月: 2023年1月

What Is a Drill Bit?

A Drill Bit is a piece that is attached to the end of a drill driver.

Since a drill driver is a tool with the functions of an electric drill and an electric screwdriver, there are various types of bits that can be attached to its tip.

The materials to be processed differ depending on the bit, such as for wood, for metal, for concrete, for stone, for plastic, and so on.

Because of the wide variety of bits available, it is common to purchase a set of general-purpose bits and then buy more as needed. Some bits are magnetized to make it easier to work with one hand when tightening or loosening screws.

Uses of Drill Bits

Drill Bits have a wide range of uses, the main ones being drilling holes in materials, expanding holes, and tightening and loosening screws and other fasteners with screwdrivers. They can be used to drill holes in a wide range of materials, including metal, concrete, and other hard materials.

In screwdriver applications, there are also screwdrivers for screws and nuts, which can be selected according to the application. In addition, grinding wheels and industrial diamonds can be used to grind materials, and cutting and chamfering of metals can also be performed.

Principle of Drill Bits

A Drill Bit is a cone-shaped piece used for drilling. Attached to a power tool such as a rotary drill, it is rotated while force is applied from above to drill a hole while cutting.

The pointed metal rod has a spiral groove drilled into it, which helps to discharge shavings backward and reduce frictional resistance when drilling. As the tip rounds off, its cutting ability decreases and its function as a drill bit deteriorates, so it is important to know when it is time to replace it.

Types of Drill Bits

1. Plus/Minus

This is the most common and most frequently used type of bit. They have a + (plus) and – (minus) tip and are used to tighten and loosen screws. They come in sizes 1, 2, and 3, so it is important to select the correct size for the screw. 

2. Square Bit

This type of bit has a square shape when viewed from above. 

3. Hexagonal Bit

The tip is regular hexagonal. It is easier to apply force than a Phillips or square bit and is suitable for use in confined spaces. For this reason, hexagonal screws are often used in furniture, home appliances, and metalworking products.

4. Torx

Shaped like a star, they are generally not used in many situations. They are used in the assembly and repair of precision equipment that should not be easily disassembled.

5. Drill Bits for Drilling Holes

Drill Bits are used for drilling preliminary holes. A wide variety of types are available, including bits for concrete, tile, aluminum, stainless steel, iron, and other metals, and woodworking.

6. Step Bit

Step bits are conical in shape and are often used for hole expansion, deburring, chamfering, etc. They are not often heard of, but they are used in construction sites and for chamfering. Although not often heard of, it is often used at construction sites and in metalworking.

7. For Polishing

Some are made of grinding stones with spherical tips, some are brush-shaped, and some are made of felt. These are used to remove rust, peel paint, and polish metal.

How to Select a Drill Bit

When choosing a drill bit, keep in mind the following:

1. Intended Use

Because of the wide range of uses for drill bits, it is necessary to use the right bit for the right purpose. While it is natural to make a distinction between the use of a drill bit and the use of a screwdriver, the use of bits for different materials is not recommended.

For example, it is possible to drill holes in wood using a bit for metalworking, but a bit for wood is not suitable in terms of durability. Considering the durability of the bit and the cleanliness of the finish, it is important to use the appropriate bit for the intended use. 

2. Size

The shape of the hole to be drilled and the screw to be tightened vary greatly depending on the length and thickness of the bit. For example, if the diameter of the bit is too large for the hole to be drilled, a screw or nut of the desired size will not fit, making the bit unusable. 

3. Shape of the Insertion Slot

In addition to the shape of the bit tip, the shape of the slot into the machine body also varies. There are straight shuts, hexagonal shafts, tapered shuts, and so on.

Be careful that straight-shut bits, which are rod-shaped, will not fit into a hexagonal-shaft electric impact drill. A part called a drill chuck must be used.

4. Material

There are various types of materials for the bit itself, in addition to the common HSS steel. For example, there are those coated with titanium nitride or chromium nitride for the purpose of extending bit life, and nickel-mixed sintered materials for the purpose of increasing hardness and machining precision.

