Higher Speed and Feed with Lower Depth of Cut for Higher Productivity - Ingersoll Case

Industrial Engineering Case Studies Collection

My suggestion to industrial engineers: 

Find 5 new engineering developments every day in elements related to facilities, products and processes in your organization and assess their use.  Best Practices in #IndustrialEngineering 

https://nraoiekc.blogspot.com/2022/06/good-and-best-practices-in-industrial.html

Alternatives.

1. 400 sfm/9.6 ipm and a 0.35-inch cutting depth.

2. 1,300 sfm/350 ipm and an 0.05-inch cutting depth with no coolant gave higher productivity.

2010

D&G Machining is a contract machine shop specializing in large parts used in Navy ships. They had to machine a prototype piece,  chromium steel guide rail for a shipboard cargo handling system. The part measured 36 inches long with a 6 x 3.5-inch cross section. A square channel has to be milled down its entire length. The process plan used was to rough this channel to within 0.05 inch of final size, send the parts for hardening and then mill off the remaining material.

For roughing out the square channel, the projected time was  a 10-minute roughing cycle, and inserts were to last for several pieces. But in working, the operation took 20 minutes and tended to break the  two-sided inserts badly enough to ruin the second edge as well.

The cutter used  was a square-corner end mill.  The 1.25-inch, three-flute tool featured two-sided rhombic inserts in a brittle grade. The tool had zero-degree lead angle.  The method  used  was five passes at 400 sfm/9.6 ipm and a 0.35-inch cutting depth. This took about 20 minutes per piece—provided the cutting edge survived. 

At the time, an engineer of the shop,  Ingersoll (Rockford, Illinois) attended "Productivity Redefined" tooling seminar.  He found out from the seminar materials that  Power Feed+ cutter, which is designed specifically to speed rough milling operations. He arranged for the  trial tool and support of technicians from ingersoll.  The finalized cutting parameters of 1,300 sfm/350 ipm and an 0.05-inch cutting depth with no coolant. This combination reduced cycle time from 20 minutes to 4 and extended insert life by a factor of six.

A major difference between the Power Feed+ and the previous tool—both three-flute cutters—is insert geometry. Specifically, the new cutter’s inserts feature a trigon shape, as opposed to the previous cutter’s rhombic inserts, as well as a 10-degree lead angle. The higher lead angle creates a gentler entry into the workpiece to reduce lateral forces on the tool and spindle during fast-feed,shallow-cut milling. The lead angle also provides improved chip thinning characteristics, Mr. The chip is thick at the front, but it thins toward the back end. Due to chip thinning, the power required to remove a given volume of metal may reduce by as much as 30 percent.

Improved chip thinning is a benefit provided by the inserts’ trigon geometry. The  shape also redirects more of the cutting forces through the spindle for greater stability. Additionally, the inserts are thicker—and therefore, stronger—than those of the previous cutter.

The new tool enabled the shop to finish a 1.5-hour rough facing operation on another job in only 40 minutes. D&G has used this high speed approach  with the Ingersoll Power Feed+ for all its steel roughing jobs. 

https://www.mmsonline.com/articles/tool-for-shallow-high-feed-cuts-speeds-roughing

Updated on 2 August 2021

Pub. 20.7.2020