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    Default Constant Surface Speed inexperience.

    So im not new to machining. But at my shop I have to program a large Inconel 718 part. And im destroying inserts like crazy. And i was told to use CSS which we rarely use. How do.I structure the program for CSS. I know the formula but where do I place the g50 and g96. Like for example.
    G00 G97 X10. Z10. T0101 S??? M03

    What speed would I put in this line.
    And then where do I place thr g50 and g96.

    Sorry its been probably 15 years since I used CSS

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    Quote Originally Posted by nissan300ztt View Post
    So im not new to machining. But at my shop I have to program a large Inconel 718 part. And im destroying inserts like crazy. And i was told to use CSS which we rarely use. How do.I structure the program for CSS. I know the formula but where do I place the g50 and g96. Like for example.
    G00 G97 X10. Z10. T0101 S??? M03

    What speed would I put in this line.
    And then where do I place thr g50 and g96.

    Sorry its been probably 15 years since I used CSS
    I usually put the G50 (spindle clamp speed) right after the first block with my cancel codes.
    Then G96 when you start the spindle
    Then position the tool

    N1 G0 G54 G40 G99
    G50 S2500
    G96 S300 M3
    G0 T0101 X10. Z10. M08
    ...
    ...
    ...

    It's not really fussy. The first 2 lines in my sample can be combined, so can the second 2 (you'd have to get rid of the M08 in the second line).

    I just like to separate them to make it easier to read through.

    Also you might need to go back to G97 at the end of the tool- when you drop the offset and G28U0 it might want to over-rev. Putting a G97 S300 (or something like that) will prevent that.

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    This is what I've been doing, seems to work well for my applications.

    (tool change stuffs)
    G50 S2000 (spindle speed limit)
    G96 (CSS on)
    S1400 M3 (1400 is your SFM)
    ...
    Cuttin yer part here
    ...
    G97 M3 (turn off CSS)
    G50 S3400 (3400 is my machine's max RPM)
    (retreat)

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    Ok 2 good examples. I dont work fridays so ill have to give it a try Monday.

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    Quote Originally Posted by nissan300ztt View Post
    Ok 2 good examples. I dont work fridays so ill have to give it a try Monday.
    You're still going to go through inserts tho, cuz that's what inconel does

    I only use css for facing cuts, myself. That uppy-downy shit annoys me.

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    I turn the Spindle on using G97, until the Tool is in position, then activate G96. But my G50 is in the program as soon as possible.

    R

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    Quote Originally Posted by EmanuelGoldstein View Post
    You're still going to go through inserts tho, cuz that's what inconel does

    I only use css for facing cuts, myself. That uppy-downy shit annoys me.
    I have cut plenty of Inconel, 600 series. And Hastalloy. Never an issue. But evem with flood coolant and 63rpm @ 8" diameter it just keeps destroying my inserts with only .070" depth of cut (.035" per side). Plus I dont have ceramic inserts.

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    Quote Originally Posted by EmanuelGoldstein View Post
    You're still going to go through inserts tho, cuz that's what inconel does .....
    It is tough on inserts. Look over your setup and ask yourself if there is anything you can do to improve rigidity of it. A very rigid setup will improve tool life in inconel. If the machine is kinda noodley there won't be much that can be done.

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    Quote Originally Posted by nissan300ztt View Post
    ..... and 63rpm @ 8" diameter it just keeps destroying my inserts with only .070" depth of cut (.035" per side). Plus I dont have ceramic inserts.
    That's ~130SFM I'd probably look at ~90SFM and see what happens. Is it burning the insert edge off or breaking?

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    Quote Originally Posted by Vancbiker View Post
    That's ~130SFM I'd probably look at ~90SFM and see what happens. Is it burning the insert edge off or breaking?
    Both. It wears the edge really bad and takes a good bit off the tip.
    Good coolant flow. I dont think the machine can physically spin any slower than 60rpm

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    Quote Originally Posted by nissan300ztt View Post
    Both. It wears the edge really bad and takes a good bit off the tip.
    Good coolant flow. I dont think the machine can physically spin any slower than 60rpm
    What Machine are you working with? It might just need a gear change.

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    I personally love inco. I get really good life out of carbide cnmg and trigons at 80 SFM with .05-.1 DOC. For big parts like that I love 1/2" round ceramics, run them about 800-900 surface feet.
    Whats nice about round ceramices you get many edges not to mention surface grind them down and put a carbide shim in the seat and you can use them all over again.
    One key for turning inco is always chamfer your start cut, if you cut on a sharp corner your insert will chip. either use an SNMG or a CNMG holder for facing(good way to get 4 more sides off your used CNMG's) to do it or start your cut with a chamfer

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    Quote Originally Posted by Delw View Post
    I personally love inco. I get really good life out of carbide cnmg and trigons at 80 SFM with .05-.1 DOC. For big parts like that I love 1/2" round ceramics, run them about 800-900 surface feet.
    Whats nice about round ceramices you get many edges not to mention surface grind them down and put a carbide shim in the seat and you can use them all over again.
    One key for turning inco is always chamfer your start cut, if you cut on a sharp corner your insert will chip. either use an SNMG or a CNMG holder for facing(good way to get 4 more sides off your used CNMG's) to do it or start your cut with a chamfer
    Uhm? You jump from 80 to 800 SFM based on the shape of the Insert?

