Rapid Prototyping Engineer

📍 Job Overview

Job Title: Rapid Prototyping Engineer

Company: Tacit

Location: San Francisco, California, United States

Job Type: Full-time

Category: Hardware Engineering / Product Development Operations

Date Posted: 2026-08-27

Experience Level: 2-5 years

Remote Status: On-site

🚀 Role Summary

• Spearhead rapid design, fabrication, and iteration of mechanical, electrical, and sensor prototypes for novel wearable devices, aligning with R&D and hardware engineering objectives.

• Develop and own assembly and test fixtures, jigs, and tooling to ensure build quality, efficiency, and repeatability for complex devices and wearables throughout NPI/NTI cycles.

• Collaborate closely with cross-functional teams (Electrical, RF, Mechanical, Firmware, Design) to integrate hardware, troubleshoot issues, and provide DFM/DFA feedback to optimize designs for production.

• Drive hands-on assembly, debugging, and troubleshooting of electromechanical systems, identifying and resolving failure modes specific to wearable hardware.

📝 Enhancement Note: This role is positioned at the critical intersection of research and development (R&D) and production-readiness in hardware engineering. The emphasis on "rapid prototyping," "fixturing," and "DFM/DFA feedback" indicates a strong focus on operationalizing innovation and ensuring manufacturability early in the product lifecycle. The role requires a blend of hands-on building skills and an engineering mindset focused on process efficiency and scalability for future production.

📈 Primary Responsibilities

• Rapidly design and fabricate mechanical, electrical, and sensor prototypes to support R&D experiments and engineering development for wearable and consumer-electronics form factors.

• Build end-to-end prototype systems: from concept sketches through CAD, fabrication, wiring, sensor/RF component integration, and validation.

• Develop quick-turn PCBs, flex circuits, wiring harnesses, and cable assemblies for prototype electronics, including hands-on soldering and assembly of delicate flex and fine-pitch components.

• Evaluate and select sensors, actuators, and off-the-shelf components for seamless integration into prototype systems.

• Design, build, and iterate on assembly and test fixtures, jigs, and tooling from the ground up to support novel processes and ensure build quality and efficiency for complex devices and wearables.

• Partner with design engineers to provide DFM/DFA feedback and drive design iterations before problems reach production.

• Build fixtures that improve repeatability, cycle time, and debug visibility for both R&D builds and early manufacturing runs.

• Perform hands-on assembly, troubleshooting, and debugging of electromechanical systems, isolating whether an issue is mechanical, electrical, or process-related.

• Identify and address failure modes specific to wearable hardware (fit, comfort, cable management, contact forces, thermal effects, wear over repeated use).

• Take initiative in driving design iterations, documenting findings, and proposing next steps with minimal supervision.

• Collaborate with electrical, RF, mechanical, and firmware engineers to integrate hardware with control systems and test software.

• Support NPI/NTI/R&D efforts, working closely with design and validation teams as products move from early prototype toward production intent.

• Communicate build status, design risks, and recommendations clearly to both technical and non-specialist audiences.

• Document designs, build procedures, and test results to support knowledge transfer and continuous design improvement.

📝 Enhancement Note: The responsibilities highlight a dual focus: first, on the rapid creation and iteration of functional prototypes to validate R&D concepts, and second, on the operationalization of these prototypes through robust fixturing and DFM/DFA considerations. This bridges the gap between ideation and manufacturability, crucial for a hardware startup. The emphasis on "wearable hardware" specific failure modes and "quick-turn PCBs" points to a fast-paced, iterative development environment.

🎓 Skills & Qualifications

Education: Bachelor's degree in Mechanical, Electrical, Mechatronics Engineering, or a related field.

Experience: 2+ years of experience in prototyping, R&D engineering, or hardware development, ideally in wearables, consumer electronics, robotics, or research lab environments. Required experience with NPI/NTI/R&D processes, taking hardware from early concept through pre-production.

Required Skills:

• Proficiency in CAD software (Onshape, SolidWorks, or Fusion 360) with strong 3D modeling and drafting skills.

