Cutting Tool Applications Professional3 weeks ago - Multimedia - Battambang - 9 views
New types of saws and better blade materials have made metal sawing a much more effective, versatile and economical process. In many cases, bandsaws are used as the primary means of shaping certain types of metal parts.
Once, sawing was considered a secondary machining process, and saws were used mostly for Cutting Tools bar stock in preparation for other machining operations.
Sawing is a process wherein a narrow slit is cut into the workpiece by a tool consisting of a series of narrowly spaced teeth, called a Granite Saw Blade. Sawing is used to separate work parts into two or more pieces, or to cut off an unwanted section of a part. These processes are often called cut-off operations and since many manufacturing projects require cut-off operations at some point in the production sequence, sawing is an important manufacturing process. Basically, sawing is a simple process: As the blade moves past the work, each tooth takes a cut. Depending on the thickness or diameter of the work, the number of teeth cutting at one time varies from two to ten or more. Saws may be of the continuous cutting (band or rotary) or reciprocating type.
All saw blades have certain common characteristics and terminology:
Rake angles: Rake angles are 0 degrees or neutral rake on most saw blades. Some have a positive rake angle.
Width: The width of a saw blade is its total width, including the teeth.
Set: The set of a Marble Saw Blade means the offsetting of some teeth so that the back of the blade clears the cut. The "raker" set is most frequently used and is furnished with all hacksaws and band saws unless otherwise specified.
Kerf: The kerf is the width of the cut made by the saw blade or the material cut away. The thickness of the blade is called the gage.
Pitch: The pitch of a saw blade is the distance between the tops of two adjacent teeth. This is specified in teeth per inch.
When the proper sawing machines and blades are used, sawing is one of the most economical means of cutting metal. The saw cut (kerf) is narrow and relatively few chips are produced in making a cut. When a bandsaw is used for cutting the contours of a complex shape only a small portion of the metal is removed in the form of chips. Therefore, only minimal power is used in removing large amounts of waste metal.
In addition to TIR (total indicator runout) is the dimension of the grinding wheel side flutter, runout, roundness and tolerance. This is accomplished by truing, dressing, forming and conditioning.
Conventional and ceramic precision abrasive Grinding Tools are trued by diamond single points, hand-set diamond clusters, diamond form blocks or rolls, blade tools, or any other means of truing, to bring the precision abrasive grinding wheel surface to within 0.0005" TIR straight and formed.
The same goes for diamond grinding wheels. CBN grinding Milling Wheels are different. They must be trued to within 0.000040" TIR straight or with a form. The reason being is that in precision grinding hard metals the swarf becomes threadlike chips and can only be made to grind correctly if the fine metal threads are formed consistently. This requires a lubric grinding coolant (8:1 mix) or with straight oil. Keep your infeeds in dressing down below 0.001" to avoid crushing the bonds.