Abstract:
The metal cutting process is the first step before the machining process is carried out so
that the raw material in the form of sheet plates is designed according to the size planned for the
manufacturing process. This cutting process is a high-speed type that takes into account the type of
coolant at each parameter setting. So it is necessary to cut the sheet according to the drawing by
adjusting the variation of the flow rate of water, pump pressure, nozzle cross-sectional area, and the
type of water quality. The parameter setting of the cutting process is carried out to obtain various
surface roughness results. By using a water jet cutting machine for the cutting process SS400 steel
with a thickness of 12 mm in the cold process reduces the thermal effect and reduces the
conductivity, HAZ in the cutting process with parameter settings. By using different types of water
quality (mineral water and clean water) to get optimal surface roughness, avoid overheating,
minimize waste chips and at the same time be environmentally friendly. With water jet technology,
you can get good surface roughness for mineral water and clean water. Variations of stand-offdistance
8, 10, 12 mm, (clean water) fluid velocity of 300 m s-1 and pump pressure of 50,000 psi on
the turbulent flow Re 4000 gets the optimum results on the surface roughness test, which is 3.45
μm. For the variation of stand-off-distance 8 mm,10 mm and 12 mm, (mineral water) fluid velocity of
300 m s-1 get the optimum result on the surface roughness test which is 3.69 μm.
