SSES Sheet

YAMZUMI CHART - HPML

Manual Poking also raises concern of cross poking, mold breakage which affects product quality & also limits production capacity.

Manual Vent Poking

B. Head Core Assembly Placement (Stage-4) :
Similarly, at this stage operator has to bend and lift the core weighing 16Kg. for 120 times/hr. This stage also challenges the endurance of operators & hence classified as ‘Yellow’ stage as per Ergonomic SSES analysis.

To overcome these issues M&M Foundry started looking for Innovative & Sustainable solution which not only improve quality of life of people but enhance Productivity, Quality thereby improving business performance.

Head core Placement

Solution Generation & Innovation :

A.Vent Poking (Stage-2) :
Manual Vent Poking operation was the most challenging task for productivity improvement. As it was having the highest work content stages among all other stages thus limiting the production to 40molds/hr. and was most fatigues stage.

Team has accepted the challenge and started working towards finding the most appropriate solutions. We studied the overall operations and recorded all operational parameters. Adopting the principal of simplicity, and to avoid failure due to process change we have decided to keep operational parameters as constant. Only manual movement to be automated. We have prepared the conceptual drawing & detailed technical scope of equipment and given to OEM of HPML. They regretted to supply the equipment as the operational principles given by us were unacceptable by their principals. Project has become further challenging and stimulating. Another OEM has given the offer of Rs. 80 Lakhs with Twin head technology Following decision matrix helped us to bang on most Frugal option of collaborative approach of M/S TRIZ+ M&M

B.Head Core Assembly Placement (Stage-4) :
We have challenged the conventional way of lifting the head core assembly & worked out various option to overcome this problem. Based on investment requirement, ease of operability, maintainability & payback time we finalized on Standard scissor lifter by seamlessly integrating it into our existing system

Implementation :

A.Vent Poking (Stage-2) :
We followed structured approach of equipment development. After freezing the Technical parameters we have taken the Statement of requirement as Customer (User) input requirement, such as tool changing and tool homing system, Cycle time monitoring as well as various safety interlocks to safe guard main HPML as well as new Vent poking equipment from any malfunction leading to accident. We have made the system robust by incorporating 20+ interlocks.
After developing the concept we have established strategic collaboration with the potential equipment developer who can work with M&M hand-in-hand for this project. Project time planner followed for timely completion of project.

We faced following challenges for implementation of this project : 

1.Limited availability of space for equipment Compact structural design with maximize axis travel.

2.Existing tool life of 4 hrs (won’t work in new equipment) Special geometry tool from Tungsten Carbide.

3.Establishing Tool Homing position which is in air Special Homing gage development.

4.Heavy foundation impossible Chemical anchoring by using HILTI technology. 130% higher bonding strength then cement foundation.

Team has successfully implemented the project in record time & successfully achieved all the deliverables. Affordable technology of X-Y Co-ordinate servo drives (X-Y-C) with Pneumatic high speed feeding (Z) system introduced for Vent Poking operation 1st time in Foundry Industry across globe as against OEM offered technology of hydraulic system.

HPML OEM M/s. DISA (I) Ltd. & M/s. KW (I) Ltd. Visited and appreciated the design concept and implementation.

Risk Mitigation : Like any other project there was risk of lower operational performance which may lead to tapering down the productivity. To mitigate this we have designed the entire equipment into ultra-compact design & hence were able to create additional station for Manual Poking as part of contingency plan.

Training of operational and maintenance operators & officers was organized for New Technology machine which includes Parameters inputs, Program selection, SOP for Tool changing, and Tool homing, Pokayoke functioning, HMI interpretation, Preventive Maintenance of L M Guide ways & other critical mechanical as well as electronic systems.

On Job Training

Auto Poking Equipment

B.Head Core Assembly Placement (Stage-4) :
After analyzing the various parameters, most frugal, Easy to implement, Easy to Operate & Maintain solution of Standard scissor lifter (Option 3) was selected and implemented.

With this Bending posture of operator is completely eliminated. We could get 10 seconds work content reduction at this stage which was utilized to rebalance the line for effectively optimizing one person per shift.

Results / Impact Value Creation and Business Impact : 

Environmental impact : 
Wastage of Natural resources like Sand, Water, Bentonite & Coal dust saved for 1200 Molds/ Year

Green Sand = 1200 Mold x 600Kg = 720000 kg = 720 T (Re-cycled)
Water (2% of Green sand) = 14400 Liters
Bentonite (1.2% of Green sand) = 8640 kg
Coal dust (0.5% of Green Sand) = 3600 kg

Scope for Horizontal Development :

Newly developed technology seen by OEMs of HPML. We have offered them to share our technical details.

Any other merits :

This type of concept was developed first time across globe. Looking at its uniqueness, we have applied for patent with Patent registration number 1562/PAT/2017

Figure 1 : Blade Nomenclature

⦁ Process Modifications to increase overall capacity of Blade Manufacturing
The process of blade machining is reviewed & the non-critical operation are shifted to underutilized machine. Some of following operations are as below

⦁ Shroud Machining shifted to 4-Axis from 5-Axis Machines :

The following is the flow chart of the sequence of operations carried out on the raw material to get the final product. The Profile machining can only be done on a 5-Axis machine, hence all the other parts were machined in the 4-Axis before getting the blade to the 5-Axis Machines. This was merely to shift the machining over higher capacity machines & to remove the bottlenecks.

