Siemens NX Sheet Metal, CAM, Simulation, and Mold Wizard Complete Guide

NX · Sheet Metal · CAM · Simulation

Overview

Siemens NX covers everything from design (CAD), sheet metal, machining (CAM), analysis (CAE), and mold automation within a single .prt file.

This page consolidates — from a practitioner's viewpoint — NX Sheet Metal and the aerospace-specialized Aero Sheet Metal, NX Manufacturing (CAM: Turning/Milling/5-Axis/Post Processor), Simcenter 3D-based Simulation (Nastran, Thermal, Motion, CFD), and the Mold Wizard / Progressive Die Wizard.

For part modeling fundamentals and Synchronous Modeling, see 02-modeling-synchronous.md; for MBD based on Drafting and PMI, see 04-drafting-pmi.md.

NX Sheet Metal Base Environment

Enter the environment with Ctrl+Shift+M or Application → Sheet Metal.

Right after part creation, set the base values first in Menu → Preferences → Sheet Metal so later features behave consistently.

Setting	Content
Material Thickness	Material thickness
Bend Radius	Default inner radius
Relief	Bend Relief type and dimensions
Neutral Factor (k-factor)	Neutral-axis position coefficient
Bend Table / Bend Formula	Empirical unfolding formula

Primary and Secondary Features

A Sheet Metal part begins with one of three primary features.

Tab — flat base. Gives a sketch profile thickness.
Contour Flange — an L-shaped flange extended along a section sketch (square ducts, covers).
Lofted Flange — lofts + auto-bends between two section curves (transitions, adapters).

Secondary Feature	Purpose
Flange	Add a flange to an existing edge with angle, length, and radius
Jog	Z-shaped step (offset flange)
Hem	Rolled-in edges (flat/open/closed/rolled)
Bend	Bend about a straight reference
Unbend / Rebend	Unfold and re-fold specific bends (to add machining features)
Closed Corner / Three Bend Corner	Seal corners or process three-way corners
Dimple / Louver / Bead / Gusset	Form features — embossing, slits, ribs
Normal Cutout	Cutout along the face normal (used in machining drawings)

Variational Flange

A flange whose length and angle vary along an edge. Used in automotive body frames and aerospace stringers, it auto-varies along the edge when a height curve is defined by sketch.

Introduced in NX 11 and then extended in the Variational section of Advanced Flange in NX 2412.

Flat Pattern

Menu → Insert → Flat Pattern / Flat Solid.

Flat Pattern: creates a "flattened" view while keeping the sheet metal feature tree
Flat Solid: fixes a fully unfolded solid (for CAM and nesting handoff)

Bend Lines, Bend Allowances, and Inner/Outer Mold Lines are annotated automatically. In the drawing, Insert → View → Flat Pattern View generates an automatic unfolded view and a Bend Table.

Sheet Metal Field Tips

Measure your K-factor: for mild steel t1.0–t3.0, expect roughly 0.44, aluminum 0.40–0.45, and stainless 0.42–0.46, but it varies by fabricator and tooling.
Bend Relief rule of thumb: width ≥ material thickness, depth ≥ bend radius.
Setting Bend Radius equal to material thickness (R = t) is the common manufacturing baseline.
Keep adjacent bends at least 4t apart to avoid die interference.
Corner Rip treatment prevents corner tears during bending after laser cutting.

> Tip: Refresh the Flat Pattern whenever a design change occurs, to track blank size. If the part exceeds available raw material width, procurement becomes impossible, so early validation matters.

Aero Sheet Metal (Aerospace-Specialized)

A licensed add-on specialized for aircraft structural parts such as stringers, frames, ribs, clips, and skin doublers — also referred to as NX Advanced Sheet Metal.

Added Features

Canted Flange: a flange tilted from the face. Expresses frame flanges that are not perpendicular to a curved skin.
Joggle: a Z-offset that smoothly absorbs skin-thickness steps (defined by Ramp length, Runout, Depth)
Lightening Cutout: one-shot creation of a round/oval lightening hole plus flange (standard feature for ribs)
Advanced Flange: variable section plus joggle combination
Beaded Flange: automatic bead reinforcement
Profile / Extruded Stringer: stringer profile sweep

Standards Integration

Integrates with bend standards such as Airbus AP2633 and Boeing BAC 5300
Bend Allowance calculation accuracy above 99.9% (versus measurement)
Provides an Airbus "Skin-Frame" BOM structure template

Aerospace Design Best Practices

Bend radius R/t ≥ 4 (aluminum 2024-T3), R/t ≥ 6 (7075-T6)
Edge Distance: hole center to edge ≥ 2D
Joggle Runout: ≥ 5t
Follow part-numbering rules for Airbus MSN and Boeing P/N

CAM (NX Manufacturing)

Enter with Ctrl+Alt+M or Application → Manufacturing. In the CAM environment, the navigators switch to a set of four.