• Working knowledge of PCB design and electronics, and comfort with soldering electrical and RF circuit components, wiring, reading schematics, and integrating sensors.

• Hands-on ability to build and troubleshoot electromechanical systems.

• Hands-on expertise with rapid prototyping methods: 3D printing (FDM/SLA), laser cutting, CNC machining, sheet metal fabrication, and manual machining.

• Demonstrated experience designing and building assembly and test fixtures, jigs, and tooling from scratch.

• Excellent project management and cross-functional collaboration skills.

• Strong track record of troubleshooting, debugging, and iterating on designs independently.

• A builder at heart: someone who takes initiative, brings creativity and problem-solving to ambiguous challenges, and can work with minimal supervision.

• Excellent communication skills and comfort operating in a fast-paced, ambiguous environment where requirements evolve quickly. Preferred Skills:

• Familiarity with wearable or consumer-electronics form factors and the constraints of designing for comfort, fit, and durability against the body.

• Experience with RF or antenna hardware integration and the fixturing challenges specific to RF test and assembly.

• Basic scripting ability (Python) for test automation, data collection, or hardware interfacing.

• Experience supporting builds across EVT, DVT, and PVT stages with contract manufacturers.

📝 Enhancement Note: The "Required Skills" emphasize a strong hands-on, generalist engineering profile with expertise in a wide array of rapid fabrication techniques and core electrical/mechanical engineering principles. The "Preferred Skills" indicate areas that would accelerate a candidate's impact, particularly in specialized hardware domains like RF or supporting contract manufacturing processes, which are crucial for scaling hardware production.

📊 Process & Systems Portfolio Requirements

Portfolio Essentials:

• Showcase a diverse range of electromechanical prototypes designed and built, demonstrating end-to-end ownership from concept to functional system.

• Include detailed examples of assembly and test fixtures, highlighting the problem they solved, the design process, and the impact on build efficiency, repeatability, or quality.

• Present case studies of hardware designs that incorporated DFM/DFA feedback, illustrating how initial concepts were iterated upon to improve manufacturability.

• Demonstrate experience with rapid prototyping techniques (3D printing, CNC, etc.) through visual examples of complex parts or assemblies.

• Provide evidence of troubleshooting and debugging complex electromechanical issues, detailing the process and the resolution. Process Documentation:

• Documented workflows for rapid prototype development, from initial design to final build and basic validation.

• Procedures for designing, fabricating, and implementing assembly and test fixtures, including considerations for repeatability and user ergonomics.

• Methodologies for integrating components (sensors, actuators, flex circuits) into prototype systems, including soldering and wiring best practices.

• Examples of how DFM/DFA feedback was incorporated into design iterations, with clear rationale and impact.

📝 Enhancement Note: For a role centered on rapid prototyping and bringing concepts to life, a portfolio is paramount. It should not only showcase the final output but also the process, problem-solving, and iterative nature of the work. Emphasis should be placed on demonstrating the ability to not just build, but to build smartly—with an eye towards efficiency, repeatability, and eventual manufacturability.

💵 Compensation & Benefits

Salary Range: $123,000 - $139,000 per year.

Benefits:

• Competitive equity package, offering ownership in an early-stage deep tech startup.

• Comprehensive medical, dental, and vision insurance to ensure employee well-being.

• Unlimited Paid Time Off (PTO) to promote work-life balance and flexibility.

• Visa sponsorship available for eligible candidates.

• 4% 401k matching to support long-term financial planning.

Working Hours: Standard 40-hour work week, with the expectation of flexibility and commitment inherent in an early-stage startup environment, particularly during critical development phases.

📝 Enhancement Note: The salary range provided is competitive for a Rapid Prototyping Engineer role with 2-5 years of experience in the San Francisco Bay Area, a high-cost-of-living region known for its deep tech and hardware innovation. The benefits package is robust, reflecting typical startup offerings with a strong emphasis on employee well-being and long-term incentives like equity and 401k matching. The "Unlimited PTO" is a common perk designed to foster trust and autonomy.

