eVTOL Vehicles

eVTOL Vehicles PC/ABS Standard Injection Molding with Arburg Allrounder 470 A

The Unforgiving Physics of Urban Air Mobility

The engineering challenge of the eVTOL Vehicles sector is a brutal exercise in managing competing physical constraints. Every gram of mass penalizes range and payload. Every component must withstand a constant barrage of high-frequency vibrations from multiple electric propulsion units. Thermal management is not an afterthought; it is a primary design driver, especially for battery packs, power electronics, and the motors themselves. In this high-stakes environment, material selection and manufacturing process control are not just line items on a bill of materials—they are fundamental to vehicle safety, certification, and commercial viability.

This is where the conversation moves beyond simple datasheets and into the nuanced world of process-material interaction. You can select the perfect polymer, but if your manufacturing process introduces internal stresses, voids, or dimensional instability, you’ve engineered a failure point. For non-structural and semi-structural components like motor cooling jackets, avionics enclosures, and internal brackets, a high-performance thermoplastic is often the ideal choice. We've found that a specific grade of Polycarbonate/Acrylonitrile Butadiene Styrene, PC/ABS (SABIC CYCOLOY C2950), offers a superb balance of impact strength, dimensional stability, and thermal resistance. However, this material comes with its own set of manufacturing challenges. It is notoriously hygroscopic, meaning it readily absorbs moisture from the atmosphere, which can cause catastrophic part failure during molding. It is also shear-sensitive; excessive injection speeds or poorly designed flow paths can degrade the polymer chains, compromising its mechanical properties.

This is the precise problem our specialized manufacturing cell is designed to solve. We combine the robust properties of this aerospace-grade PC/ABS with the uncompromising precision of Standard Injection Molding on a state-of-the-art, all-electric Arburg Allrounder 470 A. This isn't just injection molding; it's a digitally controlled, closed-loop system engineered to produce aerospace-compliant components with a level of consistency that hydraulic machines simply cannot match.

Engineering for Certification: AS9100D, FAA, and DO-160G

For any component to fly on a commercial eVTOL, it must be born from a process that is certifiable, repeatable, and fully traceable. This is a non-negotiable triad, and our Arburg-centric process is built around it.

AS9100D: The Foundation of Process Control

AS9100D is not just a quality certificate; it's a manufacturing philosophy. It demands rigorous process control, configuration management, and risk mitigation. This is where the all-electric nature of the Arburg Allrounder 470 A provides a quantum leap over traditional hydraulic systems.

• Shot-to-Shot Repeatability: Every parameter—injection pressure, velocity profile, hold pressure, screw position, and mold temperature—is controlled by a precise electric servo motor, not a valve managing hydraulic fluid. This eliminates the variability caused by fluid temperature and viscosity changes, delivering unparalleled shot-to-shot consistency. For a shear-sensitive material like PC/ABS, this means we can maintain the exact velocity profile needed to fill the mold completely without degrading the polymer. This directly translates to consistent mechanical properties, part after part, which is a cornerstone of AS9100D compliance.
• Data-Driven Traceability: Each production cycle generates a complete digital fingerprint. We log every critical process parameter for every single part produced. If a quality issue ever arises, we can trace it back to the exact machine conditions at the moment of molding. This level of data logging is essential for the root cause analysis and corrective action requirements of AS9100D.

FAA eVTOL Certification: Proving Structural and Material Integrity

While FAA standards for eVTOLs are still evolving, the core principles are clear: manufacturers must prove the airworthiness and reliability of every system and component. Our process directly addresses two key areas of concern for polymer components:

• Mitigating Internal Stress: The superior thermal stability of our molding cell, combined with precise control over cooling rates, allows us to produce net-shape parts with minimal internal stress. For a component like a motor cooling jacket, which will experience constant thermal cycling, high internal stress is a latent defect waiting to cause a crack. By molding parts that are dimensionally perfect and internally stable right out of the mold, we eliminate the risks associated with secondary machining or finishing, which can introduce their own stresses.
• Ensuring Material Homogeneity: The hygroscopic nature of PC/ABS means improper drying is a primary failure vector. Our process incorporates a closed-loop drying and feeding system that ensures the resin is at the optimal moisture content (typically below 0.02%) at the moment of injection. The Arburg's precise injection control prevents thermal degradation or "burning" of the material in the barrel, ensuring the polymer's intended properties, as specified by SABIC, are fully expressed in the final part. This provides the FAA with confidence that the part in the aircraft matches the part that was qualified.

