Face cutter cutting width

[Norman WillcoxParticipant @normanwillcox10519]

We have been using an Ingersol face cutter of 32mm diameter with 4 “multi-cut” inserts. Finish on the aluminium alloy is not very good.

Is it permissible to set the width of cut to the full 32mm or is it better to use less than 1/2 the width?

Norman

[Norman WillcoxParticipant @normanwillcox10519]

What width should be set with a face milling cutter?

[Norman WillcoxParticipant @normanwillcox10519]

No, I did see that there is another grade for aluminium. These are IN30M – whatever that means!

Cuting lubricant is Cronos MT5.

1200rpm, 250mm/min feed, 0.25mm depth, almost full 32mm width.

Is full width wise? that is up and down milling at the same time, isn’t it?

Norman

[Clive FosterParticipant @clivefoster55965]

Norman

 

When it comes to insert cutters you pretty much have to track down the book operating data and follow it. Material specific inserts are normal. Used as per book inserts perform very well indeed but most have been empirically developed to perform properly within their specified operating envelope and are pants outside it. Some will work fine outside the book values but your chances of tracking them down in the blizzard of type numbers are pretty slim. For lathe work sharp, positive rake inserts are pretty forgiving “off book” but I know of no similar general approximation for milling inserts.

 

Clive

[mgjParticipant @mgj]

What alloy is it – if it’s a cast LM4 job getting a really good finish may be interesting.

[Norman WillcoxParticipant @normanwillcox10519]

Hi mgj,

The alloy is 6082-T6. Supposed to be good for machining.

Norman

[Ian S CParticipant @iansc]

On aluminium, for similar cuts to yours I use a 50 mm three insert face cutter at about 1200rpm. Can’t remember the number of the cutters, they are 16 mm triangle with no chip breaker and no hole(held with a bridge piece), the metal comes out smooth as glass. I use 5-56, or kerosene as a lubricant, the alloy I prefer is 7075 T651 tooling plate, I get off cuts from the local supplier. Extruded bar is another story, but still machines up quite well. Ian S C

Edited By Ian S C on 21/04/2011 13:36:03

[Norman WillcoxParticipant @normanwillcox10519]

Thank you Graham, Clive and mgj for your responses. I am more confident now and no doubt a better finish will be possible.

Norman

[Anonymous]

When using a face mill you can use any percentage engagement, except around 50%. So, say up to about 35%, and from 65% to 90% or so. The reason not to use an engagement of about 50% of the tool width is that it will hammer (literally) the inserts and reduce their life.

 

As for speeds and feeds I make a 32mm cutter and 1200rpm equate to about 120m/min surface speed. That’s a good middle of the road speed for aluminium alloy. A feed of 250mm/min is a tooth load of about 0.05mm/rev, may be a little low for aluminium. Unless it’s a finishing cut a depth of 0.25mm seems very low.

 

The only reason I use flood coolant for milling aluminium is to wash away the swarf. If the inserts are specifically designed for aluminium then build up on the inserts shouldn’t be an issue.

 

Regards,

 

Andrew

[GoCreateParticipant @gocreate]

Wouldn’t a HSS fly cutter be a better option for this material when using our hobby machines?

A while back I was asked to skim an aluminum cylinder head. An old hand told me to use HSS fly cutter, put a 1/64th rad on the tool, hone the tool to a keen edge than slightly dull the edge which I did with fine wet and dry.
A high speed and fine feed with normal water soluble coolant provided a perfectly smooth finish much to my relief. The fly cutter was about 4″ dia cutting almost full width at 5 thou depth.
Nigel

 

[Norman WillcoxParticipant @normanwillcox10519]

Hi Nigel and Gray,

Thanks for your posts.

Is the 1/64″ radius ground on the outer tip of the cutter?

Norman

[Norman WillcoxParticipant @normanwillcox10519]

Hi Gray,

I have usually just used the grinding wheel to sharpen the HSS tools.

I have googled slip stones and looked at Axminster tools without seeing what I think I need. Most seem to offer stones for woodworking gouges. Do you have a particular supplier and description please?

[GoCreateParticipant @gocreate]

Hi Norman

The 1/64th rad was done using a slip stone.

Nigel

[Norman WillcoxParticipant @normanwillcox10519]

Hi Gray and Nigel,

Thank you both.

I have ordered the Norton stone.

Norman

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