What Is a Tool Set?

A tool set is a collection that includes a comprehensive assortment of tools such as wrenches, screwdrivers, pliers, and nippers.

Tool sets come in a variety, including screwdriver sets for household use, sets with standard tools for frequent use, and extensive sets for professional use. Specialized sets are also available for motorcycle maintenance, insulation work, DIY projects, and other specific applications.

The size, portability, and quantity of tools in a set can vary, ranging from compact, easy-to-carry pouch types to robust hard case, box chest, and cabinet types.

Uses of Tool Sets

Tool sets are commonly used for general household tasks, motorcycle and automobile repairs, and on construction sites. There are also sets designed for professionals in specialized fields, such as dental technicians.

Professionals often customize their tool sets to fit their specific needs by adding or removing tools. Some may purchase just the case and select tools that best fit their work preferences.

Principles of Tool Sets

Standard tool sets typically include Phillips and flathead screwdrivers, wrenches, pliers, nippers, hammers, saws, and measuring tapes. These sets not only provide all necessary tools but also keep them organized in a special tray.

Tools in a set are easy to locate and retrieve, making it easy to notice if any are lost or not returned. Additionally, purchasing a tool set is often more cost-effective than buying individual items.

How to Choose Tool Sets

With a wide range of tool sets available, it’s important to choose one that includes the tools you need without being overly cumbersome. Below are three key factors to consider when selecting a tool set.

1. Purpose

Choose a set based on your primary use. Here are some common applications and the tools they require:

Daily Use at Home
Basic tools like screwdrivers, wrenches, and pliers are usually sufficient for everyday household tasks.

DIY
DIY projects may require additional tools such as saws and hammers, alongside the basic set.

Motorcycles and Automobiles
Maintenance of motorcycles and cars requires a set that includes wrenches, nippers, and pliers, with a ratchet to improve efficiency.

2. Ease of Use

Consider the ease of use when selecting tools for your set. The quality of tools can significantly affect workmanship and efficiency, especially in specialized professional settings. Consider grip size, strength, quality, and whether electric or power tools could be beneficial for long hours or intensive work.

3. Type of Case

Choose a case type based on the work environment and needed functionality or portability. Hard case types offer convenience and portability, box chest types provide ample storage without mobility, and cabinet types combine large storage capacity with ease of movement thanks to equipped casters.

What Is a Tacker?

A Tacker is a tool used in construction to secure interior materials and insulation. It has the appearance of a large stapler, and is used to fasten thin materials. It differs from a stapler in that the tip of the needle sticks vertically without bending.

There are various types of tackers, such as gun tackers, which are manually operated, electric tackers, which are continuously operated, and air tackers, which use an air compressor.

Uses of Tackers

Tackers are used to hammer thin materials onto walls, boards, and other surfaces. Since they can be operated with one hand, it is possible to work while holding the wood or other material to be tacked with the other hand. They are widely used for attaching wallpaper, sheets, and other materials.

An electric tacker can be used for continuous needle tapping, allowing work to be completed quickly even in hazardous locations such as high places.

Air tackers are also useful for reupholstering sofa leather because of their strong needle force.

Principle of Tackers

While a stapler secures an object by bending the tip of the needle, a tacker secures an object by piercing it in a U-shape. As with a stapler, press the tacker horizontally against the desired location and press the button.

Since the tip of the staple is pointed like a needle, it can be used on thin wood, fabric, and other thick objects.

Types of Tackers

1. Gun Tacker

This is a common manual tacker, also called a hand tacker. Smaller ones are used for DIY projects such as crafts, while larger and stronger ones are used on construction sites. Staples are applied by holding the trigger by hand. 

2. Hammer Tacker

Hammer Tackers are tackers that strike like a hammer. The hammer is applied with a snap of the wrist, so the staples are applied at an approximate position rather than at a precise location.

3. Electric Tacker

Staples with the electric tacker are driven in with the power of electricity. They are suitable for long hours of work, as they can be used at the touch of a button. Corded and rechargeable types are available.

