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Hardware available in the Fabrication Lab
End Mills
Choosing the right end mill for your job is paramount. The following information will help you make your tool selection. Once you have decided the type of tool that is best for your job, use the following sources to order your end mills:
McMaster-Carr
McMaster has a good selection of inexpensive end mills. Unfortunately, you cannot specify the helix direction through McMaster. You can order directly from McMaster and orders are delivered next day.
Onsrud
Onsrud has a great selection of specialty end mills. You can choose your end mill type on the Onsrud website, but they must be ordered through a vendor. Design Services Carbide (201-569-5317) is our local supplier. They accept credit cards and can deliver next day.
TYPE:
Flat or Square End
Flat end mills are perfectly suited for flat surface and pocket cuts. They are also preferable for contour cutouts because they do less damage to the sacrificial layer on the mill bed. These end mills have end-cutting teeth, allowing the tool to cut vertically along its axis as well as radially. This makes them suitable for drilling, spot facing and counter-boring and for jobs that require drilling or plunge cutting to start a cut.
Ball End
Ball end mills, also called ball nose, are preferable for milling contoured surfaces. They should also be used for cuts that require a rounded detail, such as a slot with rounded bottom.
Straight Flute
Straight flute end mills are most beneficial for use on thin sheeting where spiral flutes would lift up the material.
DIMENSIONS:
Cutting Edge Diameter
Smaller end mills will allow for more detailed cuts, but they tend to break easily. Larger end mills can remove more material and cut faster.
Shank Diameter
The shank diameter can be the same as the mill diameter or it can be different. End mills should be ordered with shank diameters to fit one of the collet sizes we have in the lab: 1/8", 1/4", 3/8", 1/2".
Cut Length
The cut length of you end mill should be longer than the maximum depth of your cut.
FLUTES:
Number
Commonly the number of flutes ranges from two to four. Most milling done in our lab requires no more than two flutes, however you should be aware of the following information:
Fewer flutes allow for more chip removal, which keeps end mills cooler. End mills with more flutes can be fed at a greater rate and generally create a finer finish. Two flute end mills are center-cutting. When used as a slotting or drilling tool, these best maintain the slot or hole size and location because one of the flutes crosses the end center of the end mill.
Helix
The flutes of an end mill form a helix around its axis. The helix has several variables that are worth mentioning:
COATING:
Generally speaking, coatings can lengthen the life of an end mill. Much of the milling done in our lab won’t require a coated end mill. Some materials, particularly aluminum and acrylic, are relatively difficult to work with and require a coating to prevent the material from bonding to the teeth of tools. See below for recommended coatings:
Titanium Nitride (TiN)
Gold in color, this is an excellent general-purpose PVD coating that is suitable for a wide range of materials (see chart on the right). The TiN coating will improve the tool life and is used where elevated speeds & feeds are the objective, TiN provides high lubricity and facilitates chip flow which reduces heat and edge buildup on the end mill.
Titanium Carbonitride (TiCN)
Blue/Gray in color, this coating is 30% harder than TiN coatings and is the optimum choice for tool life in long production runs. TiCN end mills operate at aggressive feeds and speeds and are excellent for abrasive or difficult to machine materials.
Titanium Aluminum Nitride (TiAIN)
Dark gray color, this advanced coating is available on carbide end mills and can take the heat and thermal stresses that occurs in milling heat-treated and exotic materials. This coating allows use in dry milling applications and saves on coolant costs. TiAIN is the first choice for milling stainless and high-temp alloys as well as titanium. This coating is also used for high speed machining (HSM) applications.
McMaster-Carr
McMaster has a good selection of inexpensive end mills. Unfortunately, you cannot specify the helix direction through McMaster. You can order directly from McMaster and orders are delivered next day.
Onsrud
Onsrud has a great selection of specialty end mills. You can choose your end mill type on the Onsrud website, but they must be ordered through a vendor. Design Services Carbide (201-569-5317) is our local supplier. They accept credit cards and can deliver next day.
