CNC Milling Advantage and Disadvantage: A Comprehensive Guide

CM Milling Advantage and Disadvantage

At present, CNC milling is one of the most common machining processes in the manufacturing industry. It involves the use of computer-controlled machines to create complex shapes and precise parts from a wide range of materials. While CNC milling offers a number of advantages, it also has some disadvantages that manufacturers should be aware of. In this article, we will explore the advantages and disadvantages of CNC milling in detail.

Advantages of CNC Milling

  1. Precision and Accuracy

CNC milling machines are capable of producing highly accurate and precise parts with minimal error. This is because they are computer-controlled, which means that the operator can program the machine to perform specific operations with a high degree of accuracy.

  1. Increased Productivity

CNC milling machines are capable of producing parts quickly and efficiently. This is because they can operate continuously, without the need for frequent manual adjustments.

  1. Versatility

CNC milling machines are capable of machining a wide range of materials, including metals, plastics, and composites. This makes them ideal for a variety of manufacturing applications.

  1. Consistency

CNC milling machines can produce identical parts with consistent quality, which is essential in mass production.

  1. Cost-effective

CNC milling machines are generally cost-effective in the long run, as they reduce the need for manual labor and can produce parts quickly and efficiently.

Disadvantages of CNC Milling

  1. High Initial Investment

CNC milling machines are expensive to purchase and install, which may be a barrier to entry for some manufacturers.

  1. Limited Flexibility

CNC milling machines are limited to producing parts that can be accommodated within their work envelope. This means that larger parts may require additional equipment or manual machining.

  1. Programming Complexity

CNC milling machines require specialized programming, which may require the services of a skilled operator or programmer.

  1. Maintenance Costs

CNC milling machines require regular maintenance to ensure that they are operating correctly. This can be costly and time-consuming.

  1. Vulnerability to Power Outages

CNC milling machines rely on electricity to operate, which makes them vulnerable to power outages. This can cause downtime and disrupt production schedules.


CNC milling offers a range of advantages, including precision, productivity, versatility, consistency, and cost-effectiveness. However, it also has some disadvantages, including high initial investment, limited flexibility, programming complexity, maintenance costs, and vulnerability to power outages.

Manufacturers should carefully consider these advantages and disadvantages when deciding whether to invest in CNC milling equipment. Ultimately, the decision will depend on the specific needs and requirements of the manufacturing operation.

Essential Safety Tips


Every machine shop must adhere to a group of safety regulations and guidelines; primarily for the safety of the machinist, and second, for the sake of the business. Here at Autoline, we are aware of the dangers that can take place at any given time when on the floor, so we enforce additional protocols for caution. It is our mission to provide the best quality products on the market in a timely manner. The best way we can uphold that mission every day is to ensure we follow the set of rules created to foster a safe environment. We are always looking for ways to prevent an accident, so forming new rules is a way we stay proactive on this front.


Though some rules seem like common sense, they’re enforced because someone at some point in time over the course of machining history decided to test the risk and learned it wasn’t worth it. Since we’ve been in business, we’ve encountered very few and minimal accidents. This is because of our strong culture of safety. Outlined below are several of our basic but very fundamental rules we enforce here at Autoline.    



1. Keep machine doors closed

This is the most obvious safety rule on the shop floor. CNC Machine doors are large to accommodate the complex technology structure and functions inside. Although it might seem like common sense to keep the door shut when the machine is operating, not everyone knows. You may be surprised by the number of machinists who try to shave off a few seconds of operation time by disregarding this. There are so many safety risks at play when you open the door. A part of the tool can fly out of the machine, pieces of the stock, and even the stock itself can come soaring out the open doors and hit you. The extent of the injury varies, but it’s not worth finding out just how much.

Our machinists know this and ensure they complete the entire operation before opening the doors. Even if the cycle is nearing the end, rushing to open the doors can lead to coolant landing on you or worse, your machine malfunctioning. Trying to take short cuts can end unfavorably for the operator. So, we make sure every new machinist understands that this simple concept is extremely important for their safety.    


