There is an abundance of machining processes out there, all of which provide specific perks and unique results and side milling is no different.
Working on a vertical plane, you can create different slots and cuts with these machines. While it may seem like these are small details, they’re impactful when it comes to finished products that require smooth finishes and accurate slots to function as they’re supposed to.
Side milling has many different use cases and does differ from other milling methods you might be more familiar with.
Below, we’ve given a brief rundown of how this particular type of milling works and how it might be most useful to your day-to-day workflow.
What is Side Milling?
Side milling is a machining process that involves using the side of a milling cutter to remove material from a workpiece.
This technique is primarily used to create flat and angular surfaces with high precision. By operating the cutter along a specific axis, operators can achieve the desired surface finish and dimensional accuracy.
Side milling is essential in manufacturing industries where precision and efficiency are paramount.
Side milling involves the usage of the peripheral edges of a milling cutter to machine surfaces that are parallel or at an angle to the machining table.
This process is distinguished by the precise orientation of the cutter and workpiece, ensuring that the cutter’s rotational axis is typically perpendicular to the surface being machined.
Key parameters to consider in side milling include the following:
- Cutter Diameter: Generally, ranges from 0.5 inches to 8 inches depending on the application and desired surface finish.
- Cutting Speed (V): Optimal cutting speeds are crucial for effective material removal and typically range from 150 to 600 feet per minute (fpm) for high-speed steel cutters and 600 to 1200 fpm for carbide cutters.
- Feed Rate (f): Expressed as inches per tooth (IPT), the feed rate usually varies from 0.001 to 0.020 IPT based on the material and cutter design.
- Depth of Cut (d): Normally set between 0.010 inches to 0.250 inches to balance between material removal rate and cutter life.
- Axial and Radial Depth: Axial depth of cut affects vertical pressure on the tool, whereas radial depth involves horizontal pressure. Proper balancing of these depths is essential for tooling life and surface integrity.
Efficiency in side milling can be maximized by selecting the appropriate cutter materials, such as carbide for harder material and high-speed steel for more general applications.
Proper fixture and machine setup, as well as an understanding of the workpiece material properties, are indispensable for achieving the desired machining precision and productivity.
How Side Milling Works?
The most important distinction with this type of machining process is that the milling cutter works into the side of the workpiece, as its name would imply.
The machine has a cutter that’s mounted onto an arbor, which will slice into the material that’s clamped down to the work table.
Then, the edges or teeth on the cutter will cut into the object and create the shape or design you need. It’s a popular method that you can use in tandem with the likes of turning, drilling, and boring, too.
There are various materials you can use for side milling, including metals, plastics, and composites, which gives this machine versatility.
If you’re trying to calculate feed rate, there are a few equations you can always rely on to get the right number:
First, get the RPM, which is:
- RPM = (12 Surface Speed) / (Pi Tool Diameter) [revs/min]
Then you can get feed rate:
- Feed Rate = RPM Chip Load Number of Teeth (Flutes) [in/min]
- Remember that Pi = 3.14159
Tools and Equipment Needed for Side Milling
To make the most of side milling, you’ll need a machine with several parts. The first is a milling machine, which is the main component that will power the cutter and allow it to move in the right direction.
A side milling cutter is also necessary for making cuts into the side of an object. The arbor is also an important part because it’s the bridge between the milling machine and the specialized side cutter.
You’ll also want to have some kind of clamps or vises on hand to hold your workpiece in place, as well as a cooling system to keep friction and chips at bay.
It’s worth pointing out that the type of material your cutter is made from will also make a difference in your finished product and how nice the finish is.
For instance, a carbon tool steel cutter is great when it comes to abrasion resistance, but it loses hardness when it hits a certain temperature, making it a mediocre choice for materials that need to be cut at higher speeds.
Carbide, on the other hand, is able to handle these temperatures and cut precisely and accurately, but these cutters may be more expensive.
Side milling cutter
Side milling cutters are mainly used to machine planes, steps, grooves, forming surfaces and cutting workpieces on the milling machine.
