Engineering:Magnetic Drilling Machine

File:Magnetic Drilling Machine from BDS Machinen GmbH, Germany.jpg

A lightweight magnetic drilling machine. The image shows the magnetic drilling machine making holes on H-beam with the help of HSS annular cutter at a workshop

A Magnetic Drilling Machine is a portable drilling machine with a magnetic base (either electromagnetic or permanent magnet). It uses standard twist drill bits, and some can also be used with annular cutters, milling cutters, and other rotary cutters. A Magnetic core drilling machine (also called as a Magnetic drill press, Mag drill, Magnetic drill, Portable drilling machine or Portable drill) is a machine tool fitted with a cutting tool attachment and an electromagnet, is used for drilling holes in various metal. A magnetic core drilling machine can also perform operations like Threading (tapping), Reaming and Countersinking. A portable magnetic core drilling machine or just magnetic drill makes holes in metal with the help of a special cutting tool called a core drill bit or annular cutter or broach cutter. A magnetic core drilling machines use the metal core drilling technology to make holes. A magnetic drill is used for making holes in heavy sections of steel where a normal handheld drill cannot be used.

Description

A portable magnetic core drilling machine is a new technology machine and a faster substitute against the old technology metal hole making machines like Drill press, Geared head drill press, Radial arm drill press, Mill drill, etc.

A portable magnetic drilling machine with core drill bits makes holes from 12 mm diameter and for the holes below 12 mm diameter, one can also attach the normal twist drill bits. A magnetic drill gives and accuracy of 0.001 mm to 0.00 in steel, stainless steel, etc. The core drill bits used for this machines are generally made from a material like High-speed steels (HSS) and Tungsten carbide tipped (TCT).Depending on the nature of the material to be drilled, the user decides to use HSS or TCT core drills.

A portable magnetic drilling machine is available in various sizes, shapes, designs, electronics, and equipment depending upon the purpose of the machine. It combines the versatility of a drill press with a strong electromagnetic base enabling it to adhere to a carbon steel (ferrous metal) surface. It can be positioned to drill horizontally, vertically or even upside down. They are mostly used in structural steel but are also used in applications such as drilling truck frame rails, steel signage, guard rails, etc.

Magnetic drills use a wide variety of tools like annular cutters (core drills), twist drills, taps (threading), reamers, and counter sinks. They are extremely versatile machines that can drill a hole up to 130 mm diameter and tap M42 in steel.

A magnetic drilling drilling machine with four main components - Magnet, Stand, Motor and Arbour.

A magnetic drill has four main components: a magnetic base, a drill stand, a motor, and an arbor (chuck).

Magnetic base

The base of a magnetic drill is equipped with a powerful electromagnet to easily clamp the machine on the work piece to be drilled. When energized this magnet gets strongly fixed on the metal work piece locking the machine base to the metal profile which helps the operator to give a steady feed of the work piece. The electromagnet plays a very important role in a portable magnetic drill, as it helps the machine to be steady, does not let the machine dismount during drilling, can work with the machine overhead, horizontal or vertical. Generally, a magnetic core drilling machine is used on a ferrous material directly, but it can also be used on no ferrous material like stainless steel with the help of clamping devices.

Drill stand

A drill stand is the main body of the magnetic drill where the electric switches for motor and magnet are mounted, magnet indicator is mounted and also the clock-anticlockwise direction switches are mounted. The body of the magnetic drill holds together the motor and the magnet base. The feed handle is also attached to the body. The body of the magnetic drill helps the motor slide on it to get an upward and downward feed. The body of the magnetic drill also plays the role of a handle to lift and move the machine from one place to other. The material used for the body is generally cast iron.

Arbor

An arbor or chuck on a magnetic drill is attached to the motor. it is a type of clamp used to attach the core drills. There are mainly two types of chuck available for the magnetic drill, industrial arbor (manual tightening) and quick change drill chucks. The quick change drill chucks are easy and fast option to attach the core drills. They do not need to tighten the screws/jaws manually. The arbor or chucks have different types of spindle holder (machine taper) like Morse taper MT 2, MT 3, and MT 4.The BDS MAB 1300 core drilling machine is the only machine in the world with MT 4 tool holder. The chuck allows different types of core drill shafts (shanks) to fit in it.

