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  1. #41
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    Quote Originally Posted by litlerob1 View Post
    I was going to say something, but I figured someone else would. If you are cutting the periphery of the part, NO coolant. If you are doing a pocket, you need to get the chips out. Basically, the idea is that the hot chips are coming off the part, and the coating can deal with the heat generated in the Tool.

    But the last thing you want is to re-cut hot chips from 4140.

    R
    The coating gets harder than the carbide, and slippery as snot when it gets HOT.. 1400 or 1700
    degrees or something like that.. You easily generate those temps cutting all the time, just
    behind the cutting edge on the inside of the flute...

    And carbide can take HEAT... It can take a LOT of HEAT, what it CAN'T take very well is rapid
    heating and cooling, over and over and over again a couple thousand times a minute.

    My break point where the coolant HAS to be off is around 300sfm.. So if I'm digging around
    in pocket or slot, and I don't have an air blast hooked up on the machine, or the air isn't
    doing it, I'll slow it down before I turn the coolant on.

    As far as an air blast.. That's just to get the chips out of the way.. Like he said, the last
    thing in the world you want to do is re-cut chips. And its not that hard to hook up an air blast,
    even a mickey mouse arrangement is better than nothing.

  2. #42
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    If at all possible see if you can start thinking of getting an idea on how to hook up air blast to it.

    I had a repeat job a few years ago,probably 15 or so years ago, that had full 14mm wide slot. 45mm depth. Coming from doing it on a manual, I used to pitch holes out the length of the slot and drill about 11mm holes right through. Then put a 12mm HSS rougher in and rough from both sides. And then a 14mm long endmill to finish the slot. IT WAS TEDIOUS!

    Got my first VMC,with ZERO experience on cnc mills, and did it the same way but obviously quicker because of doing the operations in one go because now I had a toolchanger. Iscar rep walked in and gave me a 14mm finishred to try,the finish on the inside of the slots were not critical, and gave me numbers that blew my mind! He walked away without telling me about coolant so I wrote the program with flood coolant,drilling a hole on one end,plunging in,milling to the other end,retract,rapid back with air blast turned on to clear chips out of slot, and back in air off and flood back on. It worked well till the rep walked back in and told me to leave the coolant and just run air blast throughout the cut... Tool life improved MASSIVELY!! As in round about 50% more parts/cutter. From that time on when running heavy with solid carbide I try to use air blast wherever possible,obviously material dependent. And it gave me more confidence to run it harder because I could actually see the chips flying out of the slot,not worried about re-cutting.

    By the way if I can remember the numbers correctly I went from taking +- 40 min to only do the slot to just over 10min part completed with a few extra drilled/tapped holes. Carbide is the way to go! So happy that I wasn't the only one to witness it first hand on the same job.

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  4. #43
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    Thanks again guys! I am going to figure out how to get an air blast going in the machine as soon as I can. I should be able to increase my radius size so that chips don't get stuck in there. I'll see how it runs tonight with some manually applied air pressure

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    Maybe look at MQL ?
    Look at shop built micro-drop misters.

    Anyone making money should use something to cool, from air to mql to flood, imo.
    Endless reports of 2x or better tool life or cutting speeds.

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    Quote Originally Posted by hanermo View Post
    Maybe look at MQL ?
    Look at shop built micro-drop misters.

    Anyone making money should use something to cool, from air to mql to flood, imo.
    Endless reports of 2x or better tool life or cutting speeds.
    I've done that in the past. It does generate a lot of smoke when machining steel with very hot chips, all the lube ends up in the air and you'd need a big ventilation system at the machine to get the smoke out.

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    We have flood, I am worried about about thermal shock though. I could try running the air through our coolant hoses for now.

    Or stand there holding the airhose manually! Haha

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    Quote Originally Posted by SamS View Post
    99% of the stuff we do is expensive 1 - 10 qty jobs. Most of the industry that I am in, at least the shops I've worked at and visited, are still running on mostly 2.5 axis Bridgeports. So when they go over to full cnc the toolpaths, feeds and speeds don't seem to change much (machinists are faaaairly hardheaded). I was trained by someone just like that, so I am admittedly a bit ignorant on applying modern toolpaths and really getting the mrr up
    Curious, what industry is that, that most people are still using 2.5 axis Bridgeports?

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    I'll let you know once I quit my day job ;-)

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    Quote Originally Posted by SamS View Post

    Or stand there holding the airhose manually! Haha
    Right, like I haven't done that for hours. Eventually you will be using tape, to hold the trigger, then to rig it up to the enclosure....then you will think, I have spent so much time and energy jury rigging this thing, I guess I'll just do it right.