In order to ensure a sufficiently high average chip thickness and the feed amount of each tooth, it must be correctly determined. The number of side cutter teeth in this process.
For disc milling cutters, it is easy to mill deep grooves and is very efficient, and can be used on many large equipment.
With the continuous development of the society’s economy, side milling cutters are becoming more and more widely used in people’s lives and work.
Some large machine tools require milling cutters to complete production and processing. Nowadays, there are many professional manufacturers specializing in the production of milling cutters.
The quality and model of the milling cutters produced by them are very complete, and the price setting is very reasonable.
Therefore, the industry of milling cutters is already a very mature product in the domestic market. Milling knives with powerful cutting and cutting effects can help people to do a lot of difficult things.
In some municipal constructions, in the production of some workpieces, etc., milling cutters are indispensable.
Types of Side Milling Cutters
For side milling, there are several types of cutters I would consider based on the specific application and material being machined. The primary types are:
- Straight Tooth Side Milling Cutters: These cutters are designed with straight teeth that extend radially and are suitable for light to medium milling operations. They provide a clean cut and are often used for slotting and straddle milling.
- Staggered Tooth Side Milling Cutters: These feature alternating teeth that provide better chip clearance and reduced chatter, making them ideal for deeper cuts and roughing operations. The staggered arrangement helps to break up the material more efficiently, extending tool life.
- Half-Side Milling Cutters: These cutters have teeth on one side and the periphery, which allow for cutting on two faces simultaneously. They’re excellent for milling operations along the edge of a workpiece, particularly for contours and profiles.
Each type of cutter has its strengths, so my choice would depend on the requirements of the specific milling task, including material hardness, desired surface finish, and cutting depth.
Side milling cutter function
Side milling cutters are typically mounted non-reground insert hard quality alloy inserts, which are rotary cutters with one or more cutters for milling.
The side milling cutter is mounted on the spindle of the milling machine, that is, the milling cutter disc can be used for the vertical milling and horizontal milling, and then the hard mass alloy blade is pressed on the cutter head with the boring block on the cutter head. Under normal circumstances, It can be equipped with eight blades.
The large milling cutter can hold more than a dozen pieces of carbide inserts. At least one blade can be installed, and the plane can be milled.
Then the workpiece to be milled is clamped on the machine’s flat pliers, or it is pressed on the working bed surface of the milling machine, and then the spindle is turned on, the milling cutter can be rotated, and the plane can be milled.
The side milling cutter is one of the key components of the machine. The choice of the cutter head directly affects the cutting effect of the whole machine and the speed of the tunnelling.
It is even related to the success or failure of the project. Therefore, it is very important to choose the side cutter.
Types of Side Milling
As you’ll find, there are two styles of side milling that involve different types of cutters, which you can learn below:
Plain Cutters: Also called straight-tooth cutters, this type of side milling uses cutters with teeth lined up single file rather than staggered. It’s the right cutter to use if you’re doing all-purpose work, creating slots, or working on flat surfaces.
Staggered-Tooth Cutters: Alternatively, you can use a staggered-tooth cutter, which features teeth that alternate along its circumference. This is particularly useful if you want to cut down on vibration or chatter and get a smoother finish overall. It is also a great type to use in heavy-duty operations or instances where surfaces are drastically uneven.
1. Plain Milling: Crafting Refined Plane Surfaces
Plain milling, or slab milling, is the artisan’s choice for sculpting plane surfaces, especially when finesse is non-negotiable. Its spiral design empowers the simultaneous engagement of multiple teeth, ensuring a seamless operation with minimal vibrations and disturbances.
