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Activity #1 IET 120-Technology Systems. By: Edward C. Apley. Background. A high volume CNC machining operation is producing excess non-conforming product. The process is stable and has been verified; the process is robust and is running at 1.33CPK.
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Activity #1IET 120-Technology Systems By: Edward C. Apley
Background • A high volume CNC machining operation is producing excess non-conforming product. The process is stable and has been verified; the process is robust and is running at 1.33CPK. • Improvements have been made to aid the machinists to inspect their product for defects and correct the defect by making machining offsets.
Problem Definition • CNC operators are not paying attention to the quality of the products they are machining. • Quality Auditors are not performing proper audits and are contaminating full tubs of product with non-conforming product.
Goal • To eliminate the manufacture of defective product and to eliminate contaminating finish product tubs with defective product.
The 5Y • Non-conforming product is being produced; getting by the auditors and in to finish tubs. Why? • The operators are not making the proper off sets to the machines as the tooling wears. • The auditors are not properly inspecting the product before it is added to the finish tub. Why? • The operators do not know that the product is non-conforming. • The auditors do not know that the product is non-conforming. Why? • Neither operators nor auditors are not held accountable for failing to perform proper inspections. Why? • Supervisors are not held accountable for non-conforming product that is produced on their shift. Why? • Poor management.
Alternative Solutions • Mark the product with a time and date stamp that identifies when the product was manufactured so proper accountability can be maintained. • Train the quality auditors and the operators on the quality standards and perform random audits. • Create a system of accountability that enforces the quality requirement. • Have each oncoming shift inspect the finish tubs from the previous shift.
Solution Selection • The facility can not afford to purchase an ink time and date stamp for each of the fifty six machine lines (cost prohibitive). • *Re-training the auditors and the operators can never hurt and will always help the organization. • *Implementation of layered process audits to perform random checks on random lines daily. • *Creation of a system that aids in holding the operator and the auditor accountable for the quality of their work. • Having oncoming auditors inspect previous shifts work is adding non-value added work and unnecessary labor impacting pieces per labor hour (cost prohibitive) • (*asterisk indicates solutions selected for implementation)
Implementation Phases • Phase 1: Re-train all CNC operators and quality auditors on the quality standards. Explain what the issues have been, communicate the expectation, and advise of accountability intentions. • Phase 2: Implementation of a daily layered process audit using an audit sheet that is area specific to verify quality conditions on random lines. • Phase 3: Design of a process that allows for several shifts of machined product to be placed in to a finish tub, but still provides the ability to hold the operator who made defective product accountable. This system must also be designed to hold the quality auditor accountable for performing an inadequate inspection and dumping small quarantine tubs of contaminated product in to a finish tub.
Expected Results • The development of layered tubs. By using a thin durable plastic sheet that is made to the size of the interior of the finish tub we will be able to keep finished machined product separated by shift. At the start of the shift the supervisor will inspect three to five pieces of product on the top of the layer. If the product is found to be defect free the layer is pulled from the bottom of the parts and • placed on the top of the parts for the next shift to run. This inspection takes place at the start of each shift. Should defective product be discovered, the finish tub is pulled off line, a new finish tub is set in it’s place, and a quality investigation report is completed by the shift supervisor. Thus, maintaining accountability from shift to shift, for the operator and the auditor. If defective product is discovered both the operator and the auditor are counseled; two counseling’s leads to a write up, two write up’s leads to time off; two time off disciplinary actions leads to discharge.
Layer Concept Design Single shift of production Production Tub Plastic Layer (removable) Machined Parts
Added Benefits • The number of pieces to be sorted is significantly reduced. Since a finish tub of machined product can hold thousands of pieces, layering the tubs separates the bulk of the tub content by shift. Since a CNC machine line can only run 1200 to 2000 pieces in a shift it is much faster to sort and find a clean point. • The reduction of non-value added labor is possible since sort quantities are so small. • Increase of floor space within the facility. Since the sort quantities are so small they can be sorted in a short period of time and the sort can take place on line by the operator who produced the product and the auditor who contaminated the tub. Thus, the disposition area of the plant is no longer necessary.