New to CNC Lathe

[pilsnerglass]

Hello I work in a machine shop as a welder. I have been around machining most of my life as my father was a tool/die maker. I have been asked to come up to the CNC dept to learn to run a Fryer CNC lathe. Still trying to get my speeds and feeds down as i think thats the first battle. Still trying to figure out whether i run in IPR inches per revolution or IPM inches per minute.

Am geting ready to start roughing 7'' dia. pieces of 4340 HT and am trying to figure my speeds out. I forget the name of the insert i am using but its a Iscar roughing insert. I have some pics if anyone would like to see them. I dont know if this is the right spot for this post but maybe you guys could help a young guy out. Thanks

[AMCjeepCJ]

You program your feedrate in IPR (inches per revolution) and your rpm's with SFM (surface feet per minute) if you want constant surface speed or the other option is to just program a set rpm... I think the codes are G96 and G97 but I have a Yasnac controller so it might be different on yours, double check...

In other words if you were facing your stock and you programmed the SFM at 375 (375 surface feet per minute) and your IPM's (inches per revolution) at .010" lets say, your rpm's would begin low when you start the cut and would rapidly increase as your cutter approached the center of your work piece...

Your IPM's would stay constant however during the entire cut, moving in taking exactly .010" of infeed per revolution but it would appear to be cutting faster because as the rpm's increase your Z axis moves faster to keep up with the programmed IPR...

To make it more confusing, your lathe would theoretically try to hit infinite rpm's to cut the center and since this is impossible you also have a code that limits the rpm's to a preprogrammed speed... If you don't put this in the program, you'll max out the spindle on your machine which shouldn't hurt anything except it isn't safe because you could have your part fly out of the chuck and kill ya!! (Not as serious as it sounds, lol, except 7" diameter is incredibly dangerous if you didn't program an rpm limit in your code!!)

If I didn't explain it well, just say so and I'll make it clearer tomorrow...

Hope this helped a little bit at least~

The best piece of advise I could give ya is this... My experience is that if you don't have at least 2,500 hours on the machine, (18 months) don't be stupid and run anything with the door open even during setup... You really need to experience something crashing to fully respect the power of a cnc lathe... Mills break tools, lathes break buildings, floors, walls, people and themselves!! Not to mention a part flying out at 4,000 rpm's doesn't just hit the ground and stop, it bounces off everything and everyone until it decides it's tired of dancing around the room, parking lot or whatever~

[pilsnerglass]

Yeh i understand but i dont understand. I have included what i worked on last week. There were 7" 4340 HT. If i look in the machinerys handbook i look up 4340, how do i know what hardness to use as there are a bunch of ranges for diff. hardness's. Also i dont know about where it says under carbide tough or hard? I am using iscar inserts the black/grey collored ones . OK Ill use brinell hard of 225-275 Hard carbide. Book says f=feed.001 s= speed (ft/mn)
The feed is 17 and speed is 630. So 630x4=2520 divide that by the diameter which is 7" =360 rpm at .017'' ipr? I think i got the figuring rpms but idk about the ipr still.

[AMCjeepCJ]

Nice looking machine! Anything you need help with?

[AMCjeepCJ]

That is so weird... I just got an email showing post 3 a few seconds ago and it wasn't there when I wrote post 4 several hours ago!! Gremlins!!

I'll try to answer your question if I understand it...

I don't know who's formula your using but I'll try explain... If you were ONLY skim cutting at a constant 7.000" diameter you would calculate the rpm's by the following:

630 SFM (surface feet per minute)
X 12 (inches per foot)
______
7,560 (inches per minute)
/ 21.98 (divided by circumference which is pie multiplied by your diameter or 3.14*7)
______
343.95 (rpm's so round to nearest whole number)

the great things about CNC lathes is that they automatically compute this and the only time you usually need to calculate it is if you're drilling or knurling something...

Look up G96 and G97 codes in your machine manual... I think it's G96 for setting SFM but I might have them backwards...

If you are running costant rpm's you're going to take waaaaay too long cutting your part and the surface finish will suffer dramatically...

As for IPM's I think you're making it harder than it needs to be... This is simply the D.O.C. (depth of cut) on a lathe~

I hope that helped a little...

[pilsnerglass]

OK i think i am geting it. So i should be running most of my stuff on css?

[AMCjeepCJ]

Overly simple answers:

Profiling, boring, grooving, facing......Yes...

Drilling, knurling.........No

[pilsnerglass]

Im geting all this info out of the Machinerys Handbook, that big ol honkin book like 2600 pages. The newest edition

[pilsnerglass]

I have been trying to run everything from the controls at the machine. Only option i have for css is rpms and max rpms. I dont know how to go by that. We use mastercam x2. Can i just go in and set is to cut at a CSS after i input my sizes. As i say i was just kinda gave a book and said here ya go heres ya a machine.

[AMCjeepCJ]

Max rpm's are VERY important!! Always set that to something safe like 2000 or less until you get a feel for it... You'll obviously have to set it higher to make money on the machine later but put it on the safe side at first... I made my dad $270,000 in 18 months when I started out on my Mori Seiki and not once did I put it above 2000 rpms in doing so...

Do yourself a favor and send a PM to Paul, the owner of this site at:

http://www.cnczone.com/forums/member...stposter&f=189

Ask him to setup an area specifically for Fryer machinery... I know a few people who own them and it would be a good addition to this site... I started the milltronics forum on here by just asking him nicely and giving him a little background information on the company...

You'd get more specific answers that way because I'm not familiar with your exact control... I can only give you general help on setups, jargon, feeds/speeds, etc. but nothing specific to Fryers... How old is the machine again?? Will your work spring for the cost of a two day training course for you??

[pilsnerglass]

ok so in mastercam i can setup each tool i guess in the setup i have these options

feed rate
plunge rate
%of material feed/rev
spindle
% of material CS

Then it say in other bow compute from material. How goes it know the diamter of my workpiece?


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[AMCjeepCJ]

Hey buddy, try this forum for those questions:

http://www.cnczone.com/forums/mastercam/