Precision Grinding is a sub-segment of abrasive cutting processes, where machine tools outfitted with grinding wheels are used to precisely remove material from a workpiece (typically metal) and hold to very tight tolerances. Precision grinding equipment can be controlled either manually or via Computer Numerical Control (CNC).
Much like you would see with a handheld angle grinder, precision grinding equipment works by spinning an abrasive grinding wheel at high rates of speed relative to a fixed workpiece. As the wheel comes in contact with the surface of the material it removes small particles in order to reshape the surface (think of sandpaper on a metal surface). By tightly controlling the amount of contact and material being removed and by running multiple passes each taking away incrementally more material, the equipment can hold very tight dimensional and geometric tolerances (straightness and flatness) as well as extremely smooth surface finishes. There are several types of grinding technologies each designed to support different features and shapes. Several of the most common types are described below.
A Surface Grinder is used to reshape or refinish the outside surface of material to a flat shape. In this construction the abrasive grinding wheel sits above and is rotated relative to the workpiece which is held in a chuck that is mounted to the table. The chuck is commonly magnetically activated and can hold ferrous (magnetic) materials like many metals in place. A magnetic chuck can be either a permanent magnet where the magnet elements are moved in and out from the workpiece on the table to engage the magnetic force or electromagnetic which is engaged when electrically activated. Depending on the design the table either reciprocates side to side in a linear path or rotates around a path perpendicular to the grinding wheel.
Unlike cylindrical and surface grinding, which are designed to create only specific geometric features, Jig Grinding can be used to create more complex shapes and features. An easy visual comparison for a jig grinder is a milling machine. The grinding wheel is held in a spindle and spins in the same direction as a milling machine would, however the spindles typically have very high speed capability and when combined with a grinding wheel a jig grinder can create holes, slots and inside geometries with accuracies and surface finishes far superior to a traditional milling process.
A cylindrical grinder is used to reshape or refinish a surface of a workpiece in a radial shape. In this configuration both the workpiece and the grinding wheel are rotating and moved relative to each other in order to remove material. As the workpiece is also rotating it must be spun around a center axis. Cylindrical grinding equipment can be designed and used to create outer diameter and inner diameter features. The key distinction of a cylindrical grinder is that, as the name states the resultant part will be of a cylindrical or round shape. With Outside Diameter and Inside Diameter Grinders the part is held with a spindle which then spins. Another type of Cylindrical Grinder is a Centerless Grinder, where instead of holding the workpiece in a spindle the part is held between two rotary wheels which then in turn spin the part.
Our Precision Grinding Process and Approach
Precision Grinding processes provide significant advantages with respect to precision and surface finish to traditional machining approaches, and as such certainly have their place in industry. At Alle-Kiski we leverage grinding techniques to supplement our capabilities and fill gaps that traditional machining cannot fill. In addition to in house capabilities we have a strong partner network that enables to round out our Precision Grinding capability.
Our approach is focused around flexibility. We thrive in projects that range from low volumes or even single piece such as prototyping, to high volume production runs. We can support a variety of materials, from steel to stainless steel to aluminum to plastics to exotic metals and everything in between. We cover industries from medical, to energy to defense to instrumentation and robotics and more.From small high precision parts to large part requirements, our goal is to service a wide range of needs for our customers. To supplement our internal capabilities, we have built out a strong partner network that allows us to fill in any gaps, and maximize response time.
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Precision Grinding Applications
Precision grinding applications generally require greater levels of accuracy and material finish specification than those of traditional machining. Any applications requiring tight flatness or profile tolerances are generally good candidates. Some example operations include but are not limited to-
- Machining of pin holes of slots for stamping dies
- OD grinding of bearing surfaces
- Grinding of gear teeth
- Microfinishing of surfaces
The Advantages of Grinding
Due the tight control of the grinding wheel position and speed, extremely tight tolerances are able to be achieved with precision grinding. Grinding equipment can be used on a large variety of material including metallic and non-metallic, as well as very hard and/or abrasive. The surface finish that can be achieved by grinding machinery outweighs almost any other technology, making it a go-to machining solution for a variety of applications.