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    Quote Originally Posted by litlerob1 View Post
    What Machine are you working with? It might just need a gear change.
    30 year old Fortune vturn 23.

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    Quote Originally Posted by litlerob1 View Post
    Uhm? You jump from 80 to 800 SFM based on the shape of the Insert?

    Rob, you not had your coffee yet? He said 80SFM for carbide and 800SFM for ceramic inserts.

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    Quote Originally Posted by litlerob1 View Post
    I turn the Spindle on using G97, until the Tool is in position, then activate G96. But my G50 is in the program as soon as possible.

    R
    This. If you turn on CSS right from the begining, the spindle winds up and down with your approach and retract moves, and when you change tools and pick up a new offset. I turn it on right before I start the cut, and off before I retract.

    Quote Originally Posted by nissan300ztt View Post
    I have cut plenty of Inconel, 600 series. And Hastalloy. Never an issue. But evem with flood coolant and 63rpm @ 8" diameter it just keeps destroying my inserts with only .070" depth of cut (.035" per side). Plus I dont have ceramic inserts.
    718 is a whole different animal from 600/601. Inconel 600 cuts pretty similar to stainless. 718 just sucks, especially if you have to drill it. CSS will help a little if you are making a lot of passes, which changes your diameter and therefore the RPM it should be running at.

    Finding the right insert will probably help more. You need something with a fairly sharp edge prep, even for roughing. If you try to push something blunt through it, you'll work harden it quickly. The inserts will never last you that long though. Change them before they go bad, once you make a cut with a dull tool, it will wipe out the next insert edge right after you change it.

    Round whisker ceramics is another way to do it for some applications. It will get it done quicker, but the inserts are expensive, so it depends on how many you have to make. You can't go to a shoulder very well with them, and any time I've used them, it put so much heat into the part that I had to cool it down before taking a finish pass. Otherwise it will shrink undersize after it cools.

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    Quote Originally Posted by Matt G. View Post
    This. If you turn on CSS right from the begining, the spindle winds up and down with your approach and retract moves, and when you change tools and pick up a new offset. I turn it on right before I start the cut, and off before I retract.



    718 is a whole different animal from 600/601. Inconel 600 cuts pretty similar to stainless. 718 just sucks, especially if you have to drill it. CSS will help a little if you are making a lot of passes, which changes your diameter and therefore the RPM it should be running at.

    Finding the right insert will probably help more. You need something with a fairly sharp edge prep, even for roughing. If you try to push something blunt through it, you'll work harden it quickly. The inserts will never last you that long though. Change them before they go bad, once you make a cut with a dull tool, it will wipe out the next insert edge right after you change it.

    Round whisker ceramics is another way to do it for some applications. It will get it done quicker, but the inserts are expensive, so it depends on how many you have to make. You can't go to a shoulder very well with them, and any time I've used them, it put so much heat into the part that I had to cool it down before taking a finish pass. Otherwise it will shrink undersize after it cools.
    Well im forced into using what my shop has. Ill.have to look around fot something. Im running pretty standard inserts. Ill see if my box will get me some new inserts. Which I doubt.

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    Quote Originally Posted by Matt G. View Post
    This. If you turn on CSS right from the begining, the spindle winds up and down with your approach and retract moves, and when you change tools and pick up a new offset. I turn it on right before I start the cut, and off before I retract.



    718 is a whole different animal from 600/601. Inconel 600 cuts pretty similar to stainless. 718 just sucks, especially if you have to drill it. CSS will help a little if you are making a lot of passes, which changes your diameter and therefore the RPM it should be running at.

    Finding the right insert will probably help more. You need something with a fairly sharp edge prep, even for roughing. If you try to push something blunt through it, you'll work harden it quickly. The inserts will never last you that long though. Change them before they go bad, once you make a cut with a dull tool, it will wipe out the next insert edge right after you change it.

    Round whisker ceramics is another way to do it for some applications. It will get it done quicker, but the inserts are expensive, so it depends on how many you have to make. You can't go to a shoulder very well with them, and any time I've used them, it put so much heat into the part that I had to cool it down before taking a finish pass. Otherwise it will shrink undersize after it cools.
    Well im forced into using what my shop has. Ill.have to look around fot something. Im running pretty standard inserts. Ill see if my box will get me some new inserts. Which I doubt.

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    Quote Originally Posted by nissan300ztt View Post
    Well im forced into using what my shop has. Ill.have to look around fot something. Im running pretty standard inserts. Ill see if my box will get me some new inserts. Which I doubt.
    Try to find inserts with a PVD coating. CVD inserts do not hold up to 718.

    No matter what, you are going to go through a shitload of inserts. Ceramics are the way to go when hogging off 718, but you have to know how to use them to their advantage.

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    Quote Originally Posted by Philabuster View Post
    Try to find inserts with a PVD coating. CVD inserts do not hold up to 718.

    No matter what, you are going to go through a shitload of inserts. Ceramics are the way to go when hogging off 718, but you have to know how to use them to their advantage.
    Yeah. Im going from 8.05" to 4.01" and then operation 2 is gonna a bore from 2" to 4.20" my boss is gonna hate me. Guess were spending money


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