Beginner's question about facing head

[compact8]

I have got a 40 mm diameter facing head that accomodates 4 carbide inserts. I have tried it on 7075 and 6061 aluminium as well as 1018 and 303 stainless. Other than that on 1018, the finish is superb. What bothers me a bit is that the cutting tip of the inserts are not exactly on the same horizontal plane. The maximum difference is 0.03 mm or slightly more than a thou. The same amount of variation is seen on the radial distance of the tip from the center of rotation. I believe that will cause some of the inserts taking up more cutting load hence wearing out faster than the others.

My imagination is that if the most heavily loaded insert is worn out, it will not be cutting anymore and the load will be distributed ( unevenly ) to the others until all are worn out and a bad finish is produced. That doesn't sound too bad to me but is it that simple ?

 

[mmcmdl]

I wouldn't worry about this , you're talking about .001 .

 

[compact8]

I wouldn't worry about this , you're talking about .001 .

Umm.... I should have added that my mill is just a small 300 lb bench mill so it can only do very shallow cuts with a tool of that diameter.

 

[mmcmdl]

Fly cutter work for you ? Carbide face mills are great if you have good rigidity , not so good for smaller equipment . Not sure what diameter that cutter is .

 

[compact8]

Fly cutter work for you ? Carbide face mills are great if you have good rigidity , not so good for smaller equipment . Not sure what diameter that cutter is .

I have not tried fly cutters because I do not have a grinder and I am too lazy to grind HSS tools. The diameter of the cutter is 40 mm or 1.57 inch

 

[matthewsx]

I have not tried fly cutters because I do not have a grinder and I am too lazy to grind HSS tools. The diameter of the cutter is 40 mm or 1.57 inch

You're going to want to get a grinder eventually, if you were truly lazy you'd just order what you want online rather than making it yourself

P.S. You don't have to use all the inserts in your face mill....

 

[compact8]

You don't have to use all the inserts in your facing head....

I am aware of it, as a matter of fact I started cutting steel with only one insert in the head. Because of the low power of my mill, I had to lower the RPM and feed very slowly.

The motive of using multiple inserts is just to spread out the cutting load so higher feed rate is possible. Just like 4 fluters allowing higher feed rate than 2 fluters do

 

[benmychree]

What you are talking about is a face mill, not a facing head, which is like a boring head with automatic feed.

 

[Illinoyance]

The difference in insert height is most likely due to the insert tolerance. A K tolerance is given as a half thou. M tolerance is 2 to 5 thou.
If you are using APMT inserts switch to APKT.

Insert Designation Chart - provides ANSI and ISO designation code definitions for carbide insert shapes, relief angles, tolerances, chipbreaker codes, hole types, size values, thickness values, radius values, wiper lead angle, wiper clearance angle,

Carbide Insert Designation Chart

www.carbidedepot.com

 

[epanzella]

I got a pretty cheap face mill with my RF30 knockoff. I couldn't get a good finish because the pockets weren't machined the same. I took 3 cutters out and left one. A lousy face mill turned out to be a half way decent fly cutter.