    R

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    Already contacted our handyman. Just gotta get through this job

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    I bought a bridgeport VMC and the machine and the coolant tank were so nasty I have never put in coolant. I run compressed air when I really need to clear chips, but usually just give it a blast every once in awhile. I did rig a rube goldberg contraption for blowing air on a particular part non stop. Also helped to cool the part.

    If you have fusion, spend a fair amount of time experimenting. My machine has such a small memory I cannot really utilize most of the "adaptive clearing" processes. Something else to keep in mind, many guys are proponents of these types of feeds, but if your machine does not have the rapids, it spends a ridiculously stupid amount of time on all the silly movements the magic algorithm spits out. I had a job recently that the mill had 36 some movements to cut a small feature. I kept changing parameters and even with changing parameters was only able to get it down to 20 something movements. Wound up changing it to a 2D contour with 3 roughing passes and a finish pass. Not only was it SIGNIFICANTLY faster, it was also much shorter on code.

    Don't get me wrong, adaptive clearing and other strategies can be awesome, but don't forget basic machining competencies you learned on a manual mill. I ran a 3/8" rougher on a series of jobs, probably 300 pieces, mixed 4140 PH, A2, some 8620, and a few pieces of 1018. I swapped it out after all those pieces and the cutting edges were still sharp. I put it in my box for the manual mills.

    I know where you are coming from because I serve two different industries. One many are still using 2.5 axis bridgeports and manual machines and the other many are still just using manual machines. Amazing in 2018... but many subscribe to the old adage of low over head and if it supplies a quality part... why change it?

    Also, another point about feeds and speeds. Keep in mind most manufacturers are RECOMMENDATIONS. I rarely follow anything close, except Guhring for drills, they are typically pretty spot on. Sometimes that means being conservative, sometimes that means drastic increase.

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    Quote Originally Posted by SamS View Post
    .... HSM is indeed a catch all phrase now. I've always thought of it as meaning high spindle speeds and accurate enough machine to hit points accurately at speed.
    ....
    I have never thought of High Speed Machining as meaning high spindle speeds or encountered customers who did.
    If you have a 12 inch cutter 2000 rpm puts you up there into the world of very fancy cutting tools where angles fear to tread.
    Counterside, if running .008 micro endmills 30,000 is so very slow and barely enough to use carbide.
    .... So, in my opinion, not about max spindle speed and never was.
    Bob

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  17. #53
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    Quote Originally Posted by CarbideBob View Post
    I have never thought of High Speed Machining as meaning high spindle speeds or encountered customers who did.
    If you have a 12 inch cutter 2000 rpm puts you up there into the world of very fancy cutting tools where angles fear to tread.
    Counterside, if running .008 micro endmills 30,000 is so very slow and barely enough to use carbide.
    .... So, in my opinion, not about max spindle speed and never was.
    Bob
    I've come to think of HSM as the 'end of monster cuts', but with the advantage of running high feed rates with equivalent material removal rates that won't destroy the setup or the tool or the machine.

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  19. #54
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    Quote Originally Posted by Bobw View Post
    ...And did you buy just one?? You NEVER buy ONE.. If you buy one, it gets
    lonely and commits suicide.. If you buy 3, the first one wants to go
    party with the other 2 in the box, so it lasts forever.
    That's gotta be the most logical reason for buying multiple tools that I've ever seen...

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  21. #55
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    Quote Originally Posted by SamS View Post
    Part starts as a rectangle and when its done it is an L with the large leg of the L against the back jaw.
    I visited a shop where they had to make a big batch of "L" shaped parts from aluminum blocks. The inside of the "L" was about 4" x 6" x 1-1/2". Shop owner found it to be MUCH faster and cheaper to make two band-saw cuts removing 95% of the waste before putting the parts in the CNC mill for the rest of the work. And as a bonus, he sold the pallet load of "waste" blocks for a heck of a lot more than he would have gotten for the same metal in the form of chips.

    No idea if that trick would work here, just thought I'd mention it.

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  23. #56
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    Quote Originally Posted by CarbideBob View Post
    I have never thought of High Speed Machining as meaning high spindle speeds or encountered customers who did.
    If you have a 12 inch cutter 2000 rpm puts you up there into the world of very fancy cutting tools where angles fear to tread.
    Counterside, if running .008 micro endmills 30,000 is so very slow and barely enough to use carbide.
    .... So, in my opinion, not about max spindle speed and never was.
    Bob
    Definitions are definitions. It really doesn't matter because we cleared up the miscommunication but HSM does have a certain definition, whether you and the people around you use the term for something else is up to you. Modern toolpaths can be done on most machines, but to call it highspeed machining is misleading and incorrect. The basis of the theory of highspeed machining is smaller, full axial depth (when possible) cuts at high speed. The moderntool paths make this type of machining possible due to consistent radial engagement. But they certainly aren't the same thing!


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