Indexable Endmill.

[beav700]

I'm planning on making Indexable endmills on our four axis control Hurco. Does anyone know what is the best steel for endmills like that and how hard to heat treat. We cut alot of D2 and 4041 HT and keep blowing the indexable endmills all the time. Each Kenemetal or Sandvik Coromant is aroung $150 a pop. I can make ten cutters like that in three hours on our machine , but need to know what type of steel is the best.

I know this is not Mastercam question, but I don't know who alse to ask.

[gcode]

This is just an opinion with zero science behind it so Multax may have me shot ,

but I would use 4130 and have it case hardened after all the pockets were machined.

[Guest]

I have used Sandvick end mills for years. When I run into problems with the tool the source of the problem can usually be traced back to something I am doing wrong. Bad set, bad holder, bad speeds and feeds, bad programming approach. I have developed a close relationship with our local Sandvick technical representative. He has been more then happy to come to our plant and help us solve the problems we are having with his tooling. For the most part he has been able to resolve the problems we were having with our process/operation/tooling. So I recommend you contact you local factory representative and tell them what is going on. They should help you solve your problem. That way you don’t need to spend time making end mill bodies and can get on making the parts you are good at.

Good luck

[ 08-05-2001: Message edited by: mlindsey ]

[Guest CNC Apps Guy 1]

I'd also use 4130, but I would heat treat to about 40-43 Rc through. (It's hard enough to be rigid but soft enough to absorb some shock)Case hardening in this instance could promote premature cracking due to the differences in grain structure and the general shape of the pockets.

For indexable EM's I would personally (meaning no scientific basis for the opinion) suggest 3 flute. From my personal experience, they seem to cut a bit smoother and not "slap" as much, therefore not subjecting the inserts to as much "shock".

[ 08-05-2001: Message edited by: James Meyette ]

[gcode]

I think you can buy 4130 in Condition F4

which comes from the factory at Rockwell

38-42. Thats not quite as hard as you recommend, but pretty close.

OT: James, you'd best watch it with those opinions! You'll be standing next to me

when Multax puts us against the wall.

[Michael Reynolds]

I agree, a chrome moly mat'l is probably the best. Good shock resistance and can be heat treated to 40 to 50 Rc. I think you need to check with your insert dealer as to the clearance and rake angles of the inserts you buy, though. I'd guess that you'd want about 4 to 5 degrees clearance angle on your inserts. That's the key...even if I'm wrong about the angles, it sounds like the inserts are what's giving you the problem, not the holder. (If (and don't take this wrong) your speeds and feeds are right)..

Good luck!!

Mike R.

[ 08-05-2001: Message edited by: Michael Reynolds ]

[rteagan]

I used to make cutting tools, including indexable end mills, for Sandvik and we always used Flexor or P20 preheated to about 30-32 Rc. No heat treat after machining was necessary.

[Guest CNC Apps Guy 1]

Wow, that's alot softer than I would've guessed. Is that so that they can be easily modified if necessary?

[Tony]

Beav

I have Made indexable tooling.(In the last no work slump)

I used this metal called "Viscount 44"

From Arlo Specialty metals. No heat treat.

I learned about this metal from some old timers...

I engraved the Tazmanian devil with his tornado on the shanks!!

I have also engraved "Slump of 95',2000,and now 2001. Dam slumps in Chicagoland are getting closer together!

[sbrooks]

Viscount 44 is very hard to tap.Try using H13

tool steel then heat treat it to 44 rc.It is basicly the same thing visc. 44 and 2/3 the price.Or use 4340 still crome moly just alittle more alloy for strength.

[Scott Bond]

Hi

This project looks like a good use of time.

Would it be possible to e mail your holders so that we may do the same.

[lovell110]

beav,

Viscount 44 and I think its called Kapstar are new knock offs of an old material called elastuff 44 which was 44Rc but was quite machinable(the best stuff was the old stuff). We also make our own perisable tooling but we decided to use 4340 and have it hardended to the mid 40 Rc range. We found less distortion at heat treat with the 4340.

I presently make our own insert drills and endmills out of 4340 and have had great success. I would suggest using 60-65% thread engagement tap drill for your screw holes in case the hole shrinks at heat treat.

