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Why Do You Need PPAP?

Posted by Bob Soares on Mar 5, 2019 2:00:30 PM

Because the Production Part Approval Process Reduces Risk!

Imagine waking up one morning to hear that your metal stamping components are part of the design of a product that expects to exceed 70 million recalls by the time all the numbers are in. Tragically, those aren’t the only numbers tolled in the equation—there are deaths and injuries among them. More numbers: seven high-volume, global manufacturers (and their vast supply chains) have been impacted. Gulp.

Quality Process Metal Stamping_PPAPThe hope is your part may not be the one responsible for all this mayhem. More importantly, your truth is: you can prove it because your production part approval process (PPAP) system can document it. Whew! (And, no, this tragic instance has not happened to us at Larson!) 

PPAPs are integral to maintaining quality and integrity in processes—indeed, having a process at all! Yes, people grumble about change, because it means changing the PPAP, which can require re-qualifying the entire process based on even the smallest change and getting approvals from all entities in a supply chain—and there can be many. From the example above, think of how many departments, suppliers, customers, and vendors needed to be in that progression for the simplest of changes. We can also see how vital it is that it is done, as in the real-life example above of the Takata airbag inflators.       

Why PPAPs? 

If you’re involved in the precision metal forming industry—whether a supplier, vendor, or customer, you know what a PPAP is, or at least you’ve heard of it. First used in the automotive industry and then in aerospace, this standardized process is employed by manufacturers, suppliers, and customers to ensure that the production design, materials, components, and all the processes that go into the manufacture of the final product are consistent and quantifiable. No portions of the design, materials or parts procurement, or production process can be altered from the original PPAP without all parties involved approving the change. 

PPAPs create a footprint, so if something is awry or is non-conforming, parties have documentation that supports root cause investigation. Failure mode effects analysis (FMEA) documentation will disclose whether or not this was initially identified as a risk. When applied properly, a manufacturer looks at all factors that may need to be changed, not just for one that is non-conforming. Unfortunately, not every company will investigate properly to the root cause to try to identify, correct, and mitigate further instances globally. 

At Larson, we implement PPAPs as a part of our overall advanced quality planning (AQP) process. The way we use AQP at Larson is to facilitate a congruent, nimble approach to project implementation—from the beginning of the design process though to production. We establish a system, from the very beginning of the manufacturing relationship, that ensures that customer requirements are met (and exceeded) throughout the tenure of the customer/manufacturer partnership for any given tool or metal stamping part. This depth of expertise and process also helps us when working on a new part—we can build off of existing control plans to quickly get it qualified, in production, and delivered on time. 

AQP Checklist 

Our AQP checklist involves nine areas of the manufacturing process: 

  1. Customer
  2. Part design
  3. Purchased parts, services, or materials
  4. Tools and process design
  5. Inspection and test equipment
  6. Flow chart
  7. PFMEA
  8. Control plan
  9. Work instructions/production control system 

Within each area are elements to be addressed, actions required, person assigned to the task(s), and due dates. The amount of questions/concerns covered with each area varies. They cover a wide range of circumstances and contingencies, and include items such as:

  • If available, has the Customers Supplier Quality Manual been reviewed to ensure compliance? If exceptions are required, have they been communicated to the customer? (customer)
  • Has a DFMEA been requested? (part design)
  • Are new suppliers certified to ISO 9001 or applicable standard? (purchased parts, services, or materials)
  • Do purchasing specifications meet all customer requirements, including packaging, when completed by outside vendors? (purchased parts, services, or materials)
  • Have process characteristics that affect special product characteristics been identified? (tools and process design)

PPAP and Our Process PPAP Quality Process Metal Stamping

By keeping all processes and documentation in order, PPAP oversees the overall process to ensure that the parts we make are in 100% compliance to customer requirements. A process flow chart, which is how every project with a customer begins at Larson, shows each step that every part goes through. 

Because we approach our work from an engineering perspective, Larson collaborates with customers in the design phase, though we don’t initiate product design. Customers generally vet their process/design failure mode effects analysis (PFMEA, DFMEA) inhouse, and we work with them through an open process to identify any possible failures in design or manufacturing. Whether or not a customer is working from an FMEA, we make a control plan for all jobs at Larson.   

Our control plan defines all the controls in place for each step of the process. As an example—when we buy raw material, there is a process that begins once it comes through the door. We inspect it and then follow it through production, with every project following the same plan. Some elements of the plan include verifying that: 

  • Raw material complies with all proper specifications and certifications
  • Physical measurements on width and thickness match tolerances: OD, ID, flatness, parallelism, height
  • Critical specifications are as ordered 

Process Flow Chart 

We use process flow charts to chronicle each phase of production. From feeding the raw material to the presses to the job set-up and beyond, we account for every step. This involves defining all the characteristics we control on that part. Below is an example of a typical 11-step process flow for parts produced using a progressive tool. Step 5 addresses the measurements that operators on the floor take to check on the parts during active production. An element of this includes sampling plans. The sample size and frequency are based on the risks identified in the PFMEA review, as well as historical data from similar parts and processes. We measure and record them; if any measurement is “off,” the operator stops production, contains any suspect product, and contacts the quality department to initiate an investigation and product disposition through the Material Review Board. 