Here’s a detailed evaluation of this milling process:
| Characteristics | Plain Milling |
| Cutter Design | In this machine, helical design compensates for the absence of side-cutting teeth. |
| Setup Procedure | It helps achieve optimal efficiency with a wider cutter than the surface. Smaller diameter cutter chosen for enhanced precision. Critical alignment, albeit less stringent than side milling, as top surface operations are the norm. |
| Machining Methods | It involves two milling methods: Conventional Milling: Work fed into the cutter’s rotating direction. Climb Milling: Requires caution due to potential cutter breakage. |
| Safety Precautions | The use of safety glasses is non-negotiable here. Rings, watches, and jewelry should also be removed to avoid accidents. Additionally, its important to consider the prudent use of rapid traverse, avoiding abrupt movements without loosening locking screws. |
2. Side Milling: Mastering Intricate Grooves with Versatility
Side milling or external milling emerges as the virtuoso, excelling in crafting intricate steps or grooves.
Distinguished by varying widths, diameters, and adaptable tooth arrangements either straight or staggered side milling showcases remarkable adaptability in the hands of seasoned machinists.
Here’s a detailed evaluation of this milling process:
| Characteristics | Side Milling |
| Cutter Design | Adaptable design suited for cutting deep slots or grooves, with staggered toothed variants providing enhanced chip space at higher speeds. |
| Setup Procedure | Meticulous alignment is crucial for precise cuts. Precise calculation of spindle RPM based on cutting foot speed and cutter diameter. Critical feed rate calculation is contingent on the number of teeth on the cutter. |
| Machining Method | Inside Milling Operations: Conventional milling is favored for optimal results. |
| Depth of Cut | Ideal Depths: Range between 100 and 200 thousandths, achieving a delicate balance between efficiency and precision. |
| Practical Demonstration | Exemplifying the prowess of external milling, a meticulously carved groove in a previously machined part showcases the finesse and adaptability of this advanced machining approach. |
In a nutshell, the choice between plain and side milling becomes an artful decision, each method revealing its prowess in the hands of a skilled artisan. While demanding precision, these techniques grant the operator a symphony of possibilities to craft intricate pieces with unparalleled finesse.
When Should You Consider Side Milling?
Side milling emerges as a versatile machining process with diverse applications across industries, presenting a strategic choice for skilled operators in various scenarios.
Understanding when to consider edge milling is crucial for achieving optimal results in machining operations.
#1. Flat Surface Machining.
Side milling becomes the method of choice when the objective is to create expansive flat surfaces on workpieces, particularly when their size exceeds the capabilities of alternative processes like grinding or planing.
This approach proves invaluable for crafting flat surfaces on substantial components such as machine beds, bases, and tables. The precision achievable through edge milling ensures the desired flatness in these critical elements.
#2. Slotting for Gears and More.
One of the prime applications of side milling is slotting, providing an effective means to generate slots or grooves along the sides of a workpiece. This capability is extensively employed in producing gears, keyways, and splines. Edge milling’s adaptability in creating these essential features contributes to its prominence in gear manufacturing and related industries.
#3. Contouring Complex Geometries.
Side milling transforms into a proficient tool for contouring, enabling the creation of intricate geometries and precise contours on a workpiece.
This method empowers operators to manufacture components with exacting shapes and dimensions by leveraging specialized cutting tools with diverse shapes and profiles. The nuanced control offered by horizontal milling makes it indispensable for applications demanding complex and precise geometrical features.
#4. Surface Finishing Excellence.
Side milling plays a pivotal role in achieving superior surface finishes, particularly critical in industries like aerospace, where the performance of components is intricately tied to surface quality.
The process ensures a smooth and refined surface finish on the workpiece, meeting the stringent requirements of aerospace applications where even minor imperfections can impact component performance.
How to 3 Common Challenges in Side Milling?
In the intricate world of external milling, addressing common challenges is paramount to achieving exceptional results.
Let’s explore practical solutions for each aspect, ensuring a comprehensive approach to side-milling excellence.
#1. Addressing Tool Wear: Prolonging Tool Life Through Vigilance.
Tools in side milling undergo wear and tear, affecting their longevity and performance. To mitigate this, establish a comprehensive inspection routine that combines regular visual examinations with dimensional checks.
Early detection of wear signs is crucial. Additionally, consider strategically utilizing advanced coatings like titanium nitride (TiN) to enhance tool durability and increase hardness.
