Six Sigma Control Phase April 2017 5th Submission

Control Phase 16/04/17: Phase Learning's and Tools Utilised.

Control Phase:

Phase Learnings:

The Control Phase of the project is the requires monitoring, standardizing and completion of FMEA's post Improve Phase.

The key learning for this phase s the importance of standardizing the improvements and ensuring the effectivity of these improvements.

All programs with cross drilled holes have been updated and the machining parameters have will be recorded in a Process Characterization Report which will form part of the design Dossier for the parts.

It is also important to reflect on the project learnings too by form of a Lessons Learned to allow for the pitfalls and benefits to be highlighted for subsequent projects.

Within the time frame assigned for this project a simple production tracker has been introduced to assess the micro-drill process performance on all applicable batches built on the Swiss Turn Machines.

Tools Utilized:

FMEA:

The FMEA for the Process was revisited to assess the impact of the studies and the changes made during the Improve Phase. This to ensured that the required actions were completed and the impact was assesed. The final Column set in the FMEA quantifies the changes made and the new RPN for the failure mode. All identified modes have been addressed and the RPN for each mode has been reduced.

Fig1: Completed FMEA

Process Monitoring:

The current production builds are being monitored and tracked for Micro Drill Failures. 

To date after 380 parts no defects have been recorded for Micro Drill Defects.

Ideally the Control Phase of the project should allow more time to verify the results of the project. 

However the trend to date over build completed is positive with 100% yield across all batches.

Fig 2: Process Yield Metrics Pre and Post Process Improvements

Lessons Learned:

The Final tool adopted for the projects was a Lessons Learned. This was completed as part of a team review of teh project and the results of the review were documented and will be recorded within the final report. 

The Key learnings highlighted for the project were the Time lines associated with the project. At times the completion of the trials was impeded by production tasks.

The otehr key learning for the team was the benefit of the drill length setup piece. This methodology will be implemented across all the other tools on the machine to aid setup and to reduce First part yield at setup.

Six Sigma Improve Phase April 2017 4th Submission

Improve Phase 02/04/17: Phase Learning's and Tools Utilised.

Improve Phase:

Phase Learnings:

The key learning of the Improve phase was that this is the stage of the project where the testing of the determinations and assumptions of the previous phases are proven out. This phase required the project team to implement and assess the process per the potential failure modes and areas to be tested based on the FMEA and C&E prioritization matrix.
The main resultants of the previous phases led the team to implement a tool life study and to implement systems to aid the setup method on the machine and to error proof the process.

Tools Utilised:
The DOE template was the only statistical tool used within the Improve phase.
It was utilised to aid all testing that concerned the determination of process impacts on the main process focus which was Tool Life.
Outside of tasks that relied on DOE inputs documented reports where used to compile and record completion of tasks..

Documenting actions completed during this phase is key for the completion of the FMEA post change assesment.

Tasks Completed:

In order for accurate bench-marking of the action list items the Tool Life study was the first Trial undertaken by the team.

This Trial involved the utilization of a DOE to determine the best machining parameter to achieve the best tool life for the Micro Drill Process.
Trials were carried out for the 0.3, 0.4 and 0.5mm micro drill processes.
For the purpose of the Trial a tool life of 150 was deemed to signify infinite tool life and the tests were stopped when the tool life reached 150 parts.

This DOE focused on three process inputs (Spindle Speed, Peck Depth & Feed Rate) with Tool Life being defined as the Experiment Response

A number of tests were then created with a combination of the Process Inputs, these tests vary one input at a time. This allows for only assessment of the process change based on one factor change at a time.

The 8 tests were then completed and the Tool Life for each trial was collected.

From these tests we were able to determine the factors with the highest interactions within the process.

We can see from the bar graphs below that Factor B+C have the highest impact on Tool Life.
We can clearly see the interactions of each factor to tool life and also the affect of a combination of the factors.

The settings for Row 1 have been standardized as they produced the best results for tool life. These settings were then utilised as the benchmark settings for to assessment of all other trials carried out on the parts per the FMEA + C&E task list.


(These interactions will be further utilized in the future to potentially optimize Tool Life vs Cycle Time.)

Fig 1: DOE Template

Following on from the Tool life study as a bench markse was in task Completion to this effect a number of trials were carried out and the results of these were documented.
the FMEA was updated where required to address highlighted failure modes.

Some of these tasks have been highlighted below to detail how the task was completed.

FMEA Task 1: DOE
Tool Damage Study: A simple test was carried out where the integrity of a tip was assessed before installation in the machine, the tool was then impacted against titanium bar within the machine replicating the most extreme impact that could occur on the tip at installation.
A simple two factor DOE was then completed using the bench mark settings previously determined.

FMEA Task 2: Process Step
Drill Setup Piece: This tasks was completed by developing a small simple piece on the machine to verify the correct tool length. This allows for us to verify the tool is cutting to the correct depth after setup before completion of a full production piece. The machining of this tool has been added to the standard operation procedure for the machine

FMEA Task 3: Process Improvement
Implement Tool Management System:
A Tool management system has been purchased to support the production cell, the tool management system ensures that only the correct approved tools are available to the operator.
Coupled with this a Setup Sheets for each tip has also been introduced, this simple sheets details the tools required to run the part and where the tool is to be placed within the machine.

These Setup Sheets fall under the Standardise phase of 5S.

Fig 2: Setup Sheet Template

The Production area is being developed with a 5S mindset from the outset. To this effect the the 5S principles have been applied in the area and at the Machine.
5S focuses around
1: Sort: A tidy clutter free operational space has been designed for the Swiss Turn Machine
2: Straighten: The area has been laid out to promote a streamlined flow and work areas are tidy and organised with all required tools available to the cell personnel in a tidy and organised manner.
3: Shine: A Daily PM Schedule is in place in the area to ensure no clutter is built up and that the area is kept as designed
4: Standardise: The Swiss Turn area utilises written operational procedures for all aspects of the machine, For this projec the setup piece and the tool setup have been captured under this heading.
5: Sustain: The Sustain section of the 5S will be implemented when the product is launched and the area is transferred to production.

FMEA Task 5: DOE
High Pressure Coolant vs Flood Coolant: As FMEA Task 1 A simple test was carried out where the tool life was assessed with High Pressure Coolant Running and with Just Flood Coolant Running.
A simple two factor DOE was then completed using the bench mark settings previously determined