Supplier Control Plans and Design Specs

We’re setting up requirements with vendors or suppliers. We need to communicate. What’s important about the component that we’re purchasing. We also need to have an agreement between us and our supplier about expectations. We can use a simple control plan to help us facilitate those conversations. And to also keep a record of who is doing what for future analysis, what is a control plan and how can it benefit our relationship with our suppliers? Let’s talk more about it after this brief introduction. Hello and welcome to Quality during Design, the place to use quality thinking to create products others love for less. My name is Dianna. I’m a senior level quality professional and engineer with over 20 years of experience in manufacturing and design. Listen in and then join the conversation at qualityduringdesign.com.

We’re working with suppliers or vendors to choose components. These are companies that are manufacturing components for us. We purchase them and then we assemble them as part of our new product design. Sometimes these suppliers are off the shelf and sometimes they are custom, no matter which as design engineers, we’re looking at the specifications of these parts and figuring out what the important features or characteristics are. We’re designing a lot of other parts and our interfaces with that component. So what has the supplier indicated their specification to be? And what’s their tolerances. When we’re choosing components and parts, we can look at our suppliers as partners in quality. If we can, we wanna be able to communicate with them and work with them on describing what’s important and how we’re going to measure it and ensure that opponent, our part is meeting the quality standards that we need for our product control plans are used to be able to communicate that type of information, a control plan captures what’s important for the quality of that component or part as it’s going into our bigger design.

And it also gets into how we’re going to monitor that part for quality control plans can be a simple one pager. And if we can work with our suppliers to create it, that’s even better. I’ve helped teams create control plans with suppliers, for components that were critical to the overall product design and function. And what happened was a better understanding of who is doing what and when, what features or characteristics are we examining at our incoming quality assurance? Does it match up with what they’re monitoring as important for their process control? Are they inspecting this feature during their in process manufacturing, providing a report and a certificate of conformance, and then is our incoming quality assurance looking at that certificate and maybe evaluating the results of their data. If they are evaluating that data, how are they evaluating it and what would be the trigger and the reaction plan, if something wasn’t quite right control plans used for components that are supplied, help us to do lots of things.

They used to help us coordinate with the supplier, with who’s doing what inspection and when it helps the supplier to understand what’s important, how it’s measured and what will happen if it’s wrong, it helps us build better contracts between us and our supplier, because it helps set direction and expectations for that particular part. There are other departments and people in our organization that are helping to define the relationship we have with our suppliers. The control plan is helping to set expectations for this particular part, but it could also change our relationship with the supplier on the broader level with our supplier managements groups, we may have to adjust our supplier agreements depending on what’s happening with our part. There was a case where we were using a supplier to produce and create parts for us that weren’t of a critical nature, but then a new product development came along and we wanted to work with the supplier to start creating parts that were critical to the product design.

That’s at a whole different level of expectations with the supplier agreement. And we were able to work that out and it’s even been the case where we said this characteristic of a part is really important and the supplier and came back and said, well, we don’t really have any control over that part of the component because that’s done by somebody else that we hire a third party supplier that led us to further describe the specification for quality control and also changed the way that we set up our supplier agreements. Having a control plan in hand also helps us with root cause analysis. We have a breadcrumb trail that we can follow as far as who’s doing what who’s looking at, what for their process control is this a third party supplier characteristic, a control plan gives us some of that insight into where things could have gone wrong.

And it can also be a supplement to an FMEA (failure mode and effects analysis). If we have a control plan for a part, we could reference that in the FMEA’s control column. And this also allows us to divorce our FMEA from the supplier’s eyes, if, if we didn’t want them to see the things in our FMEA the control plan has a more narrow scope that focuses on what’s important and how it’s measured. So what is a control plan that would be used with a supplier? What does it look like? It could be one page or less. It’s going to list characteristics. It can list things about the product itself, the critical features or the performance measurements that are important. It can list characteristics about the process that’s important. This is especially, so when it’s something chemical, an etching wash, a plating procedure, or even soldering standards for a circuit board for the characteristics, the control plan is also going to list the specification and its tolerance.

So that’s one thing that the supplier control plan is going to list is the characteristics as you’re designing and defining specifications, you may want to start out a control plan at the same time, because one can affect the other. You may find something in the control plan that you need to specify and make clear in the design specification. In our spec, we may have included features and their dimensions and tolerances, but we forgot about the important processing specs. After each characteristic, we list out the measurement or monitoring methods. We want to think about how it’s sampled for measurement. How many are sampled? How frequently are they sampled? How critical is this characteristic to our product design. If you’re already using FM E a to determine severity and then confidence levels for your B and V testing, then you can use that same information to determine the level of inspection for any characteristic of a part from manufacturing.

If you have a characteristic that has a high criticality, then you’re going to want to sample it more frequently and have a higher confidence in your sampling level that may drive how many that you want to look at and how frequently you look at it. If you don’t use FMEA in this way, then you still want to capture the, how many and how frequent for a measurement and monitoring method. We also want to capture who is measuring it. And when is it going to be the supplier as part as their outgoing inspection or in process inspection? Are we going to do it as part of our quality assurance incoming inspection, or is it an inspection during our manufacturing? If it’s a wrong fit, the part can’t go together. The last thing that the control plan could capture is a reaction plan for when things don’t go, right, what are we going to do? When things don’t measure properly, some of this would be captured in the supplier management agreement, but when we’re thinking of our suppliers as partners in quality, it helps to capture the reaction plan on the, the control plan itself. We just need to ensure that it aligns with our supplier agreement.

So what’s, today’s insight to action. When setting up suppliers, try working with them on a control plan for your product, you’ll find it may help you to make clear specifications and communicate expectations easier. You’ll find it’ll also help you to relate everything to risk, to help you determine what those critical features and performance characteristics should be. If you like the content in this episode, visit quality during design.com, where you can subscribe to the weekly newsletter to keep in touch. This has been a production of Deeney Enterprises. Thanks for listening!