4. Air Tacker

Staples are inserted using pneumatic pressure.. Air tackers require a compressor and air hose. They are mainly used for construction work such as interior decoration.

How to Select a Tacker

When selecting a tacker, be careful about the intended use, weight, and type of staples.

1. Intended Use

It is recommended to select a tacker that matches the intended use of the work. A gun tacker is fine for fixing thin items as a DIY project, but an electric or air tacker is better suited for thicker items, such as at construction sites, or when firm fixing is required or long hours of work are required.

Recently, thanks to advances in batteries, some electric tackers are now as powerful as air tackers. Many small types are also available, and electric tackers are becoming the norm for advanced DIYers and professional job sites. Others can be used as staplers by attaching special parts.

2. Weight

Air-powered tackers are powerful but heavy, and require a compressor and air hose. Therefore, a rechargeable type or hammer tacker is suitable for work at high places. 

3. Needle Type

Needle legs range in length from about 6mm to 25mm, so the length should be considered according to the material to be fixed. The main standards are CT wire, RT wire, and J wire, and the shoulder width, section length, and foot length are determined accordingly.

In addition, depending on the staple, the available tackers may differ, such as for air tackers or hammer tackers. Therefore, it is important to select the appropriate tacker for the staple.

It is recommended to use the same manufacturer of tacker and staple as much as possible to prevent staple jamming.

What Is Friction Sawing Machinery?

Friction sawing machinery is machinery using a cutting wheel to quickly cut long, thin metal materials such as steel pipes and wire ropes.

Compared to disc grinders, which are similar products, friction sawing machinery has two main features: first, the cutting wheel is larger and the motor output is higher than that of a disk grinder. As a result, the cutting time is faster; second, while disk grinders are hand-held, high-speed cut-off machines are used on a tabletop and can cut a targeted area with high precision.

However, friction sawing machinery is a cutting-only machine and cannot be equipped with an abrasive wheel, as is the case with a disk grinder.

Uses of Friction Sawing Machinery

Friction sawing machinery can cut metal stably because the cutting wheel and the material to be cut are held in place by the arm and vise. Therefore, they are suitable for cutting thin or long materials.

Thus, friction sawing machinery can cut large quantities of metal materials in a short time and is utilized for cutting out agricultural materials and monopipe pipes. Furthermore, angle cutting is possible up to 45 degrees by adjusting the inclination of the vise. Therefore, it is also useful when making frames that combine angle materials.

Principle of Friction Sawing Machinery

When selecting a model, it is necessary to check the size of the cutting wheel, vise opening, rotation speed, and power consumption according to the application.

First, the size of the cutting wheel differs depending on the thickness of the material that can be cut. Currently, the most common cutting wheels are 305mm, 355mm, and 405mm. The 305mm can be cut up to a thickness of 90mm, making it suitable for cutting several pieces at once. On the other hand, the 355mm wheel can cut up to 120mm thick and is suitable for cutting round pipes one by one. The 405mm cut-off wheel is for professional use, and larger-size cut-off wheels are also available.

Next, select a vise opening that matches the size of the material to be cut.

The rotation speed is related to the beauty of the cut surface.

Lastly, power consumption is a factor to consider.

In addition, it is necessary to confirm the angle at which angled cutting is possible on the left and right sides of the machine, as it may differ depending on the model.

What Are Tweezers?

Tweezers are tools with a small pinch that can be picked up with the tip of a finger. They are useful for handling small parts that cannot be handled with human fingers.

Uses of Tweezers

The primary use of tweezers is to perform small tasks. Examples include attaching electronic components, threading and sewing, grabbing hair and eyelashes, and surgical procedures.

Tweezers can be used to pick up and precisely position very fine objects or objects that cannot be grasped with the fingers.

Principle of Tweezers

The principle of tweezers is that by applying force, a small knob is opened and closed to pinch an object.

They consist of two arms. One arm is usually made up of a flat surface, while the other arm has a sloped shape with respect to the flat surface. When the tweezer is closed, this sloped arm rests against the flat arm, allowing it to pick up small nibbles.

