By David O’Leary, Eric Landon, and Angela Williams, Accumold
Almost all injection molders have an internal qualification process to prepare for production. Parts used in the medical field and other critical applications may need Enhanced Qualification (EQ) to provide both confidence and documentation the molded parts meet specifications and can be delivered on time. With micro-sized parts, it is more challenging to meet capability requirements with micron-sized tolerance windows and features, making qualification even more important. Working with a micro molder to develop an EQ process can save money and time over the course of the project by ensuring a smooth transition into full-volume production.
Do I need an Enhanced Qualification process?
An Enhanced Qualification process can be helpful or even critical when a part’s feature must be manufactured to exacting specifications to fit with another part or when there is a customer conformance requirement or industry standard and/or regulatory requirements. The customer can outline data required to meet any regulatory or legal requirements. This documentation can also show reasonable steps were taken to make a good part if legal problems were to arise after the product was in use.
Another value of Enhanced Qualification is that it includes qualification parts on which additional testing can be performed. These can be used by a device manufacturer to test how a critical part performs within the device before production begins. Working through enhanced validation with a customer also provides additional cohesiveness as the product moves on to production. For example, if both parties discuss measurement techniques, then they might use the same fixtures to make measurements and carry out correlation studies to ensure both sites measure parts properly.
An EQ process also examines how the molding process can be improved to make a better-quality part. The processing parameters that require control to achieve a quality part are identified and mitigated during qualification.
What steps are involved in an enhanced process qualification?
An EQ process always starts with a plan. For products that require regulatory approval, like medical devices, customers are heavily involved in developing and carrying out that plan. The qualification plan might include reports at each step in the qualification process and require customer approval before qualification advances to the next step.
The micro molder first performs Installation Qualification (IQ). This is essentially a hardware check during which all equipment is examined to ensure it is installed correctly, functioning well, and all safety requirements are in place. Once hardware is confirmed, the tool is processed and first off tool (FOT) parts are produced to ensure the tool and process make a part that is representative of the customer model/print. The FOT parts may not be optimized, but they provide good feedback for the molder and customer. Once FOT parts have been processed, some tool or process adjustments may be required to clean up part dimensions or visual issues. Once the cleanup is finished, the tool/process can be set up for a stress run to ensure the process will run successfully for a defined period at a specified speed. Once the molder has confidence in the process, a design of experiments (DOE) will be designed by a cross-functional team. During DOE, the micro molder methodically tests process parameters at various settings to determine how they affect part features. DOE results provide information used to develop operating windows and optimal process settings.
The acceptable operating window is carried over to Operational Qualification (OQ), where high and low process setting limits are tested again to determine if conforming parts (visual and dimensional) are produced at all settings within these limits. At this point, the process capability index (Ppk) is calculated to determine the variation in the process compared to specification limits.
Performance Qualification (PQ) is then performed to test again the optimal process settings. During this qualification step, parts are molded and measured to prove the Ppk values are acceptable and the production system is robust. By simulating actual production, process qualification may also reveal issues that might cause risk in the process. It also provides the opportunity to test how various lots of material affect part variation and to qualify equivalent backup equipment.
After process qualification, a First Article Inspection (FAI) report is produced. This report provides objective evidence that the process is ready for production.
What should I look for in an Enhanced Qualification process?
When choosing a micro molder, it is important to understand the Enhanced Qualification process that will be used and how it proves the production process can repeatably produce a quality product. Some micro molders offer additional steps that can help provide assurance in their process. For example, Accumold uses a unique workflow known as production-ready equipment process (PREP) to move from the FOT to the qualification runs.
PREP involves an internal team that tests if the mold/process functions well and can run for a period of time. After a successful PREP run, the team takes apart the mold and examines it for wear or other concerns. If any issues are found, corrections are made by the team and the PREP process is repeated. Once the team feels the mold/process is running well on a repeatable basis, they approve the mold to move forward into qualification (DOE, OQ, PQ).
Because Accumold builds all molds in-house, Accumold can utilize the entire team to examine the mold, parts, and process for possible issues and improvements. Issues and improvements can be addressed quickly so the mold can be ready for the next step in the process.
A customer should look for a micro molder with tool building, molding, and processing expertise to develop the best EQ process for a particular part. A customer should also look for a micro molder that has flexibility to work on different timelines and the willingness to put in the time needed by the customer. An Enhanced Qualification for one part may take weeks, while another takes months because of various adjustments/improvements incorporated along the way.
In addition to being able to build and process molds, it is just as important to make sure the micro molder has measurement systems and equipment that can reliably separate conforming and nonconforming parts. A statistical tool called gage repeatability and reproducibility (gage R&R) is used to measure variation in the measurement system that arises from the measurement device and the people performing the measurement. If gage R&R studies reveal excessive variation, corrections can be made.
Risk assessment is another important part of qualification. Medical parts often require risk analysis, such as failure mode and effects analysis (FMEA), be performed before the first part is made.
How will paying for additional qualification lower other costs?
Although additional qualification typically entails some extra time and cost up front, it often more than pays for itself by avoiding costly problems down the road. By assuring variables and risks are taken into account, Enhanced Qualification greatly reduces the likelihood of parts not meeting specifications. This saves a great deal of time and money because parts don’t have to be scrapped or returned when they don’t work in an assembly.
Because Enhanced Qualification also considers how the mold and other hardware will handle stress over time, it helps improve supply certainty. Taking steps to assure the mold and other hardware will make good parts — not only during the first hundred runs but also as manufacturing scales up — eliminates downtime that would be spent addressing mold and hardware problems and provides additional certainty that shipment dates will be met.
In summary, an Enhanced Qualification process is a collaborative process between the micromolder and customer that can provide extra assurance as well as necessary data and documentation that prove the molder has considered every requirement for a certain part. Although it can involve some extra investment, Enhanced Qualification provides an important opportunity to avoid potential problems and to make sure the project goes as smoothly as possible.
Accumold has been continuously dedicated to micro molding for over 30 years. We remain committed to serving high-tech industries that require high-volume, small, complex, micro-injection molded parts with high quality and fast turnaround. Markets served include micro-electronics, automotive electronics, fiber/micro-optics, medical, and emerging technologies.