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).
Feeds n Speeds Hell
Hello all,
I'm having the hardest time determining the correct feed/speed even with all of the available calculators. I'm using VCarve Desktop 11 with a Bobs CNC Evo 4 and cutting into a solid piece of oak. (I switched from pine because of chipping and had some success with harder woods in a previous project.) I'm using a 1/4" 4-flute end mill (more on that in a sec).
I can't tell if I'm just at way too high of an RPM (and/or too slow of a speed) and therefore it's not "biting" and more or less just pushing into the material, but I'm aiming for the general area of the chip load as determined by various calculators. I found an excel sheet from a guy with a professional shop and for a 1/4" bit in hardwood it's suggesting 0.009-0.11 chip load. The bit sounded like it wasn't cutting properly and then in both attempts got caught or otherwise had a problem and sort of exploded the material in a small section. I was running about 17K RPMs with 600mm/min which VCarve tells me is a chipload of 0.0088, so right about what the other excel says.
Note: One thing that confuses me is that when I swap between mm/min and inch/min I'm getting much different chip load factors in VCarve. I was thinking that when I swap the measurement it would do a simply a conversion but it appears that it is simply saving the last value and I have to manually adjust? That, or is there some sort of difference between how chip load is measured between metric and standard? The difference is huge (600mm/min = 0.0088 but shows 0.0003 when I select inch/min) if I don't change any settings.
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Frustrated, I found a program written by BobCNC himself which helps identify the proper settings, however it says that using anything higher than 2 flutes isn't recommended because the router speeds are too high. I think this is likely my problem so I have a new 2-flute 1/4" endmill arriving Friday.
I'm also curious how to cut softer woods because of the chipping problem. I'd think a bit with less flute would actually contribute to that as it would be trying to cut out larger chunks at a time versus a faster/small bite.
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As the username implies--very new to this! I'm sure I'm doing loads wrong so appreciate any help.
I'm having the hardest time determining the correct feed/speed even with all of the available calculators. I'm using VCarve Desktop 11 with a Bobs CNC Evo 4 and cutting into a solid piece of oak. (I switched from pine because of chipping and had some success with harder woods in a previous project.) I'm using a 1/4" 4-flute end mill (more on that in a sec).
I can't tell if I'm just at way too high of an RPM (and/or too slow of a speed) and therefore it's not "biting" and more or less just pushing into the material, but I'm aiming for the general area of the chip load as determined by various calculators. I found an excel sheet from a guy with a professional shop and for a 1/4" bit in hardwood it's suggesting 0.009-0.11 chip load. The bit sounded like it wasn't cutting properly and then in both attempts got caught or otherwise had a problem and sort of exploded the material in a small section. I was running about 17K RPMs with 600mm/min which VCarve tells me is a chipload of 0.0088, so right about what the other excel says.
Note: One thing that confuses me is that when I swap between mm/min and inch/min I'm getting much different chip load factors in VCarve. I was thinking that when I swap the measurement it would do a simply a conversion but it appears that it is simply saving the last value and I have to manually adjust? That, or is there some sort of difference between how chip load is measured between metric and standard? The difference is huge (600mm/min = 0.0088 but shows 0.0003 when I select inch/min) if I don't change any settings.
Frustrated, I found a program written by BobCNC himself which helps identify the proper settings, however it says that using anything higher than 2 flutes isn't recommended because the router speeds are too high. I think this is likely my problem so I have a new 2-flute 1/4" endmill arriving Friday.
I'm also curious how to cut softer woods because of the chipping problem. I'd think a bit with less flute would actually contribute to that as it would be trying to cut out larger chunks at a time versus a faster/small bite.
As the username implies--very new to this! I'm sure I'm doing loads wrong so appreciate any help.
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What about the fact that the app from BobCNC is saying the router is too high of a speed even for a 2 flute? Do you all have good results at router speeds with 2 or higher?
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I run in maple, African Mahogony, to cedar etc.. I use a downtown jenny 1/4" down- cut end mill from Cadence Manufacturing. It always cuts as smooth butter and I use it every day. Greatest, smoothest cut all the time. Last week I did this little piece in Ambrosa maple for a friend, his wife pasted. I pocketed out the pocket for the 3x5 picture, and the plastic, with a snap in fit, perfectly smooth, no sanding. They have a discount code if you ask for it too. When I carve with an end mill, the downtown jenny is my go-to every time.
Ray
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Ray
Removed the extra photos. Good job on that plaque, Ray!Oppps hit the picture thing tooooo many times
Sorry,
Ray
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