Lean Six Sigma: DMAIC Principles and How to Put Them Into Action
AQP and PPAP: Keys to Building In Quality
Proper planning is important in life as well as in industry. For example, have you ever purchased furniture only to realize after delivery that it wouldn’t fit through the door? If so, you have experienced a planning-related tolerancing problem. You forgot to measure the doorway, and your goals were not met as a result.
In the industrial world, it’s even more important to be pre-emptive with respect to quality. A tolerancing problem with a critical part can cause considerable expense and delay if a faulty design has to be revised or tooling has to be changed. This is where Advanced Quality Planning (AQP) and the Production Part Approval Process (PPAP) come into play.
AQP is a standard planning method to build quality into a product from the very beginning, from the design all the way through to the finished product. PPAP is effectively the record-keeping mechanism of that planning method—a roadmap and running record of the implementation of the quality strategy.
Advanced Quality Planning (AQP)
While AQP is a standard method, it will not look exactly the same within different industries with different processes and requirements. Your industry may have a more rigidly defined version. For example, Advanced Product Quality Planning (APQP) is a specialized type of AQP with a product-based emphasis that was developed by and for the automotive industry.
AQP programs have five standard phases:
- Planning and Definition – In the initial stages, all parties must verify that they have the same understanding of what is required. Design and reliability goals, as well as other specifications and special requirements, are discussed up front.
- Product Design/Development – The design is thoroughly reviewed and verified in several ways, including the use of a failure mode effects analysis (FMEA) to assess possible problems, their chances of occurring, and the consequences of an occurrence. By this point, the necessary tooling and critical characteristics of the product and the process should be understood.
- Process Design/Development – The verification process is refocused from the part itself to the process used to make the part. Another FMEA may be performed with a process focus (these may be distinguished as a DFMEA and PFMEA for design and process stages respectively). Both the production process and the necessary quality and measurement systems are outlined and reviewed. Control plans and operator work instructions are written.
- Product/Process Validation – It’s time to put all the preparatory work to its first test. A trial production run is conducted and the results are checked—not only with the part to be produced but also with the production and measurement processes. The PPAP is completed, providing a summary of all the necessary documentation to prove that the process and product has been properly reviewed. The summary document for the PPAP is known as a Part Submission Warrant (PSW).
- Assessment/Feedback/Corrective Action – What were the results of the first production run? Did all the initial parts meet the customer specifications? Were there any measurement concerns? Feedback is gathered and used to outline the next steps, whether there are another round of corrections to be made or the process is cleared for full production.
Components of a PPAP
While the PPAP is completed during the validation step, the information necessary to complete the PPAP is gathered throughout the entire AQP process. The required PPAP elements may be industry specific, but the typical elements include design records, engineering change documents and approvals, DFMEAs/PFMEAs, process flow information and control plans, dimensional analysis and measurement systems analysis (MSA), records of compliance, and PSWs. The APQP process for the automotive industry has 18 total standard elements to be met.
How those elements are fulfilled can be a matter of negotiation between customer and supplier. Suppliers generally have standard PPAP forms and packages that may need to be tailored to meet any specific customer’s expectations.
PPAPs are provided in levels ranging from Level 1 to Level 5, with Level 1 being the most basic level (usually a PSW alone or with limited other information) and Level 5 supplying a PSW with all supporting data and a manufacturing facility review. The supplier and customer will agree on the required level of PPAP before work begins.
PPAPs are also used to manage changes. In the case of a raw material change or any form of a significant process change, the PPAP process is repeated to verify that parts made after the change will continue to meet the customer’s requirements.
AQP and PPAP at Smartrend Manufacturing Group
At SMG, AQP and PPAP are essential components of our project launch activities. Our standard Level 2 PPAP provides assurance that our products meet all quality specifications and critical parameters, and that the processes are inherently repeatable. Level 3 PPAPs are available upon request.
We can’t help you out with any oversized furniture—that’s a job for a measuring tape, and possibly a screwdriver. However, if you have a need for high-quality manufactured parts and assemblies, repeatably made to your specifications using a verified process, contact us with your details. We would be happy to put our factories to work to meet your needs.
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