Principal Manufacturing Engineer-Plastic Injection Molding

Location: Mukwonago

Principal Mfg Engineer

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* Job Description:

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* ** Position Summary*
* The Principal Manufacturing Engineer - Plastics is the technical authority for plastic injection molding  
** process development, optimization, and sustainment** . This role leads the establishment of robust molding processes that deliver consistent quality, high throughput, and competitive cost performance across production operations.

This position focuses on  
** process optimization, material performance in molding, molding parameters, and process control** , while partnering closely with tooling, quality, automation, and operations teams. The Principal Manufacturing Engineer drives manufacturing excellence through data-driven decision making, advanced process control, and continuous improvement, while mentoring engineers and influencing site and business strategy.

** Key Responsibilities*
* + Serve as the subject matter expert for plastic injection molding processes, including scientific molding principles, process window development, and process validation.

+ Develop, optimize, and sustain molding processes to meet quality, delivery, and cost objectives across a range of polymers and part geometries.

+ Help support and maintain standard molding methodologies, including start-up procedures, changeover standards, and process control plans.

+ Lead mold qualification, process validation, and ongoing process capability improvements (Cp/Cpk).

+ Analyze and optimize cycle time, cooling efficiency, clamp force utilization, part quality, and material usage.

+ Lead advanced root cause analysis for molding-related defects (short shots, flash, sink, warp, burn, splay, etc.) and process instability.

+ Apply DOE, SPC, and statistical analysis to define critical process parameters and ensure long-term process robustness.

+ Partner with Quality to drive defect reduction, scrap elimination, and corrective/preventive actions.

+ Provide hands-on technical support during process upsets, new product launches, and capacity expansions.

+ Evaluate and select polymer materials in collaboration with Product Development and suppliers to optimize manufacturability and performance.

+ Understand and manage the interaction between material properties, tooling design, and machine capability.

+ Lead trials for new materials, colorants, regrind strategies, and process innovations.

+ Research and implement advanced molding technologies (process monitoring, cavity pressure sensing, advanced cooling, automation).

+ Support molding equipment selection and capital decisions through process requirements definition, technical evaluation, and throughput analysis.

+ Lead data-driven continuous improvement efforts focused on molding efficiency, uptime, scrap reduction, labor optimization, and OEE through standardized processes and best practices.

+ Support and maintain molding process documentation, manufacturing standards, and ERP/MRP data (routing, cycle time, labor) to ensure consistent and repeatable molding performance.

+ Develop and share technical knowledge through documentation, repositories, and mentorship to build injection molding capability across the engineering team.

+ Partner with Operations, Tooling, Quality, Maintenance, and Supply Chain to ensure stable and scalable molding operations.

+ Provide clear technical direction and influence decision-making without direct authority.

+ Communicate complex process concepts through clear documentation, data, and formal presentations.

** Education & Experience Requirements*
* + Bachelor's degree in Plastics Engineering, Mechanical Engineering, Manufacturing Engineering, or related discipline.

+ 6+ years of hands-on injection molding process engineering experience in a production environment.

+ Demonstrated expertise in scientific molding, process validation, and process troubleshooting.

+ Strong working knowledge of thermoplastics, molding machines, auxiliaries, and process monitoring tools.

+ Familiarity with CAD and mold design concepts as they relate to process capability.

+ Preferred experience supporting multi-cavity, high-volume, or tight-tolerance molding applications.

+ Preferred exposure to automation, robotics, and in-mold or downstream process integration.

+ Preferred knowledge with Lean Manufacturing, Six Sigma, or equivalent continuous improvement experience.

+ Established ability to identify and communicate issues and offer proposed solutions

+ Excellent attention to detail with good organizational skills are required

+ Ability to function effectively in a fast-paced team environment

+ Effectively collaborates across functions, drives continuous improvement, and communicates clearly with both technical and non-technical teams.

_Milwaukee Tool is an equal opportunity employer._

Equal Opportunity Employer Minorities/Women/Protected Veterans/Disabled

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