Last Updated on March 1, 2023 by Charles Wilson
A milling machine is a must-have tool for fabrication shops.
The main concern of most machine shop operators who plan on buying a milling machine is: should you get a horizontal or a vertical milling machine?
With either machine, you can do various milling operations to achieve the desired finish.
In this article, I’ll discuss how to use vertical and horizontal milling machines and how they differ.
- Milling is a common machining process involving a rotating cutting tool to remove material from a stationary workpiece.
- There are two main types of milling machines: horizontal and vertical milling machines.
- A vertical mill can perform shallow, precise cuts on small workpieces. There are two kinds of vertical machines: turret and bed mills.
- A horizontal mill can do deep and heavy cuts at various angles. It is ideal for large workpieces and customized jobs.
What Is a Horizontal Milling Machine?
Manual and CNC milling are essential manufacturing processes in the metal fabrication industry.
Milling removes material from a stationary workpiece using a rotating cutting tool to cut and shape it into the desired CNC milling parts.
There are two different types of milling machines:
- Horizontal milling machine
- Vertical milling machine
In a horizontal milling machine, the milling process is horizontally-oriented.
It has an overhanging arm and a horizontal spindle that can manipulate the workpiece by rotating on a horizontal axis.
Horizontal milling machines are generally used for working on larger materials and deeper cuts.
How Does It Work?
The main parts of a horizontal milling machine consist of a spindle axis that runs parallel to the worktable, an overhanging arm, and an arbor support.
Horizontal milling machines feature shorter and thicker cutting tools that can make deeper cuts for a greater material removal rate.
In a horizontal milling machine, the workpiece is affixed directly on a worktable.
The process is done horizontally or at an angle if the machine comes with a universal table.
The cutting tool of a horizontal milling machine removes material from the stationary workpiece from different angles to achieve complex designs.
Due to its horizontal orientation, it has more cutting power and speed but may fall short on precision.
What Is a Vertical Milling Machine?
A vertical milling machine is the most COMMON type of milling equipment.
It works similarly to a horizontal milling machine, but the spindle axis is vertically-oriented.
Vertical mills have a fixed spindle that can be extended and an adjustable work table for plunge cuts and drilling operations.
The vertical orientation of this milling machine works best for shallow cuts on smaller workpieces that require precision.
How Do You Use It?
There are TWO MAIN TYPES of vertical milling machines:
Turret Milling Machines
In a turret mill, the spindle remains fixed, while the bed portion can move parallel or perpendicular to the axis depending on the cutting process.
Most turret mills have quills that can raise or lower the milling cutter to simulate a drill press.
There are two ways for turret mills to cut vertically: by adjusting the quill or moving the knee.
A turret mill is ideal for working on small parts.
Many manufacturing companies go for turret mills because they can be used for a broad range of applications.
Bed Milling Machines
With bed mills, the bed portion can only move in a horizontal direction while the spindle moves parallel to its own axis.
This setup allows the bed mill to create various features in the workpiece, such as grooves and bores.
Bed milling machines are more common in traditional machine shops and are best suited for bigger workpieces.
Differences Between Horizontal and Vertical Milling Machines
Although both vertical and horizontal milling machines perform the same operations, they differ in many aspects.
Let’s see how they compare based on different categories:
1) Orientation of the Spindle
The MAIN difference between vertical and horizontal mills lies in how the cutting tool interacts with the workpiece.
The cutting head is attached to the spindle, which moves in a certain direction.
In horizontal milling machines, the spindle is fixed in a horizontal orientation that moves parallel to the worktable.
The cutting tool is rotated on this horizontal axis to remove materials.
With vertical milling machines, the spindle moves perpendicular to the worktable. The cutting tool is held in place with this vertical spindle and rotated to make plunge cuts.
2) Tool Geometry
Vertical and horizontal milling machines also differ in the shape of their cutting tools and milling cutters.
Horizontal mills have shorter and thicker cutting tools that allow deeper cuts to remove more material.
Thick cutting tools work best for large workpieces.
For projects that require precision, vertical mills have thin cutting tools that allow for shallow, precise cuts.
The thin tools of vertical milling machines make them ideal for smaller workpieces.
Geometric specifications of milling machines AFFECT the cutting specifications, which is another consideration.
3) Cutting Specifications
The geometry of each cutting tool has an impact on the overall cutting specifications and results.
Due to their thickness and short length, horizontal cutting tools are designed to make deep, heavy cuts, making them ideal for creating grooves, slots, and other normal cuts.
Unlike horizontal tools, their vertical counterparts cannot create deep cuts because they tend to vibrate.
Instead, the thinness of vertical tools is more suited for drilling and plunge cuts.
4) Material Removal Rate
Horizontal mills can remove more materials at a faster rate because of their stability and their capacity to make deeper cuts.
In comparison, vertical mills have a lower material removal rate.
Machine shop operators typically turn to vertical milling machines for shallow cutting operations like grooving and facing.
5) Number of Sides for Machining
The orientation of a horizontal mill allows the cutting tool to approach the workpiece from various angles.
As a result, this setup is ideal for complex and customizable cutting jobs.
Horizontal milling machines are also compatible with MORE add-ons, features, and cutting tools like an arbor-mounter cutter and an end mill.
On the other hand, vertical mills can only operate on a single plane.
6) Chip Evacuation
During the milling process, milling machines produce chips that result from the excess material that the tools remove from the workpiece.
Due to the structure of horizontal milling machines, gravity aids in clearing the chips from the work table.
The chips fall to the floor, which leads to a more polished finish.
With vertical milling machines, the chips remain on the workpiece’s surface. It can result in flaws that may require post-processing.
In terms of chip evacuation, horizontal milling machines perform better.
