Cezary Stępień
Mechanical Design Engineer · Mechanical Engineering
Wroclaw, Poland
Mechanical Design Engineer specializing in structural assemblies and mechanisms for aerospace applications. Experienced in full design cycle from concept through CDR, including 3D modeling, tolerance analysis, and design for manufacturability reviews.
Expertise
- 3D mechanical design and assembly modeling
- tolerance stack-up analysis (worst-case, RSS)
- design for manufacturability (DFM)
- mechanism design and kinematics
- engineering drawing release (CATIA, GD&T)
- structural bracket and panel design
Technologies
Work History
2024-08
Released full drawing package (32 drawings) for satellite bus panel assembly into ENOVIA PDM. Coordinated first article inspection with quality team and resolved 4 non-conformances.
Challenge: One panel drawing had an ambiguous surface finish callout that the machine shop interpreted differently from the design intent. Added explicit surface texture symbols per ISO 1302 to the revised drawing.
Learned: Drawing ambiguity is a quality risk. When a dimension or note can be interpreted two ways, a machinist will choose the cheaper option, which may not be the correct one.
2024-02
Led DFM (Design for Manufacturability) review for thruster gimbal mechanism. Worked directly with manufacturing team to identify 12 features requiring special tooling and redesigned 7 of them to standard tooling.
Challenge: Manufacturing team flagged a deep pocket feature that required a custom 5-axis fixture costing €8K and 6-week lead time. Redesigned the feature to split into two standard milled parts — same function, standard tooling.
Learned: DFM reviews should happen at concept stage, not after CDR. Finding a €8K tooling problem in concept costs 1 hour; finding it after drawings are released costs weeks.
2023-07
Performed tolerance stack-up analysis for antenna deployment mechanism — verified that all 34 critical dimensions were within manufacturing tolerance across worst-case thermal and vibration loading.
Challenge: RSS analysis showed acceptable tolerance, but worst-case analysis failed for one critical clearance. Reworked the joint design to add a shimming provision, eliminating the worst-case risk.
Learned: RSS vs worst-case tolerance analysis can give very different conclusions. For safety-critical clearances in mechanisms, worst-case analysis should always be performed regardless of statistical margins.
2023-01
Designed fuel pump mounting bracket assembly for satellite propulsion subsystem. Created 3D models, assembly drawings, and interface definition with propulsion and structure teams.
Challenge: Envelope constraints from the propulsion team changed twice during detail design, requiring complete redesign of the bracket geometry. Introduced a parameter-driven model to speed up future iterations.
Learned: Parameterized CAD models pay off immediately on programs with fluid interface constraints. Rebuilding a non-parametric design from scratch costs 3x more time than the initial setup of parameters.