Opting for tools crafted from robust materials such as carbide or high-speed steel (HSS) tailored to the workpiece’s demands further extends operational life.
#2. Mastering Precision: Unleashing the Power of CNC Milling Machines.
Precision in milling operations is essential and can be achieved through leveraging the capabilities of Computer Numerical Control (CNC) machines.
The computerized precision offered by CNC technology ensures automated and consistent precision.
Here, you can utilize CNC technology or consider professional CNC manufacturers to help automate processes, guaranteeing consistently precise milling results.
Furthermore, meticulous adjustments to milling paths for heightened accuracy, coupled with software solutions for dynamic optimization, contribute to mastering precision in external milling operations.
#3. Perfecting Surface Finish: The Art of Achieving Impeccable Results.
Attaining superior surface finishes on machined components requires a meticulous approach to tool selection and parameter optimization.
Opt for tools with materials precisely matched to the workpiece’s requirements for optimal results. Specialized tools designed for achieving superior surface finishes can make a significant difference.
Additionally, fine-tuning milling parameters such as speed and feed is crucial for impeccable surface finishes.
It is also important to employ real-time monitoring and adjustment of milling parameters to adapt to changing conditions during the machining process, ensuring a perfect surface finish in horizontal milling operations.
Applications of Side Milling
This list covers some of the most important applications you can use side milling for:
- Flat surface machining: Probably one of the most popular applications, this technique flattens and smoothes down the surface, which is pretty helpful for objects that are too big for planing and grinding machines.
- Slotting: This is a very popular use for side milling and involves carving slots into the side of a piece in order to allow keyways, gears, and splines to work.
- Contouring: A side milling machine can create complex designs, details, and contours on the side of a part or workpiece.
- Surface finishing: For the smoothest finishes, you can lean on side milling. This might be particularly important for parts where a small flaw or change in texture can lead to serious consequences or severely impact how a component works, like in the aerospace industry.
Advantages and Disadvantages
Here are some of the benefits you’ll reap when working with side milling machines:
- Various textured finishes: A side milling machine can produce a wide range of surface features, such as flat vertical surfaces, slots, and intricate contours.
- Ideal for slots and grooves: When you need these types of cuts on a workpiece, side milling is the way to go.
- Range of cutter types: You can purchase cutters in plenty of sizes, types, and materials so you can really cater to the kind of work you’re doing and the specific materials you’re machining.
- Quality and accuracy: Side milling machines can give you precise and accurate finishes where other machining processes might not be able to.
There are also a few downsides of side milling to take note of:
- Only machines the sides: As its name says, this machine is built for carving into the side of an object and not other surface areas.
- External feature focus: If you’re looking for a process to machine internal parts, skip the side milling machine and opt for another service like end milling.
- Not ideal for thin workpieces: With the force that comes from these machines, you may find that thinner boards and surfaces will bend, warp, or deflect under the pressure.
What Are The Safety Considerations While Using Side Milling
To make sure your side milling operation is safe, follow these guidelines:
- Wear personal protective equipment, including hearing protection, work gloves, and safety glasses, and make sure your team or milling machine operators do the same.
- Make sure the guards are down and work properly so there are no accidents or injuries that happen with moving parts.
- Uses vises or clamps to keep your workpiece in place and prevent sliding, errors, and serious injuries.
- Inspect your side milling machines every time before you use them and always keep them well maintained.
- Train your team and ensure people are always up to speed with safety requirements, emergency procedures, and proper operation protocol for this type of machine.
- Make sure every person that uses a side milling machine and the people surrounding them know where the emergency stop buttons are.
How Side Milling Differs from Other Milling Methods
You might be curious about how side milling compares to other milling processes you’ll come across. The answer is relatively simple and present in the name: it cuts sideways.
Because of how the cutter is positioned and what it’s meant to do, it stands out from milling machines that cut on different axes or from different directions, like in face milling, where you’d cut a workpiece from the top.
It’s also built for the purpose of creating slots, contours, and designs into the sides of objects (whether on a vertical or horizontal plane) which not all other milling processes are capable of doing.