Looking for some help/input on a good starting point for cut settings.

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Looking for some help/input on a good starting point for cut settings.

This will be for an OX, with NEMA 23 steppers and a 400w Quietcut spindle. The bit is a 3.175mm ball nose TIN coated carbide, 4 flute.

The material will be 3.2 mm which 6061 Aluminum.

I am basically cutting plates and plunging holes.

Based on this, what would you suggest for the following:

Spindle RPM, Depth of Cut, Feed Rate

I have run multiple calc’s from online materials and come up with some pretty different numbers. This is what I am thinking for settings:

RPM: 9168
Depth of Cut: 1.5mm
Cut Feed rate: 180 mm/min
Plunge Feed rate 50 mm/min

Thank you in advance!

–Rod

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@Rod_Wintle I have a very similar setup, but I’m using a flat nose instead of a ball nose, here are my settings:

RPM: 14,000
DoC: 0.25 mm
Feed Rate: 30 in/min or 762 mm/min
Plunge Rate: 2 in/min or 50 mm/min

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@Alex_Lee Thank you Alex. My 400W spindle will only go a max of 12k I think. Your DOC is what I had been using at 0.2mm, but, your feed rate is much higher than I was using. Are you using a 4 flute, or a single flute?

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@Alex_Lee One more question. Do you plunge with the flat endmill?

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@Rod_Wintle I’m using a 4 flute 1/8 in bit, also TIN coated. I try use a profile cut whenever possible, including the holes.

I haven’t been cutting for that long, but I can tell by listening to the cut whether i’m going too fast or slow on the spindle speed, another way to check is to look at the chips, I noticed that they vary in size depending on how fast/slow you’re cutting.

I’m going to be cutting some plates in about an hour or so, hit my up on hangouts, if you’re interested and we can compare notes, and I can show you how I do it.

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@Alex_Lee What’s your Spindle motor type and max RPM ? Ty

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@Michael_Peters I have a Chinese watercooled 1.5kW spindle, I think it can go up to 24,000 rpms

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@Rod_Wintle Alex has provided some great feedback. You are correct about spindle speed, Alex is trouting a huge 1.5kW spindle. Nice verbiage huh?

You want to use a single flute end mill on aluminum. The single flute will give you great chip load at your machines speeds and feeds. Even on the big Bridgeport we only use 2 flute end mills on aluminum.

Save your 4-flute for heavy carbon metals and flying through hard woods.

Speeds and feeds anyone that’s on here will tell you that I will recommend extremely conservative speeds. it will up to you to find out the limit of your machine (which is highly based on assembly).

Dive or plunge, on a square end endmill. Ball or Bull nose are not diving kings. A single flute square endmill can bogey through material. do watch your cut width! the single flute may say 3, 4,5mm ect endmill but a single flute will typically be slightly under this. This can be used to our advantage later to manipulate the CAM software…

Start your travel at 110mm/m, dive at 4mm/m, again note I’m being conservative, on a single flute 3.175 endmill. Make a cut path 3.5mm wide. Spiral holes, step down large profiles. Use holding tabs.

Once you get a chance to cut something significant like this, look at the chips; it’ll look like grains of salt. Now, lower spindle speed (or) gain travel speed (or) increase drive. Note (or) between each. Cut the same thing, watch chip load again.

Your looking for small squares, not curled up strings or saw dust. The chips are just right when there’s a nice load on everything without over load on anything. :slight_smile:

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Here is a great article on single flute for aluminum: http://blog.cnccookbook.com/2012/12/23/why-use-a-single-flute-end-mill/

And here is the speed/feed calculator I have been using: http://zero-divide.net/?page=fswizard

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I also recently found a smaller endmill (1/8") runs a little better on my machine so going faster is now easier with the smaller cut width.

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Received my new endmills from SMW3D today! Pretty excited to cut some aluminum this weekend!