Introduction
Milling is an important manufacturing process used to transform workpieces into the desired shapes and geometries. During this subtractive process, a rotary cutting tool removes unwanted material from a stationary workpiece. While the basic milling operation remains constant, different types of milling machines can be used to achieve the required results. Two of these types are vertical mills and horizontal milling machines.
Both vertical and horizontal milling machines have unique features that make them suitable for particular machining operations and applications. Understanding their differences and how each system works can help you identify the right milling machine for your project. This article explores the differences between vertical and horizontal milling as well as their advantages and disadvantages, providing a comprehensive comparison of horizontal mill vs vertical mill.
What is Vertical Milling?
Vertical milling involves using a vertically oriented rotating spindle that holds the cutting tools. The vertical head, oriented perpendicular to the worktable’s surface, allows for versatile machining operations. As the cutters interact with the stationary workpiece, they remove excess material creating the desired geometries. This vertical setup is ideal for precision machining and intricate detailing.
Vertical milling has been around since the 19th century. Over time, it has seen significant advancements such as the adoption of CNC technology. CNC milling machines use computers to control the movements of the cutter. This has facilitated automation and improved precision. Today, vertical milling is used for a range of applications including mold making, product designs, and fine metal work.
Vertical milling machines typically utilize two different types of setups. Based on these setups, there are two categories of vertical mills.
Turret milling machines – With a turret mill, the spindle remains stationary during the milling process while the table is moved to the spindle axis in both parallel and perpendicular directions. This vertical machine type is suited to small geometries.
Bed milling machines – Bed milling machines are used for larger workpieces. They are composed of a vertical, rotating spindle that moves the cutting tool along the bed facilitating material removal.
Advantages of CNC Vertical Milling Machines
Vertical milling machines are widely popular in the manufacturing industry. Here are some of their advantages.
Less expensive
Vertical milling machines are generally cheaper than their horizontal counterparts. They tend to have smaller casings and fewer complex internal parts, hence the lower costs. Affordability means that even small machine shops can acquire this equipment.
Availability
Thanks to low initial and maintenance costs, vertical mills are very popular across virtually all industries. This makes it easier to find spare parts, skilled operators, and repair assistance.
Simplicity
A vertical milling machine, especially a CNC milling machine, is easy to operate and maintain. Unlike a horizontal milling system, it does not need add-ons and has fewer programming requirements.
Low-volume production
Vertical mills are the go-to for small-scale milling operations. They are ideal for such projects due to their low cost and ease of operation.
Disadvantages of CNC Vertical Milling Machines
There are some shortcomings associated with vertical milling machines. They include:
Limited to smaller workpieces
Vertical mills are not designed to handle large and heavy workpieces. Therefore, they are not the best option for heavy-duty work.
Lower production output
Compared to a horizontal setup, vertical machines have a lower material removal rate. Additionally, this machine only operates on a single plane and is not suited to complex multi-sided operations. When considering horizontal mill vs vertical mill, a vertical machine’s cutting capabilities mean that it has a low output rate compared to a horizontal mill.
What is Horizontal Milling?
Horizontal milling has some slight variations. The fundamental concept remains the same — a rotating spindle holds and moves a cutting tool that removes material from a stationary workpiece. However, the spindle would be mounted horizontally meaning that the tool also has a horizontal orientation. This setup is known for its increased cutting power and faster milling process. It also allows the cutting head to approach the workpiece from multiple angles.
With a horizontal milling machine, you can employ specialized cutters that aid in creating bevels, grooves, and radii. This type of milling machine is common when working with large workpieces or when a project requires deeper cuts.
Advantages of CNC Horizontal Milling Machines
A horizontal setup offers multiple unique benefits and has applications in various industries. Here are some of its advantages.
Increased productivity
One of the biggest advantages of a horizontal mill is its cutting efficiency. This milling machine cuts faster than a vertical mill resulting in increased output and lower lead times. Further, horizontal mills are designed to perform multiple operations in one setup while a vertical mill requires a different setup for each operation.
Superior chip evacuation
Machining operations generate chips that can lead to manufacturing flaws if not removed efficiently. In a horizontal mill, gravity aids in the natural evacuation of chips and other debris allowing for an excellent surface finish.
Capability
A horizontal machine can handle bulky workpieces that are not machinable using a vertical mill. It makes deeper cuts and supports add-ons that facilitate the creation of complex products.
