IENG 451 Lecture 05 Process Tools Process Capability

IENG 451 - Lecture 05 Process Tools: Process Capability; SIPOC and Swim Lane Diagrams 6/4/2021 IENG 451 Operational Strategies 1

Six Sigma - Motorola l l Six Sigma* = 3. 4 defects per million opportunities! • Every Motorola employee must show bottom line results of quality project – finance, mail room, manufacturing, etc. • • l ± 6 standard deviations – after a 1. 5 sigma shift! identify problem; develop measurement; set goal; close gap Long term process – 5 years to fully implement 6/4/2021 IENG 451 Operational Strategies 2

Two Process Capability Indices l Cp : • Measures the potential capability of the current process - if the process were centered within the product specifications • Two-sided Limits: • One-sided Limit: 6/4/2021 IENG 451 Operational Strategies 3

Cp Relation to Process Fallout l Recommended Minimum Cp Ratios: (D. C. Montgomery, 2001) • Existing Process 1. 25 (1 -sided) • Existing, Safety / Critical Parameter 1. 45 • New Process 1. 45 • New, Safety / Critical Parameter 1. 60 6/4/2021 IENG 451 Operational Strategies 1. 33 (2 -sided) 1. 50 1. 67 4

Process Capability Indices l Cpk: • Measures actual capability of current process at its’ current location with respect to product specifications • Formula: Where: 6/4/2021 IENG 451 Operational Strategies 5

Process Capability Indices l Regarding Cp and Cpk: • Both assume that the process is Normally distributed • Both assume that the process is in Statistical Control • When they are equal to each other, the process is perfectly centered • Both are pretty common reporting ratios among vendors and purchasers 6/4/2021 IENG 451 Operational Strategies 6

Process Capability Indices l Two very different processes can have identical Cpk values, though: • because spread and location interact in Cpk! LSL 6/4/2021 USL ENGM 720: Statistical Process Control 7

Process Capability Indices l Cpm: • Measures the current capability of the process - using the process target center point within the product specifications in the calculation • Formula: Where target T is: 6/4/2021 ENGM 720: Statistical Process Control 8

SIPOC l Is an acronym for a diagram covering flow: • Suppliers • The external / internal entities providing the • Inputs • The items that flow into the scope of your • Process • The steps (actions) within your scope to produce • Outputs • The items that flow from your process scope to the • Customers • The external / internal entities using your outputs 6/4/2021 IENG 451 Operational Strategies 9

SIPOC l Keys for a SIPOC diagram: • Identify the scope • These are the process boundaries and activities • Model at a high level now, lower model level with VSM • Identify the KPOVs and customers • Brainstorm these items • If there are too many, focus on the critical few or go to a higher level • Identify the KPIVs and suppliers • Brainstorm these items • If there are too many, focus on the critical few or go to a higher level 6/4/2021 IENG 451 Operational Strategies 10

SIPOC l Keys for a SIPOC diagram: • Identify the Process Steps and CTQs • These are the internal activities within the process • l boundaries Critical To Quality requirements must be met by the process Order of keys does not matter for a SIPOC diagram: • Definitions (being specific) does matter • Timing information is important (constraints) • All members must understand the diagram • Check definitions and scope alignment at the end 6/4/2021 IENG 451 Operational Strategies 11

Swim Lane Charts l These diagrams highlight WHO handles the flow: • Identify the different people / functions that are involved in the process • These are listed on the left side (vertical access) • Timing is shown on horizontal access • These become the swim lanes l Brainstorm the steps in the Process (SIPOC): • Identify them on notes / cards for As-Is, re-use for To-Be • Place them in the proper swim lane, in order, connect flows • Connect the notes / cards with arrows showing flow direction • Communications are noted with thin lines, show informal communications with dashed, thin lines 6/4/2021 IENG 451 Operational Strategies 12

Questions & Issues 6/4/2021 IENG 451 Operational Strategies 13