Precision Grinding
V.G.A. Precision machining company has grinding machineries to provide for precision grinding services: Cylindrical and Surface Grinding.
Precision Grinding is managed by high qualified staff and it gives V.G.A. the possibility to manage parts grinding in house while respecting high quality standards.
Precision Grinding has complete series of Measurement Tools apt to guarantee tight tolerances and finishing parameters usually required by grinding processes.
Grinding Concepts
Precision Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool.
A grinding wheel is an expendable wheel used for various grinding and abrasive machining operations. Grinding wheels may also be made from a solid steel or aluminium disc with particles bonded to the surface. Grinding practice is a large and diverse area of manufacturing and toolmaking. Surface grinding uses a rotating abrasive wheel to remove material, creating a flat surface. It can produce very fine finishes and very accurate dimensions; yet in mass production contexts it can also rough out large volumes of metal quite rapidly.
Since Precision Grinding is an expensive operation, it is used only on materials requiring a better finishing (such as bearing seats and gear profiles).
Selecting which of the following grinding operations to be used is determined by the size, shape, features and the desired production rate. Types of Grinders:
- Cylindrical grinder
- Centerless Grinder
- Surface Grinder
Cylindrical Grinding
Cylindrical Preicision Grinding, also called center-type grinding, is used to grind the cylindrical surfaces and shoulders of the workpiece, on the outside diamtere or on the inside diameter.
The workpiece is mounted on centers and rotated by a devise known as a drive dog or center driver. The abrasive wheel and the workpiece are rotated by separate motors and at different speeds. The table can be adjusted to produce tapers.
A cylindrical grinder has a grinding (abrasive) wheel, two centers that hold the workpiece, and a chuck, grinding dog, or other mechanism to drive the work. Most cylindrical grinding machines include a swivel to allow for the forming of tapered pieces. The wheel and workpiece move parallel to one another in both the radial and longitudinal directions to shave off chips.
Crankshaft grinding Machine can be an example of this kind of machining. The crankshaft is the most complex cylindrical surface to grind. The grinding of crankshafts places high demands on the tools used. In the grinding of main and pin bearings on crankshafts.
Centerless Grinding
Centerless grinding is typically used for machining long, thiny and small workpieces which are not located between the spindle and thetailstock.
In this grinding operation the workpiece is secured between two rotary grinding wheels:
- One wheel, known as the grinding wheel performs the grinding action on the surface of the workpiece by having a higher linear speed,
- The other wheel, known as the regulating wheel (moving wheel in the diagram), is movable. This wheel is positioned to apply lateral pressure to the workpiece.
A blade supports the particular during machining.
The extremely precise set-up of the machine and the careful selection of the grinding tool require great knowledge and experience, this is the reason why it is used in a wide range of sectors as automotive, bearings industry, electrical motors, tolls, textile industry etc.
Surface Grinder
A surface grinder is a machine tool used to provide precision ground surfaces.
Precision Grinding is a finishing process that uses a rotating abrasive wheel to smooth the flat surface of metallic or nonmetallic materials to give them a more refined look or to attain a desired surface for a functional purpose:
- Horizontal-spindle (peripheral) surface grinders. The periphery of the wheel is in contact with the workpiece, producing the flat surface.
- Vertical-spindle (wheel-face) grinders. The face of a wheel ,cup, cylinder, disc, or segmental wheel, is used on the flat surface.
Gear Tooth Grinding Machine is a process of finishing the surface of tools after thermal treatments as carburization, The more perfectly ground the surface of the tooth flanks, the better is the form fit. During the grinding process the tooth form is produced through virtually linear engagement of the tool in the tooth gap. This method is predestined for grinding bevel gears which are used primarily in differential gears. Here, the grinding wheel is used to cut a profile directly with a diamond-coated, high-precision dressing wheel.