2. Don’t alter the tools

Time and money are two variables constantly at stake for any industry. In machining, some operators will alter their machines to save time and money. This is a dangerous practice. Firstly, these highly powered, complex machines are designed to function in a specific way. When shops alter the tools to make them perform a job different from what it was designed to do, a substantial amount of damage can be done. Rather than risking it, we would upgrade to a modern machine that can provide the exact function we are looking for. Though it can be costly, it is safer to do this than damage the existing machine by forcing it to perform outside of its programmed abilities.

Another reason it is dangerous to alter the tools in a machine is that it can be expensive to repair. If something goes wrong because we decided to alter the tools in the machine, we could permanently damage it. Depending on the severity of the problem, it could cost close to the same amount of a new one. In addition, we personally believe that if we don’t have the machinery to perform or produce a specific function, it would be far more beneficial to us to purchase another machine. How? In addition to producing your project, we will also be broadening our own resources as a manufacturing facility. Ultimately, we know the benefits far outweigh the cost here.    


3. Keep the machines maintained

Anyone who owns a machine knows that its lifespan is affected by how well it is maintained throughout time. Take for instance your car. If you’re not getting the oil changed, checking the fluids, replacing your engine filter, inspecting the tires, testing your brakes, and regularly washing it, you will increase the likelihood of damaging the vehicle. Preventative car care will reduce the wear and tear of your car’s components, extending its lifespan. If you don’t maintain the details, costs will add up and eventually more damage will occur totaling an even greater expense. The same rules apply to CNC machines. An unmaintained machine can cause damage to them, and repairs aren’t cheap. In addition, it can also pose several safety problems. Small issues can eventually lead to bigger problems if you don’t resolve it in a timely manner.

If you don’t maintain your machine properly, it can hinder the process of producing quality parts. For example, a dirty machine can cause malfunction in the interior system and derail precision while performing, resulting in a subpar product. To prevent all these issues from occurring, we train our machinists to clean the machines several times a day. After every cycle, machinists spray down the interior and then remove the excess metal. Moreover, we schedule our machines for regular maintenance, and even sometimes undergo unscheduled servicing for extra caution. Here at Autoline, we know the importance of maintaining our workspace and work tools as well. Everything our operators lay hands on are essential to completing the job. We treat everything in the workshop with care and attention to ensure we are always finishing each project with quality tools and in a reasonable time.    


4. Keep staff trained

Last but certainly not the least! A major issue in our industry today is that unskilled workers are operating the shops. Not to say these individuals cannot acquire the necessary training, because they absolutely can. However, placing amateurs in an environment where they are unknowledgeable of all the dangers and unequipped to handle the outcome of consequential situations, is only setting them up for failure. Similarly, there are not as many skilled machinists in the field because automation has reduced the requirements of the job.

Technology has dealt the world a great deal in innumerable ways, but the expectation for machinists have narrowed the skill factor for many looking to establish themselves in the industry. To dispute this, we require our machinists to have a substantial background in machinery operation and are more likely to hire individuals with complimentary hobbies. We don’t take lightly the dangers of the job and therefore enforce strict rules and regulations. Moreover, our training is fairly extensive, and we require weekly meetings to communicate updates and to make sure machinists are adhering to protocols.



G-Code stands for Geometric code. This is the generic industry term for the computer language machinists use to control the movements of a machine. These commands direct the machine tool where to move, how fast to move, and the toolpath to follow.

Take for example the CNC lathe machine. The lathe tool is driven by the commands of the G-code to follow a specific toolpath that is programmed into the computer of the machine. In the case of 3D printing, the G-code instructs the machine to layer material to form a specific 3-dimensional figure. Without the G-code, the tools that cut or deposit materials on a machine would fail to move in the designated tool path.  

