Formula cutting speedchart

The function of 2 flutes in the ball nose end mill is creating slots and grooves on softer materials like wood or aluminum. Because the 2 flute ball nose end mill can also be applied vertically on the workpiece, it can also plunge. However, the ball nose end mill with 2 flutes is unable to work similar to 4 flute end mills.

Different materials produce different types of chips; the harder material is brittle in nature which is why it creates smaller brittle chips. Therefore, it requires cutting tools having fewer number of flutes to quickly escape the chips. This is why 2 flute end mills were commonly used.

In this article we will discuss what are the ball nose end mills, what are its functions, how it is manufactured and what are the main differences between 2 flute ball nose end mill and 4 flute ball nose end mills.

Like any other cutting tool available in the market, the ball nose end mill is also available in the market in a wide range of flutes. The ball nose end mill with 2 flutes and 4 flutes are most commonly used.

Feeds for end mills used in vertical milling machines range from .001 to .002 in. feed per tooth for very small diameter cutters on steel work material to .010 in. feed per tooth for large cutters in aluminum workpieces.  Since the cutting speed for mild steel is 90, the RPM for a 3/8” high-speed, two flute end mill is

Formula cutting speedcalculator

This chip thickness or feed per tooth, along with the number of teeth in the cutter, form the basis for determining the rate of feed.

The ball nose end mill with 4 flutes will increase productivity because of increased feed rate. This is because 4 flutes are efficient to create longer chips and evacuates them easily in softer materials.

The modern times, specialized cutting tools are preferred that are not only economical but also have ability to perform multiple functions. This will reduce the cost to buy individual tools for different purposes.

Since the ball nose end mill has a ball at its tip, it is widely used to create big corner radiuses, full grooving, contour milling, shallow slotting, pocketing etc. The ball nose end mills with smaller diameters are used for engraving on the workpiece. Due to its ability to create great round edges, it is also used to create excellent 3D contouring.

Pecking helps ensure that bits don’t overheat and break when using them to drill or tap.  Peck drilling involves drilling partway through a part, then retracting it to remove chips, simultaneously allowing the piece to cool.  Rotating the handle a full turn then back a half turn is common practice.  Whenever the bit or tap is backed out, remove as many chips as possible and add oil to the surface between the drill or tap and the workpiece.

On the milling machines we have here at LBCC, the feed is independent of the spindle speed.  This is a good arrangement and it permits faster feeds for larger, slowly rotating cutters.

Performance on soft and hard material – This is the biggest advantage of all. The 4 flute ball nose end mill works on many hard materials and works on soft material. The 2 flute end mill is unable to evacuate longer chips produced by soft materials which is 4 flute ball nose end mill exceeds the 2 flute ball mill.

Following factors affect the workmanship with ball nose end mill having any number of flute. Therefore, it is necessary to consider the factors while making a selection.

As the work advances into the cutter, each tooth of the cutter advances into the work an equal amount producing chips of equal thickness.

Once the SFM for a given material and tool is determined, the spindle can be calculated since this value is dependent on cutting speed and tool diameter.

The manufacturing process of ball nose end mills are same as carbide end mills except that the grinding wheel, installed on CNC machine, consists of diamond embedding. Because of the sophistication of the tool, multiple grinding wheels are used that has varying grits, diameter and profile shapes depending upon the tool’s design.

The 4 flute ball nose end mill works on various hard materials and also works on soft materials where 2 flute end mills fails. This is what gives an edge to 4 flute end mills. The good surface finish, faster chip evacuation and longer wear time of 4 flute end mill are why they are more widely used across the globe by many product manufacturers.

Various cutting tools in CNC milling are used to plunge, slot or make 3D contouring. The ball nose end mill is also one of those cutting tools. Its unique manufacturing and utilization in the CNC machining process makes it widely popular among machinists.

Cutting speed formulafor drilling

Surface roughness – Surface roughness is the irregularities on a workpiece. The 4 flutes ball nose end mill mills the material with higher surface roughness because firstly it has round shapes providing smooth surface contact and increased flute allow uneven surfaced material to evacuate easily.

In earlier times, India, Turkey, Euro, Egypt and USA etc. utilized 2 flute ball nose end mills but with the growing demand and increased production cost, they have moved to more flexible and versatile 4 flute ball nose end mill. The survey reported the strategy has saved much production costs of CNC machinists.

Formula cutting speedin mm

When drilling and tapping, it is crucial to use oil.  It keeps the bits from squealing, makes the cut smoother, cleans out the chips, and keeps the drill and stock from overheating.

The main challenge is the construction of shape of ball at the tool’s tip which is manufactured using relief that creates ball’s radius at the end of the ball mill. Various other parameters are set on the machine to deliver the required ball mill.

Following are the technical specification of 4 flute end mills that make them superior and recommended over 2 flute ball nose end mill:

But recently, users found with their experience that 4 flute end mills are more beneficial for them as compared to the 2 flute end mills. This is because not only 4 flute end mills cover wide range of harder materials, but also works on soft materials and delivers smoother finish on hard and soft materials where 2 flute end mills fail. This is the main reason CNC machinists around the globe are now utilizing 4 flute end mills on materials with acceptable hardness range. This in turn has saved much production cost.

Wear time – The longer the tool, the more prone it is to wearing. But comparative to more number of flutes, the 4 flute ball nose end mill shows wear time because its ball shape provides smooth rounded contact with the workpiece and also offers less resistance to material on longer operation.

