PRODUCTS & SERVICES

90 // September 2014 // Engine Technology International.com

Machining of metals has always been a challenging

task, and when dealing with metal injection molded (MIM) parts it becomes even tougher. The machining process at Indo-MIM started with a wide range of operations. However, a number of operations that were beyond MIM tolerances such as turning, drilling, reaming, tapping and surface grinding were outsourced during the companys early years.

Indo-MIM began in-house machining in 2009, establishing many critical operations, including: CNC turning with close tolerances of up to 6m; CNC milling, third and fourth axis in machines with pallet changers; high-production, single-pass honing at a rate of one part every 13 seconds; high-production profile-grinding at one part every 15 seconds, with 7m tolerance; multipart surface grinding; lapping and polishing to achieve flatness down to 2m; and ID grinding with 6m requirement.

A number of factors are helping the company to sustain its machining process. The first is selecting the right machine, a process guided by maximizing the machine running time. Indo-MIM opted for VMSs equipped with pallet changers to shorten the time lost to loading and unloading. The

company opted for small, compact and rigid machines with low torque spindles, which require less material to be removed an important feature, as most of the companys parts are small in size.

Whenever critical tolerances are to be maintained, machines have been fitted with probing systems for automatic tool-offset corrections.

Even for honing and grinding, Indo-MIM opted for machines with the facility for parallel loading and unloading of parts, while operations are carried out at other stations.

Even though Indo-MIM uses general chucking and collet systems in its turning centers, the company also has custom-built fixtures for specific parts. Having an in-house design department working on both part and fixture design helps decide the optimum clamping systems.

All Indo-MIMs milling and surface grinding fixtures are multipart, which not only helps increase productivity, but also grants the advantage of full machine bed use, irrespective of the part size.

Most of the small-batch productions have multiple parts/operations preset in the machine bed, virtually zeroing the changeover time.

Although Indo-MIM enjoys support from many tooling

manufacturers and dealers, the company works with suppliers to achieve the lowest possible per-piece rate. Tool cost alone does not inform the decision-making process the advantage of higher cutting parameters and better material removal rate are also considered when finalizing the optimal tool source. Each application is approached with an open mind, giving equal opportunity to established players such as Iscar, Sandivik and Walter, as to low-cost tool companies in India.

Indo-MIM is committed to continuous improvements by conducting kaizen events identification and tracking of improvement projects has helped the company optimize the use of man, machine and methods.

The use of statistical process control is another tool implemented to establish robust and repeatable processes. Statistics have proved useful in the study of tool wear patterns, and in establishing automatic offset corrections through program macros. The macro programs have reduced the high variability caused by operator interventions. Processes where very close tolerances need to be achieved have been established in this way, leading to major reductions in product scrap levels.

The company approaches challenges with an open mind, discussing them with machine tool suppliers, tool suppliers or work holding suppliers for optimum solutions. This helps Indo-MIM not only arrive at solutions, but arrive at them quickly. There have been instances where the outcomes of such discussions have later become standard options for the machine tool manufacturer.

With the establishment of its investment casting facility at Tirupati, Indo-MIM has taken on the challenge of machining bigger parts, which require more material removal. The machining of MIM parts has helped to quickly establish highly critical machining projects for investment-cast parts.

The companys primary objective has been, and always will be, low operating costs. Indo-MIMs management is willing to invest in suitable machines, which, although expensive, guarantee lower operating costs in the future. The companys rapid growth in the industry has seen an increase from three machines in 2009 to its current tally of 60 machines.

Equipment selection, in-house expertise and investment in facilities arevital when implementing fine machining of metal injection molded parts

Machining MIM parts

FREE READER INQUIRY SERVICETo learn more about Indo-MIM, visit: www.ukipme.com/info/etm

INQUIRY NO. 515