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.

Conclusion

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.

G-Code

G-Code

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

Meet our Production Manager

Production manager

Operating devices like a cell phone or tablet can be fairly self-explanatory to the average person. However, strip the touch screen and you’re left with a box of complex components you know nothing about. Now, imagine the complexity of your smartphone scaled to the size of three refrigerators, plus additional functions and tools attached to it. Just imagine the convolution.

Similarly, someone who possesses the skills and knowledge to operate that kind of hardware is a machinist. This is an individual who has acquired extensive training in the sector of machinery. Any manufacturing company will have one or a few who are in charge of operating and maintaining substantial machines in a warehouse or factory. This person for us is Justin. He is the official Production Manager at Autoline Industries’ headquarters in Mesa, Arizona. Production Manager

Furthermore, there are many factors that go into the manufacturing process. It takes a great deal of attention and dedication to ensure everything runs smoothly and accurately. Certainly, it is up to Justin to ensure that the “show” runs fluidly with minimal to no hiccups. In other words, a lack of precision in his position could result in a number of detrimental ways. However, our production manager has demonstrated a studious work ethic for over six years with the company. His passion for machining has translated through his dedication to Autoline’s mission of producing quality products for every customer.

“Our production manager has demonstrated a studious work ethic for over six years with the company.”

 

Prior to working at Autoline, Justin had long established a strong interest in machines. He grew up in Mesa, Arizona where his dad exposed him to the automotive world at a young age. Directly after graduating from high school, he started working at McFarland Machine & Engineering LLC. After five years , he joined the Autoline team, full-time as a programmer. Gradually, he worked his way up to the production manager position.

Today, he oversees the entire operations floor. On a normal shift, he begins by reading through paper work to ensure the accuracy of production information and policy conduction. The remainder of the day is spent overseeing a number of responsibilities. This includes: seeing that programs are functioning properly, there are enough material, set ups are organized, machinists are productive, and that work is moving according to schedule. In addition to his work here, Justin also manages operations at Quentin Defense in Gilbert. There, he manages the shop where they manufacture firearms and suppressor parts.

In conjunction with his 11-year career in machinery, Justin is also a certified aircraft pilot. In his spare time, he enjoys flying his general aviation aircraft. He is currently working on his instrument flight rating.

“It requires consistent patience, attention, practice…”

 

When asked what interesting fact about CNC machining might an average person not know, he shared that the process always takes longer than expected. Most people don’t realize the extent to which it takes to produce something through machining. The trade requires various abilities and skills which include patience, attention and practice. Moreover, it helps tremendously to have a basic interest or passion for the profession, much like Justin.

CNC Turning vs. CNC Milling- What is the Difference?

laser

 

Here at Autoline Industries we offer a wide array of services, including CNC Turning and CNC Milling. While most of our clients are already intimately aware of actions behind each service, those less familiar may have difficulty identifying the variances between these seemingly similar processes.

Although on the surface they appear to complete similar actions and produce similar results, the operations of both CNC Turning and CNC Milling can vary greatly.

 

The Basics

CNC machining is a popular term in the manufacturing space, but what exactly does it mean? To put it simply, CNC, or ‘computer numerical control,’ machining is a subtractive manufacturing processes that uses pre-programmed computer software to dictate the tools and machinery. These cutting tools then shape stock materials, including metals, plastics, wood, composites, glass and more, into custom parts.

The entire machining process begins with the creation of a 2D or 3D CAD part design. After the design process, the machinist will export it into a CNC compatible file format and then convert it into a CNC machine program. The programmed machine dictates the actions of the tools to create a workpiece. Before the machine begins operating, the operator secures the workpiece to the worktable and attaches the machine tools to the spindle. The operator will program specifications into the machining application and cutting tools. The final step is to launch the program.

Moreover, two of the key CNC machining services we are focusing on include CNC turning and CNC milling. These are high-powered methods of producing refined products that may appear to be similar in operations but are surprisingly different in several aspects. This knowledge is important to know when choosing what service might deliver the best outcome for your vision. Continue reading to learn more!

 

CNC Milling

Google defines milling as “to cut or shape metal using a rotating tool.” This is quite literally what it is. The machining process uses computerized controls and rotating multi-point cutting tools to shape and cut through material and create a custom designed piece. Commonly used material includes metals, plastic, and wood. The cutting tool rotates at speeds reaching up to thousands of RPM (Revolutions per minute) when the milling process begins.

Milling is the best service as a secondary finishing process. It supplies shape, definition, and produces features to a part such as holes, threads, pockets, and slots. The process includes removing material from an already cut piece of material to achieve the custom design preset into the computer. Furthermore, CNC milling machines are categorized into horizontal and vertical machine configurations. This means that if a machine rod is vertically oriented, then it is a vertical milling machine. And if the rod is horizontally oriented, it is a horizontal milling machine.

