How to Safety Handling Tungsten Carbides

To prevent safety risk connected with handling tungsten carbide, the following basic safety practices should be observed :

• Use a respirator and eye protection. These two protects the most vulnerable parts of your body when handling tungsten carbide. Using a respirator is important especially in situations where there is poor or no ventilation available. Even when a place is well-ventilated, using a respirator is still recommended.
• Full body protection. Wearing protective clothing for the entire body is also important. It helps prevent allergic reactions on the skin when it comes to contacts with tungsten carbide.
• Skin protection. Gloves are a must-wear when handling tungsten carbide. Its also important to apply barrier cream on the skin to add another layer protection against tungsten carbide dust or mist when working.
• Stay away from tungsten carbide work areas. if you have no business being in an area where there's work on tungsten carbide going on, stay out of it.

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Carbide Cutting tools benefits

Strength - Because carbide is a combination of carbon and variety of other extremely strong chemical elements, the results is material power full enough to cut through cast iron. Its torque strength is twice that of high speed steel and its compression strength is equally impressive.

Toughness - Carbide cutting tools on their own are tough, but with the added coatings available, they become almost indestructible tools for the machine industry to use in their cutting machines. Resistant to abrasions, thermal deformation and other material wear, carbide produces a quality cut and rarely needs repair or replacement.

Value - Because Carbide cutting tools work at high speeds without warping, and cut through even the toughest of materials, it keeps the assembly line working fast and productively. Its value is immense in that productions loads can be increased without extra wear and tear on parts, as well without any damage to the product being produced. Overall, this make carbide cutting tools a preference over high speed steel for machinists and other industry professionals.

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Cutting Speeds & RPM Calculations

Milling machines are used to perform a wide variety of machining operations. There are those operations that are strictly milling operations, but we also use milling machines to perform other operations such as drilling, reaming, tapping, and boring. The rules and principles of cutting speeds and R.P.M. calculations that apply to these "other" operations being performed on milling machines are still used in the same manner. An example of this would be reaming. Reaming is done at half the speed and twice the feed as drilling. This rule still applies on the milling machine as it does on the drill press or the lathe.

Cutting Speed for Milling- Cutting speed is the speed at the outside edge of the milling cutter as it is rotating. This is also known as surface speed. Surface speed, surface footage, and surface area are all directly related. Two wheels can illustrate a nice example of this. Take two wheels, one wheel which is three feet in diameter and the other wheel which is one foot in diameter, roll each wheel one complete turn (Figure 1).

Figure 1

Which wheel traveled farther? The larger wheel traveled farther because it has a larger circumference and has more surface area. Cutting speeds work on the same principle. If two cutters of different sizes are turning at the same revolutions per minute (RPM), the larger cutter has a greater surface speed. Surface speed is measured in surface feet per minute (SFPM). All cutting tools work on the surface footage principal. 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 (Figure 2).

Steel Iron Aluminum Lead

Increasing Cutting Speed Figure 2

The hardness of the cutting tool material has a great deal to with the recommended cutting speed. The harder the cutting tool material, the faster the cutting speed (figure 3). The softer the cutting tool material the slower the recommended cutting speed.

Carbon Steel High Speed Steel Carbide

Increasing Cutting Speed

Figure 3

The depth of cut and the feed rate will also affect the cutting speed, but not to as great as an extent as the work hardness. These three factors; cutting speed, feedrate and depth of cut are known as cutting conditions. Cutting conditions are determined by the machinability rating. Machinability is the comparing of materials on their ability to be machined. From machinability ratings we can derive recommended cutting speeds. Recommended cutting speeds are given in charts. These charts can be found in your Machinery’s Handbook, textbook or a chart given to you by your tool salesperson. In Table 4 you will find a typical recommended cutting speed chart.

