The goal was to achieve a flatness of 15 microns over a 100x100mm area when finish milling cylinder heads. Initially, using a cutter with 30 pockets and 20 inserts resulted in 100% spindle load, chattering, and a flatness of 35 microns. Reducing the number of inserts to 20 distributed the load, reducing chattering and achieving a flatness of 16 microns over 120 jobs. The key was innovatively reducing the tool weight and cutting loads through fewer inserts to consistently meet quality parameters under machine and process constraints.

1. Achieving quality thru innovative tooling
Topic: - Achieving flatness of 15 microns over cross section of 100x100mm by
altering number of inserts in finish milling cutter to achieve consistently quality
parameters for fire face milling of 497 engine cylinder head. .
Name: - Mr.Sourav Mukherjee.
Personal number: - 324831.
Division: - Autotools & P.E.
Email i.d:- sourav.mukherjee@tatamotors.com
Contact: - +919263634228.

2. Project synopsis.
The Goal was to achieve flatness value of 15 micron over cross section of
100x100 mm as per requirement for finish milling of fire face of new 497 engine
model cylinder head. Challenges where machine power constrain of 22KW ,
depth of cut of 0.6mm & over hang situation of milling working against gravity and
given the constant conditions one has to achieve the flatness as desired. The
innovation was that the cutter was closed pitch i.e. 30 pockets, where we had put
20 inserts only to balance cutting forces & achieve the quality parameters.
The spindle load on the machine was set at 60% and as the finish face milling
cutter was having 30 pockets and cast iron being the material the load was
coming to 100%. Their was chattering mark on the fire face surface and flatness
was recorded as 35 microns over cross section area of 100 x100 mm .
To avoid job rejection, the face milling cutter was re-adjusted axial & radial
runout within 5 microns & wiper insert was adjusted.
After running the cutter, once again load was recorded as 100% with sudden
cutter stoppage and chattering marks on fire face of 497 cylinder head.
The quality parameters where not achieved as surface roughness value
exceeded 3.2Ra & surface flatness value was recorded as 35 microns.
So, detailed study was made on the reason of surface finish not being achieved
with the finish cutter & excessive load. A probable assumption was made that
since the cutter is dia 250mm & weight of total assembly 3.5Kgs due to
centrifugal force working against gravity load was exceeding limit & leading to
chatter marks.
So number of inserts where reduced from 30 to 20 including wiper.
Flatness recorded 16 microns & Ra 3.2 & life recorded 120 jobs.

3. Project technical details
Line: - Cylinder head.
Line in-charge: - Mr.Sudhakar.P.Anthony.
Component: - Cylinder head, new model 497.
Material: - Grey Cast iron.
Operation: - Finish milling of block contact face of cylinder head..
Quality parameters as required: - Surface flatness 0.015mm (for cross –
section area 100x 100 mm). Surface roughness 3.2 Ra.
Machine: - Horizontal machining centre.
Machine no:-
Face milling cutter supplier: - M/s Ceratizit India pvt Ltd.
Face milling cutter description: - A273.250.R.31.A31.
TML part no for cutter:- 32524218070 / ordering in process
Insert description: - OAKU060508 SR M50 CTP3220.
Insert part no: - 34478299062 / ordering in process
Wiper description:- XPHT060525SL-M50 CTP3220.
Wiper part no: - 34478299054. / Ordering in process.
Number of jobs OK as per Q/A made with first edge of insert: - 120.
Quality parameters as per metrology measurement sheet no: - 36989.
Date of measurement: - 7/4/2012.
Flatness of block contact face – F0034:- 0.016mm.
Status: - Job OK.
Flatness of Block contact face –F0046:- 0.021mm.
Status: - Job OK.

4. Conclusion
The major criterion for this project was to achieve the quality parameters as
discussed over consistent period of time frame. The constrains where machine
parameters , tool weight and managing the cutting loads to achieve quality
parameters which where ultimately taken care of by innovative idea of putting
less number of inserts in the milling cutter & thus reducing the load and achieving
the desired result .
The tools are in ordering stage with trial signoff being taken. Thus to conclude it
can be said that with proper idea & planning & support of proper tool quality
constrains can be achieved.
Attachments in corresponding pages:-
a) Cutter trial report.
b) Metrology checking report.