Category Archives: CNC Programming

CNC Feeds and Speeds: Cutting Speed in SFM and m/min Explained

When programming CNC machines, one of the most important parameters is cutting speed. It defines how fast the cutting edge of your tool moves across the workpiece surface. Getting this right ensures good tool life, smooth finishes, and efficient machining.

G84 Tapping Cycle Made Simple: Boost Accuracy & Save Tools

The G84 canned cycle is primarily used for tapping threads inside drilled holes. Unlike drilling cycles such as G81, G82, and G83, tapping requires precise synchronization between the spindle and feed with the thread pitch. Therefore, the G84 cycle automatically controls both spindle rotation and feed, so that the tap cuts correctly and, as a result, reduces the risk of tool breakage. In addition, this automation makes the tapping process faster and more reliable compared to manual programming

G83 Canned Cycle – Peck Drilling Cycle in CNC (Fanuc)

The G83 canned cycle is used for deep hole drilling where chips must be cleared in steps (pecks) to prevent tool breakage. Unlike G81 (simple drilling) and G82 (drilling with dwell), G83 drills in repeated pecks, retracts slightly to break and clear chips, and then continues until the final depth is reached.

G82 Spot Drilling Canned Cycle (Fanuc VMC)

G82 is a drilling cycle similar to G81, but with an added dwell time at the bottom of the hole. After feeding down to the programmed depth (Z), the tool pauses for the specified time (P value) before retracting. This dwell improves hole accuracy, helps create a cleaner bottom surface, and is commonly used for countersinking and counterboring operations.

G81 Canned Cycle (Fanuc VMC): Complete Guide

G81 is the simplest drilling canned cycle. It rapids to a safe clearance plane (R), feeds straight to the programmed depth (Z), and retracts—either back to the R-plane (G99) or all the way to the initial plane (G98). Use it for shallow to moderate depth holes where you do not need pecking or a dwell.

G80 – Canned Cycle Cancel

The G80 command in Fanuc CNC programming is used to cancel any active drilling, boring, or tapping canned cycle (such as G81, G82, G83, G84, etc.). Once a canned cycle is active, it will keep repeating at every new X-Y coordinate until it is explicitly stopped. If not canceled, the cycle may unintentionally continue at the wrong positions, causing tool crashes or part damage.

What are Canned Cycles in VMC Programming?

When programming a Vertical Machining Center (VMC), certain operations like drilling, boring, tapping, and reaming are repetitive. Writing full toolpath codes (G01, G00, G02, G03) for each step would be time-consuming.

To simplify this, Fanuc controls (and most CNC controls) use Canned Cycles – pre-programmed subroutines that perform common machining operations with just one command line.

Tool Length & Diameter Offset in VMC – Explained for Beginners

In CNC machining, accuracy depends on more than just the program code – it also relies on how the machine understands tool dimensions. On a Vertical Machining Center (VMC), the concepts of Tool Length Offset (TLO) and Tool Diameter (Radius) Offset (TDO) are crucial.

Work Coordinate System (WCS) in CNC Machining – A Complete Guide

One of the most important concepts in CNC programming is the Work Coordinate System (WCS). It defines the reference point from which all machining operations are programmed. Without a proper understanding of WCS, even the most accurate CNC program can produce errors or crash the machine.

Incremental vs. Absolute CNC Programming – A Complete Guide

When it comes to CNC programming, two essential coordinate systems define how a machine interprets tool movement: Absolute Programming (G90) and Incremental Programming (G91). Understanding the difference between the two is crucial for CNC programmers, as it directly affects accuracy, efficiency, and error prevention.