Sandvik R390 PVD inserts, air or coolant?

[aaron p]

Ive been in a heated discussion with the boneheads at my work about what is the proper way to machine with Sandvik R390 Gold PVD inserts. Material is 4140 20-22 RkC. Machine is Intergex E-410. We use 1", .625", 1-1/4" cutters for ruffing. Im taking .200" deep cuts at 650sfm, .0135IPR on the 1-1/4" (3 inserts) using through-spindle air directly on the inserts and the chips are comming out very nice and shiny like they should be and the inserts are lasting a long time. The other boneheads are trying to tell me to use flood coolant and through-air! Makes no sense to me. To me that seens like it would shock the inserts and the chips and possibly mirco weld stuff onto the inserts from the rapid temp change. What are you guys using on fairly soft steel? Getting fed up with supervisors that dont know wtf their are talking about and getting pissy when I edit a program. The sandvik rep told me to use through air on soft steel with high feed rate. Tonight I was taking full width .200" deep cuts with the 1-1/4" cutter and I could touch the cutter after it finished the .800" deep slot.

[dertsap]

its not so much the coating that is important as is the grade of insert , for eg under high performace conditions 4020 inserts i like to run dry ,as i find them to be somewhat brittle and fussy , 4030 i can go either way (same coating), it also depends on whether you are recutting chips or if they are properly being evacuated ,

cermet are normaly supposed to run dry but i have had many times that the tool life increased while using coolant , for the most part it depends upon the application

air on the other hand is generally the best solution , not only does it keep your tool to a more consistant temperature , it also keeps the tool free of chips

[aaron p]

These are 2030 grade.

[Geof]

Air and flood coolant??? That does seem a bit bone heady. Are you doing enough parts that you could set up an experiment? How many parts per insert your way, how many theirs?

[dertsap]

Originally Posted by aaron p These are 2030 grade.

sorry i was thinking of the 2030 and 2040
its been a while since i used them , 4030 was for the cast we ran

i'd say try it with coolant and see what the difference is if any , those are good inserts and are fairly resistant to shock , but if they are working good for you dry then leave it

[aaron p]

Usually, we run a smaller part using the 1" 2 insert cutter and I can get 25-30 parts with just 1 set of inserts. They change inserts atleast 3 times im sure for the same amount of parts. The main problem is that we have Tooling vending machines, so they look at it as its just candy or some ****. They get 6-9 inserts at a time, and I just get a pack of 3 for my shift. I usually come in and see that the insert seat pocket on the cutter is all tore to hell b/c they busted a insert using coolant and didnt pay any attention. Nobody wants to listen to me b/c im the newest guy and they say "well, weve been doing it this way for years". Just a bunch of damn button pushers!

[aaron p]

These guys put a M51 on a tool that has a solid shank! lol

[dertsap]

this may help you tweak things to get more life out of your tools , the numbers are almost scary at times but the calculator is bullet proof , it changed our whole way of machining at another company i worked at

http://coroguide.coromant.sandvik.co...DMMillMenu.asp

[aaron p]

Originally Posted by dertsap this may help you tweak things to get more life out of your tools , the numbers are almost scary at times but the calculator is bullet proof , it changed our whole way of machining at another company i worked at http://coroguide.coromant.sandvik.co...DMMillMenu.asp

I was a little nervous today running the 1" cutter at 38IPM and 2600rpm. But it worked great. Seems these inserts like to be pushed hard.

[aaron p]

Originally Posted by dertsap this may help you tweak things to get more life out of your tools , the numbers are almost scary at times but the calculator is bullet proof , it changed our whole way of machining at another company i worked at http://coroguide.coromant.sandvik.co...DMMillMenu.asp

What do I put for the working engagement and working engagement start values? Also lead angle?
Heres a drawing of the R3901704M insert
http://coroguide.coromant.sandvik.co...mpage=infotype

[dertsap]

theres an error on your link
if i remember correctly if the tool is 90 deg then use 0
work engagement is how much your tool is engaged into the part

i must appologize , ive completely talked myself in a circle , skratch what i said about the grades previously , we used the 4020 and 4030 on the steel and 3040 on casts , too many numbers to remember after so long

[dertsap]

the numbers you will get using the calculator will be solid and as optimal as you can get , speed wise and life wise