approach. Dependent variable is surface roughness, while independent variables are laser power and cutting speed. The control chart used within this paper is a variation of the moving means chart of experimental data samples, that calculates mean and range values using the three consecutive individual values. Applying the criteria often used in the SPC methods for the assessment of "out of control" situations, it may be inferred that increasing the cutting speed leads to worsening of control status for the process with lower laser power used