Figure 5 : Sequence flow chart

⦁ End Machining Operations shifted from 4-Axis to 3-Axis Machines

The end Machining operation basically means removal of the holding allowances. These holding allowances depends on the machine it is to be clamped into. This operation is a non-value adding activity, and hence occupying a critical & bottleneck machine for it was not advisable. With a customised fixture, different tooling parameters and machining strategies, we shifted this operation on less critical machine i.e. the 3-Axis Machine.

Figure 7 : Shifting of End Machining Operation from 4-Axis to 3-Axis Machines

⦁ Developing Fixtures & Advance Cutting Tools

Tooling becomes a major concern when we talk about machining. It directly affects our quality and productivity. Machining parameters, required accuracies and the surface finish are a few factors we consider while deciding the tools for any job. To introduce latest innovations in tooling’s, we interact with tool manufacturers on a regular basis.
In our case, we tried to work on the form cutters which were used to machine a Fir tree Root type Blades. The HSS Form cutters after replacing with the brazed type form cutters, gave us the opportunity to increase the parameters and get a reduced cycle time on 4-axis machines. In addition to this, the application of a few advanced tooling like the High Feed Cutters and better coatings allowed us to utilise higher parameters which in turns reduced the cycle time further.

Figure 8: Fir tree form cutter before & after

Figure 9 : Hi feed cutter & inserts

⦁ Raw Material Optimisation

Steam turbine operates at very high temperature & pressure, the material of blades should withstand these operating conditions. Special alloy steel is used for blade manufacturing. Generally forged bar is used as raw material for blade. The amount of wastage is as high as 75-80% of total raw material used. The raw material in the manufacturing of a blade is generally an addition of the Blade dimensions and the holding and machining allowances over the same. Both of which are non-value adding to the final product. Thus the lesser the allowances, the more efficient the process is in terms of cycle time.
Following picture shows the raw material & finish product. Average 12 to 15% of raw material is converted in finish goods. Hence it is very important to reduce the technological holding allowance.

Figure 10 : Raw material for Blade Average weight 65 Kgs

Figure 11 : Finish Blade Average Weight 7.8 Kgs

As stated above, technological holding allowance has been reduced by change in process, holding methods& other improvements. Figure 12 shows the comparison of holding allowance before & after improvements.

In addition to Cycle time, the reduction in holding and machining allowances provided major savings in raw material cost & energy consumption.

⦁ Reduction in the Spare Quantity

The spare quantities are the numbers of units produced over the actual requirements cater to the process deviations. The quantity to manufacture was pre-decided to be 10% more than the required batch size over the actual quantities, which gradually was reduced to 2%. This happened because of the importance given to kaizen initiatives in the organisation and deeply workman involvement in it through various QC tools to achieve the right quality at the first go.
All the above developments have eventually added value to the productivity as a whole, which in turn has doubled the blade produced by minimal increase in energy usage.

⦁ Machine Modifications to increase overall capacity of Blade Manufacturing

Considering the availability of 3 & 4-axis machines, we planned to shift some of non-critical machining operations on these machines which were being performed on 5-axis machines. By adding rotary axis to 3-axis machines, we have converted it to 4-axis machines, which are now able to perform the rough machining of blade. Similarly we have added 5th axis to 4-axis machine to convert it to 5-axis machine. These modification in machine allowed us to take blades on 3 axis machine for rough machining & finishing on 4 axis machines. Following figures shows the modification of machine by adding additional axis.

Figure13 : Modification of machines from 4 to 5 & 3 to 4 axis machines

Results / Impact :

After the implementation of the improvements stated above and other Kaizen initiatives, we plotted the following graph. The YOY Average has increased from 2253 nos of blades per month to 5066 nos of blades per month over a span of three years.

Figure 14 : Quantum of Blade manufacturing

Environmental impact :

The life cycle of the product consists of three phases: manufacturing, service and recycling. The manufacturing phase alone accounts for one-fourth of global energy usage. The leading consumer of energy within this sector is the production machinery. There are numerous motivation causes to reduce this energy consumption. The leading cause for the operating company is the reduction of the Total Cost of Ownership (TCO) but the higher goal is the sustainable manufacturing of goods with minimal energy required with a smaller environmental footprint.
By reducing the overall cycle time of Blade manufacturing on machine, here we reduced the energy consumption. We able to reduce the energy uses from 86KWh to 36KWh per blade we manufactured.
Thus reduction in carbon foot prints to the society.
Secondly, when we reduce the raw material requirement, we are reducing the natural resources for steel manufacturing & also the consumables requirement per no of blade.

Figure 15 : Specific Energy consumption per Blade

Scope for horizontal deployment /Sustainability :

Any system or improvement stands right only when it gives a sustainable scope. The trend of the current Financial Year, after all our Improvements and Implementations have shown a drastic improvement in quantity of blade manufacturing from the previous Financial Years. The new process adopted is giving better output with improved norms in quality of blade produced.

Figure 16 : Blade manufacturing data for FY2017-18