Eating up TiN cated HSS endmills need helP!

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stevos758

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Ok I am trying to machine a large plate that comes with a quick change tool post for my lathe.

I am pretty new when it comes to milling. This will actually be the first job I am doing where I need it to turn out nice.

I have a grizzly g 0704 and the little machine shop TiN coated HSS endmills. I've dulled/chipped 5 endmills in the last two days trying to figure this out!

I have no idea what kind of steel I am cutting or why I am burning these up so fast?

Let me know if you need any more info. Ill get some pics of the end mills.
 
Just a guess is that your spindle speed is way too high. You might also test the workpiece with a file to get an idea of how hard it is. Also do you have a solid setup, and conventional cutting rather than climb cutting? Conventional cutting is moving the cutting edge into the work against the direction of rotation. Your mill will not climb cut except for very light cutting. Climb cutting tries to pull the work into the tool bit and if your machine is not pretty heavy, and you have ball lead screws it just won't work.
 
It seems to file ok. I was running 900 rpm with the 5/8 4 flute then 2000 with the 2 flute. And everything in between but it may have been to late.

The part is small enough to fit in the vice, I have the gibs pretty tight. Lots of choice words were just used! LOL LOLOLOLOOL



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The T-nut blank should be mild steal. post up some pic's of your setup. and what you are doing , We need spindle speed depth of cut.How are you feeding it and so forth.
 
Spindle speed... I have tried everything from 500 - 2000 with 2 and 4 flute.

I was taking halfish diameter cuts at .01 - .02" at a time tried .04 and .01" too.

I have a 4 inch vice and the part is on parallels in the vice. Very secure and minimum part stick out.
 
OK, 900 is way too fast. More like 700 would be in the ballpark at 120 FPM for mild steel. I would start at about half of that, so maybe around 350 RPM. In most cases it is better to start slow and work up.

Spindle RPM = (FPM * 3.82) / Tool DIA
 
Ill try that and report back. Not going back out there tonight... to frustrated.
 
Witch direction are you cutting. againest rotation (conventional) good, With rotation ( clime milling) bad.
 
I tried both climb and conventional. Conventional seemed much better.
 
i have not used the TIN coated tooling from LMS,
but, if it's anything like the TIN coated stuff from HF, i'd throw it in the garbage and try a USA made endmill or a European made endmill (Germany,Poland,Austria,Switzerland,Sweden,Italy etc all make finer tooling)

i really don't like to use very inexpensive tools and tooling.
for me it does 2 counterproductive things
1, wasting time changing out inferior broken tooling
2, aggravation, after taking the time to do a proper set up fouling a piece of work that is nearly completed because i wanted to save a couple bucks on some cheap tooling.
after i set up, i want to complete the operations until it is necessary to change tooling for other operations.

good tooling can be broken too, i can attest to that.

i do believe that better materials + better tooling = superior work
 
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