Structure of Tweezers

Tweezers are generally constructed with a thin, pointed tip. This is to allow them to pick up small objects and get into tight places.

In addition, the arms of the tweezer may have ribs to prevent slipping and grooves for gripping. These structures allow for precise manipulation and help prevent the tweezer from slipping during use.

How to Choose Tweezers

There are many types of tweezers available, and it is important to choose the right one for your application.

1. Knob

Tweezers with a flat knob close the knob parallel to the flat surface, thus applying a constant pressure. Tweezers with a rounded knob close the knob against a rounded surface, thus applying pressure more evenly. Tweezers with an angled knob can be angled. 

2. Material

Tweezers are also classified according to their material. For example, metal tweezers and plastic tweezers. Metal tweezers are durable and heat-resistant, making them suitable for handling hot objects or working with strong force. Plastic tweezers, on the other hand, are lightweight, easy to handle, and scratch-resistant, making them suitable for working with soft or delicate materials. 

3. Shape

Tweezers are available in long and narrow or curved shapes. Elongated tweezers can enter and work in tight spaces and deep places. Curved tweezers are suitable for working in curved or hard-to-reach places.

Types of Tweezers

There are many different types of tweezers, depending on their use and shape. Among them, special tweezers are as follows:

1. Precision Tweezers

Precision tweezers are used for particularly small parts and precision work.

2. Vacuum Tweezers

Vacuum tweezers are a type of tweezer that uses the force of a vacuum to attract objects.

3. Hot Tweezers

Hot tweezers are repair tools that have a tweezer-like tip on the end of the tool.

4. Vacuum Tweezers

Vacuum tweezers are tools that use a vacuum to pick up objects.

5. Suction Tweezers

Suction tweezers are tweezers that use a pump or other suction force to pick up spherical or small parts that are normally difficult to grasp.

What Is a Press Service?

A press service is a process of deforming soft metals and other materials using a press machine.

A die is pressed against the material and strong pressure is applied by the press machine to deform it into the desired shape. The pressing mold is used by cutting and turning alloy steel such as pre-hardened steel and stainless steel.

A press service is characterized by the fact that the metal is deformed and formed in a single press by applying strong pressure. The greatest advantage is that a large number of pieces can be mass-produced at once in a short time because the processing time is extremely short.

Presses also require an initial investment and are recommended when products need to be mass-produced over a long period of time.

Uses of Press Services

Press services are used for the mass production of a single part.

It is often used to form familiar metal products because it is a simple and easily mass-produced process. Many of the frames of automobiles and home appliances are made of metal, and most of the parts are press-formed because they can be processed to the same shape with high precision.

Generally, it takes 3 to 6 months to produce a single die, including fine adjustments to improve dimensional accuracy during processing. In order to accurately shape complex bends and curved surfaces, such as those found in the outer panels of automobiles, it is necessary to press a single sheet multiple times using multiple molds.

Press services are not suitable for parts used only in small quantities because of the time and cost required to prepare the dies.

Principle of Press Services

The principle of press services is to cause plastic deformation of the metal to be formed by pressing a die against it while applying high pressure with a press machine.

When a load is applied to a metal, a force is generated that tries to return the metal to its original shape. This is called plastic deformation. By causing plastic deformation in a press machine all at once, large quantities can be produced in a short time with high accuracy.

Types of Press Services

There are three major types of press services:

1. Shearing
2. Bending
3. Drawing

These three processes may be combined to perform a series of processes on a single workpiece of metal.

1. Shearing

Figure 1. Shearing

Shearing is a process of cutting a workpiece to a desired size or shape by preparing two blades on the top and bottom of the workpiece and pressing them together at once. As a processing method that applies shearing processing, there is also a processing method called punching processing in which a target mold is punched like a cookie cutter to cut out the desired shape from a flat plate-shaped processing agent.

2. Bending Processing

Figure 2. Bending process

Bending is a process for bending metal by pressing a V- or L-shaped bending die against the material to be processed using press services. Since many metals are hard and cannot be bent without strong pressure, it is important to bend them with a press machine that can apply strong pressure at once.