Disadvantages of CNC Horizontal Milling Machines
Despite their benefits, there are some drawbacks to using horizontal milling machines. They include;
They are expensive
Compared to vertical mills, horizontal milling machines are significantly more expensive to acquire and maintain. Thus, you’re more likely to find this equipment in large manufacturing companies. Small businesses tend to have vertical milling machines since they don’t require a hefty capital investment.
Scarcity of trained operators
Horizontal mills are not very common. As such, there is a shortage of operators who have direct experience working with this equipment.
Require more floor space
A horizontal milling machine tends to take up more floor space compared to its vertical counterpart. Therefore, this option is more suited to larger shops with enough room to accommodate this equipment.
The Difference Between Vertical and Horizontal Milling
While horizontal and vertical milling share some similarities, there are some significant differences that you need to be aware of. They include:
The Orientation of the Spindle
Spindle orientation is one of the main differences between vertical and horizontal milling machines. The spindle is a critical component in milling machines that holds and drives the cutting tool to rotate. As the name implies, a horizontal milling machine features a horizontal setup. The spindle moves parallel to the worktable’s surface, and the cutting tool removes material from the workpiece along this horizontal axis. This orientation is ideal for depth cutting across huge workpieces.
With vertical milling machines, a vertical spindle holds and rotates the cutting tool. This vertical head is oriented perpendicular to the worktable’s surface, allowing for versatile applications. Therefore, the cutter is perpendicular to the workpiece and the spindle moves it up and down as required. The vertical orientation allows for high-precision cutting.
Tool geometry
Another distinction between the two types of milling machines is the geometry of the cutting tools. Vertical mills typically use long, thin, cylindrical cutting tools known as end mills or dovetail cutters. On the other hand, horizontal cutters are usually shorter and thicker.
Cut specifications
The different tool characteristics affect the cutting specifications of each milling machine. Horizontal mills use short and thick tools that provide the stability required to withstand resistance when making deep and heavy cuts. Vertical cutting tools generate precise but shallower cuts on smaller workpieces. Attempting to use vertical tools for depth-cutting would result in vibrations that affect the final results.
Cost
Vertical and horizontal machines come with varying price tags. Horizontal mills are designed for heavy cuts, require highly skilled operators, and are generally more expensive. They make up for the heavier investment with speed and production efficiency and are mostly found in well-established manufacturing companies.
On the other hand, vertical machines are cheaper to acquire, operate, and maintain. As a result, most small-scale machine shops utilize this machine type. Nevertheless, both horizontal and vertical machines are necessary for milling operations. The ideal kind of machine will depend on the product characteristics and industry requirements.
Material Removal Rate
With regards to material removal rate, horizontal milling machines have a superior performance thanks to their enhanced stability and capacity to produce deeper cuts. Conversely, vertical machines excel when it comes to precision but have a slower material removal rate. This is because they are designed to make shallower cuts.
Number of Sides for Machining
Horizontal milling is a multi-sided machining operation that enables you to approach the workpiece from multiple sides and several planes. Conversely, the cutting tool in a vertical mill moves along a single plane. Further, horizontal machining systems excel in complicated and customizable projects. You can incorporate various add-ons in a horizontal setup that would not be applicable in a vertical machine.
Horizontal Vs Vertical Milling: Which to Choose?
Choosing the right milling machine comes down to several factors including;
Size of the workpiece
If your project calls for large and heavy workpieces, horizontal milling machines are the obvious choice. Unlike vertical mills, these machines are specially built to accommodate bulky materials.
Material Removal Rate
Horizontal tools have a high material removal rate allowing you to achieve the desired results exceptionally fast. They are often preferred for large-scale manufacturing and time-sensitive projects. Similarly, vertical mills are suitable for small-scale projects with longer deadlines.
Cost
Another key consideration is your budget. While horizontal milling machines offer exceptional cutting capabilities, they are expensive to install and maintain. On the other hand, vertical mills are generally more affordable. If your project demands a horizontal mill but you don’t have the budget, consider approaching a CNC machining service.
Project
Vertical mills are useful in precision cutting projects that require detailing and less cutting. Also, if machining is to be completed on a single plane, this system is adequate. However, if you require multi-sided machining, you’ll need to go with a horizontal milling machine.
Let Aria Manufacturing Help With Your Project
Today milling machines are more advanced than ever and play a crucial role in product manufacturing. Vertical and horizontal milling machines complement each other and understanding their differences is critical when picking the ideal machine for your project.
When you opt for CNC milling services from Aria, we do all the heavy lifting for you. Our seasoned experts employ the best and most cost-effective processes for your project. Contact us today and find out how we can help you.