🎯 Team & Company Context

🏢 Company Culture

Industry: Deep Tech / Hardware Innovation (specifically rethinking human-computer interaction with novel hardware).

Company Size: 30-50 people. This indicates an environment where individual contributions are highly visible, and there's significant opportunity for direct impact. It also suggests a close-knit team dynamic where cross-functional collaboration is essential.

Founded: Early-stage startup, backed by prominent VCs (General Catalyst, Khosla Ventures, Greylock Partners). This implies a fast-paced, high-growth environment with a strong focus on innovation and product development. The founding team's background (Stanford, BrainGate, Oculus, Tesla) suggests a high caliber of talent and ambitious goals.

Team Structure:

• The "Rapid Prototyping Engineer" will likely be part of a core hardware engineering team, working closely with specialized groups in electrical, RF, mechanical, firmware, and design.

• Reporting structure is likely to a Hardware Engineering Lead or Director, with direct collaboration across multiple technical disciplines.

• Cross-functional collaboration is critical, as the role acts as a bridge between R&D concepts and manufacturability, requiring constant interaction with design, sensing, electrical, and firmware teams. Methodology:

• Data-driven iteration and rapid feedback loops are expected, given the R&D and prototyping focus.

• Emphasis on turning concepts into tangible, testable systems quickly to accelerate learning.

• Design for Manufacturability (DFM) and Design for Assembly (DFA) principles will be integrated early in the process, driven by the prototyping team.

• Agile development methodologies are likely employed, requiring adaptability and quick responses to evolving requirements.

Company Website: https://tacit.ai/

📝 Enhancement Note: The company culture is described as "deep tech" and "early-stage startup," which typically translates to a dynamic, challenging, and innovative environment. The backing by top-tier VCs suggests significant potential and ambitious goals. The small team size implies a high degree of autonomy and impact for each individual, but also a need for strong collaboration and adaptability.

📈 Career & Growth Analysis

Operations Career Level: This role is an individual contributor, focused on hands-on engineering and prototyping. It's a mid-level position (2-5 years of experience) that requires significant technical depth and autonomy. It sits within the broader hardware engineering function, bridging R&D and New Product Introduction (NPI).

Reporting Structure: The Rapid Prototyping Engineer will likely report to a Senior Hardware Engineer, Engineering Manager, or potentially the Head of Hardware/CTO, depending on the organizational structure. They will work closely with engineers from electrical, mechanical, RF, and firmware disciplines.

Operations Impact: The role's direct impact is on accelerating the product development lifecycle by rapidly turning R&D concepts into buildable prototypes and providing critical DFM/DFA feedback. This operational efficiency directly influences time-to-market, cost of development, and the ultimate manufacturability and reliability of the final product. Success here means enabling faster iteration and reducing risks associated with scaling production.

Growth Opportunities:

• Technical Specialization: Deepen expertise in specific areas like wearable design constraints, RF fixturing, advanced PCB fabrication, or automation for prototyping.

• Process Development Leadership: Lead the development and refinement of internal prototyping and NPI processes as the company scales.

• Transition to NPI/Manufacturing Engineering: With experience gained, transition into roles focused on scaling production, working with contract manufacturers, and managing EVT/DVT/PVT builds.

• Mentorship: As the team grows, opportunities to mentor junior engineers in prototyping techniques and best practices.

📝 Enhancement Note: This role offers a foundational experience in hardware product development for a cutting-edge technology company. Growth opportunities are geared towards deepening technical expertise in hardware design and manufacturing readiness, or moving into leadership roles within the engineering or operations functions as the company scales. The emphasis on NPI/NTI processes is a strong indicator of a structured path towards production.

🌐 Work Environment

Office Type: On-site in San Francisco. This indicates a collaborative, in-person work environment essential for hands-on hardware development.

Office Location(s): San Francisco, California. This location provides access to a rich ecosystem of tech talent, suppliers, and potential partners.

Workspace Context:

• Expect a hands-on lab or workshop environment equipped for rapid prototyping, including 3D printers, CNC machines, soldering stations, and testing equipment.

