CNC Machinist

20+ CNC Machinist Interview Questions and Answers

Updated 6 Jul 2025
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Q. Do you have programming knowledge? If yes, can you demonstrate it with our drawing?

Ans.

Yes, I have programming knowledge and can prove it in your drawing.

  • I am proficient in G-code programming

  • I have experience with CAD/CAM software such as SolidWorks and Mastercam

  • I can read and interpret technical drawings and blueprints

  • I have successfully programmed and machined complex parts with tight tolerances

  • I am familiar with various cutting tools and their applications

Q. What is system in thermodynamics and classification, explain with defination and exams

Ans.

A system in thermodynamics refers to a specific region or object under observation.

  • A system can be classified as open, closed, or isolated based on the exchange of matter and energy with the surroundings.

  • An open system allows both matter and energy to be exchanged with the surroundings, while a closed system only allows energy exchange.

  • An isolated system does not allow any exchange of matter or energy with the surroundings.

  • Examples of systems include a piston-cylinder, a refr...read more

Q. What is entropy? What is enthalpy?

Ans.

Entropy is the measure of disorder or randomness in a system. Enthalpy is the measure of heat energy in a system.

  • Entropy is a thermodynamic property that increases with the degree of disorder in a system.

  • Enthalpy is the sum of the internal energy of a system and the product of its pressure and volume.

  • Entropy is often associated with the second law of thermodynamics, which states that the total entropy of a closed system always increases over time.

  • Enthalpy is commonly used in ...read more

Q. Explain the API connection drawings and connection names, along with the relevant calculations.

Ans.

Understanding API connection drawings is crucial for CNC machinists to ensure proper machine operation and integration.

  • API (Application Programming Interface) connections allow CNC machines to communicate with software systems.

  • Connection drawings illustrate how different components of the CNC machine are linked to the API.

  • Common connection names include 'Ethernet', 'USB', and 'Serial'.

  • Calculations may involve determining the required bandwidth for data transfer between the CN...read more

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Asked in Wakefit

6d ago

Q. What is mean by rpm Types of machines Types of cutting tools

Ans.

RPM stands for revolutions per minute and refers to the speed at which a machine's spindle or cutting tool rotates.

  • Types of machines include lathes, mills, drills, and grinders

  • Types of cutting tools include end mills, drills, taps, and inserts

  • RPM is an important factor in determining the cutting speed and feed rate for a given material and tool

  • Different materials and tools require different RPMs for optimal performance

1d ago

Q. What is gravity die casting?

Ans.

Gravity die casting is a casting process where molten metal is poured into a permanent metal mould under the force of gravity.

  • Also known as permanent mould casting

  • Used for producing high-quality, consistent parts

  • Moulds are typically made of steel or cast iron

  • Commonly used for casting aluminum and copper alloys

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3d ago

Q. 1. draw first angle symbol

Ans.

The first angle symbol is a triangle with one corner pointing upwards.

  • The symbol is used in engineering drawings to indicate the orientation of a part or feature.

  • It is also known as the 'European' or 'ISO' symbol.

  • The symbol is drawn with a solid line for visible edges and a dashed line for hidden edges.

  • Example: ▲

Q. What is an orthogonal view?

Ans.

Orthogonal view is a 2D representation of an object from different angles.

  • Orthogonal view shows an object from three different angles: top, front, and side.

  • It is used in engineering and design to accurately represent an object's dimensions.

  • Orthogonal view is also known as 'multiview projection' or 'engineering drawing.'

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3d ago

Q. What is your knowledge of documentation?

Ans.

Knowledge of documentation is crucial for CNC machinists to ensure precision and compliance in manufacturing processes.

  • Understanding technical drawings and blueprints is essential for accurate machining.

  • Familiarity with CNC programming documentation helps in setting up and operating machines effectively.

  • Maintaining logs of machine operations and maintenance schedules ensures compliance and efficiency.

  • Knowledge of quality control documentation, such as inspection reports, is v...read more

1d ago

Q. Give one drawing to make a program

Ans.

A drawing of a simple rectangular block with holes on each face

  • Create a 3D model of the block with holes in a CAD software

  • Export the model as a STEP or IGES file

  • Import the file into CAM software and create toolpaths for each hole

  • Generate G-code from the toolpaths and load it onto the CNC machine

  • Run the program and verify the dimensions of the machined block

Asked in Wakefit

1d ago

Q. Convert 1 inch to millimeters and centimeters.

Ans.