7) Cost of the Machine
Vertical mills are generally more affordable than horizontal milling machines, which explains why they’re more common.
They are also easy to use and require less maintenance, making them ideal for small-scale shops.
Horizontal milling machines are PRICIER compared to their vertical counterparts.
They have higher maintenance costs and have limited skilled operators who know how to use them.
That said, horizontal machines provide better production output and benefits that many manufacturing companies find worth investing in.
How to Choose Between Horizontal vs. Vertical Milling Machines?
Horizontal and vertical milling machines are both capable of doing various cutting operations.
The right machine would depend on the size and performance specifications you need and your overall budget.
Below are the pros and cons of both types of milling machines to help you make an informed decision:
Vertical Milling Machines
Many advantages of a vertical mill lie in its low cost and ease of use. At the same, it also has drawbacks in terms of cutting capabilities.
See the pros and cons of getting a vertical mill:
Advantages of Vertical Machines
- Costs Less
A high-quality vertical mill can get up to $60,000, but it is only a fraction of the price of an entry-level horizontal machine.
Its comparatively lower cost makes it a more accessible option for small businesses to invest in.
Because they have lower initial costs, the production cost savings are typically passed onto the customers.
Due to their low cost and maintenance requirements, many operators turn to vertical mills to do cutting processes.
You can readily find vertical milling machines in most shops, and many trained operators know how to use them.
- Simple Operation
Another noteworthy advantage of a vertical mill is that it is fairly easy to operate.
It offers greater visibility for operators to see the operation as it happens. You don’t need to have advanced technical requirements to make it work.
The simplicity of a vertical milling machine means less lead time and less planning and programming needed to operate the machine.
It’s an ideal choice if you are only doing low-volume orders and quick jobs.
Disadvantages of Vertical Machines
- Limited Cutting Capabilities
The thin cutting tools of vertical mills result in the reduced cutting capability to make deep and heavy cuts.
Vertical mills, like bed milling machines, only move on a horizontal plane, which does not allow for complex designs.
It is also less stable than a horizontal mill.
- Low Production Output
Vertical milling machines have a much lower material removal rate than horizontal mills. It also CANNOT operate on large parts.
These factors result in lower-volume output.
Horizontal Milling Machines
Like vertical mills, horizontal milling machines can be used for a broad range of applications.
They are the perfect equipment for large-scale jobs but have high upfront and maintenance costs.
Consider the pros and cons of a horizontal milling machine below:
Advantages of Vertical Machines
- Solid Construction
Horizontal milling machines are heavy-duty equipment built to handle larger production jobs.
They are less prone to vibration and deflection to handle the heavy cuts of complex jobs.
- Better Chip Evacuation
This feature helps keep chips off the workpiece.
The horizontal setup of this milling machine means there’s less risk of melting and flaws. The result is a polished, machine finish.
- High Production Output
With higher material removal rate and broader cutting capabilities, horizontal mills allow for greater output in a shorter amount of time.
One horizontal mill can do the job of three or more vertical mills in terms of productivity.
- Diverse Cutting Capabilities
A significant edge of a horizontal mill is its ability to interact with a workpiece at various angles.
You can equip a horizontal mill with a universal table to create complex shapes and designs that would be impossible on a vertical mill.
Disadvantages of Vertical Machines
The most significant barrier to this milling machine is its high price.
Not only are the initial costs high, but so are the maintenance costs to keep it in good condition.
As such, horizontal milling machines are typically reserved for large-scale manufacturing companies.
- Limited Skilled Operators
It’s also significantly harder to find trained operators who know how to handle this machine.
Unlike vertical mills, horizontal mills are not so readily available, which means less operators who are familiar with the equipment.
Frequently Asked Questions
If you’re still debating about horizontal vs. vertical milling machines, below are related questions that might help you:
How Much is the Cost of These Machines?
Vertical and horizontal CNC milling machines can come in various price ranges depending on the model.
You can get a desktop CNC milling machine for as low as $3,500, while an entry-level vertical machining center can go up to $60,000.
Before purchasing a new machine, consider the specifications, brand, size, and programming of any equipment.
How to Properly Maintain a Milling Machine
Milling machines are durable equipment that can last for many years if properly maintained.
Here are the best practices to keep your machine in top shape:
- Lubrication – To ensure all parts are moving smoothly, you need to properly lubricate your machine. Check the specs to find out how often and how much you need to use.
- Cleaning – Clean the machine after use to prevent the build-up of dirt or other contaminants.
- Regular Inspection – Assess your machine daily to check its condition or if there are minor issues. Contact a local machine shop for help if you need to repair anything.
What Are the Limitations of Milling Machines?
There are a handful of reasons that limit the functionality and appeal of a milling machine.
CNC milling machines pose significant drawbacks when it comes to size, tool capabilities, axis movement, and cost.
Milling equipment is more expensive than other machines, and the process itself costs more than other fabrication processes.
Not only is a milling machine bulky, but it is also heavy to transport. You’ll need a dedicated workspace for one.
A trained operator is also required to operate the machine.
Which Milling Machine Is the Best?
The right milling machine would depend on the requirements of your business and your budget.
If you’re looking for an affordable machine that is relatively easy to use, you can go for a vertical milling machine.
A horizontal mill can provide greater production benefits and output. It also has better chip evacuation that can lengthen tool life.
Horizontal machines are the best choice if you intend to do complex and customized jobs.
Final Verdict: Which One Should You Use?
Horizontal and vertical milling machines are powerful equipment that can perform a variety of applications.
A vertical mill costs less and is easier to operate than a horizontal machine. However, they have limited cutting capabilities.
On the other hand, a horizontal machine can perform more complex cutting jobs but comes at a steep price point. Finding the best milling machine depends on the needs of your business, your budget, and what jobs you intend to do.