Mach 122: Abrasive Machining Abrasive Processes & Machines Objectives: Identify different types of grinding machines Explain the machining processes performed by different grinding machines Created by: Ronald C. Schwartz 8/27/2009

Abrasive Processes & Machines SURFACE GRINDERS One of the most common grinding machines is the surface grinder, which include: Type I: Horizontal spindle with reciprocating table Type II: Horizontal spindle with rotary table Type III: Vertical spindle with reciprocating or rotary table. Created by: Ronald C. Schwartz 8/27/2009

SURFACE GRINDERS TYPE I The grinding wheel is on a horizontal spindle, and the face (periphery) of the wheel is presented to the work-piece. material is usually held on a magnetic chuck. The chuck (wheelhead) may be moved in & out and raised & lowered. Created by: Ronald C. Schwartz 8/27/2009

SURFACE GRINDERS TYPE I Sizes of surface grinders range from a small 4 x 8” size, to large machines able to grind 6 by 16 ft, or larger. A common machine shop size has 6- by 18-in. table A surface grinder can produce a flat surface within +/- .0001” Contoured surfaces can be with special shaping of the grinding wheel. Created by: Ronald C. Schwartz 8/27/2009

SURFACE GRINDERS TYPE II The face of the wheel is brought into contact with the work- piece, with work-pieces mounted on a rotary table & run under the wheel. Created by: Ronald C. Schwartz 8/27/2009

SURFACE GRINDERS TYPE III This grinder has a vertical spindle, and the side, (or grinding face) of the wheel is brought into contact with the workpiece. The worktable may be reciprocating, or rotary. Created by: Ronald C. Schwartz 8/27/2009

SURFACE GRINDERS TYPE III Vertical spindle grinding machines are often seen in large sizes. Created by: Ronald C. Schwartz 8/27/2009

SURFACE GRINDERS TYPE III Special wheel shaping (dressing) adds to the versatility of surface grinders (reciprocating table version). Created by: Ronald C. Schwartz 8/27/2009

CYLINDRICAL GRINDERS Cylindrical grinders are used to grind the diameters of cylindrical workpieces, and include: Center-type Roll-type Centerless Internal cylindrical Tool and cutter Created by: Ronald C. Schwartz 8/27/2009

CENTER-TYPE GRINDERS This type, also called a center grinder, grinds the outside diameter of a cylindrical work-piece mounted between centers. Created by: Ronald C. Schwartz 8/27/2009

CENTER-TYPE GRINDERS Typical application of the angular center- type grinding machine showing angled grinding wheel finishing both diameter and shoulder. Created by: Ronald C. Schwartz 8/27/2009

CENTER-TYPE GRINDERS Cylindrical grinders with computer numerical control (CNC) can perform the functions of the universal cylindrical grinder under program control. Computer numerically controlled (CNC) cylindrical grinder showing a variety of applications that can be accomplished under computer control. Created by: Ronald C. Schwartz 8/27/2009

ROLL-TYPE GRINDERS Roll grinders are used to grind and resurface large steel rolling mill rolls. Fig. Roll grinding machine for grinding steel mill rolls. Heavy rolls are supported in bearings while in the grinding machine. In larger roll grinding machines, the wheelhead is traversed along the rotating work-piece to accomplish grinding. Created by: Ronald C. Schwartz 8/27/2009

CENTERLESS GRINDERS grinding of cylindrical work-pieces without the use of centers for support. The work-piece is fed between the grinding wheel and regulating wheel. The grinding wheel travels at normal speeds & the regulating wheel travels at a slower speed to control the rate of spin of the work-piece. Created by: Ronald C. Schwartz 8/27/2009

CENTERLESS GRINDERS Centerless grinding is also suited to the grinding of conical parts, and parts with different diameters. Centerless form grinding. Created by: Ronald C. Schwartz 8/27/2009

INTERNAL CYLINDRICAL GRINDERS Cylindrical grinding processes apply to internal as well as external surfaces. Fig. L-21 Principle of internal cylindrical grinding. Created by: Ronald C. Schwartz 8/27/2009

INTERNAL CYLINDRICAL GRINDERS The centerless principle applied to internal concentric parts. Created by: Ronald C. Schwartz 8/27/2009

TOOL & CUTTER GRINDERS A variety of grinding wheel shapes are used with tool & cutter grinders. Their primary application is the sharpening of milling cutters. Created by: Ronald C. Schwartz 8/27/2009

Misc. Grinding Machines On a form grinder, the grinding wheel is dressed to a precise “mirror image” of the shape of the tooth to be ground. Form gear grinding machine. Created by: Ronald C. Schwartz 8/27/2009

REVIEW Name the three types of surface grinders. Describe the major identifying feature of each type of surface grinder. Name the five types of cylindrical grinders. Name three types of specialty grinders. What is a tool and cutter grinder used for? Created by: Ronald C. Schwartz 8/27/2009