Navigator	Purpose
Program Order Navigator	Machining order program tree
Machine Tool View	Tool list
Geometry View	MCS, Workpiece, Feature geometry
Machining Method View	Roughing, semi-finishing, finishing, inspection methods

Initial Setup Order

Place the MCS (Machine Coordinate System) under Geometry View → MCS.
Workpiece: define Part (finished shape), Blank (stock), and Check (fixtures).
Tool definition: in Create Tool, specify diameter, length, flute count, and Holder.
Choose a method: Rough (deep cuts), Finish (prioritize surface finish), etc.
Create Operation: choose machining type → set parameters → Generate Tool Path.

Milling

2.5-Axis: Face Milling, Pocket, Drill, Plunge, Bore
3-Axis: Cavity Mill (roughing), Z-Level (finishing), Fixed Contour, Streamline
5-Axis: Variable Contour, Variable Streamline, Tube Milling, Flow Cut, Valley Finishing
Tool-axis control: Tilt, Lead/Lag, 4-axis normal to drive, 5-axis normal to part

Turning / Mill-Turn

Supports traditional turning — Rough Turning, Finish Turning, Groove, Thread, Axial Drill, Center Drilling, and Boring — plus Mill-Turn (multi-task machines) with Live Tooling.

High-Speed Machining (HSM)

Trochoidal machining (constant tool engagement) extends tool life by 5–10×
Look-Ahead control, smooth connections
Constant Tool Engagement (Adaptive Roughing)

Tool Path Display & Verification

Verify (Gouge Check): auto-checks tool-part interference
Simulate (Machine Simulation): runs the entire machine model in 3D to check Collision/Limit
IPW (In Process Workpiece): accumulates the material-removed state from the previous operation and reuses it as the next operation's input

Post Processor

Converts the tool path into actual G-code/M-code.

Post Hub: cloud-based, containing on the order of 1,000 machine kits
Post Configurator: fine-grained customization per controller — Fanuc, Siemens 840D, Heidenhain iTNC, Mazak Matrix, etc.

CAM Automation

Feature-Based Machining (FBM): auto-recognizes features like holes and pockets, and automatically applies library strategies
Machining Knowledge Editor: codifies in-house machining know-how as rules
Template-Based: clones a template onto similar parts

CAM Field Tips

Place the MCS at the part's top center with Z+ as the tool axis — this is a Japanese machine-tool convention. Europe tends to prefer an X-Y plane reference.
Stock defaults: pre-finish margin 0.2–0.5 mm, final-finish margin 0.05–0.1 mm.
Pick the Cut Pattern to match the shape: Zig-Zag for flat-dominant, Follow Periphery for curved-dominant.
Minimize Air Cuts by tuning Engage/Retract well. Helical Engage reduces entry shock.
Record measured tool life in the Tool Library to enable auto-replacement alerts.
Always finish Machine Simulation collision checks before DNC handoff.

> Note: Post Processor customization errors can cause abrupt acceleration/deceleration or incorrect Tool Changes on the real machine, which can damage the spindle. Always validate new posts with air cuts before running real stock.

Simulation (Simcenter 3D)

NX Nastran was rebranded to Simcenter Nastran from 2019, and Simcenter 3D serves as the integrated Pre/Post environment. Its strength is a seamless workflow that shares bodies with NX CAD.

Supported solutions: Linear Static, Modal, Buckling, Dynamic (Transient/Frequency/Random), Nonlinear, Thermal, Optimization, Rotor Dynamics, and Aeroelasticity.

FEM Workflow

Create the FEM File (.fem) — holds mesh and material properties
Idealize Geometry — remove unnecessary features, extract mid-surfaces
Assign Material & Physical Property
Meshing — 1D (Beam/Rod/Bar), 2D (Shell CQUAD4/CTRIA3), 3D (Solid CHEXA/CTETRA/CPENTA)
Create the Simulation File (.sim) — boundary conditions, loads, solver type
Constraints & Loads — Fixed, Pinned, Force, Pressure, Torque, Gravity, Inertia
Solve — choose Simcenter Nastran, ABAQUS, ANSYS, LS-DYNA, or MSC Nastran
Post-process — Contour/Deformation/Stress/Strain/Animation

Thermal / Motion / CFD

Thermal: Steady-state / Transient, with Conduction, Convection, and Radiation using the TMG solver. Used for electronics thermal, engine cylinder-head thermal stress, and brake disc analysis.
Motion (Multibody Dynamics): RecurDyn or Simcenter 3D Motion. Define Joints (Revolute/Translational/Cylindrical/Spherical/Universal/Planar/Gear/Cam) along with Force/Torque and Contact. Adams solver integration is also possible.
CFD: Concepteur CFD (added in NX 2412, based on FloEFD) performs fluid and thermal analysis inside the design environment, with heavier work handed off to Simcenter STAR-CCM+.