DO-160G: Surviving the Operational Environment

DO-160G, "Environmental Conditions and Test Procedures for Airborne Equipment," is the gauntlet every aerospace component must run. Our manufacturing approach ensures parts made from CYCOLOY C2950 can meet these requirements.

• Vibration and Shock (Section 8): The inherent toughness and impact resistance of the PC/ABS blend are key. However, process-induced weaknesses like knit lines or voids can become failure points under vibration. The Arburg's ability to precisely control injection and packing pressure ensures these features are minimized and located in non-critical areas, resulting in a robust, monolithic structure that can withstand the rigorous vibration profiles specified in DO-160G.
• Temperature and Thermal Shock (Sections 4 & 5): A motor cooling jacket will experience rapid temperature changes. The material's max service temperature of 96°C is adequate, but only if the part is molded correctly. Our process stability eliminates process drift during long production runs, guaranteeing that the dimensional tolerances critical for proper fit and thermal transfer are maintained across the entire batch. This ensures consistent performance under the thermal shock testing mandated by DO-160G.

Core Process & Machine Parameters

This isn't a generic molding service. This is a precision manufacturing cell optimized for a specific set of demanding applications. The table below outlines the critical parameters that define this capability. We are not just providing parts; we are providing guaranteed process control.

Cost Dynamics and the TCO of Precision

This manufacturing solution is specifically optimized for production volumes between 200 and 2,000 units. This range represents the typical lifecycle of early-stage vehicle programs, pre-production runs, and initial low-rate production where quality and consistency are paramount. While the initial tooling investment for injection molding makes it uneconomical for single-digit prototypes, this process cell finds its sweet spot before scaling to multi-cavity, high-speed tooling for runs of 100,000+ units.

The true economic advantage, however, lies in the reduction of the Total Cost of Ownership (TCO), a direct result of our core factory advantage. Processing a hygroscopic, shear-sensitive PC/ABS blend for aerospace applications demands absolute process control. This is where the all-electric Arburg Allrounder 470 A provides a distinct advantage. Its electric drives deliver unparalleled shot-to-shot consistency and precise control over injection speeds and pressures. This capability is critical for us to manage the material's sensitive viscosity, preventing thermal degradation and ensuring complete mold filling. The machine's superior thermal stability eliminates process drift during continuous runs, guaranteeing every part meets the stringent dimensional requirements for eVTOL components like motor cooling jackets.

Let's break down the TCO reduction:

1. Drastically Reduced Scrap Rate: Inconsistent molding of PC/ABS leads to splay (from moisture), short shots, and burn marks. Each scrapped part is a waste of expensive, aerospace-grade material and machine time. The Arburg's precision minimizes these defects, driving scrap rates toward zero and lowering the effective cost per good part.
2. Elimination of Secondary Operations: At MechanoFab, this allows us to produce net-shape parts compliant with AS9100D standards directly from the mold. There is no need for secondary CNC machining to correct for warpage, no manual deburring of flash, and no reaming of holes. This mitigates thermal stress risks without secondary finishing. These post-molding operations add significant labor cost and introduce process variability and potential for damage. By delivering a finished part from the tool, we remove entire steps—and their associated costs—from the value chain.
3. Lowered Inspection and Quality Costs: When a process is demonstrably stable and repeatable, the burden of 100% dimensional inspection can often be reduced to statistical process control (SPC) and periodic audits. Knowing that every part is a "clone" of the one before it reduces the time and cost associated with quality assurance, a significant expense in any aerospace program.

The upfront piece-part price from this process may be higher than that from a general-purpose shop using older hydraulic machines. However, for any serious engineering program, the TCO—factoring in scrap, rework, secondary operations, and quality assurance overhead—will be substantially lower. You are not just buying a plastic part; you are buying a guarantee of compliance, consistency, and reduced program risk.

Conclusion

For engineers developing the next generation of eVTOL aircraft, component manufacturing cannot be an afterthought. Our specialized cell, pairing SABIC CYCOLOY C2950 with the all-electric precision of the Arburg Allrounder 470 A, is a purpose-built solution for producing certifiable, reliable, and cost-effective polymer components. We speak the language of process control, traceability, and aerospace compliance because we have built our systems around it.