Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PowerPoint to accompany Krar Gill Smid Technology of Machine Tools 6 th Edition Contour Bandsaw Parts and Accessories Unit 36

36-2 Objectives Name the main operative parts of a contour-cutting bandsaw and state the purpose of each Select the proper tooth form and set for any cutting application Calculate the length of a saw band for a two-pulley machine

36-3 Vertical Bandsaw Latest machine tool to be developed –Early 1930s Widely accepted by industry Fast and economical method of cutting metal and other materials Continuous cutting action on workpiece

36-4 Advantages of the Vertical Bandsaw Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

36-5 Advantages of the Vertical Bandsaw Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

36-6 Advantages of the Vertical Bandsaw Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

36-7 Contour Bandsaw Parts Fabricated from steel Basic parts –Base –Column –Head Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

36-8 Base Supports column and houses drive assembly Provides drive for saw blade Lower Pulley –Supports and drives saw band –Driven by variable-speed pulley Can be adjusted to various speeds by variable speed handwheel

36-9 Base Table –Attached to base by means of trunnion –Can be tilted 10 to left and 45 to right –Turned by table tilt handwheel Lower saw guide –Attached to trunnion –Supports blade to keep it from twisting Filler plate slide and center plate –Removable and mounted in table

36-10 Column Supports head, left-hand blade guard, welding unit and variable speed handwheel Variable speed handwheel –Used to regulate speed of bandsaw blade Blade tension indicator and speed indicator Welding unit –Used to weld, anneal, and grind saw blade

36-11 Head Upper pulley –Supports saw band, adjusted by tension and tracking controls Upper saw guide –Attached to saw guidepost –Supports/guides saw blade to stop twisting Saw guard and air nozzle –Keeps area free from chips

36-12 Types of Band Machines Smaller capacity –has two band carrier wheels –Used in many toolrooms Larger capacity –Have three carrier wheels –Both upper wheels may be tilted –When blade becomes too short, can be shortened to fit over upper and lower band carrier wheels

36-13 Bandsaw Common Applications Notching –Sections of metal removed in one piece Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Slotting –Quick and accurate without expensive fixtures

36-14 Bandsaw Common Applications Three-dimensional shaping –Simply follow layout lines Radius cutting –Internal or external contours –Internal sections removed in one piece Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

36-15 Bandsaw Common Applications Splitting –Accomplished quickly with minimum waste Angular cutting –Work clamped at any angle –Table may be tilted Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

36-16 Coolants Power-feed models have cooling system –Circulates and discharges coolant against faces of blade and work Mist coolant system –Uses air to atomize coolant and direct it (efficient) –Recommended for high-speed machining of nonferrous metals Grease-type lubricants and coolants may be applied directly to blade on machines with no system

36-17 Power Feed Work and table fed toward blade by hydraulic system Fixed-table machines use gravity to provide steady mechanical feeding pressure –Allows operator to use both hands to guide –Work forced into blade by cables, pulleys, and weights Force –Varied up to about 80 lb. (regular lbs)

36-18 Bandsaw Blade Types Three kinds of blades commonly used –Carbon-alloy –High-speed steel –Tungsten-carbide tipped For best results, must consider –Kind of saw-blade material and tooth form –Pitch set –Width –Gage needed

36-19 Tooth Forms Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Precision (regular) –Most generally used –0º rake angle, 30º back clearance –Used for fine finish Claw (hook) –Positive rake on cutting face –Faster cutting, longer lasting than buttress Buttress (skip) –Teeth spaced farther apart –Tooth angles same as precision teeth –Used on thick work sections

36-20 Pitch Numbers of teeth per standard reference length –Inch standard = No. teeth/inch –Metric standard = No. teeth/25 mm Thickness of material to be cut determines pitch of blade to use –Coarse: thick, Fine: thin Two teeth in contact with work at all times

36-21 Set Amount teeth offset on either side of center to produce clearance for back of band –Wave set Group of teeth offset to right and next to left Structural steel or pipe –Straight set One tooth offset to right and next to left Light nonferrous castings –Raker set One tooth offset to right, one to left, and third tooth straight Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

36-22 Width Wide blade used for straight, accurate cuts Narrow blades used to cut small radii Radius charts show proper width of blade are found on all bandsaws –Choose widest blade that can cut smallest radius

36-23 Gage Thickness of saw blade Thick blades stronger than thin blades Thickest blade possible should be used for sawing tough material Standardized according to blade width ½ in wide are.025 in. thick 5/8 in. and ¾ in. wide are.032 in. thick 1 in. wide are.035 in. thick

36-24 Job Requirements Bandsaw operator should be familiar with various types of blades –Select one that will do job to specified finish and accuracy at lowest cost Table 36.1 in text provides guide

36-25 Calculate Length of Saw Blade Packaged in coils 100 to 150 ft. in length Cut length required and weld ends –Twice center distance between each pulley and add it it one pulley's circumference Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CD Blade length = 2 (CD) + µ D D