• Close proximity and direct interaction with other engineering teams (electrical, mechanical, firmware, design) will be common, fostering a collaborative and iterative design process.

• Access to essential tools and technology will be provided, with opportunities to suggest and implement new equipment or software for the prototyping lab.

Work Schedule: While a standard 40-hour work week is mentioned, the nature of an early-stage startup, especially in hardware development, often requires flexibility and dedication. Periods of intense build cycles or critical deadlines might necessitate longer hours, balanced by the unlimited PTO policy for overall well-being.

📝 Enhancement Note: The on-site requirement is critical for a role involving physical hardware prototyping, assembly, and testing. The San Francisco location places the role within a hub of technological innovation. The workspace will be geared towards hands-on work, emphasizing collaboration and rapid iteration.

📄 Application & Portfolio Review Process

Interview Process:

• Initial Screening: Review of resume and portfolio, focusing on relevant experience in prototyping, CAD, electronics, and fixture design.

• Technical Interview(s): In-depth discussion of past projects, technical challenges faced, problem-solving approaches, and hands-on skills (e.g., explaining a complex build, troubleshooting a hypothetical issue). Expect questions on CAD proficiency, electronics integration, and rapid fabrication methods.

• Portfolio Review: A dedicated session to walk through selected projects from your portfolio. Be prepared to discuss your role, the design process, challenges, solutions, and the impact of your work. Focus on demonstrating the "builder at heart" mentality and iterative problem-solving.

• Team/Hiring Manager Interview: Assessment of cultural fit, collaboration style, ability to work in an ambiguous environment, and alignment with Tacit's mission. Questions may probe initiative, communication skills, and how you handle evolving requirements.

• Potential Practical Assessment: May include a small build, design, or troubleshooting exercise to evaluate practical skills in real-time.

Portfolio Review Tips:

• Show, Don't Just Tell: Use high-quality photos, videos, and CAD renderings of your prototypes and fixtures.

• Structure Your Projects: For each project, clearly outline the problem, your role, the design/build process, key challenges, solutions implemented, and the outcome/impact (e.g., improved cycle time by X%, enabled Y experiment).

• Highlight Fixturing: Dedicate specific examples to assembly and test fixtures, detailing their purpose, design considerations, and effectiveness.

• Emphasize Iteration: Showcase how you iterated on designs based on testing or feedback, demonstrating your problem-solving and adaptability.

• Quantify Impact: Where possible, use metrics to demonstrate the value of your work (e.g., "reduced assembly time by 30%," "enabled testing of 5 new sensor configurations").

• Be Ready to Discuss Details: Be prepared to answer detailed questions about your design choices, fabrication methods, and troubleshooting steps.

Challenge Preparation:

• Problem-Solving Scenarios: Anticipate questions asking how you would approach designing a fixture for a specific component, troubleshooting a non-functional prototype, or integrating a new sensor.

• DFM/DFA Application: Be ready to discuss how you would provide feedback to a design engineer to improve a part for manufacturability or ease of assembly.

• Ambiguity and Initiative: Prepare examples of times you've worked with unclear requirements, taken initiative to solve a problem, or driven a design forward with minimal supervision.

📝 Enhancement Note: The interview process is designed to rigorously assess both technical proficiency and the candidate's operational mindset. The portfolio review is a critical component, serving as tangible proof of the skills and experience required. Candidates should prepare to articulate their process, problem-solving abilities, and the impact of their work with concrete examples.

🛠 Tools & Technology Stack

Primary Tools:

• CAD Software: Onshape, SolidWorks, or Fusion 360 (proficiency required). These are essential for mechanical design and fixture creation.

• Rapid Prototyping Hardware:

  • 3D Printers (FDM/SLA): For quick iteration of plastic parts and enclosures.
  • CNC Machining: For higher precision parts and tooling.
  • Laser Cutting: For sheet metal and acrylic components.
  • Manual Machining Tools: For custom fabrication and modifications.

• Electronics Tools:

  • Soldering Irons (including fine-pitch and hot air rework).

  • Multimeters, Oscilloscopes, Logic Analyzers for debugging.