The use of press services allows the angle of bending to be set precisely, but there is a limit to the angle of bending that can be set because undercutting may occur, where the product cannot be pulled out of the die after processing.

3. Drawing Process

Figure 3. Drawing process

Drawing is a processing method in which a flat sheet of metal is deformed into a container shape by preparing a concave part of the desired shape on the receiving side of the press services and a convex part on the extruding side and applying it to the press machine.

Since the concavities and convexities are aligned to form the desired shape, right-angle bending cannot be handled, but a three-dimensional shape with a rounded edge can be formed. Compared to bending, it is necessary to hold down the outer circumference firmly because it is pressed against the mold, so the material is required to be one size larger, and the material cost tends to be higher.

These processing methods can be combined to create more complex shapes.

Other Information on Press Services

Machines Used in Press Services

1. Types of Presses by Power Source

• Mechanical Press Machine
  A mechanical press is a machine that presses by rotating a motor and moving a slide up and down.
• Hydraulic Press Machine
  A motor-driven pump applies pressure to the oil in the cylinder to move the piston and press the slide in an up-and-down motion. Although it can be processed in a wide range, it is not suitable for mass production because the processing speed is slow.
• Hand Press Machine
  A hand press is a machine that presses by manually moving a handle or lever.

2. Types of Presses by Shape

• C-type Press
  This is a versatile press machine that looks like the letter C when the machine is viewed from the side.
• Straight Side Press Machine
  This is a press machine with a press force exceeding 2500 kN.
• Transfer Press
  This press machine is used for line press services.
• Servo Press
  Driven by a servo motor, this press is capable of complex, high-precision processing.

What Is Plating

Plating is a process in which a workpiece is immersed in a specified solution to form a thin metal film on the surface of the workpiece.

The types of plated metals began with nickel plating, and today there are many types of metal (zinc, gold, silver, copper, etc.) plating. The plating industry made great progress when electroless nickel plating was invented in the United States after World War II.

Subsequently, plating became possible on ABS resin, a well-known plastic material. As a result, it is now used in various fields, including home appliances and automotive parts.

Types of Plating

1. Nickel Plating

Nickel plating is used as a base plating for stainless steel plating and gold due to its high adhesion to other metals. It can improve corrosion resistance and heat resistance. Generally, electrolytic and electroless plating is used for plating.

2. Chrome Plating

Chrome plating is divided into decorative chrome plating and hard chrome plating according to the thickness of the plating. Decorative chrome plating provides luster and corrosion resistance to the workpiece surface and is often used for automotive parts and home appliances that require a high-end appearance.

3. Rhodium Plating

Rhodium plating is used in various industrial fields such as optical and electronic equipment because it is chemically very stable, has very high hardness, is scratch resistant, has good abrasion resistance, and does not oxidize at temperatures below 500℃.

4. Gold Plating

Gold plating is used for various parts because of its high electrical conductivity and corrosion resistance. Specifically, it is used for electronic circuit boards and connector terminals due to its high electrical conductivity, and for accessories due to its corrosion resistance. Electrolytic plating is the most common plating method.

5. Zinc Plating

Zinc plating is often used to prevent rust on steel products. When the surface of a steel product is scratched, zinc leaches into the scratched area and forms a film called passivation, which has a high rust-preventive effect. Electrolytic plating is used for decorative purposes, while electroless plating is used for corrosion resistance.

Principle of Plating

Plating methods are divided according to whether or not the solution used is electrically conductive.

1. Electroless Plating

Electroless plating is a method of depositing a thin metal film by immersing a workpiece in a plating solution and performing a chemical reaction without an external power supply. Plating is possible even on ceramics and plastics where electricity does not flow, and a uniform metal thin film can be formed. Furthermore, it has the advantage of being able to evenly plate workpieces with complex shapes.

2. Electrolytic Plating

Electrolytic plating is a method of depositing metal on the surface of a workpiece through an electrochemical reaction. A workpiece is placed in an aqueous solution (electrolyte) containing metal ions, and a DC current is passed through the electrolyte as the anode and the immersed workpiece as the cathode. Then, the metal ions in the electrolyte move from the anode to the cathode, and the workpiece surface is plated.

