Side Milling with a 3" Shell
Close
Login to Your Account
Results 1 to 10 of 10
  1. #1
    Join Date
    Apr 2021
    Country
    UNITED STATES
    State/Province
    Arkansas
    Posts
    3
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    1

    Default Side Milling with a 3" Shell

    New to the site, hope to find some help. Im new to side milling with a shell mill. I bought a Sumitomo 3" 5 flute shell mill with 90 degree inserts. My current cutting specs are,600sfm 763rpm 0.006fpt 25ipm .04stepover .3depthofcut on 3"thick A36 plate that has been burned out. Im getting a surface finish that looks good, but i can see each step every .3 down. It is cutting like the inserts are not a true 90 but they are. The rake on the inserts is somewhat aggressive. I originally thought it was my depth of cut, but I ruled that out by taking smaller cuts.

    Sumitomo Shell mill part #WEZ33000R05
    Sumitomo Inserts part #A0MT170508PEER-G

    I hope I have explained this well enough to not cause confusion. I've only been programming for a few years now.

    Thanks

    -Alex

  2. #2
    Join Date
    Jun 2012
    Location
    Michigan
    Posts
    5,857
    Post Thanks / Like
    Likes (Given)
    5534
    Likes (Received)
    3738

    Default

    That's just the nature of the beast.
    I'm curious as to why only a .04" stepover?

  3. Likes CORONA VIRUS liked this post
  4. #3
    Join Date
    Apr 2021
    Country
    UNITED STATES
    State/Province
    Arkansas
    Posts
    3
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    1

    Default

    Im not confident with it yet. Do you think I could go the full .12"? I also just tried running a light .005 finish pass to see if it would clean up. But it did not. I can still visibly see the ridges and feel them. Any help or suggestions would greatly be appreciated.

  5. #4
    Join Date
    Jun 2012
    Location
    Michigan
    Posts
    5,857
    Post Thanks / Like
    Likes (Given)
    5534
    Likes (Received)
    3738

    Default

    Has the A36 been annealed? Or does the burned edge have a hard crust?
    With that shell mill you should be able to bury it in A36 or even 4150PHT for that matter.
    IF your machine is capable of it.

    The ridges are typical of a 90 deg mill, it's almost impossible to not have blend lines.
    Slap an indicator on the outer edge of the inserts and rotate the cutter, what is the runout from insert to insert?

  6. Likes IronSupremacy88 liked this post
  7. #5
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Florida
    Posts
    6,204
    Post Thanks / Like
    Likes (Given)
    2461
    Likes (Received)
    3084

    Default

    Are you sure your inserts are true 90dg? I'm not up to speed on new tech for inserted tools, but they (at least what I remember) they have a slight back taper, like a drill. And if your pockets aren't perfect they will shift as they are cutting, ever slightly if the pocket isn't trash, but maybe enough to see/feel the steps between passes. easy check, indicator on table or vise and spin the tool by hand to check insert runout, then up and down in Z to see if there is any taper.

  8. #6
    Join Date
    Feb 2013
    Location
    Madison, WI
    Posts
    1,240
    Post Thanks / Like
    Likes (Given)
    1286
    Likes (Received)
    803

    Default

    As already stated. It's the nature of an indexable cutter to leave steps when side milling.

    With that cutter, you should easily be able to go .300" deep with a stepover of .12". For a frame of reference. In 4140 I can full slot .32" deep with my 2" Iscar HM390 shell mill. Now granted it's probably a different geometry than what you're using, but the fact remains. For a cutter of that size you should be able to take a much bigger cut ASSuming you have the horsepower to drive it and rigidity to hold it.

  9. #7
    Join Date
    Apr 2021
    Country
    UNITED STATES
    State/Province
    Arkansas
    Posts
    3
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    1

    Default

    UPDATE

    Mtndew suggested that I put an indicator on my inserts. I did. From the top of the 17mm insert to the bottom was .004 of protrusion. I contacted my dealer who i bought it from a few weeks ago, he will be sending me another one. Thanks for all the help!

  10. Likes Mtndew liked this post
  11. #8
    Join Date
    Feb 2020
    Country
    UNITED STATES
    State/Province
    Alabama
    Posts
    366
    Post Thanks / Like
    Likes (Given)
    151
    Likes (Received)
    103

    Default

    Your cutter diameter is much bigger than you need. You would have benefitted more with a 1-1/2 insert mill. But, even that will not remove your side steps. Leave .01" on the wall and finish with a 3/4" carbide 5 flute endmill.
    As for your feeds and doc, they are way too low. With a 1.5dia cutter I would start out at 40% rdoc, .25adoc and .005"ipt feed to start.

  12. #9
    Join Date
    Jan 2007
    Location
    Flushing/Flint, Michigan
    Posts
    10,317
    Post Thanks / Like
    Likes (Given)
    596
    Likes (Received)
    8398

    Default

    Quote Originally Posted by IronSupremacy88 View Post
    ... It is cutting like the inserts are not a true 90 but they are.
    -Alex
    They are not true 90. Looks like it but not and never will be.
    It is almost impossible to design a true 90 indexable cutter if any rake in the lenghtwise axis.
    The only off the shelf ones that can be true 90 are those terrible TPG things with no axial rake and they work not so good.
    Everything else a design tradeoff except for really special cutter bodies and custom inserts to fit.

    The big places can buy anything they want custom made for costs at or below catalog standard prices.
    Most of the real world has to live with the tradeoff in a family.
    Bob

  13. Likes Garwood, Bobw, TeachMePlease liked this post
  14. #10
    Join Date
    Oct 2009
    Location
    Oregon
    Posts
    5,945
    Post Thanks / Like
    Likes (Given)
    6435
    Likes (Received)
    3309

    Default

    I can't believe the vendor took it back.

    I wouldn't call it a finishing tool unless you're OK with steps.

  15. Likes Bobw liked this post

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •