Welcome to the forum! That looks like an upcut bit and that's why you're getting splintering. Use a downcut bit for that type of cut. I don't use metric but converting 600 mm/min get me to about 24 ipm and that's extremely slow for a feed rate with a 1/4" bit. I cut around 175 ipm to 250 ipm with bits like that for comparison (would be around 4445 mm/min to 6350 mm/min).