Operations

The magnetic drills are meant primarily for users in the field of plant and machine constructions and heavy engineering industry. These machines are ideal to be used both onsite as well as in the workshops. This machines are not only made for core drilling but are also very flexible to perform an operation like twist drilling, reaming, countersinking and tapping (threading).

A twist drilling requires a drill press or machine to turn the cutting tool. Due to the physical design of the drill bit, twist drilling requires a machine with more horsepower - most often a bulky, bench-mounted machine that is traditionally vertically configured and less portable. The larger the hole, the more time and horsepower are required to evacuate the material.

But, core drills can cut at higher feed rates with lower horsepower consumption, meaning they can run on smaller machines and drill 2x to 4x faster.

A wide variety of portable magnetic mounted drills exist to drill holes, on-site, for repair or construction of structural steel. These newer, lightweight machines can also be used in manufacturing or fabrication shops. Configurable in both horizontal and vertical positions, magnetic drills are also available with pneumatic or hydraulic power for underwater/hazardous locations.

Unless you’re making blind holes or holes less than 12 mm diameter, core drilling is worthy of serious consideration, especially if your application is not under controlled shop conditions.

Mechanism and Working

Magnetic Drilling Machine in working

A magnetic core drilling machine or magnetic drill works basically same as a normal drilling machine, but the advantage is one can take the magnetic drill to work and no need to bring the work at the stationary drilling machines, this makes the magnetic drill very portable and useful. The mechanism of the magnetic drill motor is same as DC motor with speed and torque controls.

The working of a magnetic drill is very simple and easy and can be explained in following steps,

1. Keep the magnetic drill on the plate/tube to be drilled.
2. Place and position the magnetic drill where the hole is to be made.
3. Attach the desired core drill cutting tool to the arbor according to the diameter of the hole to be made.
4. Connect the machine to the power source and switch on the magnet switch.
5. Switch on the motor.
6. Switch on the lubrication tap.
7. Give a downward feed to the machine to drill. This creates a hole in the plate of the size of the core drill bit.
8. Pass the complete drill through the plate and then give a reverse feed and bring the motor to the initial position.
9. A metal core will fall down making a perfect hole in the plate.

This process of hole making in the metal is considered as 2 to 3 times faster than the traditional drilling machines with less horse power (HP) and energy consumption.

Types

There are several types or models of Magnetic core drilling machines depending upon the uses, drives, shapes, feed, etc. Some of the popular types are as follows,

Light weight models

Very light weight types magnetic drills are very popular to perform several operations where the weight of a machine to carry is a great concern like working on an electric pole, mobile tower, TV tower, Bridges, etc.

Automatic and semi-automatic feed models

Magnetic core drilling machines with fully and semi-automatic drill feed are very popular these days. These machines help in saving time and energy and resulting in more production.

Pneumatic driven models

Pneumatic core drilling machines are specially used where there is a danger of fire due to electricity. This model used for the more secure purpose. The motor is driven by pneumatic medium and the magnetic is a permanent magnet instead of an electromagnet.

Battery driven models

Battery operated magnetic core drilling machines are used for a work place where there is no electricity. The motor is driven by a rechargeable battery. The magnet for these machines is either electromagnet of the permanent magnet.

Horizontal models

Horizontal magnetic core drilling machines with angular gears are specially used for most confined drilling situations.

Applications

The portable drilling machines or magnetic drills are used in many files, almost all the manufacturing company needs a drilling machine, for example

• Bridge construction
• Heavy engineering companies
• Manufacturing industries
• Fabrication industry
• Boiler manufacturing
• Railway track drilling
• Automobile industries
• Tower and pole construction
• Stadium, Airport and Building constructions, etc.

Advantages

Bringing the Machine to the Workpiece!

