Good book to learn feeds & speeds 6

[knobhead]

Can anyone recomend a good book that can really teach me about all I need to know about feeds and speeds for all sorts of machining,(milling,turning,boring, multiaxis, everything!) including the more exotic materials? (Titanium, Ni alloys, etc)

At the moment, for me, it's a process of relying on the advice of more experienced guys, (who more often than not contradict each other) and trial and error to get the results I need, or wading through Machinerys Handbook each time. I get the answers, but I don't know WHY.
There seems to be so much bullsh!t talked about this area, that I'm no longer sure what I need to know, and what is just irrelevant, and I never seem to get anywhere! I just want a book that tells me what I need to know.
(or failing that, a good website source!)

Any advice?

 

[Drazen]

I would like to know what problem do you have with "Machinery Handbook". That data should be OK. Maybe it is not practical to go through because of format? If you need basic information about virtually everything, not crowded with every imaginable detail, only tips for start, I warmly recommend John Walker's "Machining Fundamentals". By the way, your lathe manual should provide you with authoritative data.

 

[knobhead]

Machinery's is my bible, but the materials I work with are very rarely in it's list of speeds and things, so i have to use the nearest looking one. And really, i'd just like a better understanding of what's going on when i cut stuff. It seems for most people it's an art, not a science, and I want the science part.
My lathe's manual, (a mori seiki) is pretty crap. I think it was translated directly from Japanese, and is amusing at least!

 

[knobhead]

Hmm, that book is a bit basic for what I'm thinking. I'm not explaning what I need very well I think.

I'm a Prod Eng, machining is not a problem, different techniques are not a problem, and I can program and set most types of machine tool, draw up planning, 3,4 and 5 axis milling, live tooling, the whole bit. No worries on manufacturing techniques at all, EXCEPT I've always had a bit of a blind spot when it comes to selecting feeds and speeds. I can get the results, but it always involves a bit of messing around during tool proving. I've never once just stuck a program in a machine, and not had to touch the feeds or speeds that I've programmed. It's a limitation, and it annoys me, and I'd like to teach myself the how and the why.

So, I can cut metal, no problem. I can get good results no worries, but I'd like to know whats going on at the insert. WHY does chaning the feed/speed get me better results?
I'd like a straigth forward explanation, without getting all bogged down in equations explaning the insert geometry and so on.

 

[Drazen]

Now I see. It's more advanced then I use it. Maybe material vendors can help with recommendations for "more exotic" materials. But, yes, they normally offer the range and again you have to make trials. I think I can understand your frustration about discrepancy among CNC programming accuracy and "try and adjust" data that you have for feeds and speeds. It looks like global problem for this kind of literature.

 

[gbent]

Hi knobhead: Part of the problem you are having relates to the fact speeds and feeds are about 50% art and 50% science. There are many more factors at work than just insert selection, material, SFM, and feed rate. There are tooling, machine, and workpiece rigiditys. There are coolant concentration, flow, and aiming issues. There are harmonics in everything. The same number insert from different manufactures may behave vastly different. There are differences in materials from different lots or casting pours. Ambient conditions can cause differences.

My solution was to use the center of the recommended range for new situations. As I became more experienced, I would favor one side or the other. I kept a log of what inserts or tools would work in what situation, so I had a good baseline. With some experience, I could make a good part with initial setings about 90% of the time. Then the job could either be run out with the initial settings (short run jobs), or the settings would be tuned for optium production (not always fastest cycle time) on production jobs. Then, when new jobs are slow, revisit old production jobs to see if they can be improved. The closer the job is tuned to the edge, the more succeptable it is to problems.

Always remember, if it was pure science, anyone could do it!

 

[weir]

Hi knobhead just wanted to throw my experience into the ring and agree that speeds & feeds are one of the black arts.I think that if you get the prog right first time its TOO SLOW it is the unwritten law you gotta TWEAK .I defy anyone to pass a machine cutting away and not have some little noise or hum they want to tweak out of it .What you are really up against is the engineers natural instinct to tweak.My advice is to add a little into the setup time and get tweaking.

