Hi! I’m new and still trying to learn as much as possible, so I’m sorry if I use the wrong terms and such…
I’ve read a lot of articles about feeds and speeds, because I live in Africa, and my bits are pretty precious because I can’t buy them here. I want to do everything I can to extend their life.
From what I understand, it’s very important to get just the right chip size to remove enough heat and get long tool life, clean cuts and fast job times. (Thanks to this article for that.
I understand the concepts, and I’m even OK with measuring chip sizes if I need to but when I sit down to a project in VCarve, I’m at a loss. I guess I’m just missing something.
For example, VCarve has the tool database with parameters like spindle speed, feed rate, plunge rate, etc. I thought all of this was tool-specific, like these parameters are fixed based on the manufacturer’s specs, but the VCarve help document says, “…The Feedrate and Plunge rate you should use will vary depending upon the material being machined and the tooling being used.” This is confirmed in the tutorials where the user monkeys with these tool database settings prior to launching a job.
So that’s where I get all tangled up every time I look at all the speeds and feeds formulas. What comes first? Richard Shannon in the above linked post gives these formulas:
If you know Feed and RPM………Feed Rate / (RPM x # of cutting edges) = Chip Load
If you know RPM and Chip load ………….RPM x # of cutting edges x chip load = Feed Rate (IPM)
If you know feed and Chip Load ………Feed Rate / (# of cutting edges x chip load) = Speed (RPM)
So, that’s my first question… When you sit down to work on a job, what number(s) do you start with, and what parameters do you typically change?
Is it the cutting speed of the material? If so, what source do you use to determine that?
I’m just trying to understand the process.
Lastly, I have a bunch of Inventables bits from their shop, but there aren’t any detailed specs about speeds to run them, etc. I stumbled on a post referring to that at some point but I can’t find it anymore.
Thanks so much for the help. I’m anxious to learn but very protective of my bits.