
Closed
Posted
Mechanical/Product Design Engineer — PLA Prototype to Manufacture-Ready Rigid Shell + Silicone Overmold Overview We have a working 3D-printed (PLA) prototype of a small electronics case with an internal sliding compartment, custom PCB, embedded magnet, and Hall-effect sensor. We need a mechanical/product design engineer to redesign it into a manufacture-ready rigid shell with a silicone overmold, and deliver a finished, consumer-presentable prototype for user testing. What we need done Redesign for manufacturing (DFM): Convert the existing case into mold-ready CAD — a rigid inner shell housing the PCB, battery, magnet, and sensor, and forming the sliding compartment mechanism, plus a silicone overmold over the exterior for grip, shock absorption, and water resistance (leaving the moving compartment free of overmold). Include proper wall thickness, draft angles, mounting bosses, and undercuts for a secure silicone bond. Material and process spec: Document the recommended rigid substrate material, silicone/LSR grade and hardness (Shore A), and bonding method — clear enough to hand directly to a manufacturer for quoting. Manufacture-ready files: Final CAD in native and neutral formats (e.g., STEP), with separate parts for the rigid shell and overmold, ready to submit to an injection molder (e.g., Protolabs, Xometry, Fictiv, or an overseas manufacturer). Finished prototype: A working unit (or small batch, ideally 3–5) with the rigid-shell-and-overmold construction and our existing electronics integrated. The final product must be genuinely consumer-ready in look and feel for hands-on user testing. For this project—a phone case—it is critical that the delivered product is finalized as "one-and-done," requiring no further iterations or adjustments after delivery. What we're looking for Proven experience designing plastic/rubber parts for injection molding and overmolding specifically (not just general CAD work) — please share examples of past projects where you took a design through this exact rigid-plus-silicone-overmold process. Comfort working with small mechanical assemblies (sliding/drawer mechanisms, embedded magnets, PCB mounting) inside a consumer electronics enclosure. Ability to either produce the physical prototype yourself or manage sourcing it through a rapid-prototyping manufacturer (Protolabs/Xometry/Fictiv or similar) on our behalf. Clear, organized documentation habits — we need the process spec to be something we can hand to a factory later without you in the room.
Project ID: 40702194
24 proposals
Remote project
Active 3 days ago
Set your budget and timeframe
Get paid for your work
Outline your proposal
It's free to sign up and bid on jobs
24 freelancers are bidding on average $23 USD/hour for this job

Hi, I am uniquely equipped to bring your innovative project to life. I am well-versed in the intricate process of designing for injection molding and overmolding, ensuring that key factors such as draft angles, wall thickness, and undercuts are meticulously incorporated into the final design. My past experience involves taking rigid-plus-silicone-overmolded projects from conception through to manufacturing - making me an ideal fit for your exact needs. In addition to my expertise in plastic/rubber part design for small mechanical assemblies, I have a profound understanding of consumer electronics enclosures, including sliding/drawer mechanisms, and embedded magnets — all critical aspects of this project. Drawing from my extensive experience, I will create a final product that not only meets engineering specifications but genuinely impresses in terms of look and feel. Finally, clear documentation is an essential part of any project- one that impacts the delivery process significantly. I make precise documentation a priority ensuring the spec aligned with your preferred manufacturers. Overall, I firmly believe that my technical competency and professional commitment make me your best bet for turning this PLA prototype into a successful manufacture-ready rigid shell with a silicone overmold. Let's work together to bring this incredible project into fruition!
$20 USD in 40 days
6.8
6.8

With my extensive experience in the mechanical industry and advanced skills in product design, I am confident in my ability to turn your PLA prototype into a manufacture-ready rigid shell with silicone overmold that meets all your requirements. I have been involved in a variety of projects involving design for manufacture (DFM), especially for injection molded plastic parts like your case. In fact, I've successfully carried out similar projects with plastic and rubber parts, taking them through the exact rigid-plus-silicone-overmold process you're seeking. Examples of these projects include designing HVAC enclosures and automotive bodies. Aside from this specific expertise, I'm also comfortable working with small mechanical assemblies with sliding/drawer mechanisms, embedded magnets, and PCB mounting - all crucial elements in your electronic case design. Moreover, my proficiency in leading CAD software including Solidworks (CSWP certified) ensures the deliverance of accurate, detailed, and manufacture-ready files which will require no further iterations or adjustments. This is precisely what you need for your project. With me handling this project, you gain not only a skilled productivity-design engineer but also a proactive team player ready to contribute dedicatedly to making your vision a reality.
$20 USD in 40 days
6.3
6.3

Hi, I understand you need to turn the PLA prototype into a production-ready rigid shell with a properly engineered silicone overmold. I can redesign the enclosure for injection molding with correct wall thickness, draft, bosses, clearances, and overmold bonding features. I’ll carefully integrate the PCB, battery, magnet, Hall sensor, and sliding compartment mechanism. I’ll provide manufacturer-ready native CAD, STEP files, separate rigid and silicone parts, and complete DFM documentation. I can specify suitable rigid plastic, LSR/silicone grade, Shore A hardness, and bonding method for production. I’ll also ensure the moving compartment remains completely free from the silicone overmold. I have 10+ years of experience with electronics hardware, PCB integration, mechanical enclosures, and product development. I can coordinate rapid prototyping and ensure the finished unit has a clean, consumer-ready look and feel. Could you share the existing PLA CAD/3D model and confirm the target dimensions, material preference, and expected production quantity? I’m ready to take the existing prototype through DFM, manufacturing, and a final working prototype.
$20 USD in 40 days
6.1
6.1

With three decades in the hardware information systems industry, I have a proven track record of matching detailed designs to real-world applications. My skills in CAD/CAM and DFM are a perfect fit for your project; I understand how crucial it is for the ideal design created and presented. Both my work on submarines and active combat rovers centered around designing fiber glass structures to be a range of rugged scenarios, underlining my familiarity with materials like PLA and processes like overmolding. Your insistence on finished product quality before the commencement of manufacturing resonates deeply with me. All of my projects aim for the highest standards without needing further iterations—your one-and-done policy aligns perfectly with what I strive for. My experience working with surmountable physical constraints in complex systems and dedication to clear, organized documentation underscore my ability to meet your project requirements.
$20 USD in 40 days
5.5
5.5

The PLA prototype's integrated sliding compartment mechanism is the technical risk, it needs precise feature definition for reliable injection molding. I will build this into a manufacture-ready rigid shell using Solidworks, defining the sliding surfaces and tolerances for injection molding, so also designing the silicone overmold geometry for a clean interface and proper adhesion. What is the draft draft tolerance for the sliding compartment features in the rigid shell? I need the existing PLA prototype files to start. 5.0 rating across 10 reviews on here, and Preferred Freelancer status.
$25 USD in 7 days
2.3
2.3

Bloomington, United States
Payment method verified
Member since Oct 9, 2025
$30-250 USD
$250-750 USD
$30-250 USD
$15-25 USD / hour
$10-30 CAD
$10-30 CAD
$200-300 USD
$250-750 AUD
$15-30 USD
₹600-1500 INR
$250-500 USD
$15-25 USD / hour
$250-750 USD
£20-250 GBP
€30-250 EUR
€30-250 EUR
$10-20 USD
$10-30 CAD
₹600-1500 INR
$10 AUD
$15-25 USD / hour
₹12500-37500 INR
$10-30 CAD