 

[knobhead]

Thanks for the advice, I guess I'm just gonna have to keep muddling through. I simply can't afford to tweak too much, as a lot of the castings I start with are >8-9K GPB before I even start! Which is why it would be nice to get things off first go..

Keeping a 'diary' of what I've used and where is a good idea, I think I need to start one.

 

[knobhead]

blimey, was thatwritten for me or what?

And I've been looking at Makinos too...absoleutly mind bending machines. Excessive accuaracy is a sign of poor breeding. -Socrates.

 

[gogsie]

knobhead,
I may be able to help you.
Speeds and Feeds for us like yourself was a bit of a bug bear. So myself and a team of other engineers collectively allocated time to create a speeds and feeds catalogue for use on our cnc turning machine shop.
It covers many exotic materials such as Inconel and Titanium as well as standard stainless such as S80 and MSRR6522.

Regards,
Gogsie.

 

[prototypeman]

Try Kannametal
I have used their speeds and feeds charts for years. I no longer do the machining, now I make plastic prototypes, so it has been a while since I have used their handy slide rule charts. They worked great for me. Remember that NO MATTER where you get the information, it is always meant as a starting point. There ARE NO hard and fast exact speeds and feeds for ANY metal. The reason is because there are always going to be variables, no matter how perfect you think everything is.
Good luck!

 

[Jimbo51]

Unfortunately there is no one source for this information as is is reall a combination of material, machine regidity, insert or tool geometry, coolant, depth of cut, diametral depth of cut, tool material, fixturing, horsepower. All of these factors must be considered to generate good feed and speed settings. You can use the cutter sfm recomendations as a starting point and adjust the feed from there. I thought the suggestion about cataloging this info was a good one, BUT...It's good for his machines and may not work so well for your different situation.
In other words...There ain't no easy answer, But trial and error has worked for years. If you follow the insert mfg's recomended starting points though you will reduce the error part of trial and error
Hope this sheds a little light on this
Jim

 

[knobhead]

Yeah, but trial and error is causing me to write off a 20000 quids worth of blisk casting everytime I do the 'error' bit!

ah well, they DO make nice paperweights. Excessive accuaracy is a sign of poor breeding. -Socrates.

 

[mrainey]

knobhead,

I've written a free program aimed at people like you. It's in the beta stage right now, but is still pretty useful. You, or anyone else who needs speed/feed (and a lot more) information, take a look:

screenshot:

http://bellsouthpwp.net/r/s/rsnmar/MachiningBeta1.jpg

program:

http://bellsouthpwp.net/r/s/rsnmar/MachiningBeta1.zip

 

[ajit2002]

Knobhead & all the other folks,

Almost all points are covered and the highlights are (Excuse repetitions):
1. Recommendations are starting points from where we move in the desired direction*
2. Variables affecting the process should be understood:
Workpiece material, Tool material and coating on the tool, hot hardness of the tool, tool geometry, coolant, friction at the work-tool interface, temperature at the zone of cutting etc.
3. Rigidity of fixturing, horsepower available at the spindle.

Other considerations:

It may be noted that each of the variables like cutting speed, feed and depth of cut has a different impact on the tool life and prodcution rate. Keeping two variables constant (in turns) while varying the other parameter by say 50% will provide valuable data for entry into the DIARY (REMEMBER THE DIARY STARTED EARLIER?)

*Consequently, we can arrive at a range of parameters for a single job which would on the one end yield maximum tool life, and the other end, maximum productivity. The objective need not always be the same. The above data can be used to arrive at different parameters to obtain maximum tool life or maximum productivity or a balance between them.

Trust some summing up and another dimension has been presented.

Cheers

 

[Jan1]

knobhead,

We at Fokker Aerospace in Europe use for some years a simulation package called AdvantEdge from Third Wave Systems. Using this software you will see why and how cutters behave during machining.
Have a look at their website at

http://www.thirdwavesys.com

Jan1