Making Injection Molding More Efficient
When it comes to injection molding, traditional manufacturing methods involve a very calculated process that requires molders to re-validate parts every time a mold is going to run in a different machine. This has become a major design headache for device makers, especially for those creating high-precision devices.
This re-validation requirement was costing device manufacturers millions of dollars every year and would often lead to weeks or even months of machine downtime. This would often result in lost revenues for both the molders and original equipment manufacturers. That is until recently, when a group of medical device equipment manufacturers set out to design a more-efficient part development and validation process for injection molding that can be transferable between different machines.
This new process was able to execute a real-world proof-of-concept event that could enable molders to replicate transferable plastic conditions that can completely eliminate the need to 100% re-validate the tool every time it is moved to a new machine, MD+DI has been told. Using this reduced PQ verification run, molders could potentially save millions of dollars every year, while also reducing risk based on the confirmation of repeatable statistical results.
To better understand the significance of this new process, MD+DI reached out to Scott Scully, a master molder and plastics veteran for more than 39 years. Scully has spent the last 17 years working for Terumo Cardiovascular Systems, a company that specializes in the development, manufacturing, and distributing of medical devices for cardiac and vascular surgery. Scully has also created a validation and troubleshooting team to help assist suppliers with developing validation procedures that are compliant and cost effective.
Scully will be speaking about this new validation and part process at this year’s MD&M Minneapolis conference on November 1. He’ll be part of the panel discussion, “Part Process Development and Validation for Multiple Machines.” In anticipation of his talk, MD+DI decided to discuss with Scully the significance of this new injection molding process and the impact it could have on device development. (Joining Scully in the discussion will be Matt Therrien, business development manager - medical, RJG Inc.; and Paul Robinson, vice president operations, QSCS. Download the white paper before the conference: "OEM Shares Methodology to Validate a Part to Save Money.")
MD+DI: For starters, can you talk a little about the traditional validation and part processes, specifically the process of re-validating a part every time the mold runs in a different machine? Why is this required, and how does it negatively affect medtech manufacturers?
Scully: Traditionally the validation was centered on machine settings, not taking into account what was actually happening in the cavity. Processes were based on inputs, not on the outputs these settings created. This mindset required a full validation when moving from machine to machine, as it was unknown what different setting on a different machine was affecting the physical properties of the polymer. This unknown required full validation to ensure part functionality and ensure safety to the patient. This mindset handicaps the original equipment manufacturer in being nimble with scheduling changes and changing suppliers, as the cost and resources can be prohibitive.
MD+DI: So how does this new part process work, and how will it enable molders to replicate transferable plastic conditions? Will this eliminate the need to 100% re-validate the tool every time it is moved to a new machine?
Scully: By validating the process instead of the machine, we can replicate the same process with Machine Independent Variables, known as MIVs. The original full validation documents the outputs of the machine settings inputs. By replicating the outputs, you will ensure that the properties of the polymer are unchanged from one machine to another. However, a PQ/process capability study is still required to ensure the process is capable and in control.
MD+DI: What kind of an impact do you think this new process could have on both the process of manufacturing and the cost?
Scully: The savings to move a mold will be in the tens of thousands per part. The ability to react to changes in scheduling will improve throughput and prevent back orders tremendously.
MD+DI: How can this process help reduce and mitigate risk when it comes to statistical control?
Scully: Risk must be mitigated during the initial validation. If done properly, it will carry through from machine to capable machine. By measuring the outputs that are independent from the machine, you are replicating the original process and not creating a new one.
MD+DI: How do you think this methodology can help drive continuous improvements and sustain the required statistical control? Do you think that time saved is the biggest upside to this new process?
Scully: The required statistical control must be proven in the original validation. The new machine must be capable, proper volume, injection speed, tonnage, etc. With that, the original process can be replicated. However, every process is different, and capability must be proven with a PQ. Success is not guaranteed, so empirical data from a PQ must be created and shown to be capable and in control. Time and ability to free up resources are definitely the biggest upside, and both can help drive continuous improvements.
MD+DI: Finally, I realize the future can be difficult to predict, but how soon do you think this methodology can be adopted across the molding industry? In your own eyes, how important do you think this step could be when it comes to advancing medical device development and manufacturing?
Scully: It is being adopted as we speak. At least one member of the consortium has already created a team to introduce and implement this methodology at all of their molding sites.