Topology Optimization / Generative Design

The Simcenter Topology Optimization solver recommends a mass-minimized shape given a design space, a preserved space, and loads.

Automatic Lattice Structure generation is especially valuable for 3D-printing lightweighting.

Analysis Field Tips

Mesh convergence check: halve the mesh size and confirm the result difference is within 5%
When the thickness-to-length ratio is 1:10 or more, 2D Shell is faster and more accurate than 3D Solid
For welds, connect with RBE2/RBE3 Multi-Point Constraints or model as stacked solids
For contact analysis, move Glued → Linear contact → Nonlinear contact progressively
Use agreement within 10% versus hand calculations (simple beam theory) as a reliability benchmark

> Note: Feeding the CAD model straight into analysis lets small fillets and holes wreck mesh quality. Use Idealize Geometry to suppress features irrelevant to analysis before meshing.

Mold Wizard (Injection Mold Automation)

An NX add-on that standardizes injection mold design into a 10-step workflow.

Project Initialization — load the product part and set material and shrinkage rate (ABS 0.5%, PC 0.6%, etc.)
Mold CSYS definition — mold reference coordinates
Workpiece — insert outer box
Multi-cavity Layout — cavity arrangements such as 1×2, 2×4, or Radial
Parting Design — Region Analysis (classify Cavity/Core faces) → Parting Line → Parting Surface → separate Core & Cavity
Mold Base Library — auto-load catalogs like Hasco, Meusburger, DME, Futaba, and LKM
Standard Parts — Ejector Pin, Locating Ring, Sprue Bushing, Slider, Lifter, Sub-Insert, Runner
Cooling Channels — straight, angled, and pocket cooling layouts
Gating — Sprue, Runner, Gate (Edge, Pin-point, Tab, Submarine, Banana)
BOM & Drawing — auto-generate BOM, drawings, and a Mold Cost Report

Mold Wizard Advanced Features

Parting Check: auto-detects Undercuts → flags regions needing Slider/Lifter
Patch Body: auto-patches holes before parting
Shrinkage Scale: apply shrinkage uniformly or per axis
Mold Analysis: comprehensive Draft Angle, Thickness Check, and Undercut review
Electrode Design module: auto-generates copper electrodes for EDM + WEDM integration

> Tip: Cavity/Core created by Mold Wizard flow directly into NX CAM via the Master Model structure. The ability to eliminate file-handoff mistakes from design to machining is the single biggest reason it is adopted.

Progressive Die Wizard (PDW)

Automates sheet-metal progressive die design, managing the blanking → bending → forming → piercing stages.

Blank Generator: Flat Pattern → Nesting → Strip Layout
Strip Layout: allocate stages (Pilot, Pierce, Blank, Form, Cut-off)
Die Design: Punch, Die, Stripper, Die Plate
Insert Standard Parts: standard punches, pins, and bushings from Misumi, Fibro, and Dayton
Cost Estimation: material utilization and die cost estimation

Die Design Field Tips

Die Clearance: reference by material and thickness (SS400 t1.0 ≈ 7%, SUS304 ≈ 10%)
Bridge (web) minimum width is 1.5–2× material thickness
Pick a Carrier Strip — Edge Carrier vs Center Carrier — according to product characteristics
From the 2nd station onward, Piloting Holes are mandatory (to prevent accumulated stage-position error)

Field Checklist

Sheet Metal: Preferences thickness, K-factor, and Relief match the team standard
Verify the Flat Pattern is in sync with the latest design
When using Aero Sheet Metal, confirm the OEM bend standard setting (Airbus AP2633, etc.)
CAM: MCS origin and orientation match the machine reference
Configure Stock/Finish margins according to the surface-finish target
Run Machine Simulation for Collision/Limit check before posting
Simulation: keep a record of mesh convergence validation (within 5%)
Verify FEM agrees with hand calculations within 10%
Mold Wizard: Shrinkage Scale, Draft, and Undercut checks complete
PDW: Strip Layout material utilization meets the 70%+ target