  • PCB Design Software (familiarity needed, even if not designing complex boards from scratch).

  • Wire stripping, crimping, and harness assembly tools. Analytics & Reporting:

• While not a primary focus, basic data collection or scripting (e.g., Python) might be used for test automation or logging results.

• Documentation tools (e.g., Confluence, Google Docs) for recording procedures and findings.

CRM & Automation: Not directly applicable to this role's core function, but understanding the broader product development pipeline and how prototypes feed into it is beneficial.

📝 Enhancement Note: The technology stack heavily emphasizes hands-on fabrication and electrical assembly tools. Proficiency in CAD is a given, but the ability to operate and maintain various prototyping machines and perform delicate electronic assembly and soldering is equally critical. Basic scripting for test automation is a plus, indicating a leaning towards efficiency.

👥 Team Culture & Values

Operations Values:

• Builder Mentality: A core value is the intrinsic drive to create, build, and solve physical problems. This translates to taking initiative and enjoying hands-on work.

• Bias for Action & Speed: In an early-stage startup, moving quickly and iterating rapidly is paramount. This means prioritizing getting things done and learning from them, rather than getting stuck in analysis paralysis.

• Collaboration & Communication: Working effectively with diverse engineering teams requires clear, concise communication and a willingness to share knowledge and provide constructive feedback.

• Problem-Solving & Resilience: Tackling novel engineering challenges means embracing ambiguity, troubleshooting effectively, and persevering through setbacks.

• Focus on DFM/DFA: Integrating manufacturability considerations early in the prototyping phase demonstrates a commitment to long-term product success beyond just functional validation.

Collaboration Style:

• Cross-Functional Integration: Expect to work closely with design, electrical, RF, and firmware engineers, acting as a key liaison for physical implementation and testing.

• Feedback Loops: A culture of open feedback, where insights from prototyping and fixturing are shared readily to inform design improvements.

• Knowledge Sharing: Documenting processes and learnings to build collective expertise within the hardware team, especially as the company scales.

• Experimental Mindset: Encouraging experimentation with new techniques, tools, and materials to find the most efficient and effective prototyping solutions.

📝 Enhancement Note: The culture emphasizes a hands-on, fast-paced, and collaborative approach to hardware development. The "builder at heart" ethos is central, complemented by a strong drive for speed, problem-solving, and cross-functional teamwork. This environment is ideal for individuals who thrive on creating tangible products and enjoy direct problem-solving.

⚡ Challenges & Growth Opportunities

Challenges:

• Ambiguity and Evolving Requirements: As an early-stage deep tech startup, the exact product specifications and R&D directions may shift frequently. Adapting to this ambiguity and maintaining momentum will be key.

• Novel Hardware Integration: Integrating cutting-edge sensors and components into novel wearable form factors presents unique mechanical, electrical, and thermal challenges that require creative solutions.

• Balancing Speed and Quality: The need for rapid prototyping must be balanced with the requirement for reliable builds and insightful testing, demanding efficient processes and careful execution.

• DFM/DFA at the Cutting Edge: Applying DFM/DFA principles to entirely new hardware designs and manufacturing processes can be challenging, requiring foresight and proactive engagement with design teams.

Learning & Development Opportunities:

• Deep Dive into Wearable Technology: Gain in-depth knowledge of the specific engineering challenges and design considerations for wearable devices, including ergonomics, power management, and sensor integration against the body.

• Advanced Prototyping Techniques: Master new fabrication methods and technologies as they become relevant to Tacit's product development roadmap.

• NPI Process Immersion: Learn and contribute to the New Product Introduction (NPI) process, understanding the transition from R&D prototypes to production-intent builds and contract manufacturing.

• RF and Sensor Integration Expertise: Develop specialized skills in integrating and testing RF components or advanced sensors, a key differentiator for the company.

• Mentorship and Leadership: As the company grows, opportunities to mentor junior engineers and potentially lead aspects of the prototyping or NPI efforts.

📝 Enhancement Note: The primary challenges stem from the inherent nature of working in an early-stage deep tech startup: high degrees of innovation, rapid iteration, and evolving requirements. Growth opportunities are focused on deepening expertise in specialized hardware domains and understanding the full product lifecycle from R&D to production.