The number of flutes in ball nose end mill affects heavily on the tools ability to clear chips. The more flute ball nose end mill have, the shorter the flute length which may clog the flute and break the tool.

Cutting speed formulafor turning

The cutting depth on a workpiece is dependent on the contact length of ball nose end mill. The length of the tool ensures precise cutting on a workpiece and prevents from overhanging. To calculate the tool’s length, multiply the cutter dia by 5.

The ball nose end mills are great cutting tools that delivers smooth rounded surfaced compared to other end mills. Due to its functionality, it is preferred in making 3D contouring and rounded edges. The ball nose with 2 flutes are used on hard materials like metal while 4 flutes ball nose end mill deliver smoother finish and used to mill, plunge or slot softer materials.

Cutting speed formulaPDF

The hardness of the cutting tool material will also have a great deal to do with the recommended cutting speed. The harder the drill, the faster the cutting speed.  The softer the drill, the slower the recommended cutting speed (See Figure 2).

Manufacturing Processes 4-5 Copyright © by LamNgeun Virasak is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

Cutting speed is defined as the speed at the outside edge of the tool as it is cutting.  This is also known as surface speed.  Surface speed, surface footage, and surface area are all directly related.  If two tools of different sizes are turning at the same revolutions per minute (RPM), the larger tool has a greater surface speed.  Surface speed is measured in surface feet per minute (SFM).  All cutting tools work on the surface footage principle.  Cutting speeds depend primarily on the kind of material you are cutting and the kind of cutting tool you are using.  The hardness of the work material has a great deal to do with the recommended cutting speed.  The harder the work material, the slower the cutting speed.  The softer the work material, the faster the recommended cutting speed (See Figure 1).

Feed rateformulafor milling

The ball nose end mill with more flutes will deliver smooth surface compared to 2 flute end mill therefore it is used mostly on soft materials like aluminum, wood etc.

The 2 flute end mills are great cutting tools that delivers lower chip load and works on harder material. Comparatively, the 4 flute end mills are attracting popularity due to its versatility and ability to perform many functions compared to 2 flute end mills.

Feed per tooth, is the amount of material that should be removed by each tooth of the cutter as it revolves and advances into the work.

In this article, we will cover the basic function between 2 flutes and 4 flutes end mills, what is the function of ball nose end mill in CNC milling, and finally, why users are now preferring 4 flute ball nose end mill over 2 flute ball nose end mill.

The ball nose end mills are used as roughing tools but their primary usage is for dies and molds where 3D contouring, corner picking, slotting or profiling with a semi-finished or finished surface is required.

On the contrary, the 4 flute ball nose end mill is mostly used for side milling and surface milling. Increasing the number of flutes in an end mill will deliver smoother finished surface but simultaneously increase chip load and lesser chip evacuation. But ball nose end mill with 4 flutes is widely used because it works on most of the material and also performs somewhat similar function to 2 flute end mill. So there is no necessity for specifically purchasing ball nose end mill with 2 flutes if 4 flute ball nose end mill can be afforded.

The ball nose end mill’s cutter diameter is responsible to deliver required width of the slot. The cutter diameter also affects the chip removal rate during side milling. Therefore, before purchasing, it is necessary to ensure what is the tool’s cutter diameter and will it deliver the requirements.

Before knowing the difference between the two flutes in a ball mill, it is necessary to understand what is the basic function of flutes in any end mill. The flutes are spiral grooves, with sharp edges in an end mill’s surface. Its basic function is forming chips of material and its evacuation during milling. The harder material will require more flutes and softer material will require less flutes.

Surface finish – The ball nose end mill with 4 flute provides smoother finish because it has more flutes compared to 2 flutes. It is therefore used on materials where more smoothness is required on slotting, plunging etc.

Drilling machines that have power feeds are designed to advance the drill a given amount for each revolution of the spindle.  If we set the machine to feed at .006” the machine will feed .006” for every revolution of the spindle. This is expressed as (IPR) inches per revolution

Cutting speedcalculator

The feed (milling machine feed) can be defined as the distance in inches per minute that the work moves into the cutter.

Also known as the ball mills or full radius end mills, the ball nose end mill is cutting tools in which the radius of the nose is half of the tool’s diameter. With this function, the ball nose end mill delivers a curved smooth surface on a workpiece with a constant single radius at the end of the tool without any straight edge.

Chip evacuation – The 4 flute ball nose end mills is better than 2 flute ball nose end mill because it evacuates harder as well as soft material chips. The hard material breaks into smaller brittle chips like metal, bronze etc. while softer materials like wood or aluminum etc. chips into longer flexible material. The ball nose with 4 flutes evacuates them all quickly.

Tap guides are an integral part in making a usable and straight thread.  When using the lathe or the mill, the tap is already straight and centered.  When manually aligning a tap, be careful, as a 90° tap guide is much more accurate than the human eye.

On the contrary, the soft material produces long chips and so it requires cutting tool having more flutes. For softer materials, 4 flute end mills are used.

Vertical accuracy – The 4 flute ball nose end mill are longer than 2 flutes so they can plunge more deeply into the material and offer precise accuracy comparatively. The 2 flute ball nose end mill have lesser cutting depth due to less flute which is why it is unable to plunge deeper and accurately.