While electrolytic plating can be applied quickly and at a low cost, its disadvantage is that it does not produce a uniform metal film. Furthermore, since it cannot be used on materials that do not conduct electricity, such as ceramics and plastics, the products that can be used are limited.

3. Substitution Plating

Substitution plating is a plating process that utilizes the ionization tendency of metals. In plating, the workpiece is first placed in an aqueous solution containing metal ions. Then, due to the difference in ionization tendency between metals, the metal in the solution replaces the work metal, and the solution metal precipitates on the work surface.

Plating is possible without the use of electrical energy or reducing agents. However, since displacement plating uses the ionization tendency of metals, it cannot be used for products with low ionization tendency or non-metallic products.

Plating Methods

Electroless plating, electrolytic plating, and displacement plating are all plated by a method known as the wet process, in which plating is performed while immersed in an electrolyte solution.

What Is a Soldering Service?

A soldering service is a technique for joining metal materials by fusing an alloy called solder.

In advance, impurities such as oil are removed and flux is applied to improve the adhesion of the solder.

Uses of Soldering Services

Soldering services are mainly used on the circuitry of electrical products.

• Prototyping printed circuit boards.
• Fabrication of electrical and electronic circuits.
• Joining metal piping and copper tubing.
• Stained glass fabrication.
• Fabrication of accessories and models.

Although this joining method is primarily used for industrial applications, it is sometimes used in the fabrication of accessories.

Principle of Soldering Services

Soldering services use heat to melt solder to bond materials together.

1. Solder

Solder is an alloy that uses metals such as tin. It is characterized by a lower melting point than other metal materials and melts easily when heat is applied.

2. Soldering Iron

A soldering iron is a special tool with a heater attached to the tip. The heater heats the tip of the soldering iron to a temperature that melts the solder. There are two types of heat sources for heaters: electric products and gas products. The tip of the soldering iron needs to be replaced or sanded periodically because the solder sticks and burns when used for a long period of time.

3. Flux

Flux is soldering services accelerator. It is used to remove contaminants from the surface of the material while improving the spread of solder. Acidic materials such as hydrochloric acid are sometimes used, but basically pine resin and synthetic resins are used. It also plays a role in preventing oxidation of the material surface.

Types of Soldering Services

There are various methods of soldering services other than hand soldering.

1. Hand Soldering Services

As explained prior, manual soldering services are method in which soldering is performed by hand. It is mainly used for prototyping and experimenting with circuit boards. In addition to temperature control, there are many other operational precautions that must be taken, and There are qualifications such as soldering services certification and electronics assembly technician certification.

2. Dip Soldering Services

After electronic components and connectors are mounted on a printed circuit board, solder is blown up from the underside of the board in a molten solder bath called a dip tank.

3. Reflow Soldering Services

After mounting electronic components on a printed circuit board, soldering services are performed by heat using cream solder. Cream solder is a solder mixed with fine flux in the form of a cream with high viscosity. Since cream solder can be applied to the board in advance, it is characterized by high adhesion accuracy.

As with dip solder, it is used for mass production of electronic circuits, etc. In the surface mounting process known as SMT, a series of operations from cream solder application to chip component mounting to passing through the reflow oven can be performed in succession.

Other Information on Soldering Services

1. Lead-Free Solder

Solder materials are required to have a low melting point and good compatibility with adhesive metals. Alloys of lead and tin have been used for a long time, but the toxicity of lead has become an issue. Therefore, in recent years, the development of lead-free solder has been promoted from the viewpoint of protecting the natural environment.

In particular, solder materials that are widely used include tin-silver-copper or tin-bismuth systems. Tin-gold solder also exists. Another drawback is that many materials have a higher melting point than lead-containing solders, requiring more energy.

2. Soldering Services for Pipe Connections

Soldering services may be used to connect copper or water pipes. Brazing is another technique that uses molten metal to bond pipes together.

