In the demanding field of aerospace injection molding, the pursuit of robust process development is pivotal for enhancing efficiency and product quality. A recent encounter with an aerospace company in Los Angeles highlights the transformative impact of advanced process-development software, exemplified by Nautilus, on injection molding practices.
When initially challenged by the companys skeptical owner about the necessity of such software, given his years of successful operation without it, a practical demonstration proved insightful. By integrating Nautilus into their operations, we achieved a remarkable 16% reduction in cycle time (from 32 seconds to 26 seconds) for a four-cavity mold, simultaneously reducing inspection frequency and establishing a no-tweak, robust process. This hands-on demonstration clearly underscored the softwares capability to significantly boost operational success and profitability in aerospace component manufacturing.
It is essential to acknowledge a common oversight in the industry: the attempt to mold aerospace components to exact specifications on the initial run. The focus should instead be on two aspects. Firstly, ensuring the mold design supports a tweak-free, maintenance-minimal operation once production commences. Secondly, verifying that the product quality consistently meets specified limits without needing ongoing adjustments, which could be influenced by shift changes or environmental factors.
A robust molding process, therefore, should consistently produce parts that meet quality specifications without any need for adjustments in process parameters throughout the entire production cycle and beyond. Such a process minimizes variations stemming from diverse sources such as machinery, materials, environment, measurement systems, and operational personnel, aiming for what can be described as 'cruise control' in molding.
The cornerstone of scientific moldingand by extension, scientific processinglies in meticulous attention to the journey of the plastic pellet from reception to shipping. The initial phase of process development involves exploring the 13 process parameters (11+2 if pack and hold phases are combined) to establish the Cosmetic Process Windows (CPW). This phase is critical for determining the process' robustness independent of specific dimensions.
Following this, a Designed Experiment (DOE) should be conducted in the second phase to correlate dimensional stability with the process setting range, helping establish a Dimensional Process Window (DPW). The wider this window, the greater the process robustness, steering clear of the proverbial 'edge of the cliff' scenario, where slightest variances could lead to subpar parts.
Ultimately, if the dimensional window is restrictive, the options are recalibrating the cavity dimensions of the mold or adjusting the part specifications themselveswith a preference for the former whenever feasible. It is vital that such decisions are backed by robust data from DOEs to ensure any modifications lead to a genuinely more efficient and reliable molding operation.
This approach not only fortifies the aerospace injection molding process but also equips it to handle the inherent variability of production environments, ensuring high-quality outcomes consistently. Adopting such advanced methodologies and tools is not merely about keeping pace with technological advancement but about setting new benchmarks in aerospace manufacturing efficiency.
About the Author: Suhas Kulkarni, founder and president of Fimmtech, San Diego, specializes in Scientific Molding with over two decades of experience in aiding molders develop robust processes. His book, Robust Process Development and Scientific Molding, is a vital resource in the field.
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