💡 Interview Preparation

Strategy Questions:

• "Describe a time you had to build a complex prototype with limited resources or unclear specifications. What was your approach and what was the outcome?" (Focus: Ambiguity, Initiative, Problem-Solving)

• "Walk me through the process of designing and building an assembly fixture for a novel electronic component. What were your key considerations?" (Focus: Fixturing, DFM, Process Design)

• "How do you approach troubleshooting an electromechanical system where the failure mode is not immediately obvious? Give an example." (Focus: Debugging, Analytical Skills)

• "Imagine you're given a rough CAD model for a wearable device. What are the first few steps you'd take to start prototyping it, and what DFM/DFA feedback might you anticipate providing early on?" (Focus: Prototyping Process, DFM/DFA) Company & Culture Questions:

• "Why are you interested in Tacit and our mission to rethink human-computer interaction?" (Focus: Motivation, Alignment)

• "Describe your ideal work environment. How do you thrive in a fast-paced, startup setting?" (Focus: Cultural Fit, Adaptability)

• "How do you balance the need for rapid iteration with ensuring the quality and reliability of your prototypes?" (Focus: Operational Judgment)

• "Tell me about a time you had to collaborate closely with engineers from different disciplines (e.g., electrical, mechanical). What were the challenges and how did you ensure effective communication?" (Focus: Collaboration) Portfolio Presentation Strategy:

• Select 3-4 Key Projects: Choose projects that best showcase your breadth of skills (mechanical, electrical, fixturing, troubleshooting) and your impact.

• Tell a Story: For each project, frame it as a narrative: the problem, your solution, the process, challenges overcome, and the results.

• Highlight Your Role: Be clear about your specific contributions, especially if it was a team project.

• Demonstrate Process: Show your CAD work, fabrication steps, wiring diagrams, and test setups. Explain why you made certain design choices.

• Quantify Results: Use metrics whenever possible to demonstrate efficiency gains, successful iterations, or problem resolution.

• Be Prepared for Deep Dives: Anticipate technical questions about materials, tolerances, electrical components, and fabrication techniques.

Challenge Preparation:

• Practical Skills: Review your proficiency with CAD software, soldering techniques, and common rapid prototyping equipment.

• Problem-Solving Scenarios: Practice articulating your thought process for common hardware development challenges. Think about how you would approach designing a test setup for a new sensor or improving the ergonomics of a wearable device.

• Communication: Practice explaining complex technical concepts clearly and concisely, as you'll need to communicate with both technical and non-technical stakeholders.

📝 Enhancement Note: Interview preparation should focus on demonstrating a blend of deep technical skill, a proactive and problem-solving mindset, and strong communication abilities. The portfolio is your primary tool for showcasing practical experience, so preparing a compelling and well-structured presentation is crucial.

📌 Application Steps

To apply for this Rapid Prototyping Engineer position:

• Submit your application through the provided link on Ashby.

• Curate Your Portfolio: Select 3-4 of your most impactful projects that demonstrate your skills in mechanical design, electrical integration, rapid fabrication (3D printing, CNC), and fixture design. Ensure each project clearly outlines the problem, your solution, the process, and the outcome.

• Tailor Your Resume: Highlight keywords from the job description, such as "Rapid Prototyping," "Wearables," "CAD," "PCB Design," "Fixture Design," "DFM/DFA," and "Electromechanical Systems." Quantify your achievements wherever possible.

• Prepare Your Narrative: Practice articulating your experience and projects clearly and concisely, focusing on your problem-solving approach, iterative design process, and ability to work independently and collaboratively. Be ready to explain the "why" behind your design choices.

• Research Tacit: Understand the company's mission, its deep tech focus, and its commitment to innovative hardware. This will help you articulate your interest and align your responses with their goals during interviews.

⚠️ Important Notice: This enhanced job description includes AI-generated insights and operations industry-standard assumptions. All details should be verified directly with the hiring organization before making application decisions.