The difference between the two is the bonding temperature: soldering services requires temperatures below 450°C to bond solder, while brazing service requires temperatures above 450°C. Therefore, metals such as copper and silver are used for brazing.

Because of the lower temperature, soldering services are heated with a torch, while brazing service is heated with a gas burner.

What Is a TIG Welding Service?

A TIG welding service is a type of arc welding that uses heat from an arc to weld a workpiece.

TIG is an acronym for Tungsten Inert Gas. A tungsten electrode is used for the welding electrode and an inert gas such as Ar or He is used for the shielding gas.

In MAG welding, which uses active gas as the shielding gas, metals that react with active gas, such as aluminum, cannot be welded.

The high heat of arc discharge generated by TIG welding reaches 11,000°C at the center of the spark, making it possible to process any metal. Shielding gas such as argon or helium gas is used to prevent spattering and ignition during welding.

A TIG welding service is an easy-to-use welding method for beginners because it does not produce sparks and is quieter than conventional EDM.

Uses of TIG Welding Services

1. Uses of DC Welding

• When joining products where the aesthetics of the welded part is important.
• When welding stainless steel pipes, sheets, etc. by individuals.
• When welding wheel parts, muffler parts, etc. at automobile repair stores and motorcycle stores.

2. Uses of AC Welding

AC TIG welding services are used when processing metal sheets such as aluminum and magnesium, etc., on which surface oxide film is formed.

Principle of TIG Welding Services

TIG welding services are similar to general arc welding, in which a high voltage is applied between the electrode and the base metal to break down the insulation between the electrode and the base metal, and then an arc current flows. In TIG welding, thermionic emission from the tungsten electrode is used, so basically the electrode is often used as the cathode and the base material as the anode.

In MAG welding, welding proceeds as the electrode melts. However, in TIG welding services, the electrode is basically used only to supply electrons.

Types of TIG Welding Services

There are two types of TIG welding services, depending on the combination of current used and electrode polarity.

1. Direct Current Welding

DC Positive polarity
As described in the TIG welding services principle, when welding with DC positive polarity, electrons emitted from the electrode side (cathode) reach the workpiece side (cathode), resulting in a very high temperature on the workpiece surface. Direct current welding is a method of welding metals by means of high heat.

DC Reverse Polarity
This welding method enables the welding of metals with oxide films on their surfaces, such as aluminum and magnesium, which cannot be processed with DC-positive polarity. In both of the above metals, oxide films with high melting points (>2000°C ) exist on the metal surface. Therefore, if TIG welding services are executed without measures to prevent oxide film, the temperature difference between the metal surface and the metal interior becomes too large to weld the workpiece.

To solve this problem, reverse polarity welding is a method in which the electrode polarity is reversed, with the positive (⊕) pole on the electrode side and the negative (⊖) pole on the workpiece side. By welding with reverse polarity, the oxide film on the surface of the base metal can be removed (cleaning action).

However, when the polarity is reversed, a large number of electrons collide with the electrode, resulting in significant electrode wear. In addition, since the cathode spot moves around, the heat input to the base material is dispersed and the amount of penetration is reduced. As a result, it is not possible to perform high-quality welding with DC reverse polarity.

2. AC Welding

AC welding is a welding method in which the polarity of the electrode is cyclically converted, alternating between DC positive and DC reverse polarity. High-quality welding by DC positive polarity and cleaning action by DC reverse polarity can be used together. It is possible to suppress electrode wear caused by DC reverse polarity.

Other Information on TIG Welding Services

Advantages and Disadvantages of TIG Welding Services

The following is a summary of the advantages and disadvantages of TIG welding services based on the explanations given so far.

Merits

• Almost all metals can be welded.
• No sparks are produced during welding.
• Low work noise.
• Beautiful weld bead (weld finish).
• Welding can be done in any posture.

Disadvantages

• Poor welding efficiency.
• Inert gas is expensive.
• Shielding gas is used, so measures such as wind protection are necessary.
• Welding quality depends greatly on the skill of the welder.