Drilling machining process

Posted on Jul 21, 2020

Drilling machining process

Drilling creates a round hole in a workpiece. A drill press or tapping machine is designed for drilling, but this process can also be performed using a milling machine. Chips are the bits of waste metal produced when machining a workpiece. The shape of the drill bit helps chips fall away from the workpiece, keeping the workpiece free of debris.

Placing the drill bit perpendicular to the workpiece reduces drifting or leading-off. For even more precision, a center drill operation is often added before drilling. Some drilling operations need angular drilling. Angular drilling requires special work-holding tooling. Other options include: rotation of the head on a manual machine or use of multiple axis’on a CNC machine.

Ways to prevent drifting include:

● Casting/molding/forging a mark

● Center punching

● Spot drilling/center drilling

● Spot facing

As with turning operations, there are different drills for specific drilling operations. Below are some special drills with their specific uses.

Point drilling - short drills used to create shallow or pilot holes. If you use a longer drill bit for these shallow holes, it may tend to drift.

Hollow drilling - Frequent withdrawal of the drill helps remove chips from the workpiece and prevents drift.

Drills for screw machines - these drills are short and can create straight and accurate holes without the need for prior detection.

Fastening reamers - are used to enlarge previously drilled holes to very accurate diameters.


Machine Tooling
The desired form of material will determine what kind of tools you will need for work. The two basic types of cutting tools are single and multi-point tools. Use single-point tools for drilling, turning, boring and planing. Use multi-point tools for milling and drilling. Proper use and maintenance of cutting tools for quality purposes is necessary. Unfortunately, proper maintenance of machines and tools can be expensive.

Machining cutting tools
The tooling is available in a variety of materials. The most popular are carbide steel and high speed steel. High-speed steel (HSS) can be used for general milling. But choose carbide for machining harder and harder tool steels.
:: Read more : Here's What People Are Saying About Metal Cutting Band Saw

Cutting Speed, Feed Rate, Depth
Cutting speed, feed speed and depth of cut are all parameters that must be considered when machining. The workpiece material, tool material and dimensions will affect these parameters. The cutting speed refers to how quickly the cutting tool penetrates the workpiece material. It is measured in feet of surface per minute. Cutting feed refers to how quickly the workpiece moves along its axis towards the cutting tool. It is measured in inches per minute.

Like artistic carving, the workpiece is first subjected to one or more rough cuts. Their purpose is as close as possible to the finished shape and dimensions. After the roughing phase, a finish is applied to get the final dimensions, tolerances and surface finish. Finishing cuts are usually made at low feeds and depths. The use of cutting fluid during both cutting phases cools and lubricates the cutting tool.

Turning involves the rotation of the workpiece while the cutting tool moves in a linear motion. It gives a cylindrical shape. A lathe is the machine of choice for all turning operations.

Like most machining operations, turning is done either manually or automatically. The disadvantage of manual turning is that it requires constant supervision. Automatic rotation no. With the help of computer numerical control or CNC, you program all movements, speeds and tool changes on your computer. These instructions are then sent to the lathe for execution. CNC allows consistency and efficiency of high production series.

The single-point cutting tools used in turning have different shapes. They are set at different angles for different results.

Milling machining process

Milling operations include the use of multipoint rotary knives to remove material from the workpiece.

There are two main types of milling operations: face milling and peripheral milling. Face milling cuts flat surfaces into the workpiece and flat cavities. The channel can be horizontal or vertical. Circumferential milling cuts deep grooves, threads and gear teeth.

The workpiece can be fed to the cutting tool in two ways. Traditional milling involves feeding the workpiece against the rotation of the milling cutter. This is the recommended method for hand-held milling machines. On the other hand, climbing milling feeds the workpiece in the same direction as the rotation of the cutter. This is the preferred method of CNC milling.

Milling is best used as a secondary process to an already processed workpiece. It helps to define features and serves as a "finishing layer". Use milling as an additional process to add features such as holes, slots, pockets and contours.

Milling speed and feed calculator

Innovations in machining

There are many things that require machining of a perfectly smooth, precise and functional workpiece. This requires great attention to detail and experience. Turning, drilling and milling are just some of the most common machining processes. They have been around for many years. Fortunately, thanks to the development of CNC machining has improved enormously. While conventional machining still has its purpose in production, CNC machining occupies a leading position. It helps in facilitating large production runs while maintaining consistency and efficiency.

:: Read more : What to expect from CNC Milling machines in the future?

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