Problem E32 collet not enough for 5/8 end mill in steel?


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Thread: E32 collet not enough for 5/8 end mill in steel?

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    Default E32 collet not enough for 5/8 end mill in steel?

    Been trying to cut some steel using 5/8 end mill.
    Cut one without much drama then started on the second. Broke the end mill. Probably due to chatter as it was chattering pretty bad. Broke off in the collet.

    Just had a problem with the second end mill. It worked it's way out of the collet and dug into the steel then broke. Why would it work it's way out of the collet?
    I'm thinking maybe collets are not the way to go for something like this.

    Cutting A36 steel plate, 48x10x0.5, running 3000 rpm at 42 in/ min (500sfm, 0.0036 chip load) 0.2 DOC. No coolant, air blast. 5/8 end mill, TiAln coated.
    CAT40 ER32x4" collet holder by Talon, 5/8 collet by Talon. pull stud is Maritool.

    Chips running straw to light blue.

    Suggestions??

    James

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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    Hi....I may be wrong but I think a feed rate of 1,066 mm per minute (42"/min) is a bit high with a depth of cut at .200"

    What machine are you running?

    The fact that the cutter chatters is enough to vibrate it out of the collet.

    If the tool chattered that bad you should have stopped the job and analysed your cutter rates.

    That's 2 carbide end mills you've broken you must be in the high upper middle class income bracket or your dad owns the store.
    Ian.



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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    I was hoping for more advice, less insults.

    I own the shop and my father has been dead for a few years.
    Upper Middle Class? I retired from a $200K plus job if that qualifies.

    I am not a machine shop. I have a mill, HAAS VF4SS, and lathe, HAAS ST-10, to produce the things I sell.
    A friend wanted some work done for his company. He turned to me.
    I have tons of experience with aluminum and plastic but I have never milled steel and never anything that required a 5/8 end mill.

    The feeds and speeds I use are from various sources, including the end mill manufacturers website. All are pretty close. 500 SFM, 0.0036 chip load.
    Using trochoidal milling, the end mill was doing very well. I had adjusted the F&S till I felt it was in the sweet spot. Nice surface finish, nice chips and it just sounded good.
    When it got to the tighter spots, that's when it started chattering. I turned to adjust the F&S but it quickly got worse and by the time I hit the e-stop the end mill had worked it's way out of the collet and cut through the part and into the table.



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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    I know on smaller collets they told me they are toast once a tool breaks. I've found that true with small diameter collets (in plastic) but it might still hold true for steel on larger ones.

    Sent from my LG-D852 using Tapatalk

    In case anyone is wondering, I'm the twin of the other gfacer on cnczone...


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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    Quote Originally Posted by gfacer2 View Post
    I know on smaller collets they told me they are toast once a tool breaks. I've found that true with small diameter collets (in plastic) but it might still hold true for steel on larger ones.

    Sent from my LG-D852 using Tapatalk
    The first collet was toast for sure, the inner diameter was mangled by the collet breaking inside and spinning for the few seconds before I stopped the machine.
    I tossed the second as well, never be able to trust it again.

    what's funny is that I have an 1/8 end mill that I've been using to engrave the logo. About a 2.5 hour run. It's still going strong after at least 6 logos. Same brand as the 5/8.



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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    I use a Haas vf3/4 every day at work. They cut steel just fine but you have to be extra conservative because they will not do heavy cuts well. Always the same problem you mention they chatter on engagement and tight corners. Try backing off on your feeds and speeds. I would probably start at 250-300 sfm .002 chipload .1-.2depth.

    Ben



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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    Hi....no insults intended.....metaphors speak louder than words etc.

    One thing you can inspect and that is the backlash in the ball screws......climb milling is a beloved practice with CNC machine users but it does rely on having a tight ball screw otherwise you'll get the tool grabbing the table to take up the slack.

    Somewhere in your set-up you have a situation that allows chatter to happen.......either in the column flexing or slack ball screws or linear rails.....worse if you have slack dove tails to allow easy sliding with the steppers.

    Milling aluminium is not a problem but steel is a whole different ball game as your machine is letting you know.

    I assume you are running carbide?

    BTW.....end mill manufacturers try to out do one another in cutter performance and tend to boast figures reflecting their claims to secure the market they would like to own.......why are you running flat out for a one off job?
    Ian.



