Feeds and Speeds

[slow-poke]

I have ignored the feeds and speeds aspect of milling for too long. I think I have a bad habit of using cutting depths shallower than ideal.

For perspective I'm using a 4" round column mill, a VFD and mach3. I have no flood coolant setup and often cut dry. Sometimes I do brush on some Relton option1 for steel or A9 for aluminum. I typically use 2 flute for aluminum and 4 flute for steel.

I'm familiar with this formula for spindle RPM = 4 x CS / diam. CS for HSS in steel is 100, AL 400, do I need to tweak that formula when cutting dry or when just brushing on a bit before a pass?

I also seem to recall that depth of cut should not be more than radius of cutting tool, is this correct?

When trying to remove as much material as possible should I aim for dept of cut = radius of tool?

What about when you do a final cleanup pass with say a 1" depth and just taking off say 0.001"?

So assuming I have the RPM and depth of cut sorted out, how do I best determine IPM feedrate? formula or table or a Windows utility?

Any advice appreciate, I need to graduate from the "lets see what happens and why are my cutting tools smoking and turning blue phase.

 

[thestelster]

Hi @slow-poke I use an app called FSWIZARD. It's free, and it has a ton of information other than speed and feeds. I have it on my phone, and use it constantly. I've actually now put it on an older phone so I don't get my new cell all oily and dirty. It takes a little while to get use to all the features of the app, but it is great.

 

[Former Member]

One comment without flood coolant, you MRR is going to be limited by the heat generated during the cut and the effect it has on both cutter and material.

I still use HSS cutters on occasion, but when I want to push Carbide hands down, actually its my cutter of choice and as my HSS cutters wear out and are ground down, they will only be replaced with Carbide.

Coolant also has the effect of chip removal reducing the load on the cutter.

 

[slow-poke]

One comment without flood coolant, you MRR is going to be limited by the heat generated during the cut and the effect it has on both cutter and material.

I still use HSS cutters on occasion, but when I want to push Carbide hands down, actually its my cutter of choice and as my HSS cutters wear out and are ground down, they will only be replaced with Carbide.

Coolant also has the effect of chip removal reducing the load on the cutter.

Good point, most of my cutters are HSS, however I am moving in the carbide direction. Where are you sourcing your carbide tools?

 

[Former Member]

KBC obvious one (here buy the better stuff and yes you pay, the less expensive stuff is well cheep), Maple Tool Supply good quality are the most common, the most common. I have a few other suppliers but I have to look up their name.

Shars.com

 

[slow-poke]

KBC obvious one (here buy the better stuff and yes you pay, the less expensive stuff is well cheep), Maple Tool Supply good quality are the most common, the most common. I have a few other suppliers but I have to look up their name.

Shars.com

I'm trying to get a sense for quality vs. price. Looking on KBC website I'm not sure what is considered not so good vs. the better stuff.
For example 1/2" 4FL :
The KBC house brand is about $30 and at the top end $123 for the Niagra brand. At maple they have HGT brand for $55.

Should I avoid the KBC house brand?
What should I expect to pay for a 1/2" 4FL?

Thanks

 

[Former Member]

Price unfortunately does not always define quality.

Things that define it are carbide density and structure, this is hard to see unless you have specialized tools. You quickly notice this on life of cutter.

The second is cutter geometry here are are reliant on the descriptions you read, unless you have specialized tools. Also there are specialized geometries for specific materials, but good general cutters can do very well. Here you notice it on cut quality and sound generated by the machine.

Coats can greatly help in cuts , but if you are one cutter multiple materials type (cost savings) stay with uncoated cutters as they type work in everything. Some coating enhance the life and cut in one material and degrade life and cut in others.

Cutter lube is good but coolant is better. Can be extemely messy but it offers benefits.