45 Degree Facemill Theory

Staying with Facemills and the Chip Thinning Factor takes me into 45 Degree Facemills. Compared to a facemill with inserts located at 90 degrees that are positioned to make square shoulders, if you are simply slabbing off material to get to a certain dimension, the 45 degree lead will make a thinner chip, requiring less horsepower, so you can increase the chipload and utilize the available horsepower.

If you viewed the video from Ingersoll showing what they deemed was a

300HP cut, you would be amazed by the metal removal rate and how you could see the chips being formed right in front if you eyes. Here is the link once again if you didn=92t see it.

They show the cutting parameters of the tool going across the screen. The parameters are enough to put you in shock but to see the cutter working is really cool. But the one thing, probably one of the most important things beside the spindle rigidity is how the lead angle of the cutter they are using makes for a more efficient, less power consuming cut than if they were using a 90 degree cutter. Either way you look at this it is a monster tool working as it was designed to work if not better. I always get a kick out of the brush or broom catching on fire from the heat of the chips then seeing the heat disipate from the pile of chips at the end of the video. I would say the parts was cool to the touch, the cutter was warm but those chips are the signature of transferring heat with the chips. Sometimes you just have to shut the coolant off.

One such number they show is a MRR (Metal Removal Rate) of 300 Cubic Inches. By calculating the Width of Cut 18=94 x Depth of Cut .750=94 x Feedrate 22 IPM it calculates out to 297 Cubes per Minute, close enough for me to call it 300 cubes. BUT, and it=92s a BIG BUTT, that doesn=92t mean it=92s a 300 HP Cut, or does it?

Machinability Rating for the 2714 Forged Steel was 80% from the very first site that I Googled. So let=92s take the 300 HP and multiply it by .8 and we get 240HP that we could debate is really getting consumed instead of 300HP. Again, it=92s an awesome cut, but let=92s do the math Boys.

But there is still one more factor to consider here. The Lead Angle of the Cutter. Let=92s just say that the Ingersoll Shear Clear cutter is a

45 degree cutter. (which I don=92t know that it is but let=92s use 45 degrees anyway for this math exercise) This lead angle is 30% more efficient than a 90 degree style cutter. So now let=92s take the 240HP and multiply it by .7 (100%-30%) and we get 168 HP that is what I would say is much closer to what is being consumed by that monster ass cutter.

Why did I do this? I=92m going to take this back into saving time. If you could speed up your processes that did not require a square corner and made it necessary to use a 90 degree cutter then you could use a facemill like a 45 degree lead cutter and reduce cycletimes resulting in more throughput, reduced labor, more jobs going across the machines, less need for more machines, more profit in your bank account.

So with the High Feed Cutters, (using a ballnose factor) as with the

45 Degree Lead Cutters (more efficient) you can achieve what is perceived as a heavy duty cut on a light duty machinery, making you more profitable.

Let me know if you like this stuff. I love talking about it and helping shops out in these tough times.

JR