1 inch is equal to 25.4 millimeters and 2.54 centimeters.

  • 1 inch = 25.4 mm

  • 1 inch = 2.54 cm

Q. Which CNC control systems are you familiar with?

Ans.

The control used in CNC machining depends on the specific machine and its manufacturer.

  • Different CNC machines use different controls, such as Fanuc, Haas, Siemens, or Mazak.

  • The control system is responsible for interpreting the CNC program and executing the machining operations.

  • Each control has its own programming language and features.

  • Operators need to be trained on the specific control used in their machine.

  • Examples of controls include Fanuc 0i, Haas NGC, Siemens Sinumerik,...read more

6d ago

Q. Which machine is used?

Ans.

CNC machines, like mills and lathes, automate machining processes for precision manufacturing.

  • CNC Mills: Used for cutting and shaping materials like metal and plastic.

  • CNC Lathes: Ideal for creating cylindrical parts, such as shafts and fittings.

  • CNC Routers: Commonly used for woodworking and creating intricate designs.

  • CNC Plasma Cutters: Used for cutting metal sheets with high precision.

Q. Cogsdill tool attachment use

Ans.

Cogsdill tool attachment is used in CNC machining for precision hole finishing and deburring.

  • Cogsdill tool attachments are used to achieve precise hole finishing and deburring in CNC machining.

  • These attachments are designed to fit into the CNC machine and perform operations like reaming, burnishing, and chamfering.

  • They are commonly used in industries like aerospace, automotive, and medical device manufacturing.

  • Cogsdill tools can be used for both internal and external hole fin...read more

4d ago

Q. How can you improve your confidence level?

Ans.

Confidens level badhane ke liye vyakti ko apne skills aur knowledge par vishwas karna chahiye, sath hi practice aur feedback lena bhi zaroori hai.

  • Apne skills ko samjhein: Apne kaam ki khoj karein aur unhe sudharne ki koshish karein, jaise ki naye tools ya techniques seekhna.

  • Practice karein: Regular practice se aapki skills aur confidence dono badhenge, jaise ki CNC machine par alag-alag projects karna.

  • Feedback lein: Apne seniors ya colleagues se feedback lein, unki salah se a...read more

1d ago

Q. 2. types of fit

Ans.

Types of fit refer to the degree of tightness or looseness between two mating parts.

  • Clearance fit: parts are intended to have a gap between them

  • Interference fit: parts are intended to be pressed or forced together

  • Transition fit: parts have a combination of clearance and interference fit

  • Examples include press fit, slip fit, and force fit

2d ago

Q. How to improve OEE?

Ans.

OEE ko badhane ke liye production efficiency, quality, aur downtime ko sudharna zaroori hai.

  • Production Efficiency: Machine utilization ko badhakar, jaise ki scheduled maintenance se downtime kam karna.

  • Quality Improvement: Defective products ki sankhya ko kam karne ke liye quality control processes ko sudharna.

  • Reduce Downtime: Regular maintenance aur quick changeover techniques ka istemal karke downtime ko kam karna.

  • Employee Training: Operators ko training dekar unki skills ko...read more

5d ago

Q. 4. types of steel

Ans.

There are many types of steel, including carbon steel, alloy steel, stainless steel, and tool steel.

  • Carbon steel is the most common type and is used in construction and manufacturing.

  • Alloy steel contains additional elements like nickel or chromium to improve strength and durability.

  • Stainless steel is corrosion-resistant and often used in kitchen appliances and medical equipment.

  • Tool steel is used for making tools and dies, and is known for its hardness and resistance to abras...read more

4d ago

Q. 3. M6 drill size

Ans.

M6 drill size refers to the diameter of the drill bit used for making holes with a metric thread size of 6mm.

  • M6 drill size is commonly used in manufacturing and engineering industries.

  • The diameter of the drill bit for M6 size is approximately 5.2mm.

  • M6 drill size is used for creating holes in materials such as metal, plastic, and wood.

  • It is important to use the correct drill size to ensure the hole is the correct size and the thread fits properly.

2d ago

Q. Loss time reduce

Ans.

Loss time can be reduced by implementing efficient processes and minimizing downtime.

  • Implementing preventive maintenance schedules

  • Optimizing tooling and equipment setup

  • Reducing setup and changeover times

  • Minimizing machine breakdowns through regular inspections

  • Providing training to operators to improve efficiency

  • Using automation to reduce manual labor

  • Improving communication and coordination between departments

  • Implementing a continuous improvement program

  • Encouraging a culture o...read more

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