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Milling-Machine Operations

Table 4. Recommended Cutting Speed for Milling in Feet per Minute (fpm)

Work Material	Hardness, Bhn	Cutting Speed, fpm
		High-Speed Steel	Carbide
Plain Carbon Steel, AISI 1010 to AISI 1030	to 150 150 to 200	110 100 to 140 100 80 to 120	600 400 to 900 450 300 to 700

The milling machine speed must be set so that the milling cutter will be operating at the correct cutting speed. To set the proper speed we need to calculate the proper revolution per minute or RPM setting. We stated earlier that cutting speed or surface speed would change with the size of the cutter. So to keep the surface speed the same for each size cutter we must use a formula that includes the size of the cutter to calculate the proper RPM to maintain the proper surface footage.

Calculating RPM- The RPM setting depends on the cutting speed and the size of the cutter. The RPM setting will change with the size of the cutter. As the milling cutter gets smaller the RPM must increase to maintain the recommended surface footage. Again, take the case of the wheel. Think of the cutter as a wheel and the cutting speed as a distance. A larger wheel (cutter) will need to turn fewer revolutions per minute to cover the same distance in the same amount of time than a smaller wheel (cutter). Therefore, to maintain the recommended cutting speed, larger cutters must be run at slower speeds than smaller cutters.

The milling machine must be set so that the milling cutter will be operating at the proper surface speed. Spindle speed settings on the milling machine are done in RPMs. To calculate the proper RPM for the tool we must use the following formula:

Cutting speed (CS) X 4
Diameter of cutter (D)

This simplified version of the RPM formula is the most common formula used in machine shops. This RPM formula can be used for other machining operation as well.

Lets put this formula to work in calculating the RPM for the machining example below. Use the recommended cutting speed charts in Table 5.

Milling-Machine Operations

Table 5. Recommended Cutting Speed for Milling in Feet per Minute (fpm)

Work Material	Hardness, Bhn	Cutting Speed, fpm
		High-Speed Steel	Carbide
Plain Carbon Steel, AISI 1010 to AISI 1030	to 150 150 to 200	110 100 to 140 100 80 to 120	600 400 to 900 450 300 to 700
AISI B1111, AISI B1112, AISI B1113, Steel	140 to 180	140 110 to 200	650 400 to 1200
Plain Carbon Steel, AISI 1040 to 1095	120 to 180 180 to 220 220 to 300	195 80 to 120 85 70 to 110 60 30 to 80	600 400 to 800 350 300 to 500 200 100 to 300
All Alloy Steels Having .3% or Less Carbon Content: AISI 1320, AISI 3120, AISI 4130, AISI 4020, AISI 5020, AISI 4118, AISI 9310, etc.	180 to 220 220 to 300 300 to 400	80 65 to 100 60 30 to 80 40 30 to 50	350 300 to 600 300 200 to 350 125 100 to 150
All Alloy Steels Having More Than .3% Carbon Content: AISI 1340, AISI 2340, AISI 4140, AISI 4150, AISI 4340, AISI 5140, AISI 5150, AISI 52100, AISI 8660, AISI 9260, etc.	180 to 220 220 to 300 300 to 400	80 60 to 100 55 30 to 80 30 20 to 50	325 275 to 450 250 180 to 300 100 80 to 130

A milling cut is to be taken with a 0.500 inch high speed steel (HSS) endmill on a piece of 1018 steel with a brinnel hardness of 200. Calculate the RPM setting to perform this cut.

Cutting Speed = 90 (fpm)

Diameter of Cutter = 0.500

Since the available spindle speed settings are generally not infinitely variable, the machine cannot be set precisely to the calculated RPM setting. Some judgment must be made in selecting the speed to use. Try to get to the speed which is nearest to the calculated RPM, but if you can’t consider these conditions. Are you roughing or finishing? If you are roughing, go slower. If you are finishing go faster. What is your depth of cut? If it is a deep cut, go to the slower RPM setting. Is the setup very rigid? Go slower for setups that lack a great deal of rigidity. Are you using coolant? You may be able to go to the faster of the two settings if you are using coolant. The greatest indicator of cutting speed is the color of the chip. When using a high-speed steel cutter the chips should never be turning brown or blue. Straw colored chips indicate that you are on the maximum edge of the cutting speed for your cutting conditions. When using Carbide, chip colors can range from amber to blue, but never black. A dark purple color will indicate that you are on the maximum edge of your cutting conditions. Carbide cutting tools are covered in much greater detail in other section of your learning materials.

