Who needs surface grinders?

Posted on Aug 14, 2020

Surface Grinders

Surface grinding is a common grinding technique. The abrasive wheel rotates on a spindle and extends over a piece of material, metal or non-metal. This gives the desired surface finish together with the ability to grind to extremely high tolerances.

The workpiece is held on a chuck, usually a magnetic chuck for metallic workpiece clamping and a vacuum chuck for non-magnetic parts. The machines that perform surface grinding are called surface grinders.

The grinding wheel required depends on the type of component being ground, and there are many different mixtures available for different grinding materials. After selecting the correct circle, you can either sand with a flat disc to get a flat surface or you can place the mold outside the circle for a specific shape, it will be a mirror image of the shape on the wheel.

Surface grinding is used to obtain a smooth finish on flat surfaces. It is a widely used abrasive machining process in which a rotating disc coated with rough particles cuts shavings of a metallic or non-metallic substance from the workpiece, making the surface flat or smooth.
 

How Does a Surface Grinding Process Go?

Surface grinding is the most common grinding operation. This is a finishing process that uses a rotating abrasive wheel to smooth the flat surface of metallic or non-metallic materials to give them a more refined appearance by removing an oxide layer and debris from the surface of the workpiece.

A surface grinder consists of an abrasive wheel, a working handle, and a reciprocating/rotary table. The gripper holds the material in place during processing. This can be done in two ways: ferromagnetic components are held in place by a magnetic chuck, while non-ferromagnetic and non-metallic components are held in place by a vacuum or mechanical means. A machine vise (ferromagnetic steel or cast iron) placed on a magnetic chuck can be used to hold non-ferromagnetic components if only a magnetic chuck is available. Factors to consider when grinding are the material of the grinding wheel and the workpiece.

Common workpieces are cast iron and mild steel. These two materials do not tend to clog the wheel during machining. Other materials include aluminum, stainless steel, brass, and some plastics. When grinding at high temperatures, the material tends to become weakened and is more inclined to corrode. This can also result in a loss of magnetism in materials where this is applicable.
 

Equipment Contained in a Surface Grinder

A surface grinder is a machine tool used to precisely grind a surface of a critical size or to finish a surface. In order to hold the workpiece in place, clamping tools such as magnetic chuck or vacuum chuck are used. Besides the chuck and the grinding wheel, a surface grinder consists of some other equipment that helps the grinding process proceed properly.

Normally, the machine is constructed with a table that moves along and across the face of the wheel. The longitudinal feed is usually hydraulically powered, as is the crossfeed, however, any mixture of manual, electric, or hydraulic may be used depending on the end-use of the machine. The grinding wheel rotates in the spindle head and can also be adjusted in height by any of the methods described above. Modern surface grinders are semi-automatic, the cutting depth and spark out can be pre-set to the number of passes, and once set, the machining process requires little operator intervention.

Depending on the material of the workpiece, machining is usually held by a magnetic chuck. It can be an electromagnetic chuck, or a manually operated, permanent magnet type chuck; both types are shown in the first image. The machine has provision for the application of coolant as well as the extraction of metal dust.
 

:: Read More: Surface Grinding Machines in the Automotive Industry

 

Surface Grinders with a Horizontal Spindle (Circumferential)

The periphery (flat edge) of the wheel is in contact with the workpiece to form a flat surface. Peripheral grinding is used for precise work on straight flat surfaces; conical or curved surfaces; slots; flat surfaces by the shoulders; recessed surfaces; and profiles.
 

Vertical Spindle Grinders (Disc)

The face of the wheel (cup, cylinder, disc, or segment wheel) is used on a flat surface. Face grinding is often used to remove material quickly, but some machines can perform high-precision work. The workpiece is held on a reciprocating table that can be changed depending on the task, or on a rotary table machine with continuous or indexed rotation. Indexing allows one station to be loaded or unloaded while grinding operations are performed on the other. An alternative term is snow grinding.
 

Disc and double-disc Grinders

Disc grinding is similar to surface grinding, but with a larger contact area between the wheel and the workpiece. Disc grinders are available with a vertical and horizontal spindle. Double disc grinders work simultaneously on both sides of the workpiece. Disc grinders are able to achieve particularly close tolerances.
 

Grinding Wheels for Surface Grinders

Aluminum oxide, silicon carbide, diamond, and cubic boron nitride (CBN) are four commonly used abrasives for grinding wheel surfaces. Of these materials, alumina is the most common. For reasons of cost, diamond and CBN grinding wheels are usually manufactured with a less expensive core material surrounded by a diamond or CBN layer. Diamond and CBN wheels are very hard and are suitable for the economical grinding of materials such as ceramics and carbides that cannot be ground with aluminum oxide or silicon carbide wheels.

As with any grinding operation, the condition of the disc is extremely important. Abrasive dressers are used to maintain the condition of the grinding wheel and can be bench mounted or mounted in the grinding wheel head where they can be easily applied.

 

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MTS gathered worldwide surface grinder manufacturers into this online platform. Browse and search for your next supplier with us.

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