January 24, 2022

What is a CNC grinder?

Grinding machines are commonly helpful in the hard-fine machining of workpieces. A CNC grinder machine is a device that uses a rotating grinding wheel to cut and remove material from a metallic workpiece. Most of the grinding machines use high-speed rotating grinding wheels. CNC grinding machines also come with CNC surface grinders, for example, CNC coordinate grinders, CNC forming grinders, etc.

There are several CNC grinding machines; CNC roll grinders, CNC crankshaft grinders, CNC plain cylindrical grinders, etc. Generally, CNC grinders work with specifications that the technician types into the computer and the grinding machine starts to work. With precise measurements and high-quality grinding tools, the device removes the excess material from metallic pieces resulting in a fine product of your choice.

A typical grinding machine comes with a computer controller, computer-driven grinding wheels, and a power supply unit. The grinding wheels allow the device to control the operating speed, the cutting depth, the diameter of the workpiece, the drill stroke, and the belt drive torque.

How it works

A CNC grinding machine works with commands fed by a programmer to initiate a task according to user specifications. The grinding machine listens to the instructions and moves parts such as the grinding head onto the workpiece to perform as requested. 

Two options are available to remove the excess material from a workpiece. The first option is advancing the grinding head across a workpiece slowly, and another option is to allow the grinding head to spin at high speed going through the surface of the workpiece.

The CNC grinding machine has a coolant tank to spray a coolant on the grinding head and workpiece to regulate temperatures by preventing overheating. The coolants can be oils, oil-water emulsions, gels, pastes, etc. The coolant also prevents rusting of the machine and makes it last longer.

What is a CNC grinder used for

A CNC grinding machine has many uses, and its primary purpose is to reduce the particulate size of different materials with precision. It is most common in the mining industry to extract valuable metals such as silver and gold. Grinding machines are also helpful in the production of gears. A grinding wheel shape known as the grinding worm works to complete the grinding tasks. Other applications of grinding machines are

Flute grinding, broach and hob grinding, surface grinding, roamers, step-drill grinding, etc. A variety of industries are now using grinding machines for different purposes. Some of these industries are

  • Automotive industry

Automotive industries use OD and ID grinding, including brake cylinders, brake pistons, hydraulic steering pistons, etc. OD grinding of these products ensures the concentricity of the shaft to its centerline.

  • Aerospace industry

The aerospace industry requires materials that are tough to the machine. The high-strength materials allow components to survive the environment of the aerospace engine. Some aerospace components made by grinding include turbine rings, inner and outer rings, turbine shafts, etc.

  • Die or Mould industry
  • Machine tools manufacturers
  • Medical industry

The medical industry uses grinding to produce dental drill bits, hip stems, hip balls, surgical drills, etc.

  • Tooling industry 

The History of CNC grinders

Grinding machines were developed in the 1830s by the United Kingdom, Germany, and the United States people using abrasive wheels. They were already ready-made machine tools such as lathes and planners, and they introduced the addition of a grinding head to these machines to become grinding machines. The idea came to adapt to the hardening of parts such as bicycles, sewing machines, watches, etc. 

The first machine designed by Brown and Sharpe Company of the United States that had the basics of a modern grinding machine is the Universal Cylindrical grinding machine. The machine came into existence at the Paris Exposition Exhibition in 1876. It has an internal grinding accessory, and its workpiece headstock and tailstock rests on a reciprocating table that increases the rigidity of the machine.

The company came with another surface grinder in 1883, which has a grinding head mounted on a column and table.

In 1900, many artificial abrasives and applications of hydraulic transmissions came into existence, promoting the development of grinding machines. Different types of grinding machines came with the advancement of the automotive industry and the modern part. At the beginning of the 20th century, we saw the development of crankshaft grinding machines, camshaft, planetary inner grinding machines, etc. 

In 1908, an automatic measuring device existed on the grinding machine and then centerless grinders, double face grinders, guide grinders, and honing machines in 1920. Moreover, a high-precision cylindrical grinding machine used for mirror grinding existed in the 1950s. High-speed grinders with a line speed of 60-80 m/s and massive depth cutting with slow feed surface grinders appeared at the end of 1960. Around the 1970s, many advanced technologies, including digital control and adaptive control of microprocessors, appeared.

Tips for using a CNC grinder

  • Ensure you do not operate the CNC grinder at speeds above the recommended limit.
  • Remove any leftover swarf from the grinder after the grinding process is over.
  • Check all the cables of the CNC grinder before switching it on, making sure that they aren’t loose.
  • The grinding wheel type should be the correct size for your application, and select one with your desired levels of precision according to the abrasion levels.
  • Make sure the wheels have no cracks, do not use a damaged wheel.
  • Always keep the coolant clean.

CNC cylindrical grinder

A cylindrical grinder is helpful in metalworking, requiring extreme precision engineering. Cylindrical grinding is more similar to centreless grinding. No chuck or spindle holds or secures the workpiece; instead, the cylindrical machine consists of two rotating wheels, the grinding wheel, and a control wheel. These rotate at different speeds in the same direction, determining the metal removal rate from the workpiece. The work rest blade will always balance the workpiece.

A cylindrical grinding machine shapes the outside surface of an object. It rotates the workpiece, requiring grinding around a central axis. The cover can be stepped, tapered, or straight.

CNC grinding machine manufacturers

There are many CNC grinding machine manufacturers, and most of them come from India. Some of the manufacturers are:

  • Amey Engineers & Traders
  • Prayosha Enterprise
  • Micromatic Grinding Technologies Limited
  • HMT Machine Tools Limited
  • Precision Machine Tool
  • PLUTO 18
David D. Hughes
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