G‑Code, M‑Code & Machine Control
This G‑code tells the machine to move as fast as possible to a position without cutting
G00
These must be worn at all times when operating or standing near CNC machines to protect your eyes from chips and coolant
Safety glasses
On a print, this value represents the ideal size of the feature before tolerances are applied
Nominal Dimensions
In CAM, this term refers to the calculated motion the tool will follow to remove material and create the part.
Toolpath
These are the two linear axes most commonly used on a standard 2‑axis CNC lathe
X & Z
This G‑code is commonly used for a standard drilling cycle where the tool feeds down, then rapids back up
G81
Before pressing cycle start on a new program, this check ensures the part is clamped securely and the workholding cannot move
Fixturing/Workholding
A callout of 1.000 ±0.005 means the part can measure between these two values and still be acceptable.
0.995 and 1.005 inches
This type of operation is used to quickly remove bulk material, usually with larger step‑downs and step‑overs
Roughing
This is the axis on a lathe where the main spindle rotates and the workpiece is held
Spindle
This code pair is used to apply a work offset and a tool length offset before cutting
G43 G54
This emergency feature stops all machine motion immediately in case of danger or a serious mistake.
E-stop
These common measuring tools are typically accurate to 0.001 inch and 0.0001 inch, respectively.
Calipers & Micrometers
For a closed pocket, this 2D milling strategy is often chosen instead of a simple contour toolpath
Pocketing
This term refers to tooling on the turret that has its own motor so it can rotate and perform milling or drilling operations
Live Tooling
This line is often placed near the start of a CNC program and includes mode settings like plane, feed mode, and tool length compensation to make sure the machine is in a known state
Safe Start line
This process involves aligning a vise or fixture so its jaws or face are parallel to one of the machine’s linear axes.
Indicating
This GD&T symbol controls how far a surface can vary from a perfectly flat plane.
Flatness
This term describes the sideways distance between adjacent tool passes and has a big impact on surface finish and cycle time
Stepover
This type of live tooling operation drills along the centerline of the spindle on a lathe
Axial Drilling
Given the line G00 G54 X-2.0 Y0. Z2.0, explain what the machine will do in terms of active offset and axis motion
it activates work offset G54, then moves the tool rapidly to X‑2.0, Y0.0, Z2.0 in that work coordinate system
You are switching from machining mild steel to 6061 aluminum. Name two changes you would typically make to your cutting parameters or setup to keep the process safe and efficient
increase surface footage and chip load, and possibly change to a tool with more flutes or different coating
A print calls out a hole position with a true position tolerance. Briefly explain how you would verify that the hole location is within tolerance using a CMM or layout tools.
establish datums, measure the actual hole center relative to those datums, calculate its deviation from the basic location, and compare it to the positional tolerance
You need to machine a 1‑inch deep pocket in steel efficiently. Name one strategy to reduce tool wear and one strategy to shorten cycle time using CAM toolpath choices or parameters.
high‑efficiency (constant engagement) roughing path to reduce wear and increase feed/optimize step‑down/step‑over or use larger tools where possible to shorten cycle time
You are using live tooling to drill holes around the diameter of a shaft at four equally spaced locations. Describe which axis or axes you would index and what type of drilling this is called.
Index C-Axis