Robotic Fettling for Iron Castings- A revolution in the foundry industry

By Niraj M Wanikar, Chief Editor, CNCTimes.com, 2018-06-30 11:56:00

The Author – Sameer Kelkar, Silver Medallist and Graduate of IIT Bombay, and MS in Robotics from the University of California, Berkelet, is CEO and R&D Head of Grind Master Machines Pvt. Ltd, pioneers Robotic Metal Finishing Technologies. “Explorer” at heart, Sameer Kelkar is venturing into new horizons of Robotic Applications such as Grinding, Deflashing, Fettling, Machining and many others. This article is written using research, data and application experience over the past 5 years.

Delivering an Eight-fold increase in productivity with quality, accuracy, consistency and safe working conditions

Robotic Iron Casting Fettling Cell

The manufacturing industry is undergoing a revolution in efficiency, quality, and EHS but this is not the case with the foundry sector, which has been lagging behind for still practicing age-old methods, non-adoption of new techniques like robotics and automation.

Robotic automation has come a long way in the past few decades where robots are used in manufacturing setups for applications like welding and machine handling in the automotive industry. Industrial robots are widely used in the foundry – iron, and aluminium cast industries, including pouring, extraction, and handling.

Fettling is a process of removing excess material from castings often formed by the die’s parting lines during the casting process when molten material is injected into the die/mould. A process of removing excess material from casting formed by the divided lines by the casting process using the robot as a positioning tool. It is the process carried out with consistent efforts with results emphasising the establishment of technique and performance of the casting profile, which requires efforts of manual labour, working in unsafe and unhealthy conditions.

Fettling is one of the important activities in foundry but sadly neglected. Many leading foundries in the country consider fettling unimportant. Fettling is a process, especially in the iron casting industry, completely manual and labour intensive.

Many a time there are conditions where there is no sufficient light, unhygienic and unsafe working conditions, no safety, lack of proper tools and machines. Such situations need to be considered with utmost priority where fettling works become simple, easy that gives required output with desired quality with safe and healthy working conditions.

Fettling is the last process in most casting shops, after which the workpiece is sent for machining in the machine shop. Operators use a variety of tools, including belt grinders, files, chisels and hammers to fettle castings having the most complex shapes such as holes, recesses, inaccessible areas. Operators work in environmentally dangerous conditions such as temperature, fumes, dust etc. Considering the conditions machine selection must carefully consider the conditions specific to the deployment area to ensure reliability over a long period.

Robotic Automation

Heavy Duty Robotic System for Iron Casting Fettling

Robotic Automation is the use of Industrial Robots to automate and standardise repeatable manufacturing processes/tasks. Automation of this process brings several key benefits to the manufacturers of castings like an increase in productivity, upgradation in quality, healthy and safe working atmosphere. The technology behind Robotic Fettling and how it may be successfully deployed across the iron casting industry serves as a guide of dos and don’ts for good executions. Iron castings of manufactured parts, as you are all aware, have the most complex shapes. And here is where automated robots come to the rescue by delivering quality with accuracy down to the last thou (a thousandth of an inch).  

“With the advent of this new revolutionary technology, Robotic Fettling for Iron Castings will see the sector in an upswing. Using automated robots brings enhanced benefits including an up to eight-fold increase in productivity, exceptional quality that meets international standards and safe working environment while exceeding client’s expectations” says Sameer Kelkar, a silver medallist and Graduate from IIT Bombay, CEO and R&D Head of Grind Master Machines Pvt. Ltd., pioneers of Robotic Metal Finishing Technologies who is venturing into new horizons of Robotic Applications in grinding, de-flashing, fettling and machining. Grind Master is an established trusted partner to some of the largest iron casters in India for fettling while providing a holistic solution for surface finishing requirements including machine, customised consumables, support and process know-how.