A twist drilling requires a drill press or machine to turn the cutting tool. Due to the physical design of the drill bit, twist drilling requires a machine with more horsepower - most often a bulky, bench-mounted machine that is traditionally vertically configured and less portable. The larger the hole, the more time and horsepower are required to evacuate the material.

But, core drills can cut at higher feed rates with lower horsepower consumption, meaning they can run on smaller machines and drill 2x to 4x faster.

A wide variety of portable magnetic mounted drills exist to drill holes, on-site, for repair or construction of structural steel. These newer, lightweight machines can also be used in manufacturing or fabrication shops. Configurable in both horizontal and vertical positions, magnetic drills are also available with pneumatic or hydraulic power for underwater/hazardous locations.

One final benefit of core drills is evident after the job is complete – cleanup and recycling. When twist drilling, many sharp chips are intermingled with the lubricant. Separating the two for environmental and recycling purposes is difficult, time-consuming and costly. Scrap from annular cutters consists of a minimal amount of swarf and a solid slug. Separating a solid chunk of metal is easier, plus it will generate more profit when selling back the scrap.

• Two to three times faster hole making compared to other technologies
• Saves time
• Saves money as the drill bits last longer
• Less removal of material while drilling
• Portable machines
• Take machines to the work piece
• Drilling in Horizontal, Vertical, Cross-way, Side-way direction possible
• Less noise
• Eco-friendly
• Easy to transport
• Economical
• Robust

Core drills

The magnetic core drilling machine requires cutting tools for hole drilling: these cutting tools are called core drill or annular cutters or broach cutters. Portable drilling in applications such as construction, steel fabrication and more poses many challenges - the method of hole creation is just one of them. Understanding the difference between twist drilling and annular cutting, and the equipment, power and time required, will have you efficiently and expertly cutting holes in steel, stainless steel, and other metals.

Twist drilling- the creation of holes in metal with a drill bit, is probably the most recognized method of hole making. But, with only two cutting edges, twist drills require more time, power and slower feed rates because the complete area of the hole is removed and turned into chips.

Core drilling- the cutting of metal with a hollow-core bit is an efficient way to create holes 12 mm to 150 mm diameter (up to 110 mm deep) with an accuracy of 0.01 mm - 0.00 mm in steel, stainless steel, etc.

Unlike twist drills, Core drills have multiple cutting teeth which cut only the material around the periphery/circumference of the hole, forming a solid metal slug/core.

The wall thickness of the cutter is approximately 5 mm thick, meaning that no matter what size hole you are cutting, you are only removing a small amount of material around the edge of the hole.

Because the cutting surface of core drills is spread out over multiple cutting edges (teeth), they remain sharper longer and can create 5 to 10 times more holes than traditional twist drills.

Final holes are smooth and burr-free - no reaming is required. Additionally, hole cutting with core drills requires no predrilling or stop drilling. Core drills are commonly used to do on-site repair and to make mechanical openings and pipe thru holes.

The core drill creates the hole in a 3-step process:

1. The pilot pin accurately centers the cutter over the area to be drilled.

2. During drilling, the pilot pin retracts and allows the internal lubrication to reach the cutting teeth.

3. When the hole is complete, the slug/core is automatically ejected from the cutter, leaving an accurate, finished hole.

Another unique feature of core drills is their tapered inner wall. On high-quality precision-engineered cutters, the tapered wall design serves two functions. Primarily, it accommodates for the effect of frictional heat, which causes the expansion of both the cutter and the internal metal slug (coupon). Secondly, it facilitates the smooth, easy ejection of the slug.

Conclusion

Magnetic core drilling machine is the best option so far to make quick and easy holes in metal. With clamping devices, these machines can also be used on the nonferrous material. Until and unless there is no need for the blind holes magnetic drill is excellent but, to make blind holes is not possible with this machines. Metal core drilling technology is comparatively a new concept and will take some more time to get popular. The magnetic drills and core drills have a big potential in almost all industries. A magnetic drill saves time, money, power, energy and more than all its eco-friendly compared to another process of hole making.