The world of CNC machines consists of various types of machines with distinct specifications, serving different industries. Two such dominating names in the types of CNC machines are vertical machining centers and horizontal machining centers. Although both machines are designed for the same type of machining work, their different operational styles attract different user bases. Both of them have their advantages and disadvantages, so whenever one needs to decide what they want to buy, they need to do deep research about both of these machining centers. So, if you are also trying to do the same thing, then don’t worry because we’ve got you covered. Let’s dive deep into finding out the key differences between the CNC vertical machining centers and the CNC horizontal machining centers.
What are CNC Machining Centers?
Let’s answer what CNC machining centers are at first. CNC machining centers are advanced computer controlled machines that have rotatory cutting tools to remove material from a workpiece. These machines can perform different types of operations like milling, tapping, drilling, and boring. These machines bring high repeatability, precision, and speed to the manufacturing process.
There are two types of these machining centers – Vertical and Horizontal, which are defined by the orientation of their spindle.
- For VMCs, the spindle is oriented vertically.
- For HMCs, the spindle is oriented horizontally.
Anatomy and Basics of Operation:
Here are the basic differences between the two types of machining centers based on their anatomy and style of operation:
Vertical Machining Centers:
- The spindle moves up and down as it is mounted vertically.
- The worktable is fixed or moves in X and Y.
- Has simple loading features; you can place the workpiece on a flat table below the spindle.
- Gives you easy visual access to the tool and the workpiece.
- It is suitable for operations like milling, fastening, drilling, and contouring.
Horizontal Machining Centers:
- The spindle is mounted horizontally.
- The tool approaches the workpiece from the side.
- The machines are often equipped with rotatory pallets for multi part fixturing.
- This is ideal for multi sided operations in a single setup.
Chip Evacuation, Coolant, and Rigidity:
Here are the differences between VMCs and HMCs on the basis of chip evacuation, coolant, and rigidity:
Vertical Machining Centers:
- The chips fall on the bed or table, which needs future air, washing, or manual cleaning.
- Chip congestion can take place due to deep pocket machining, which affects the tool life and surface finish.
- They’re highly rigid machines for light or medium load machining.
Horizontal Machining Centers:
- The chips fall due to gravitational pull, leading to efficient removal of material.
- Arbor-mounted tools allow for deep and heavy cuts, helping in maximising MRR.
- They are robustly constructed, which helps them manage heavier workpieces seamlessly.
Setup, Operator Access, and Productivity:
Here are the differences between VMCs and HMCs based on setup, operator access, and productivity:
Vertical Machining Centers:
- The machines are compact, which is great for small shops.
- The setup and programming doesn’t need back breaking efforts.
- Frequent part handling leads to an ideal time.
Horizontal Machining Centers:
- They have comparatively larger footprints.
- Programming of these machines is a bit more complicated.
- They are also fast in production speed due to minimized fixturing and pallet swaps.
Advantages and Disadvantages of Vertical Machining Centers:
Here are some of the major advantages of vertical machining centers:
- Lower initial investment: The VMCs come at a cheaper cost than HMCs, which makes them accessible for businesses of small and medium size. The lower upfront costs help newbie manufacturers to start their business.
- Compact footprint: The vertical machining centers are more compact, so they can save your rental cost if you’re renting or just help you to start with one machine in your garage.
- Operator visibility: The vertical orientation of the VMCs helps you get a clear sight of the workpiece, making setup, adjustment, and monitoring easier for the operators.
- Simpler setup and programming: One of the best things about VMCs is their easy to setup feature and also easy style of programming, which makes it fit for a shop with newbie operators.
Here are some of the major disadvantages of vertical machining centers:
- Chip accumulation: Chips tend to gather and build up on the workpiece and tooling area, affecting the surface finishing of the final product and reducing the tool life.
- Size constraints: Vertical machining centers CNCs are generally not capable of handling large workpieces due to column height and table size.
- Lower productivity for complex parts: Changing setups during operation can lead to a slow speed of production for parts with complex geometries.
Advantages and Disadvantages of Horizontal Machining Centers:
Here are some of the major advantages of horizontal machining centers:
- Better productivity: Horizontal machining centers are 25-30% more productive than vertical machining centers, especially when doing complex machining work. VMCs need multiple setups for complex tasks, while HMCs can do that in a single setup, leading to less downtime and more output volume.
- Better chip evacuation: Due to the horizontal orientation of the spindle, the chips fall away from the cutting area naturally, which further reduces the chances of recutting chips, helps with better surface finish, and extends tool life.
- Better for large and heavy parts: Horizontal machining centers can work with much heavier parts compared to vertical machining centers. Their robust construction and optimal table design support working on larger and heavier workpieces.
- Better precision and accuracy: The horizontal machining centers don’t need multiple fixturing to get the work done, which decreases the possibility of human error, increasing the accuracy and precision of CNC machining.
Here are some of the major disadvantages of horizontal machining centers:
- Higher initial costs: Mostly horizontal machining centers have higher upfront price tags compared to vertical ones, making them unsuitable for someone just starting or small sized shops.
- Larger footprints: HMCs take up a lot of space due to their basic structures, which makes it problematic for small shops to adjust these machines in their workplace.
- Complex setup: Fixturing and programming a horizontal machining center, for which you will need more skilled operators and better upfront planning.
Perfect application for VMCs and HMCs:
Here are some actions that can be done by vertical machining centers best:
- VMCs are better at prototyping due to their fast setup and flexibility.
- Precision and ease of use of VMCs make them suitable for the creation of molds and dies.
- They are better for general machining work like milling and drilling.
Here are some actions that can be done by horizontal machining centers best:
- HMCs are great for high-volume automotive manufacturing.
- They are better for precise aerospace machining.
- HMCs are great for manufacturing large industrial parts like valves or pumps.
How to choose the right machining center for yourself?
Here are some of the factors that you need to consider before you make the call to purchase any of the horizontal machining centers or vertical machining centers:
- What’s your required production volume, small batches or high volume?
- What’s the part complexity you are going to manufacture? Simple ones or the ones that need multi sided machining?
- Are you going to work with small, medium, or large workpieces?
- What is your initial investment capacity?
- How much floor space can you get for one machine?
- What’s the experience or skill level of your operators?
- Which industry are you in or trying to serve? Aerospace, defense, automotive, or general machining?
Final Selection:
- Choose a VMC if you need: cost effective machines, small sized machines, simpler programming, easy loading and inspection, or have low or medium volume production needs.
- Choose an HMC if you need: high volume repetitive production, machining of large and heavy parts, multi faced machining, automation integration, and efficient chip handling.
Set up strategy and best practices:
Here are some of the practices to follow while setting up or operating your machining center:
For VMC users:
- You must opt for thermal control, linear guides, and higher speed spindles.
- Make more investments in tombstones and high quality fixtures, which will help you minimize reclamping.
- Do regular chip conveying and cleaning for better tool life.
- Do use 4th axis accessories for moderate multi-face work.
For HMC users:
- Have a large tool magazine for flexible machining work.
- Get robot loaders or automated pallet changing systems integrated.
- Focus on expertise in programming and thorough toolpath planning.
- You can also implement twin pallet setups for continuous output.
Conclusion:
CNC vertical and horizontal machining centers are both very important and efficient workhorses that serve the needs of two different groups of customers. You should make your purchase after researching deeply about both types of machines, and when you finally decide which one to buy, you can check our collection of used vertical machining centers and used horizontal machining centers.