11 Steps 

  1. Incoming raw material (coil stock)
  2. Raw material storage
  3. Raw material requisitioned to press department F.I.F.O basis
  4. Set-up (progressive die) samples to inspection
  5. Manufacture parts
  6. In-process storage (non in-line tumbling)
  7. Cleaning and deburring
  8. Shipment release inspection
  9. Package
  10. Finish good storage
  11. Ship to customer 

Control Sheet  

From the control plan, we generate a process control sheet. These are originally generated by our engineering group, as they are familiar with the risks involved in the manufacturing processes, and are then reviewed by a cross-functional team to ensure all appropriate controls are considered to address the identified risks. These comprise the controls that are established and implemented for all personnel to follow and that the quality group closely updates, monitors, and maintains. 

The control sheets work as checklists for the overall control plan. For instance, in step 5, an operator fills out a control sheet to document an in-process inspection. The operator records the current measurements and makes a determination on the integrity of the part and production performance—all of which is communicated with our quality team. 

The control sheet can be either a physical or digital document, which runs through our statistical process control (SPC) software, allowing us a direct data dump into the program. This offers quick, aggregated, time-stamped intel on our processes, and will identify any out-of-control or non-conforming situations. 

Inside Look at Larson 

We understand process and why it is so important. We live it and have adopted it from our base philosophy through to our procedures and outreach to customers. We know how important material sourcing is—and that any changes with suppliers need to be vetted, qualified, approved, and documented. Having long-standing, trusting relationships with vendors and customers helps us maintain control over the material process and ensures that our sourcing will remain consistent and uninterrupted. This an extension of our vendor-managed inventory (VMI) program and allows us to manage the process for all stakeholders. 

Education and Outreach 

We regularly meet with key suppliers of our materials. On-site, quarterly reviews are held with the key suppliers to review their metrics, which include on-time delivery and quality performance. Together, we review the controls—their control and processes, as well as ours—to maintain consistency and quality. 

Not everyone is up-to-date on PPAPs, so we will go to some of our suppliers and train them. We’ve taught vendors how to create and implement a control plan, or a proper failure mode and effects analysis. We teach them how to rank the lists and stress priorities that they should constantly be working on: high-risk items top the list. As mentioned, PPAP qualifications can ripple throughout the supply chain. We’ve held training classes for several suppliers so they could be in compliance with our requirements; which, in turn, allowed us to be in compliance with our customer requirements, and they for their customers. We have worked with them on how to establish and implement the core tools. The peripheral benefit for them was that this training expanded their ability to be compliant for other customers that needed to meet similar specifications. 

Once stakeholders define the process at hand (which includes design, materials, etc.) we do not deviate from it. By not changing or introducing anything new to the process, that translates to no new risks. PPAPs are inherently predictors of risks, as they require us to define those risks up front. Because we actively implement PPAPs and extend education and training for our customers and suppliers, we mitigate risk throughout our supply chain. 

Documentation and Traceability 

PPAPs provide documentation and traceability. Because of this, if something is deviated on the production line, we will know almost immediately, minimizing quality issues and downtime. Everything is monitored: changing to a different piece of equipment, process settings, lubrication type and amount, as well as the cleaning and finishing process settings. By knowing what the controls on our processes are, we have the instant ability to reduce and eliminate risk.  

At Larson, our PPAP allows for minimal measurement errors—with lower than 10% measurement error on all systems where statistical control is required. All custom-built measurement devices, and those used for statistical process control, are reviewed using the measurement system analysis (MSA), which allows us to compare the processes capability versus the defined tolerances and process variation. Gage repeatability and reproducibility (gage R&R) ensures that we can repeat and reproduce these measurements and that multiple people can use the measurement system with statistically similar results. This ensures confidence that the measurement system will detect shifts and out-of-control conditions in the process. 

Benefits to You 

These controls are what has kept us around for 99 years, and why our customers are so loyal. We will not side-step any portions of the process because a customer needs something quickly. And because our processes are part of our blueprint, we don’t have to—we are efficient and can still remain nimble if we need to pivot. If it is a demanding change or request, we would rather vet a process fully and take a little longer so we can do it right. 

Customers depend on our quality systems because they don’t get rejections and can rely on delivery as scheduled. Larson’s on-time delivery record is phenomenal precisely because we have this down to a system. PPAP in metal stamping is everyone’s best assurance that you will receive quality goods and on-time delivery. 

What all this translates to is that—whether your next project requires progressive die stamping, deep drawing, in-die assembly, or value-added operations—Larson is well-equipped to do the job. Find out first-hand, and contact us now to see for yourself. 

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Larson Tool & Stamping offers a broad range of precision metal stampings and assemblies capabilities, including: 

  • Forming
  • Stamping
  • Deep drawing
  • Assembly
  • Brazing
  • Painting

We’d love to help solve your difficult design and production challenges by providing high-quality, cost-effective solutions. Contact us for a quote.

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