Re: [CAD_CAM_EDM_DRO] Newbie End Mill Calculator (Some questions)

James,

Thanks for posting your spreadsheet. What I like about your spreadsheet is
that I can experiment with cutter size, etc to see how that would affect my
machining.

For example, I recently "hurt" a piece of aluminum I way trying to machine.
I was using a 1/8" end mill but I am sure that I had the RPM set to about
3000. According to your spreadsheet, this was way to slow and probably a
significant contributor to why my cuts looked terrible.



As a beginner, I had thought of making up a similar sheet however I'm still
trying to grasp some of the concepts.

Your spreadsheet brings to mind some key questions:

I'll start by asking some basic questions based on your spreadsheet:

1. You have a place in which to enter the desired chip thickness

I don't know enough to know where I should get this number from. My
parts will be Aluminum or Plastic.

Should I just accept your default of 0.006 - is that a good working
chip size?


2. You have an entry "SFM" Which I assume means "Surface Feet/Minute??" Is
this correct? Would I learn this number from Machinery's Book?

3. Likewise, you have an entry for "Tool Feed Inches/Tooth" - Again, I
must ask, what is the best place to look to obtain this information?


4. Is the feedrate that you compute feet per minute or Inches per minute?
(As you can see, I'm revealing just how new this stuff is to me)

For example, you show aluminum with a 1/8" cutter should have an RPM
of 7633 and a feed rate of 106.

I am using Dolphin for my CAD/CAM and I can enter a feed rate when I
define my tool. It asks me to enter a feed rate in INCHES/MINUTE.