βΆWhat is the difference between CAD and CAM?
CAD is design: you create a 3D model of a part, define dimensions and tolerances, add colors and materials, and generate drawings for manufacturing and assembly. CAM is manufacturing: you load the CAD model into CAM software, define how the machine will make the part (which tools, what paths), simulate the machining process, and generate G-code that controls the CNC machine. Modern tools like Fusion 360 integrate both: you design the part in the CAD module, then seamlessly switch to CAM and generate tool paths using the same model. In job shops and contract manufacturers, a CAM programmer might load a customer's STEP file (CAD export format) and generate tool paths without ever meeting the designer.
βΆWhat is parametric design and why use it?
Parametric design means defining a model using relationships and variables instead of just coordinates. Example: you define a bracket with four bolt holes, and the spacing between them is a parameter (say, 2.5 inches). If the customer later asks for 3.0-inch spacing, you change that one parameter, and all dimensions update automatically. Without parametric design (history-free or 'dumb' solid modeling), you'd manually edit every dimension, a tedious process prone to errors. Parametric design is the industry standard in CAD (Solidworks, Fusion 360, NX all do it). It's especially powerful for assemblies: if you change a part dimension, the whole assembly updates and you see interference conflicts immediately.
βΆHow do I handle assemblies with thousands of parts?
Large assemblies (an entire vehicle, aircraft, or industrial machine with 10,000+ parts) become slow to load and navigate in CAD. Modern approaches: break the assembly into sub-assemblies (engine assembly, transmission assembly, chassis assembly), then reference sub-assemblies into the main assembly. Use simplified or low-resolution representations of parts you're not editing. Use assembly visualization tools that hide/show parts by layer or property (show only detail parts, hide large housings). Some companies use dedicated assembly-management software (Enovia, Teamcenter) that sits on top of the CAD tool. Cloud collaboration tools (Fusion 360 Team, Solidworks Cloud) let multiple engineers edit different sub-assemblies in parallel without stepping on each other.
βΆWhat is FEA and when do I use it?
FEA (Finite Element Analysis) is the simulation of how a part behaves under load, temperature, or vibration. You define the material properties (steel, aluminum, plastic), apply forces and constraints (push here, support there), and the software divides the part into thousands of tiny elements and calculates stress, strain, and deformation. If the stress exceeds the material yield strength, the part will fail. FEA is used to: verify a design before manufacturing (avoid costly prototypes), optimize wall thickness and rib locations (reduce weight), and troubleshoot failures (why did this bracket break in the field?). Linked to CAM, FEA can inform tool-path strategies: if stress is concentrated at a corner, add a fillet to reduce stress concentration.
βΆWhat is a STEP or IGES file and why are they important?
STEP (Standard for the Exchange of Product model data) and IGES (Initial Graphics Exchange Specification) are neutral file formats that carry 3D geometry between different CAD systems. If a customer uses NX and you use Solidworks, they send you a STEP file (you can open it, but you can't edit the native model). STEP is the modern standard (IGES is older, still used). Advantages: you can load a customer's design and generate tool paths, you can share models with suppliers who use different software, and you have a permanent archive format (vendor software might go obsolete, but STEP is open-source). Disadvantages: importing a STEP file often loses some information (custom parameters, assembly structure, sometimes surface details).
βΆHow do I generate a tool path in CAM and what can go wrong?
Tool-path generation: select the operations you want to perform (face, mill a pocket, drill holes), select a tool from the tool library (specify diameter, flute count, cutting speeds), define the workholding setup (where the part sits, what you can't cut), then let the CAM software calculate how the tool should move to complete the operation. The software generates rapid moves (tool moving fast to the next cut, not touching the part) and feed moves (tool cutting at controlled speed). Modern CAM software includes collision detection: if the tool would hit the vise, spindle head, or clamp, it alerts you. What can go wrong: specifying the wrong workholding (tool paths assume a part held in a vise, but if it's actually in a fixture, collision happens on the real machine), forgetting to account for tool diameter (path is calculated for the tool centerline, but edge-to-edge distance must be checked), or running out of stock to machine (too-aggressive depths of cut).
βΆWhat is post-processing and why is it necessary?
Post-processing is the conversion of neutral CAM output (tool paths) into machine-specific G-code. Mastercam generates a tool path (X, Y, Z coordinates, feed rate, spindle speed) that's generic. A post-processor script converts that to the specific dialect your machine understands: Haas control, Siemens Sinumerik, Fanuc, etc. Different machines have different syntaxes for tool changes, coolant control, spindle speed ramping, and rapid vs. feed moves. Most CAM software comes with post-processors for common machines; if your machine is unique or old, you might need to customize the post-processor (or write a custom one). A bad post-processor can generate invalid code (spindle speed out of range, invalid G-code syntax) that doesn't run on the machine.