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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    collet holders aren't the right choice for that kind of cutting , The purpose of er holders is more for precision and not hogging . Get a side lock holder , the tool won't pull and it's likely to help with the chatter if not eliminate it completely , provided your using decent quality tools

    A poet knows no boundary yet he is bound to the boundaries of ones own mind !! ........


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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    Thanks everyone for the comments and tips.
    I ended up going with a shorter collet chuck holder, ramping the feed down to around 30in/min at 3000rpm and running coolant.
    Cut the entire second plate without problems. About to start on the third. End mill looks brand new.

    On the flexing of the column. I was setting up a vise with an indicator, I grabbed the spindle nose and pulled toward me, the needle moved about 0.001" !!!
    Is that normal? I was expecting something more rigid....



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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    A corn cob cutter would be helpful if you purchase another end mill for future needs.

    CAD, CAM, Scanning, Modelling, Machining...


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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    Quote Originally Posted by jdholbrook View Post
    I was hoping for more advice, less insults.

    I own the shop and my father has been dead for a few years.
    Upper Middle Class? I retired from a $200K plus job if that qualifies.

    I am not a machine shop. I have a mill, HAAS VF4SS, and lathe, HAAS ST-10, to produce the things I sell.
    A friend wanted some work done for his company. He turned to me.
    I have tons of experience with aluminum and plastic but I have never milled steel and never anything that required a 5/8 end mill.

    The feeds and speeds I use are from various sources, including the end mill manufacturers website. All are pretty close. 500 SFM, 0.0036 chip load.
    Using trochoidal milling, the end mill was doing very well. I had adjusted the F&S till I felt it was in the sweet spot. Nice surface finish, nice chips and it just sounded good.
    When it got to the tighter spots, that's when it started chattering. I turned to adjust the F&S but it quickly got worse and by the time I hit the e-stop the end mill had worked it's way out of the collet and cut through the part and into the table.
    Anyone with your experience, should know, that a collet is not used for any serious milling, it seems everyone jumps on the, buy ER32 collets, ( one size fits all ) which is not the case,and are a complete waste of money, I don't have any over ER20, and would never ever consider a ER32 for use on a CNC machine, solid Holders with a locking screw work ok, if you have the weldon flat on the Cutter, the best, if you have money are shrink or Hydraulic Holders, shrink being the best, if know how to look after and use them

    You also don't mill your work directly mounted onto the table, always your part, should be mounted on a fixture plate,or a scrap piece of plate which does not matter then if you have a problem, like you did, it saves the mill's table from any damage

    Mactec54


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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    Hi.......just to clarify the "serious'" aspect of collets and milling.......for the last 60 years or so I have used Autolock tool holders with collets.......and that is some very serious milling I can assure you.

    Yes I know they are only suitable if the cutter has a threaded shank........the cutters with plain shanks were designed...... and I may be wrong on that statement..... for Bridgeport R8 use, hence the plain shanks.

    I currently use ER32 chucks on my manual mill.....because they work, and used with discretion will never let you down.
    Ian.



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    Default Re: E32 collet not enough for 5/8 end mill in steel?

    You also don't mill your work directly mounted onto the table, always your part, should be mounted on a fixture plate,or a scrap piece of plate which does not matter then if you have a problem, like you did, it saves the mill's table from any damage
    Lesson learned!!

    I seldom go over 6 to 8 mm in cutter size and ER collets have served me well.
    I have a few setscrew holders but didn't have one in 5/8". Rather than sink more money into a job for a friend (Ok he paid me $1200 for all four) I took the chance and it didn't workout for me.
    In fact that job was jinxed from the very start.
    I've had it almost 6 weeks. In that time I've lost settings in the mill 3 times, came down with the worst flu of my life, gouged my mill bed, bent my Y axis way cover and leaked about 2 gallons of coolant on the floor, used (broke or wore out) 3 of the 5/8 end mills at about $80 each, ruined 2 ER32 collets, burned up one hand grinder, burned up one metal cutting blade on the saw and finally, heavily cussed at Fusion 360.

    I'll never take steel again, especially 48x10x0.5 A36 plate.

    Thanks



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E32 collet not enough for 5/8 end mill in steel?

E32 collet not enough for 5/8 end mill in steel?