CNC machinists use computer numerical controlled machines to make or fix precise tools and products out of different materials. They are also called CNC machine operators or CNC operators.
When interviewing CNC machinists, the best candidate will show that they are good at math, have great communication skills, and be willing to set a good example. Be wary of candidates with low confidence, low energy or poor computer skills. Special Offer.
To get a job as a CNC lathe machinist, you need to show off your skills and knowledge during the interview. There are a lot of things that employers look for in a candidate: they need to know how to program, read blueprints, pay attention to detail, and work safely.
To help you prepare for your upcoming interview, here are the 15 most common cnc lathe machinist interview questions with example answers:
1. What machines do you have experience with?
When answering this question, focus on the specific CNC lathe models you’ve used rather than listing every machine you’ve operated. Mention brand names like Mazak, Okuma, Haas, etc. along with the ways you’ve used each machine (maintenance, daily operation, programming, etc). Highlight any similar machines to those your potential employer has.
Example: “I have 2 years of experience operating and programming various Haas CNC lathes including the TL-1, TL-2, and TL-3 models. In my current role, I work on the TL-2 daily where I am responsible for production runs, quality checks, and preventative maintenance.”
2. What programs do you have experience with?
Again, tailor your response to the specific programming languages and CAM software used at the company. Common programs include Mastercam Fusion 360, GibbsCAM Esprit, G-code, conversational programming, etc. Discuss your competency level and type of use with each one.
“I am beginner to intermediate with Mastercam. I use it to program toolpaths and post G-code for our Okuma machines.” I’ve also used our Mazak Integrex’s conversational programming to enter and change programs on the machine. ”.
3. How many hours of experience do you have operating CNC machines?
Find out how much experience you have with CNC lathes, as many employers want to see between one and three years of hands-on experience. Estimate your total hours spent setting up, running, and maintaining the machines. Having a couple thousand hours or more exhibits your depth of knowledge.
Example “Over the past 2 years, I estimate I have about 2,500 hours of experience operating CNC lathes. On average, I spend 6-7 hours a day at the machine where I am responsible for loading/unloading parts, monitoring the program run, measuring finished parts, and keeping the work area clean”
4. Have you ever done product checks?
Product checks involve measuring finished parts to ensure they meet specifications and quality standards. Share examples of the types of product checks you’ve been responsible for and your process for approval/rejection and documentation. Accuracy and attention to detail are key here.
Example: “Yes, I measure every part that I machine with calipers to check size, tolerance, and surface finish. I compare my measurements to the blueprint specifications and document the values on our company’s product check form. If the tolerances are not met, I adjust offsets and run another part to verify before approving the batch.”
5. What experience do you have reading blueprints and schematics?
CNC machinists must be able to interpret detailed drawings and CAD models to understand the machining operations required. Discuss what you look for when reviewing prints and your comfort level with GD&T (geometric dimensioning and tolerancing) symbols.
Example: “I am comfortable reading basic blueprints and schematics. I review the views to visualize the part, identify critical dimensions and tolerances, material specification, and machining notes. I also look for GD&T symbols and have experience with position, profile, and runout tolerances which communicate the design intent.”
6. How do you ensure you are meeting quality standards?
Demonstrate you work carefully and methodically to achieve consistent, high-quality results. Mention quality control processes like visual inspection, gage R&R, and statistical process control. Share an example of catching and correcting an issue before it impacted production.
Example: “I visually inspect each part I make and keep detailed notes on any abnormalities. Our shop also utilizes a gage R&R process where I periodically measure a sample using the same instruments to ensure consistency. One time I noticed the burrs on an edge were larger than normal which led me to discover an insert was chipped.”
7. How do you stay focused when performing repetitive tasks?
CNC machinists must repetitively perform similar operations for hours at a time. Share what helps you maintain focus and attention to detail without getting bored or distracted. Mention personal strategies as well as workplace practices that help minimize errors.
Example: “Having a checklist that I follow step-by-step helps keep me focused for each part run. I also listen to podcasts and audiobooks which I can pay attention to while keeping my eyes on the machine. Taking microbreaks to stand, stretch, and reset helps me come back feeling focused.”
8. Describe your experience with preventative maintenance.
Explain your involvement in routine maintenance activities like cleaning, lubricating, adjustments, and inspections to minimize machine downtime. Share examples of issues you’ve identified through PM and steps taken to address them. Emphasize safety practices.