Furthermore, milling has many advantages over other manufacturing processes. CNC milling is a fast and effective way to produce components with a high degree of accuracy. It supplies a smooth finish and can produce any 2D or 3D shape so long as the machine can reach the needed cutting surface. Examples of CNC Milled parts include Automotive components, Molds, Firearms, Gears, Enclosures, Bracketry, Building, and Fabrication Components.

 

CNC Turning

CNC is a sub-category of lathing. What is lathing? It is a process much like milling but slightly different. In contrast to a milling machine in which the workpiece moves as it is cut, a lathe machine will hold the workpiece in place as it is cut. Not only does the lathe hold the piece in place, but it also rotates it. This is unlike milling where the workpiece is continually moving. Turning requires complete stabilization. One way to think of this is a pottery wheel. The clay is the workpiece, and the hands are the cutting tool. The spinning wheel is the lathe stationing the workpiece so that the potter can sculpt the clay.

Due to technological advancements, CNC lathe machines are quickly replacing other traditional production machines. Furthermore, turning encompasses several benefits including an easy set up and operation. It offers superior dimensional accuracy and high-quality finishes on all surfaces. In addition, turning supplies immense accuracy in production and repeatability.

Moreover, CNC turning is “a machining process that uses a cutting tool to remove material for creating cylindrical parts…” Like milling, it is another subtractive machining process. With turning, a spinning piece holds a workpiece in place as a cutting tool deducts material. However, unlike milling, turning focuses on creating a helical toolpath. Turning can also cut material like metal, wood, or plastic. In short, the biggest difference between milling and turning is that the latter requires a secure hold of the workpiece while the spinning tool does the cutting. In other words, the tool moves along a workpiece or a tool head shoots it.

Sometimes in turning, the spin tool will rotate the workpiece at high speeds and then cut the tool. The tools and workpiece in a milling machine will move simultaneously. It achieves this by moving a static cutting tool against the piece. Moreover, people choose milling for more complicated geometries. In contrast, others resort to turning for rotational, axisymmetric, cylindrical shapes with many features like grooves, tapers, and contoured surfaces.

 

Conclusion

While both forms of machining share many similarities and are even complimentary to each other, they each serve a key purpose and understanding these differences ultimately leads to better results. To learn more about CNC turning and milling, or one of the many other services we offer here at Autoline, contact us today! Our friendly and knowledgeable team is here to assist you. With our top of the line equipment, tools, and experience across a wide range of industries, we can help complete your next project.

 

Autoline’s Turning and Milling Services

Our top of the line CNC turning, and Milling services are the preferred method for removing large amounts of material on rounded stock as quickly and precisely as possible. Autoline houses state of the art machines ideal for larger production runs.

If you are looking for high volume, and quick turn around on simple components our CNC machining options are going to be provide you with the best service.

 

Arrival of the Makino A61

Passing through the warehouse
Delivery diver begins to loosen straps for Makino A61 Machine
The Makino A61 machine arriving to the Autoline Warehouse. The delivery man loosens the straps
40-feet semi truck with Makino A61 machine still strapped to it
The Autoline Production Manager assists in unstrapping the machine from the truck

 

 

 

 

 

 

 

 

 

 

 

 

 

Joining the impressive collection of CNC machines at the Autoline Industries warehouse is the Makino A61. On August 18th , the massive machine arrived at its new home on a large 40 foot semi-truck. Firstly, in a temperature of 109 degrees, our Production Manager along with the truck driver worked carefully to unstrap the giant machine buckle by buckleOnce the forklift arrived, the entryway of the warehouse was cleared to make way for the A61. As some of our team members awaited its entrance from inside, the anticipation grew, but the process to remove it was both lengthy and climactic. The Makino machine was hauled off in three parts, each section slowly forklifted off the truck and directed in by the delivery crew. As it made its way to its official home, several of us stood by capturing the moments with our phone and cameras.  

Autoline Warehouse- U.S. based
Slowly making its way in through the warehouse

Furthermore, the Makino A61 officially takes the title as the largest machine in the warehouse. It is a horizontal machining 4-axis giant that takes part productivity, precision and reliability to the next level. Additionally, it offers robust casting design and features a 14,000-rpm high-speed, high-power spindle with 303 Nm of torque. Unlike the other machines, the A61 primarily serves to create horizontal designs. Moreover, our engineers project a 1-2-week time frame to completely program and set up the CNC machining center before it is ready for use.  

Forklifting it in
Forklifting the machine in
Makino Logo #1 sign
Makino Milling Machine Co., headquartered in Tokyo, Japan
The A61 Logo
Horizontal machining center
Full body view
The machine features 14,000-rpm high-speed
Wiring and hoses
High-power spindle features 303 Nm of torque