P.S. I personally think the endmill mfgs make them soft on purpose! Sneaky arent they!

[ 08-07-2001: Message edited by: lovell110 ]

[beav700]

Thank you guys for your input.At least I know now what steel to look for.

I havent thought about the design yet. 1" with two inserts or 1.25 with three. Can't fit three inserts on 1" bar. Decided to go with square 3/8 inserts. They seam to last longer and I get four cutting edges. On top of that , they have a bigger hole for a bigger screw and are thicker so they don't break as easily as the Coromant 390 inserts.

lovell110, Yeah, the hardness on Coromant 390 holder is RC 32. Thats way too soft. The chips alone distroy the cutter after two hours of milling. Same thing with Kenemetal.That's how they make money. It takes 10 minutes to make a cutter like that (not much work to it)and they sell it for $150.

[ 08-08-2001: Message edited by: beav700 ]

[Multax]

Dear Beav700

I find your project compelling and in the best spirit of American ingenuity, perhaps my suggestions and OPINIONS can help you complete a successful project. Beav700, many of the respondents to your thread have proffered what type of metal to use for you indexable end mill. If you have the time, try to locate an authoritative and recently published 2000 or later metal’s handbook and compile a table that lists ALL of the metallic properties of each metal type listed by the post respondents, in fact you might even find a better type of metal in an exhaustive source. With this list, you should have enough data to eliminate most of the suggested metals and thus you can narrow your choices to three or less. The material’s handbook should cover heat-treatment and help you decide if the material you have chosen can benefit from heat treatment in general and what TYPE of heat-treatment in particular will produce the qualities YOU want your end mill to have. Beav700, you may want to READ the numerous articles printed in the “Modern Applications News” magazine www.modernapplicationsnews.com. from the December 1998 issue on that covers heat treatment technology. The March 1999 issue on page 92 covers deep cryogenic treatment to -300̊F. This process might provide most or all of the strength and hardness properties you desire in your indexable end mill. Finally, when you have decided what type of metal you want to use, YOU MUST BUY THE FINEST FORGED BAR STOCK MONEY CAN BUY, preferably a piece of bar stock that has a BIRTH CERTIFICATE!

In terms of indexable end mill design, you may want to produce an exact copy of your present Kennametal or Sandvik tooling or find an existing indexable end mill design that you like. That will allow you to use THEIR cutting data as a baseline to start from and allow you to accelerate the development process as a consequence of your introduction of two NEW variables into the cutting data equation. Remember Beav700, even with an EXACT copy of your present Kennametal or Sandvik, or brand X tooling, you have introduced two significant changes, the type of metal and its hardness and grain structure. This can cause the cutting environment your inserts operate under to change from the insignificant to the profound. So, proceed with great CAUTION when you attempt your first cut with your new cutting toy. I have melted, shattered, and snapped the flutes off too many high quality end mills to joyride with an unproven toy tool. Beav700, use your common sense when you make your first cuts and parts with this tool, treat this new and UNPROVEN tool as though you had a hand grenade in your hand with the pin pulled!!! Beav700, you do not want to add your tool project to the recent CRASH thread!!! Make sure you speak to the technical support people at Kennametal and Sandvik and squeeze every once of information and data they have on your chosen inserts. You MUST know every chemical and mechanical aspect of these inserts that affects cutting performance and safety. If your machine has through the spindle coolant capabilities, make sure your indexable end mills have the proper passages to utilize pressurized coolant. However, ask the tech people if YOUR chosen inserts can withstand the thermal shock of coolant in a cutting environment. I hope my suggestions and OPINIONS can help lead you in the right direction, however, do not trust anyone and PLEASE DO YOUR OWN RESEARCH to confirm or destroy EVERYONE’S OPINIONS!!!

Multax

Dear Gcode

Thank you for an extremely good laugh!

“This is just an opinion with zero science behind it so Multax may have me shot”

Thank you again for an extremely good laugh!

“OT: James, you'd best watch it with those opinions! You'll be standing next to me

when Multax puts us against the wall.”

[ 08-09-2001: Message edited by: Multax ]