When to Choose Horizontal Machining Over Vertical

Horizontal Machining Centers are a popular choice in machining centers today. Designed for production and accuracy, these machines can reduce cycle times greatly and eliminate multiple part setups all while increasing tool life and part accuracy. Adding the capability of multi sided machining and natural chip flow these machines can make short work of precise parts and lend themselves to better production quantities and part repeatability. 

Before we can delve too deeply into the advantages of Horizontal Machining it is important to understand the differences between this machine and the traditional style, Vertical Machining. As both of these types of machines share a common CNC Controller, Tool Exchanger and a few other features it is important to set what differentiates them from one another and  more importantly, what advantage to the CNC Machinist this presents.

What Is Horizontal Machining? 

Horizontal Machining Center Machine Design

A Horizontal Machining Center is a machine that utilizes a spindle setup that is parallel to the floor as opposed to being perpendicular to it. Often designed with multiple part pallets these machines are capable of maintaining more spindle “ON” time as parts are removed and replaced outside of the working zone and while the spindle is in process, machining away. Further this design often includes a more robust tool changer allowing for increased tool capacities for more complex operations or even better yet, redundant tools that are applied after a certain number of cycles whereas the primary tool is “retired”. Lastly this design is simply more robust than the Vertical Machining Center Design as components are heavier providing a more rigid design reducing tool vibration.

Chip Flow

The design of a Horizontal Machining Center also lends itself to rapid chip removal from the cutting zone. Due to the machining surface being held at a vertical plane, the chip flow naturally falls off the machined surface and away from the cutting area, further saving time from necessary chip removal. Most Horizontal Machining Centers are equipped with dual augers or chip conveyors to then quickly remove the scrap material away from the working zone and out into a collection bin for easy waste recycling. 

Rotating Pallet

The machined parts on a Horizontal Machining Center are typically mounted on a pallet that is exchanged from inside the workzone to outside for setup and part removal. These pallets can have a variety of fixtures on them to assist in holding one or more parts securely for presentation to the spindle for the machining work. These pallets, while inside the working zone, can also be rotated and depending on the machine, either indexed 90°, or at a lower value of 1° or even at a continuous rate of rotation allowing for 360,000° of motion. This rotating effect allows for at least 3 sides of machining to be possible during one setup thereby increasing part accuracy and eliminating manual part setups. 

Advantages Horizontal Machining Center 

• Rigidity = Better Tool Life, Part Finish, Accuracy
• Faster = Generally the Horizontal has a much faster cycle time.
• Multi Sided Machining Capability = Less Set Ups
  Chip Flow = Less Tool Breaks and Stoppage
• Automated Design = Exchange parts on the exterior while the machine continues in operation.  

Disadvantages Horizontal Machining Center

• Price
• Travels/Work Zone Capacity
• Requires More Floor Space 
• Fixturing is usually more expensive

What Is Vertical Machining?

Vertical Machining Center Machine Design

A Vertical Machining Center is a CNC Controlled milling machine with a spindle orientation perpendicular to the floor. These are the most common machines found in almost every machine shop in the world. They are often designed with a small tool changer capable of holding 20-30 tools and a single table that must be unloaded and reloaded while the machine cycle is paused. They do provide better visibility than their horizontal cousins and generally they are priced ½ - 2/3rds that of a Horizontal Machining Center. Although these machines are CNC controlled, providing some level of automation, they are not generally run unattended as machine cycle time and chip management (cleanup) requires a more vigilant operation. 

Vertical Machining Center Options

While a Vertical Machining Center may have its design flaws, it certainly can be optioned up with many features to make it more versatile. Features available such as probing, rotary tables, larger tool changers, pallet exchange systems etc. all can add value to and keep the spindle rotating on these systems but it is important to note that a well optioned Vertical can often surpass the price of an equally equipped Horizontal. 

Advantages Vertical Machining Center 

• Price
• Larger Work Area 
• Visibility
• Versatility
• Fixturing Cost

Disadvantages Vertical Machining Center

• Chip Build Up
• Less Rigid
• Slower machining cycle times in general

How to Find the Right Fit: Horizontal Machining Center (HMC) vs. Vertical Machining Center (VMC)

There are several key factors to include when deciding on which machining system is right for you. First off is the size of your parts as the smaller they are the more they lend themselves to being easily fixtured in a Horizontal Machining System. Next is part quantity, the higher the required part quantity the more a Horizontal Machining Center makes sense as they are just better suited for production runs. Also you will need to consider your Floor Space available as a Horizontal Machining Center can take up 1.5-2X the space of an equivalent traveling Vertical Machine. Lastly you will need to consider your budget, as a well equipped Horizontal Machining Center can be 2-3X that of an equivalent capacity Vertical 

5 Reasons to Choose Horizontal Machining Centers Over Vertical Machining

In general whenever you can afford a Horizontal Machining Center you should consider it strongly as the benefits far outweigh the negatives. You will enjoy faster crystal times, less tool wear and breakage, better finishes and part accuracy and more spindle ON time. However if you're still not sure there are a few quick and simple checks you can make to see if a horizontal machining center is right for you.  

1. Part Size: Smaller leans more to Horizontal
2. Quantity: The more, The easier to justify the Horizontal
3. Part Accuracy: With fewer setups required & multi-sided machining capabilities the Horizontal is an easy favorite. 
4. Floor Space: Can you afford the floor space for a Horizontal?
5. Price: Although more expensive a Horizontal can quickly make up the price difference in throughput.

At Southern Fabricating Machinery Sales, Inc. our experts in machining can assist you in choosing the right Horizontal or Vertical Machining Center to meet your needs and budget. Call or email us today for more information on how we can assist you in choosing the right machining solution.