There might be advantages to starting some sort of community excel worksheet listing the criteria of the recommended feed rates. Such as, depth of cut, feed rate, type of bit, type of wood (material) being cut etc…
Each parameter influences the other in some fashion. Without capturing what matters most will not be very beneficial. This way everyone who would like to list a successful, or unsuccessful setting would be encouraged to do so, and would have the parameters needed to report this information. Just a thought.
In the Wiki there are places to report these in both the Router Bits and Stock Materials pages.
Reviving this old thread…
Fusion 360 has roughing / finishing passes built in to 2d contours, as well as “Feed Optimization” which automatically slows down the feedrate on corners. There’s a lot of parameters to look at, but Fusion 360 has really excellent mouseover tooltips, and I think the defaults are probably more for conventional mills and will require some tweaking to work well with a maslow, but they’re there.
So after doing a cut with Fusion 360’s Feed Optimization, I think a trapezoidal speed adjustment in Ground Control (read: acceleration) would be really nice. It didn’t end up causing any particular issues on my piece because it was going so slow, but it was a bit odd to see the machine jerk from one speed to another. The acceleration ramp up/down probably only needs to be a few millimeters at most but it would probably make for much smoother feed rate transitions.
@bar &/ @dlang So speed around 750mm/m (30"/m) and plunge around 4-8mm (0.15-0.30")
But at what spindle/router speed/rpm? Do you usually set the DeWalt for lower or higher speeds? And would a spindle with lower speed range be better or worse to use?
I generally do 1800mm/min and set the dewalt to 2. Those settings seem pretty ideal for a single flute router but cutting plywood
with the maslow, the movement is slow enough that you generally want lower rpm
the key thing to look at is the results, are you creating dust or chips. you
want chips, not dust.
you want the maslow moving as fast as you can with the bit spinning as slowly as
you can. Bar posted that he does 1800mm/min with a speed of 2 with a single
flute bit
if you have a 2 flute bit, you would want to be spinning half as fast (not
possible with this router) or moving twice as fast (probably not possible with
this machine)
David Lang
Thank you David,
That means it could be advantages to use a spindle with lower rpm reach. Comparatively they are much cheaper and I could then use the Dewalt as a normal router with all the attachments that came with it… And buy tools with less flutes…
Thanks again
what actually matters is the surface speed of the cutter against the material
compared to the feed rate. With smaller bits you want higher speeds or more
flutes.
so if 1800mm/m feed rate at 12k rpm is correct for a 1/4" bit, then for a 1/16"
bit (1/4 the bit diamter) you would want to do 900mm/m feed rate @2400 rpm (1/2
the feed rate and 2x the rpm)
IMHO, a 1/4" bit is a reasonable starting point, smaller bits are MUCH easier to
break, larger bits are more likely to run into problems of being bigger than the
details you are wanting to cut. get comfortable with them before extending to
larger bit (which allow for deeper passes or just faster material removal) or
smaller bits (more details, but more likely to break if they are abused)
David Lang
Thanks for the answer but I think you are confusing things. If you 1/2 the feed and double the rpm you get the same speed of the tools relative to the work. So if your tools is 4 times smaller that means it would do 4 times less doesn’t it? I think you meant 1/2 the feed and 1/2 the rpm gives you the same cut speed with a 4x smaller tool. Right?
Gijs wrote:
Thanks for the answer but I think you are confusing things. If you 1/2 the
feed and double the rpm you get the same speed of the tools relative to the
work. So if your tools is 4 times smaller that means it would do 4 times less
doesn’t it? I think you meant 1/2 the feed and 1/2 the rpm gives you the same
cut speed with a 4x smaller tool. Right?
no, with the rpm, the faster the rpm or the bigger the bit the faster the bit is
moving relative to the surface, so if you cut the bit diameter in half you need
to double the rpm to get the same surface speed (the feed rate is trivial
compared to the rotational speed)
but I did shortcut things, it’s not just the surface speed, it’s how big a bite
are you taking with each pass of the bit, which is why you then need to slow the
feed rate down (but just to complicate things further, smaller bits have to take
smaller bites)
so I may be slightly wrong in explaining the need to cut the feed rate in half
once you run out of the ability to increase the rpm, but I’m prettu sure that
you need to.
David Lang
Yeah it is quite complicated, I am trying to write down the formulas for it but I keep thinking of more factors… Nice puzzle though.
if you research “chip load” and “feeds and speeds” you will find lots of
explinations and details, mostly targeted at production machining of metal
As such, they are working to optimize how fast they remove material over a long
timeframe (so they look for ‘acceptable’ tool wear, you can but faster, but the
tools wear out faster, normally cutting slower just means you don’t get as much
done, but there are times when cutting smaller chip loads actually causes
problems) Wood cutting is a lot more forgiving.
David Lang
I know all these things in theory, I just haven’t used them in reality. I have only used hand routers (and CNC machines programmed by professionals in a factory) and with hand routers you can just feel your way through, and if it doesn’t work you go faster or slower or get a new bit When programming yourself it becomes quite a lot more complicated. The things your brain can compensate for when hand routing is amazing.
I’m extremely interested in this thread concerning bits and feed rates and speeds. This is all relatively new to me and like Gijs says I’ve used handheld routers and router tables for over 25 years as woodworker…lots of experience with using those. But a CNC…I have none! Can anyone recommend a bit brand, a selection of bits to start with, etc? Spiral up cut, Down cut, compression, etc…There’s just so many possibilities that to think about it all it’s kind of overwhelming!
For starters I’ll probably just be doing your basic cutting of 1/2"-3/4" plywood to build out basic furniture and some basic wood sign carvings…so recommendations based on that would be nice…Thanks!
Chuck