Guidelines for successful bandsaw operation

Blade Width Selection

The dimension from tooth tip to back edge of the blade is the blade width.The greater the width,the greater the resistance to deflection while cutting.For straight cutting applications,use the widest blade the machine can accept.For contour cutting use the widest blade that the contour radius will permit.To cut close tolerance radii the following factors must be considered:blade width,material thickness,machinability,feed force,and location of pivot point.

Teeth Per Inch

The pitch of blade is defined by the number of teeth per inch(TPI.)Nonferrous materials such as brass,bronze andaluminum require a large chip area.A low TPI,or "coarse pitch,"prevents the tips from clogging and blinding together in the gullets,which can diminish sawing and damage the blade.

On thin walled pipe,tubing,and sheet goods,many teeth per inch are required to avoid damaging or breaking the teeth.Alow TPI blade is the best blade for cutting large cross-sections.The ability of each tooth to cut into the workpiece is increased because the saw's feed pressure is distributed over fewer teeth.A coarse pitch blade increases productivity and provides large chip clearing gullets.

Blade Break-In

Set bandsaw machine at recommended speed for material to be cut.When cuting easily machined metals,cutting rate should be set at 1/3 to 1/2 the recommended rate for the first 50 to 75 square inches.

When cutting difficult to machine metals,such as tool steels or work hardened alloys,set cutting rate at 75% of the recommended rate for the first 25 square inches.Gradually increase the feed until you achieve the recommended cutting rate after 50 to 60 square inches.

Tooth Pitch Selection

For lowest cost per cut,always select the narrowest cross section of the material to be cut for added beam strength,more teeth in cut,longer life,higher band speed,and shortest cut time.

When stacking material,multiply the area of each piece by the number of pieces,then divide by the DT(distance of travel)to obtain average cut width for selection of proper tooth pitch.

When using a smaller tooth pitch than normal,use the MR(multiplier rate)listed for the proper selection to minimize over-filling the gullets of the smaller teeth.

For increased production,after determining the beam strength,material clamping,coolant,tooth pitch,and machine condition are all apropriate,the MR(multiplier rate)can be increased up to 25%.

Blade Break-In

It is important to run all new bandsaw blades at a reduced rate to break them in.This helps to remove any uneven edges that imparted on cutting tools during the manufacturing processes,and can double the life of the blade.To break in a blade:

1)Set machine to the recommended band speed for the material being cut.

2)Multiply the recommended cut time by:  

a.2- for band speeds 250 fpm and higher    

b.1.75-for band speeds 175 to 250 fpm      

c.1.5- for band speeds 120 to 175 fpm    

d.1.25- foe band speeds 80 to 120 fpm      

e.Band  speeds less than 80 fpm require minimal break-in        

3)Gradually increase cutting rate to proper cut time over the next:  

a.80 to 100 sq.in.                    

b.60 to 80 sq.in.                      

c.40 to 60 sq.in.                    

d.20 to 40 sq.in.                      

e.20 or less sq.in

Tooth selection

Tooth selection is based on the principle that there is a tooth pitch best suited for the cutting job.Blade selection should be based on the size,shape accuracy, material and cutting rate expected.

Keep in mind these numbers:3,6,12,and 24.There should be a minimum of three in the work at all times for bi-metal bands and a minimum of six teeth for carbon bands.Ideally ,6-12 teeth should be in contact with the work;24 teeth in the work is too many.

Feed Pressure

Chips tell you what is happening with your feed pressure and your blade.Powdery or fine chips indicate that not enough feed pressure is being applied.Heavy,thick or blue burned chips mean you're pushing the blade too hard, creating too much heat and load for the teeth.Loosely curled chips tell you everying is going well.Speed should be determined by the class of material(this should remain constant.)Feed would be adjusted until desired chip formation is achieved.