Optimum Cutting Speed, Feed and Depth Of Cut calculation

[ajxxx]

Everyone,

Need some advise on how to calculate the optimum cutting speed, feed and depth of cut for machining:

Operation - Facing BUT "NOT single point cutting" - It is "Plunge Facing" with R5 Insert

Machine - Vertical Lathe

Job Specifications - variable diameters and thickness.

How would we be able to determine job rotation speeds and feed rates to get optimum tool life and better machining?

 

[MiketheEngineer]

Call your supplier - they can usually be very helpful!!

 

[tomwalz]

Figure out what you want, first.

Some people like to buy cheap inserts and make them last forever. Think hobbyists. Some people want to run as fast as possible and don’t care how long the inserts last. Think Boeing trying to optimize output from a $50 million dollar mill

An awful lot of time and money is lost in the world every day because purchasing / management thinks tooling is expensive but machine time and labor are not important.

Start with Machinery Handbook, the cutting tool supplier's recommendation and the material supplier's recommendation then experiment.

Put a really good operator on it, one who is very familiar with the machine. Get QC involved for cut quality.

Find out just how strong your fixturing is before you start.


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[BillPSU]

There are some many variables which you have not defined.

What is the material? What condition annealed, normalized, heat treated? If this is a casting is there inclusions(cast austinetic stainless)?
How rigid is the setup?
How long does it take to change a tool?
What is the cost of the raw material(part)?
What is the hourly rate on the machine?
What is the hourly rate of the man?

You will have to determine your optimum costs. Rigidity of the setup and material are probably your most important parameters starting out then with experience machine and labor costs become the deciding factors.

High dollar part costs will also drive you to never have a catistrophic insert failure insert failure which scraps the part.

Good Luck
Bill

 

[ajxxx]

thanks everyone,

More than anything else right now I would be only interested in theoretically calculating speed and feed data to determine if we indeed are somewhere near those. The suppliers in India are not much useful as they tend to do more trial and error than have any justified theoretical logical behind them.

Yes, do understand the calculated values would vary in practical conditions but believe they should be used as a basis behind any judgement.

 

[berkshire]

It has been many years since the company I used to work for had parts machined in India.
We asked them how they arrived at their speeds, and feeds? The answer came back, "we run the feed up until the tool breaks, then back off 10%.".
B.E.

 

[hasanaltan]

CutPro and ShopPro softwares are commonly used in industry to answer these questions.
If you're working for a large company then it would be possible to acquire such softwares.

 

[MikeHalloran]

You can compare heterogeneous cutting operations by keeping track of the Metal Removal Rate, measured as volume removed per unit time. All operations for a given part material and a given cutter material should approach the same limiting MRR, providing that other factors like spindle speed, spindle power, chip clearance, or cutter rigidity do not interfere.

It's not the only thing you should measure, but it can help you find process steps where there's room to improve.




Mike Halloran
Pembroke Pines, FL, USA