Senior Product Integration Engineer; CAD

Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, Next Era Energy Resources, Schneider Electric, and more.

The core values that ground our work, guide our decisions, and connect us together:

• Pragmatic Optimism
• Excellence without Ego
• Proactive Collaboration

Mainspring is seeking a Senior Product Integration Engineer (CAD) to own and maintain the integrated CAD definition of the Linear Generator as designs evolve. Design Engineers will continue to own the technical design and subsystem CAD; this role will make sure those designs are incorporated into authoritative POR and future-state reference assemblies and work together correctly in the context of the complete product.

This role combines product-definition ownership with hands‑on whole‑product CAD integration. The ideal candidate is exceptionally strong in 3D CAD, understands how complex mechanical systems fit together, and enjoys resolving packaging, interface, and configuration problems across multiple engineering teams. This role will be a key user of CATIA for full-product assemblies that exceed the practical limits of Solid Works.

• Build, maintain, and continuously improve authoritative POR and future-state reference assemblies for the Linear Generator
• Integrate subsystem CAD from multiple Design Engineering teams into full-product CATIA assemblies and keep those assemblies current as engineering changes progress
• Maintain clean full-product CAD structure, references, interfaces, metadata, and configuration logic across major assemblies
• Perform packaging studies, interference checks, clearance reviews, routing studies, service-access checks, and assembly-access evaluations
• Identify conflicting space claims and work with Design Engineers to negotiate interfaces and converge on practical whole-product solutions
• Create and maintain reference geometry, interface geometry, envelopes, simplified models, and other integration artifacts needed to support cross-team design work
• Support design reviews with clear visualizations of clashes, interfaces, access constraints, and product-level integration risks
• Identify and resolve inconsistencies among integrated CAD, drawings, EBOM structure, and the intended product configuration before release
• Support Product Release and Configuration Management by providing a clear, traceable digital definition of the product state being released
• Help establish scalable methods and standards for CATIA, large-assembly performance, imported geometry, simplification, reference assemblies, and cross-CAD workflows

• BS in Mechanical Engineering, Product Design, or a related technical field, or equivalent relevant experience
• 5+ years of experience in mechanical CAD, product design, packaging, product integration, or complex equipment design
• Advanced proficiency with CATIA, NX, Creo, Solid Works, or another advanced 3D CAD platform; strong CATIA experience is highly preferred
• Demonstrated experience building and maintaining large, complex, multi-subsystem assemblies with disciplined reference and configuration practices
• Strong mechanical intuition and ability to identify packaging, clearance, routing, serviceability, assembly, and interface issues from 3D CAD
• Strong understanding of mechanical interfaces, drawings, GD&T, BOMs, revisions, and…