Depth of cut...how deep can you go...

[airbrush]

Just curious if anyone does a depth of cut deeper than the diameter of the bit....currently i'm using a small 1/8" bit with just over 1/8depth of cut to reduce time..feedrate of 40. LOC is .75 on the endmill...wondering if i can do a 1/4 cut? speed up router? slow down feedrate slightly?

Anyone tired? results?

essentially i can reduce my passes to two ... instead of 4 currently

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[ger21]

Just curious if anyone does a depth of cut deeper than the diameter of the bit

Yes, but not with a 1/8" bit. Why don't you just cut faster. You can probably cut close to 300ipm with an 1/8" bit, 1/8" deep. Unless you are cutting small parts.

What's the total depth?

[airbrush]

reason being i could reduce the slight little step edge i get with each depth of cut(tool deflection? plunging the tool?)...would reduce sanding time for me since i'm producing hundreds of these parts...only one way to find out i guess....give it a whirl and see what happens

total thickness of stock is 1cm but the last pass is 1/8 deep with tabs left to hold everything together

So if i can get it down to two passes...one pass down to the last 1/8" of material would leave no steps and reduce sanding time, which starts to add up fast x100+ parts

[steve323]

I usually do a multi-pass rough cut at high speed that is offset about 0.005" outside the line. Follow this with a full depth final pass on the line at a slightly lower speed. This seems to reduce the cut lines.

Steve

[airbrush]

hmm...maybe....more time added to cutting but maybe reducing the sanding time....which i hate sanding but necessary
I don't think i would even have to do an offset...just do a full depth pass again around the part to clean it up...could be worth a shot, speed up first passes a bit and add another final pass...really depends, sometimes there are steps sometimes not..its wood, so never the same

[ger21]

Triple your speed, and offset all passes except for the last by maybe .01". The last pass will remove all the lines. I would think that you can probably go to 3/16 (5mm)/pass, and still cut faster than you are now. 40ipm is very slow for shallow cuts like that.

[airbrush]

okay..maybe i'm just being too cautious and not pushing the bits like i should...will try it out...actually i think i was wrong on the number...i believe it may have been 60ipm and then i slow to 30ipm on the radius'.
So maybe two passes at 80ipm and a final clean up at 60ipm..? will probably work out to the same time, but end up with a cleaner result. Running poplar right now, but i'm going to be doing some in walnut which is much harder....so will have to slow it down for that

[ger21]

Walnut is one of the softer hardwoods, and cuts like better. I would not slow down at all when cutting walnut.

[airbrush]

really?! the hardness scale of wood, poplar 540 - walnut around 1100

maybe i'm babying my machine and tools too much

Honestly i've never pushed my machine past 80ipm(and that seemed really fast to me)...not sure how confident i feel about those cheap chinese motors and bearings that are on this machine.

[Biggs427]

...
maybe i'm babying my machine and tools too much
...

On the contrary, going too slow will burn your cutter unless you dialed the rpm way down to accommodate such a slow feed rate.

[airbrush]

On the contrary, going too slow will burn your cutter unless you dialed the rpm way down to accommodate such a slow feed rate.

hmmm maybe what i'm describing at 60 feedrate is not in IPM...i'm using bobcad, doesnt say what that number value is for cutting feedrate?
I assumed it was IPM...newb here

[airbrush]

Run my cuts on the walnut...didn't slow it down....cut it no problem...was worried about the hardness from walnut to the poplar i usually cut at the same rate...not an issue.
Just sounds like a screaming banshee is all...

[wizard]

In more conventional milling depth of cut is often used to control horsepower required. In wood you might never reach the spindles rated horsepower output so your depth of cut "can" be deeper. The question then becomes should you go that deep and that depends upon the specifics of what you are doing but generally I'd say no. The general practice, as described above by others is to take a clean up cut after finishing multiple passes.

The other possibility, if you are having significant distortion in the frame is to stiffen up the machine to minimize the steps. That will work to a point but you will still get cutter deflection, especially with small diameter cutters. This brings up cutter diameter which should be as large as the project allows for (given room for the clean up passes). You may have to use 1/8 cutters and if that is the case you will likely be better off going fast with relatively shallow depths of cut. The small diameter means deflection will be very real and chip clearance could be a problem too. You are likely to even have deflection on clean up cuts.

[airbrush]

i am using 1/8 downcut bit...doing two passes now instead of three and doing a third clean up pass...was more worried about the deflection of the tool bit...but doesn't seem to be a problem...