PRODUCT/PROCESS CAPABILITY STUDIES
Where failure costs, e.g. scrap, rework, returns and credit/warranty costs are over budget, process improvement will assess present process capability, identify and correct process variables causing excessive variability and track the improved process with statistical process control. Stability studies are conducted to assess and correct any process instability. Product capability studies are run on the critical product characteristics to establish an initial baseline and subsequently on component parts of the process when the key process variables are identified. See Process Improvement Flowchart
Designed experiments using factorial designs, along with regression and correlation methods are used to identify and quantify the key process variables and combinations of process variables, i.e. those causing the greatest components of overall process variability. The entire sequence may involve a multitude of experiments ranging from screening studies to final validation. See Process Improvement Flowchart
KEY VARIABLES STUDIES
Capability studies may be run on individual key variables to determine the capability of each variable relative to the requirement. The variables may involve operators or operator training, materials, machines (including machine settings), measurement systems and environmental variables. The Key Variables Studies produce recommendations to bring the key variables in conformance with the requirements or better. See Process Improvement Flowchart
STATISTICAL PROCESS CONTROL
A final process capability study is performed on the process to ensure that it meets or exceeds requirements. Statistical process control is established at key points in the process to ensure that the process will remain in control or that out-of-control conditions will be noted and reported. See Process Improvement Flowchart
If excessive failure costs are eroding your firm's profits, contact us for assistance in process improvement. The first year's savings usually more than pays for the consulting and training costs.