Let’s try some more examples.

A milling cut is to be taken with a 6.00 inch (HSS) side milling cutter on a piece of 1045 steel with a brinnel hardness of 300. Calculate the RPM setting to perform this cut.

Cutting Speed = 55 (fpm)

Diameter of Cutter = 6.00

A 1-inch (HSS) drill is used on a piece of 1010 steel with a brinnel hardness of 100. Calculate the RPM setting to perform this drilling operation.

Cutting Speed = 140 (fpm)

Diameter of Cutter = 1.00

A milling cut is to be taken with a 3.00 inch carbide face milling cutter using coated inserts on a piece of 4140 alloy steel with a brinnel hardness of 200. Calculate the RPM setting to perform this cut.

Cutting Speed = 400 (avg. fpm)
Diameter of Cutter = 3.00

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Picture of TCT Router Bit

TCT Router Bit is Unique Tools for Wood Cutting. We will discuss more about TCT Router Bit in the coming posts.

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TCT Profile Cutter Picture

TCT Profile Cutter comes in different Cutting and Function from different manufacturers. Here is a picture of a simpleTCT Profile Cutters with The Process Machining.

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Carbide Grades

Carbide hardness and toughness can be altered, dependent upon the relative quantities of Carbide and matrix metal powders in the mix prior to cementing and sintering. The International Systems Organisation (I.S.O.) have produced codes to simplify selecting the correct grade of Carbide. CUTTING CONDITIONS CODE COLOUR Finishing Steel, high cutting speeds, light feeds, Favourable conditions P01 BLUE Increasing wear resistance Increasing cutting speed. Increasing shock resistance. Increasing feed. Finishing & light roughing of Steel & Castings with no coolant P10 Medium roughing of Steel, less favourable conditions. Moderate cutting speeds & feeds. P20 General purpose turning of Steel & Castings, medium roughing. P30 Heavy roughing of Steel & Castings, Intermittent Cutting, low cutting speeds & feeds. P40 Difficult conditions, heavy roughing/intermittent Cutting, low cutting speeds & feeds. P50 Finishing Stainless Steel at high cutting speeds. M10 YELLOW Finishing & medium roughing Alloy Steels. M20 Light to heavy roughing Stainless Steel & Difficult to cut materials. M30 Roughing tough skinned materials at low cutting Speeds. M40 Finishing Plastics &Cast Iron K01 RED Finishing Brass & Bronze at high cutting speeds & feeds K10 Roughing Cast-Iron, Intermittent cutting, low speeds & High feeds. K20 Roughing & finishing Cast-Iron & non-ferrous materials. Favourable conditions. K30

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Type of TCT Finger Joint

4 Finger Joint Types

1. HS-Hp Type Finger Joint Cutter
Application : Structural Finger Joints
Machine : Batch feed and through feed machines
Material : Softwoods
Edge material : HS-HP

2. Finger Joint Cutter Head
Application : Structural Finger Joints
Machine : Batch feed and through feed machines
Material : Softwoods
Edge material : HS-HP

3. Finger Joint Cutter Head
Application : Millwork Finger Joints
Machine : Through feed machines
Material : Softwoods, Hardwoods
Edge material : HS-HP

4. Disc Type Cutter
Application : Millwork Finger Joints
Machine : Through feed machines
Material : Tropical woods, Hardwoods
Edge material : HC-UP

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Finger Joint Process

Finger Joint Process and result of joint

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Finger joint

Finger Joint

The finger joint (also known as a comb joint) is made by cutting a set of complementary rectangular cuts in two pieces of wood, which are then glued. To visualize a finger joint simply interlock the fingers of your hands at a ninety degree angle; hence the name "finger joint." It is stronger than a butt or lap joint, and often forms part of the overall look of the piece.