The advanced systems built by Grind Master for fettling operations including riser and gate cutting, parting line grinding, de-burring sharp edges, milling inaccessible areas and breaking into holes. Robotic iron casting fettling technology addresses key issues that show up such as effectively managing complex shapes/heavy components, reducing hazardous working conditions, heavy stock removal, variety in component geometry, with manual/automatic load, unload using pallet exchangers, automatic tool changer, automatic path corrections, dust collector system and more. The Critical challenges overcome by the system include -

Gate/ riser cutting                                                               Parting Line Cutting

Hole breaking                                                                                      Parting Line Grinding

Optimization of Light Weight Parts           

Lightweighting has resulted in optimized designs of castings whereas inconsistency in fettling leaves marks, scratches, dents etc on surfaces. These can result in fatigue failure of the part where consistency in fettling is essential for manufacturing such to have aesthetic value.

Production Volumes – Part Variants

Many iron casting components are made in medium volumes of maybe 100 parts/day where any automation system is scalable, fast producing and extremely reliable to cater to this requirement. It should accommodate multiple part variants in the same system with quick setup change, simple fixturing and easy part programming are essential for this.

Component – Component Variations

Fettling operation is done on as cast parts, which have part-to-part variations inherent to the casting process where these variations pose challenges in Fettling Automation – starting from location and fixturing, to the uniformity of force applied during fettling, to making adjustments for part variations.

Robotic Fettling – Tool Selection

Robotic Fettling Systems arrangement is a combination of tools for completing the requirements. A knowledgeable system integrator is able to choose wisely the tools used for a specific job requirement. Tool Selection is critical because the process reliability, cycle time and running cost of the system are majorly based on the type of tools used. In certain cases, it is observed that selecting the most advantageous tool can reduce cycle time and cost running by as much as 90%. The most commonly used tools in Robotic Fettling include diamond-plated wheels for cutting and grinding.

Robotic Fettling – Quality Improvements

Robotic Fettling gives tremendous improvements in the consistency and completeness of fettling. Manual operations are subject to numerous variations through the days, weeks and months of the year where more than one operator never works in the same style. Multiple operators work on one component leading to handling damages. Cutting tools manually operated invariably causing scratch marks, dents; dig into unwanted areas, which are a major cause for rejection of castings.

Robotic Fettling – Cost of Operations and Economic Feasibility

Robotic Automation Systems have various costs associated with them, which have to be considered while calculating cost per piece over the long run such as the maintenance costs (Annual Maintenance, Spares etc), energy costs, consumables costs (use of customised tools for robotic application can save significantly); retooling, reprogramming costs and labour costs (including future rise in the same). Significant improvement in quality is considered while calculating the investment returns of a robotic fettling system. A drastic reduction in rejection rate and removal of rework/checking stations also brings space savings. Correct selection of application and wise implementation can ensure a Return on Investment of Robotic Fettling Systems within 2 years.

Key Precautions to be taken for Deployment of Robotic Fettling

Most iron casters have a large number of manual operators for fettling operation. In order to successfully implement robotic automation across the manufacturing setups following key steps are to be considered:

1. Long-term commitment to deploy automation

Fettling Automation will go through learning, implementation, horizontal deployment phases and management must have long-term commitment to do this. 

2. Reliable Partner for Fettling

Deburring and grinding process knowledge are key ingredients of any success in Robotic Fettling, which acts more like a machine tool than an automation system. A competent machinery maker with this expertise is a partner for Robotic Fettling.

3. Successful implementation of the first application is a key for confidence in the team about Robotic Fettling.

Conclusion

Robotic Fettling is a revolutionary technology in the iron casting industry. It leads to key benefits such as consistency in quality, high productivity and health, and safety on the shop floor. Iron Casters can deploy this technology in a foundry by taking certain precautions to ensure success. In the near future, Robotic Fettling is likely to sweep the Iron Casting industry setting the new benchmark for shop floor practices and methodologies, especially for fettling. 

• Follow @CNCTimes