In the machining of parts, there are two processes by which a part is shaped by removing material. These processes are chip removal or abrasion .
In the abrasive machining process , the cutting edge used to remove material is not defined. One of the tools to be able to carry out abrasive machining is the grinding machine.
What is a rectifier
The grinding machine is a tool that performs the machining process by abrasion. It has a robust abrasive wheel as a material removal tool, which means that it does not have a defined edge.
With this machine , a finished part with more precise dimensions and less roughness than a chip removal process is obtained .
READ MORE : Milling machine (works by chip removal process)
What is a grinding machine used for?
Grinding is a process performed on parts that have certain very small tolerances . These can be dimensional (such as diameter , length or angle) or surface finish (such as roughness, scratches, impurities).
Grinding is often done after a chip removal process. Chip removal is performed to remove larger areas, and then a surplus is left that will be removed by abrasion (with the grinder). The result will be more precise and neat.
How does a grinding machine work?
The grinding machine is a complex but easy to use machine. First of all, for it to receive energy, the electromagnet must be activated. The electromagnet will be in charge of holding the piece and not moving.
Once the piece is placed in the electromagnet, we turn on the machine and the spring starts to rotate. Then we start moving the flywheels that make the electromagnet move in the x,y directions.
NOTE : In large grinders there is usually a hydraulic pump so that the movements are not heavy or hard.
We leave the part under the spring and using the handwheel that moves the spring in the z direction, we go down until the spring comes into contact with the part .
Then, through automatic control, we allow the electromagnet to oscillate in such a way as to achieve the desired dimensions and finish.
Types of grinding machines
There are several types of grinding machines that can depend on the objective (it can be for surface finishes, dimensional precision), the piece to be ground, the technology used, its size or the need for repetitions, among others.
NOTE: The enormous degree of precision of a CNC grinder is barely measurable with micrometers .
Flat or surface grinders
- Front grinding machines: In front grinding machines , the grinding wheel is located on a horizontal axis and moves rectilinearly over the part (from right to left). It is used to quickly remove material, with less precision than other grinders.
- Tangential grinding machines : In this case, the grinding wheel rotates on a vertical axis with circular and pendulum movements . In these cases the work done is much more precise.
Cylindrical grinding machines
- External cylindrical grinding machines : Grinding is done on the external cylinder of one piece . This allows the part to rotate in the same direction as the grinding wheel.
- Internal cylindrical grinding machines : In this case , the grinding is carried out inside a hollow cylindrical part . The grinding wheel must always have a smaller diameter than the inside of the piece
- Centerless cylindrical grinding machines: It is for grinding small cylindrical parts. In this case , there are two grinding wheels that rotate in the same direction and the piece is placed between them .
They are in charge of machining bodies of revolution , which makes them larger and more robust machines than the others. These machines are used to produce, among other things, camshafts , pistons , liners, crankshafts , etc.
CNC grinding machine
These machines were a consequence of technological advance. Grinding machines with CNC technology are machines that perform the same procedure, only their control is computerized.
This has several or rather many advantages:
- Decrease in operator intervention as it is automatic.
- Improvement in operation times.
- Increased finishing accuracy .
- Possibility of programming and establishing a series of steps to follow .