Example: “As part of my daily responsibilities, I clean the work area, lubricate bearings, and check for leaks/wear. One time while greasing the lead screw, I noticed some binding so I alerted the maintenance team who realigned the axis to prevent further damage. I also check emergency stops are functioning properly.”
9. How do you ensure safe working practices around CNC equipment?
Machine tools require proper safety protocols to prevent injury. Share important practices like:
- Wearing PPE (glasses, gloves, closed-toe shoes).
- Keeping long hair/clothing secure and avoiding loose items.
- Using proper techniques for handling cutting tools and materials.
- Operating with guards/doors/shields engaged.
- Identifying pinch points and other hazards.
Emphasize your commitment to safety above all else.
10. What is your experience with fixtures, jigs, and other workholding devices?
Explain your familiarity with different workholding methods like vises, chucks, collets, rotary tables, tombstones, etc. Share an example of how you had to get creative or make a custom fixture to properly machine a challenging part.
Example: “We utilize pneumatic vises, hydraulic chucks, and collet adapters for most of our workholding needs. For one tricky manifold block, I had to machine a soft jaw that matched the profile of the part’s bottom contour in order to cut the top surface flat while indexing the part.”
11. How do you verify accuracy of a program before a production run?
Describe methods you use to validation CNC programs by dry running the toolpaths in simulation software or by trial machining in scrap material first. Emphasize the importance of discovering and correcting any mistakes before attempting the actual production run.
Example: “I always simulate new programs in Mastercam first to visualize the toolpaths and ensure no collisions. For existing programs, I measures the dimensions of a trial part and make fine adjustments to offsets, speeds and feeds as needed until the process is proven out.”
12. How do you prioritize when several jobs are due at once?
Explain factors you consider when planning your workflow and determining which tasks need to be completed first to keep production moving smoothly. Share an example of juggling multiple urgent jobs successfully.
Example: “I keep a schedule of which parts are due on which days and plan ahead based on job priority and run times. If an urgent job comes up, I shift my schedule to run it first but will inform others if it requires bumping other deadlines. Communication is key to balancing priorities when things are hectic.”
13. Describe a time you had to problem-solve a machining issue. What was the cause and how did you fix it?
Recount a specific example that highlights your troubleshooting skills, critical thinking, and mechanical aptitude. Focus on the systematic process you used to diagnose the root cause, devise a solution, test your remedy, and implement permanent corrective action.
Example: “One day our lathe started leaving a poor surface finish on parts. I isolated the problem to the Y-axis by running a test program and inspecting the finish. I checked for loose gibs/bearings but didn’t see anything obvious. I then noticed some binding when moving the saddle manually. I alerted maintenance and it turned out the encoder strip was damaged and needed replaced.”
14. What experience do you have working with carbide inserts and tooling?
Discuss your knowledge of inserts, toolholders, and tool selection to match different materials and operations. Share specifics on brands/grades you’ve used and how you optimize insert life through practices like tracking usage time and adjusting speeds/feeds.
*Example: *“I have experience selecting and changing inserts for roughing, finishing, grooving, threading, and other operations. Based on the material and part geometry, I’ll choose between carbide grades like C5 and C6 from manufacturers like Iscar and Kennametal. I track insert hours to swap them out before fracturing occurs.”
Interview Questions for CNC Machinists:
Tests knowledge of machines and maintenance procedures.
What do you look for when inspecting finished workpieces?
Tests basic CNC skills and understanding of productivity challenges.
Interview Question & Answers for CNC Operator Post | Freshers | Experienced | Mechanical Candidates
What questions should you ask a machinist in a job interview?
For both groups, here are 50 CNC job interview question ideas to get you started. They’re divided into the following broad categories: – Machining: The basic nuts and bolts of making chips on a machine. – Metrology: Measurement and precision is very important to machinists. Is your candidate up to snuff?
What questions should you ask a CNC machinist?
21. Describe a challenging project you have completed as a CNC machinist and the steps you took to ensure its success. This question allows hiring managers to gauge your problem-solving skills, technical expertise, and ability to overcome obstacles in your work.
What skills do CNC machinists need?
Problem-solving is a critical skill for CNC machinists, as they often encounter unexpected challenges during the production process. Interviewers want to know that you can think on your feet, analyze the situation, and find solutions to keep the production running smoothly while maintaining quality and efficiency.
What skills do machinists need?
They’re divided into the following broad categories: – Machining: The basic nuts and bolts of making chips on a machine. – Metrology: Measurement and precision is very important to machinists. Is your candidate up to snuff? – Personality and Problem Solving: Skills are just table stakes.
