I have a question and correct me if im wrong, so if you change the rpm will the feedrate also follow along with the rpm and be faster in motion? I'm a machinist student and I sometimes struggle with the surface finish, and I suppose the rpm also has direct effect on surface finish depending on diameter of the material right? So any good advice on how to indicate if I have too much rpm/feedrate or vice versa?
feedrate is in mm/revolution - so everytime spindle rotates 360°, tool moves x mm - i usually use something between 0,07-0,1mm/rev for finishing as lower feedrates are unnecessary and require inserts with different chipbreakers and higher feedrates leave eye-visible spirals on workpiece, you don't really care about RPM as you care about surface speed per minute (m/min)
So as long as you can adopt to rpm by adjusting your feed rate then it should not matter how fast or how slow your rpm is right? And yes about the chipbreakers, sometimes I get blurry surface when using slow feed rate with chips that has bigger nose radius. So I guess lower feed rates works best with smaller radius chipbreakers.
@@divedo9108 feedrate is always the same, no matter how fast your spindle is rotating, the tool always moves 0,1mm (or whatever you set your gears) every time spindle rotates of course when you run spindle on 150 RPM, the tool visibly moves much much slower than when your spindle spins on 2000RPM - but the tool always moves 0,1mm per revolution if i understand you correctly, you just choose wrong inserts and cutting conditions - look on the back side of your carbide insert package, there should be label with chart containing information about the insert: name of the insert: ex. DNMG 110408/NM4/WSM20 - which means D=55° diamond shape (you may meet with V 35° diamond, C 80° rhomboid, W 80° triangle, etc.), N=negative clearance (which allows you to just flip the insert upside down and have additional cutting tips - just look from the side of the insert and you see it's "square" - negative inserts are good for ROUGHING, not FINISHING, you want insert with atleast C 7° clearance) M and G are letters according to insert tolerances and clamping, 1104 are numbers according to size of insert BUT the important for you is 08 - it's nose radius and for finishing you want 04 (R0,4) or 02 (R0,2) nose radius, 08 and more is good for ROUGHING NM4 is manufacturer's designation of chipbreaker, you can visit manufacturers website to find chipbreaker you use - chipbreaker is vital for FEEDRATE (mm/rev) and DEPTH OF CUT also known as aP WSM20 is insert grade - material of which its made and which materials it can machine - ex. WSM20 is for common stainless steel also there should be chart with color boxes and numbers - you probably care about blue P that is for steel, yellow M that is for stainless steel, green N that is for aluminum (depends on what material youre machining) - they contain recommended cutting speeds from which you calculate what RPM you going to use - the formula is n[RPM] = (1000 × v[cutting speed]) / (3,14 × D[diameter you are machining]) so ex. if I want to machine diameter 50mm with cutting speed 220m/min, my RPM will be (1000 × 220) / (3,14 × 50) = 1400 RPM - but don't be an idiot, you're inexperienced and don't want fast rotating metal stuff hit your head, use higher RPMs with caution and well tightened clamps also don't forget about depth of cut! for finishing steel i use something between 0,1-0,5mm depth of cut - so if you're finishing diameter 50 and want to cut 0,2mm, you must rough diameter to 50,4 (depth of cut×2) and then finish to 50 - too small depth of cut will leave you with scratched surface and too high with rough or plucked surface just try DCMT shape insert with 04 or 02 radius, i hope this will help you
@@adamsevcik7708 For some reason I kept confusing myself between Vc and feed rate. But it all makes sense now as rpm is more connected to Vc for turning and feedrate is more connected to feed pr tooth for milling. But thanks anyway, it was a lot of information most of it makes sense, still a lot to learn though. I guess time will come.
Cost machine please
I have a question and correct me if im wrong, so if you change the rpm will the feedrate also follow along with the rpm and be faster in motion? I'm a machinist student and I sometimes struggle with the surface finish, and I suppose the rpm also has direct effect on surface finish depending on diameter of the material right? So any good advice on how to indicate if I have too much rpm/feedrate or vice versa?
feedrate is in mm/revolution - so everytime spindle rotates 360°, tool moves x mm - i usually use something between 0,07-0,1mm/rev for finishing as lower feedrates are unnecessary and require inserts with different chipbreakers and higher feedrates leave eye-visible spirals
on workpiece, you don't really care about RPM as you care about surface speed per minute (m/min)
So as long as you can adopt to rpm by adjusting your feed rate then it should not matter how fast or how slow your rpm is right? And yes about the chipbreakers, sometimes I get blurry surface when using slow feed rate with chips that has bigger nose radius. So I guess lower feed rates works best with smaller radius chipbreakers.
@@divedo9108 feedrate is always the same, no matter how fast your spindle is rotating, the tool always moves 0,1mm (or whatever you set your gears) every time spindle rotates
of course when you run spindle on 150 RPM, the tool visibly moves much much slower than when your spindle spins on 2000RPM - but the tool always moves 0,1mm per revolution
if i understand you correctly, you just choose wrong inserts and cutting conditions - look on the back side of your carbide insert package, there should be label with chart containing information about the insert:
name of the insert: ex. DNMG 110408/NM4/WSM20 - which means D=55° diamond shape (you may meet with V 35° diamond, C 80° rhomboid, W 80° triangle, etc.), N=negative clearance (which allows you to just flip the insert upside down and have additional cutting tips - just look from the side of the insert and you see it's "square" - negative inserts are good for ROUGHING, not FINISHING, you want insert with atleast C 7° clearance)
M and G are letters according to insert tolerances and clamping, 1104 are numbers according to size of insert BUT the important for you is 08 - it's nose radius and for finishing you want 04 (R0,4) or 02 (R0,2) nose radius, 08 and more is good for ROUGHING
NM4 is manufacturer's designation of chipbreaker, you can visit manufacturers website to find chipbreaker you use - chipbreaker is vital for FEEDRATE (mm/rev) and DEPTH OF CUT also known as aP
WSM20 is insert grade - material of which its made and which materials it can machine - ex. WSM20 is for common stainless steel
also there should be chart with color boxes and numbers - you probably care about blue P that is for steel, yellow M that is for stainless steel, green N that is for aluminum (depends on what material youre machining) - they contain recommended cutting speeds from which you calculate what RPM you going to use - the formula is n[RPM] = (1000 × v[cutting speed]) / (3,14 × D[diameter you are machining]) so ex. if I want to machine diameter 50mm with cutting speed 220m/min, my RPM will be (1000 × 220) / (3,14 × 50) = 1400 RPM - but don't be an idiot, you're inexperienced and don't want fast rotating metal stuff hit your head, use higher RPMs with caution and well tightened clamps
also don't forget about depth of cut! for finishing steel i use something between 0,1-0,5mm depth of cut - so if you're finishing diameter 50 and want to cut 0,2mm, you must rough diameter to 50,4 (depth of cut×2) and then finish to 50 - too small depth of cut will leave you with scratched surface and too high with rough or plucked surface
just try DCMT shape insert with 04 or 02 radius, i hope this will help you
@@adamsevcik7708 For some reason I kept confusing myself between Vc and feed rate. But it all makes sense now as rpm is more connected to Vc for turning and feedrate is more connected to feed pr tooth for milling. But thanks anyway, it was a lot of information most of it makes sense, still a lot to learn though. I guess time will come.