TYPE:
Flat or Square End
Flat end mills are perfectly suited for flat surface and pocket cuts. They are also preferable for contour cutouts because they do less damage to the sacrificial layer on the mill bed. These end mills have end-cutting teeth, allowing the tool to cut vertically along its axis as well as radially. This makes them suitable for drilling, spot facing and counter-boring and for jobs that require drilling or plunge cutting to start a cut.
Ball End
Ball end mills, also called ball nose, are preferable for milling contoured surfaces. They should also be used for cuts that require a rounded detail, such as a slot with rounded bottom.
Straight Flute
Straight flute end mills are most beneficial for use on thin sheeting where spiral flutes would lift up the material.
DIMENSIONS:
Cutting Edge Diameter
Smaller end mills will allow for more detailed cuts, but they tend to break easily. Larger end mills can remove more material and cut faster.
Shank Diameter
The shank diameter can be the same as the mill diameter or it can be different. End mills should be ordered with shank diameters to fit one of the collet sizes we have in the lab: 1/8", 1/4", 3/8", 1/2".
Cut Length
The cut length of you end mill should be longer than the maximum depth of your cut.
FLUTES:
Number
Commonly the number of flutes ranges from two to four. Most milling done in our lab requires no more than two flutes, however you should be aware of the following information:
Fewer flutes allow for more chip removal, which keeps end mills cooler. End mills with more flutes can be fed at a greater rate and generally create a finer finish. Two flute end mills are center-cutting. When used as a slotting or drilling tool, these best maintain the slot or hole size and location because one of the flutes crosses the end center of the end mill.
Helix
The flutes of an end mill form a helix around its axis. The helix has several variables that are worth mentioning:
Up-Cut: Up-cut helices eject chips upward, resulting in a smooth bottom of the material. These tools are not recommended for milling laminated woods because they tend to cause fraying.
Down-Cut: Down-cut end mills push chips downward, producing a smoother top of the material. Another benefit of down-cutters is that they push material downward, reducing the number of screws required to secure it and resulting in less chatter. These are a cost efficient tool for cutting contours in sheet material, especially laminated woods.
Compression-Cut: Compression-cut end mills have a helix that changes direction. The majority of the compression-cutter helix is down-cutting, while a small section at the end is up-cutting. This results in a smooth surface on both the top and bottom, which is perfect for laminated woods. This type of end mill creates a superior finish, but they cost significantly more than up-cut or down-cut types.
COATING:
Generally speaking, coatings can lengthen the life of an end mill. Much of the milling done in our lab won’t require a coated end mill. Some materials, particularly aluminum and acrylic, are relatively difficult to work with and require a coating to prevent the material from bonding to the teeth of tools. See below for recommended coatings:
Wood- none
Foam - none
Plastic - TiCN
Nonferrous Metal - TiCN
Metal - TiAIN
Titanium Nitride (TiN)
Gold in color, this is an excellent general-purpose PVD coating that is suitable for a wide range of materials (see chart on the right). The TiN coating will improve the tool life and is used where elevated speeds & feeds are the objective, TiN provides high lubricity and facilitates chip flow which reduces heat and edge buildup on the end mill.
Titanium Carbonitride (TiCN)
Blue/Gray in color, this coating is 30% harder than TiN coatings and is the optimum choice for tool life in long production runs. TiCN end mills operate at aggressive feeds and speeds and are excellent for abrasive or difficult to machine materials.
Titanium Aluminum Nitride (TiAIN)
Dark gray color, this advanced coating is available on carbide end mills and can take the heat and thermal stresses that occurs in milling heat-treated and exotic materials. This coating allows use in dry milling applications and saves on coolant costs. TiAIN is the first choice for milling stainless and high-temp alloys as well as titanium. This coating is also used for high speed machining (HSM) applications.