Carbide Insert DOC and Feed Rate Info

[erikmannie]

I made this post because I have only seen the following “chart” one time in all of my reading:



One gets to these charts by clicking on:

Search Page

and then navigating to the type of insert that you are using. Once you are on the product page for a particular insert, click on “Click Here to View Product Information” (a link in bold blue type).

 

[erikmannie]

The drawback here is that this recommended range of DOC and feed rate is specifically for this brand (which happens to be the house brand for Carbide Depot) of insert.

I imagine that it wouldn’t be the worst thing to use this data as a starting point for other brands, however.

 

[macardoso]

If you are buying inserts from reputable manufacturers, they should all have this info available individually for each insert. Those numbers vary based on geometry, grade, coatings, and material being cut.

Too low on the SFM and depth of cut/feed rate and you'll have poor finish and difficulty breaking chips.

Too high and you'll smoke the insert.

For most of us, these numbers are difficult to attain on our equipment. I bet your lathe can do it though.

 

[erikmannie]

I’ve also seen that Iscar puts similar data on their boxes, which I believe is helpful.

This last round, I bought Kennametal inserts, and I did not see this data either on the packaging or on the Kennametal website. I wonder if Kennametal has that information out there, and that I missed it.

 

[erikmannie]

In any case, maybe these Carbide Depot charts could be a starting point for fine tuning DOC and feed rate, with RPM varying for different diameter work.

Yesterday, for example, I was working on 4” 1018 and 1045 steels. This was before I found the above charts. My starting point was .040” radial DOC and my best finish was achieved with .014”/rev feed. My RPM was 620 for turning and 900 for facing. The surface finish was acceptable, but it was far from great.

I did break a tip on a Kennametal CCMT while chamfering (no power feed, of course) 3.9” OD at 620 RPM. I believe that I should have either decreased the RPM or fed in more slowly.

 

[benmychree]

In any case, maybe these Carbide Depot charts could be a starting point for fine tuning DOC and feed rate, with RPM varying for different diameter work.

Yesterday, for example, I was working on 4” 1018 and 1045 steels. This was before I found the above charts. My starting point was .040” radial DOC and my best finish was achieved with .014”/rev feed. My RPM was 620 for turning and 900 for facing. The surface finish was acceptable, but it was far from great.

I did break a tip on a Kennametal CCMT while chamfering (no power feed, of course) 3.9” OD at 620 RPM. I believe that I should have either decreased the RPM or fed in more slowly.

That seems too fast RPM to me.

 

[Ischgl99]

I couldn’t find anything on the Kennametal site either when I was researching insert grades, but MSC has some info that might be helpful.

https://www1.mscdirect.com/images/solutions/kennametal/kennametalChipCntrl.pdf

 

[macardoso]

I'm not sure about Kennametal directly. I'd probably call a distributor and ask for the datasheets (They will have them for sure). I know that Sandvik has easy to find data, and most brands are printed on the box. Even my import ones (Korea) have great data sheets.

It is a good place to start to decide whether an insert is appropriate for an application. For example, if the DOC/WOC is moderately large, then I know the insert will have a honed edge with low sharpness. This is great for machines that can rough and finish with deep cuts (i.e. CNC machines), but not good for me in the home shop who likes to sneak up on dimensions. Those same numbers will also tell you if it will successfully break a chip. Most insert chipbreakers will not work until you reach a minimum SFM and DOC/WOC.

Often these numbers are given at 80% of optimum conditions so feel free to deviate. If you have a huge machine with an incredibly rigid setup, you can often do better than the specs on the box. Alternatively for most of us, we will need to drop the SFM and feed below recommended due to machine limitations. If the insert wants a 5HP minimum cut and my machine only has 1.5HP, then I'm not going to meet spec.

It is satisfying to punch in the numbers on the box and have the insert start making perfect little curly Q's as the chipbreaker engages correctly.

 

[mksj]

You often need to look at the full catalog download, they heave general guidance as seen below.