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CNC Programmer interview questions & mock practice

A CNC Programmer interview in 2026 runs across 4 rounds — technical screening, programming round, machine & setup round, hr & fit. Below are the most-asked CNC Programmer interview questions and a focused prep plan. Rehearse every answer with OnJob's free AI mock interview and get instant, specific feedback before the real one.

G-code & M-codeCNC ProgrammingCAM (Mastercam / Fusion 360)Machine SetupTooling & FixturingGD&TSpeed & Feed Calculation
Free interview practice · CNC Programmer

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Step through the 13 most-asked CNC Programmer questions one at a time, under a timer, just like the real thing. Jot your answer, then reveal what a strong answer covers. No signup needed to practise.

Interview rounds

The CNC Programmer interview process

G-code programming, CAM and machine setup — the CNC interview for precision machining, tool rooms and manufacturing units across India.

1

Technical screening

G-codes, M-codes, work and tool offsets and coordinate systems.

2

Programming round

Manual programming and CAM (Mastercam, Fusion 360) for milling/turning.

3

Machine & setup round

Tooling, fixturing, cutting parameters and machine operation.

4

HR & fit

Drawing interpretation, quality, scrap reduction and shop coordination.

Most-asked questions

Most-asked CNC Programmer interview questions

13 of the questions CNC Programmer candidates are asked most often in India. Practise answering each one out loud in your AI mock interview.

  1. 1. What is the difference between a G-code and an M-code?
  2. 2. What does G00, G01, G02 and G03 mean?
  3. 3. What is the difference between absolute (G90) and incremental (G91) programming?
  4. 4. What are work offsets (G54-G59) and tool offsets?
  5. 5. What is cutter radius compensation and why is it used?
  6. 6. What is the difference between climb milling and conventional milling?
  7. 7. How do you calculate spindle speed (RPM) and feed rate?
  8. 8. What is the difference between a canned cycle and a subprogram?
  9. 9. What is the difference between G-code programming and CAM programming?
  10. 10. What is the role of M03, M05, M06 and M08 in a program?
  11. 11. How do you set the work coordinate system (zero) on a CNC machine?
  12. 12. What are the common controllers like Fanuc, Siemens and Haas, and how do they differ?
  13. 13. How do you reduce cycle time without compromising surface finish?
How to prepare

How to prepare for your CNC Programmer interview

Know your G-codes and M-codes cold, plus offsets, coordinate systems and canned cycles — these are the bread and butter.

Be fluent in your CAM software (Mastercam, Fusion 360 or NX) for both milling and turning toolpaths.

Practise speed and feed calculations and cutting-parameter selection for different materials and tools.

Be ready to read a drawing with GD&T and explain how you would program and set up the part.

Carry examples of cycle-time or scrap reduction you achieved through better programming or tooling.

Practise other roles

CNC Programmer interview — FAQs

What questions are asked in a CNC Programmer interview?

Common CNC Programmer interview questions include: What is the difference between a G-code and an M-code? What does G00, G01, G02 and G03 mean? What is the difference between absolute (G90) and incremental (G91) programming? What are work offsets (G54-G59) and tool offsets? Interviews usually run across 4 rounds — Technical screening, Programming round, Machine & setup round, HR & fit. Practice all of them with instant AI feedback using OnJob's free mock interview.

How many rounds are in a CNC Programmer interview?

A typical CNC Programmer interview has 4 rounds: Technical screening (G-codes, M-codes, work and tool offsets and coordinate systems.); Programming round (Manual programming and CAM (Mastercam, Fusion 360) for milling/turning.); Machine & setup round (Tooling, fixturing, cutting parameters and machine operation.); HR & fit (Drawing interpretation, quality, scrap reduction and shop coordination.).

How do I prepare for a CNC Programmer interview?

To prepare for a CNC Programmer interview: Know your G-codes and M-codes cold, plus offsets, coordinate systems and canned cycles — these are the bread and butter. Be fluent in your CAM software (Mastercam, Fusion 360 or NX) for both milling and turning toolpaths. Practise speed and feed calculations and cutting-parameter selection for different materials and tools. Then run a full AI mock interview on OnJob to rehearse out loud and get instant, specific feedback before the real thing.

What skills do I need for a CNC Programmer role?

Core CNC Programmer skills tested in interviews include G-code & M-code, CNC Programming, CAM (Mastercam / Fusion 360), Machine Setup, Tooling & Fixturing, GD&T, Speed & Feed Calculation. OnJob shows you exactly which of these skills stand between you and a 100% match on every live CNC Programmer job.

Is OnJob's CNC Programmer mock interview free?

Yes. OnJob's AI mock interview is free to start (₹0) and gives you instant feedback on your answers. Pro (₹99/month) adds unlimited interview-prep AI alongside recruiter tracking and unlimited applications.

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