The history of the finger joint is believed to have begun with wooden produce boxes or crates in the days before modern, man-made materials. Finger joints were originally cut by hand with saws and sharp chisels. In modern times they are easily and quickly made with a tabel sae or router and a jig or fixture, which can be shop-made or purchased from a specialty woodworking supply store. A finger joint jig typically consists of a moving fence with an indexing pin that is used to evenly space out the cuts. The fence is moved over a cutting blade making a cut that is then moved over the indexing pin so the next cut can be made.

The strength of a finger joint comes from the long-grain to long-grain contact between the fingers, which provides a solid gluing surface. The number of contact points also allows for more gluing surface as opposed to a butt joint or a rabbet joint.

While the spacing of finger joints is mostly an aesthetic decision, it is commonly less than or equal to the thickness of the material being joined. For example, one might decide on 1/8" fingers on 1/4" material unless the length of the mating surfaces lends itself better to a 1/4" finger joint, which would appear less "busy" to the eye.

Although finger joints are usually evenly spaced, it's not unusual for woodworkers to experiment with varying spacing between cuts.

While it is relatively easy to make using computer aided manufacture, a table saw or a wood router with a simple jig, some common problems include:

• Tear out on the back side
• If using a table saw, the top of the joint may not be exactly flat, depending on the tooth set of the blade
• Spacing problems and difficulty dialing in the exact index

The finger joint can also be invaluable when fixing tables and chairs and also can be used in such things as floor boards, timber roof and door construction. This is also used in design technology for students. Finger joints can be hard to make without the right tools.

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History of Tungsten Carbide

Tungsten carbide was first used in the 1920s when a German light-bulb company sought ways to make cheaper wiring for the light bulbs. Since tungsten carbide has a high melting point, this compound worked perfectly for light bulbs because the temperatures inside them get very hot. The production of tungsten carbide was perfected by the 1930s and other elements were also added in order to make the compound useful for other applications.

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Tungsten Carbide Applications

Carbide cutting surfaces are often used for machining through materials such as carbon or stainless steel, as well as in situations where other tools would wear away, such as high-quantity production runs. Carbide generally produces a better finish on the part, and allows faster machining. Carbide tools can also withstand higher temperatures than standard high speed steel tools. The material is usually called cemented carbide, hardmetal or tungsten-carbide cobalt: it is a metal matrix composite where tungsten carbide particles are the aggregate and metallic cobalt serves as the matrix.

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Type of Sawblades

Type of Sawblades and Application

1. Timber Max
   Application : Heavy duty rip sawing and re-sawing
   
2. Timber Max TK
   Application : Cutting solid timber into thin slats used in the production of parquet flooring, blind, etc.
3. Tough Black
   Application : Special coating on the saw blade body to reduce friction between the saw blade body and solid wood.
4. Super Finish Saw Blade
   Application : Ripping solid wood in glueline (super finish) quality.
5. Cross Cut
   Application : Cross Cutting of solid wood.
6. Scoring Saw Blade
   Application : Scoring of laminated panel material to avoid tear outs on the bottom side.
   

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Tungsten carbide

Tungsten carbide (WC), also known as tungsten steel, is an inorganic chemical compound containing equal parts of tungsten and carbon atoms. Colloquially, tungsten carbide is often simply called carbide.

Calcium Carbide

In its most basic form, it is a fine gray powder, but it can be pressed and formed into shapes for use in industrial machinery, tools, abrasives, as well as jewelry. Tungsten carbide is approximately three times stiffer than steel, with a Young's modulus of approximately 550 GPa, and is much denser than steel or titanium. It is comparable with corundum (α -Al2O3) in hardness and can only be polished and finished with abrasives of superior hardness such as silicon carbide, cubic boron nitride and diamond amongst others , in the form of powder, wheels and compounds.

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