CAD/CAM Software

CAD/CAM (computer aided design/computer aided manufacturing) is the software CNC machines use for design and machining. Certainly, the tools are synonymous with each other, but they function separately. CAD software is a computer aided program used to create, modify or apply a design. CAD involves the use of geometric shapes to construct a figure that can be 2D or 3D shapes. Designs in the CAD can be drawn using lines, points, and circles allowing for the creation of parts used in multi-axis CNC machining. CAD is the first essential function in the design process of manufacturing. Once the design is completed, it’s processed into a computer aided machine that programs coded language to be read by a CNC machine. Machinists refer to that language as G-Code.

Simply put, CAD deals with the creation of a design. CAM creates a code based on the transferred design. Tools like a lathe or mill read the language of the G-code and follow the specific toolpath programmed by the CAM to form the desired shape out of a piece of material.

To the average person, G-code would appear perplexing. However, a machinist should not find it any more difficult to read than their native language. In fact, one may even argue that G-code is written in a straightforward way.

Each line of code directs the machine to carry out a specific action. In other words, the code controls the speed, position, rotation, etc. These sets of codes that deliver point-by-point directions to the machine form a figure. A simple product can require hundreds and even thousands of lines of code because every movement entails complete precision to produce a flawless result.


G-Code Example

For better understanding, here’s a single line of G-code:

G01 X247.951560 Y11.817060 Z-1.000000 F400.000000

As previously mentioned, this may appear perplexing at first, but it is a formula that can easily be understood.

A line of code begins with “G”. Following that will be a set of numbers; in this case, it’s 01. What this means is the machine needs to move in a straight line. Like the coordinates on a plot, X, Y, and Z are the dimensions. The F value represents the feed rate, or the speed.

Moving on to the next set in the G-code line, X247.951560 Y11.817060 Z-1.000000 is directing the machine to move in a straight line to the coordinates, X247.951560, Y11.817060 and Z-1.000000. The last set of the code, F400.000000, explains the speed at which the tool will move to the coordinates, which is 400 mm/min. Units will not always be set to millimeters.  Machines can modify units for this command.


Common Commands

In addition, some of the more frequent G-code commands include G00, G01, G02, and G03.

G00 indicates rapid positioning. This will command the machine to move all axis simultaneously at maximum travel speed to a specified point. This is a non-cutting movement instead moves the tool to a specific position to begin cutting, layering, or printing.

G01 indicates linear interpolation. Like in the first example, this G-code will instruct the machine to move in a straight line at a set speed. The G01 is a fundamental command that is often executed in cutting material and extrusion material.

G02 is circular Interpolation clockwise. This command instructs the machine to move in a circular motion clockwise.

G03 command represents circular interpolation counterclockwise. Reverse of G02, his command instructs the machine to move in a circular motion counterclockwise.

These commands require a defined center of rotation. The starting point of a new command is the end point of the previous. Furthermore, the complexities of G-code can certainly intimidate any person. But what may seem like an infinite set of confusing combinations of letters and numbers is a string of logical instructions that deliver a high-performing function. Customers looking for machining services that produce perfect quality can depend on Autoline to provide just that.

Brief History of the CNC Machine

photo collage. Top is old CNC machine and bottom is modern CNC machines.

The Infamous CNC machine

CNC machines have an extensive history. For centuries, technology has evolved tremendously and with every advancement, the machining industry has always been directly affected. At one point in time, manual machining was the only way to manufacture certain products. However, after the discovery of automation technology, the world came to embrace CNC machining. Though traditional machining methods paved the way for modern manufacturing, it no longer stands a chance as the premier choice for high quality production. Since it’s inception, the CNC machine has made strides in the industry. The benefits include a quicker production time, boost in production volume, and an increase in safety. The most notable benefit is the precise and detailed machining.

Automated machining precision has permitted a small margin for error, almost completely eliminating human inaccuracy. Furthermore, the device that would require a punch tape method is now an automated powerhouse dominating the machining industry. Today, modern CNC machines are software driven, more dynamic and faster than their original NC counterparts. Here’s a brief timeline of CNC machining. 

CNC history