ChatGPT CNC Lathe G71 Canned Cycle Errors, Explained
G71 is where ChatGPT G-code fails hardest: two incompatible formats in the training data, strict contour rules, and U/W double meanings. The error map.
Posts tagged Lathe from the G-Code Sprint team.
G71 is where ChatGPT G-code fails hardest: two incompatible formats in the training data, strict contour rules, and U/W double meanings. The error map.
On system A Fanuc lathes, U and W are incremental X and Z: same axes, different reference. Why lathes got dedicated letters, and the rules that follow.
A cutoff nub has three parents: tool above or below center, an X endpoint that stops short, and centerline speed physics. The fixes, code and setup both.
Dedicated turning-only G-code simulators are rare, and most free tools are mill-first. Where lathe simulation actually works, what breaks, and the fixes.
G50 carries two unrelated jobs on lathes: the modern spindle-speed clamp with S, and the legacy coordinate-system-setting form. The words after it decide.
G92 cuts one synchronized threading pass per block you write; G76 plans the whole sequence from two lines. When manual control of passes earns its keep.
Most cross-threaded parts are scrap, and knowing why takes one paragraph. For the salvageable cases, the thread pickup procedure is the real answer.
Diameter programming won the lathe world because prints and micrometers speak diameter. How both modes work, where each lives, and the words that follow X.
Taper turning in G-code is two diameters and a Z length: program both X ends and let G01 interpolate. The formulas, a worked example, and the comp trap.
M23 and M24 commonly toggle the chamfered thread pullout on Fanuc-family lathes: the angled exit at the end of each pass. What it does, and the caveats.
G97 locks the lathe spindle to one RPM, so you compute it yourself: surface speed and diameter in, RPM out. The formula, the diameter choice, the cases.
A lathe that cuts exactly twice as deep as programmed is almost always a diameter vs radius mix-up. Here is the X rule, the four places it hides, the fix.
أكواد الخراطة هي النواة المشتركة زائد G18 والبرمجة بالقطر والتغذية لكل دورة وG96 مع سقف G50 ودورات G71/G70/G76. جدول مرتب وشرح للمفاهيم والأخطاء الشائعة.
Lathe broaching cuts keyways with a locked spindle and Z strokes: orient, plunge a few hundredths, stroke, step, repeat. The program shape and its guardrails.
The GSK 980TDb speaks a largely Fanuc-compatible lathe dialect: standard motion, G96/G50, G71-class cycles. The list framework, plus where the manual rules.
A sub-spindle pickoff hands the part from main to sub spindle mid-cycle: synchronize speeds, approach, grip, cut off, retract. The sequence and its traps.
G28 moves through an intermediate point you specify, in the active coordinate mode. In G90, G28 Z0 goes to workpiece Z0 first, which can be inside the chuck.
On a lathe, G50 S sets the maximum spindle RPM. Leave it out with constant surface speed and the spindle can run away near the center. Here is why and the fix.
The core M-codes are identical on lathes and mills, so learn them once. The real difference to remember is the tool change: M06 on a mill, the T word on a lathe.
Two anchors end the lathe axis confusion: Z is always the spindle axis on every machine, and X is the diameter. Here is why the mix-up happens and the fix.
A boring bar hits the back of the part when the Z depth runs too far: wrong depth, wrong Z zero, an absolute mix-up, or a bad retract. Here are the causes and fixes.
G71 roughs with passes along Z for shafts and long profiles, G72 roughs with passes along X for faces. Here is how each cycle works and which to pick.
The motion core is identical; six differences do the damage: default plane, diameter programming, feed modes, CSS, cycle families, and comp mechanics.
A left-hand tap runs on M04, the reverse spindle code, with the G74 cycle on mills. For single-point threading, the spindle and feed direction together set the hand.
A bar puller pulls fresh stock out of the collet for the next part. Here is the logic of the G-code behind it, explained conceptually for learners.
A lathe operator hands-on test checks chucking, offsets, turning a part, and reading the program. Here is how to prepare, with the turning codes you need cold.
Turning shares the common codes with milling but adds lathe-specific ones: constant surface speed, diameter mode, and turning cycles. Here is what to practice.
A TESDA CNC lathe assessment is competency-based: reading a turning program, setup, and producing a part. Here is how to practice, lathe codes first.