The life of a bandsaw blade shortens due to things like cutting speed, depth of cut, chip thickness, tooth geometry, the materials being cut, cutting fluid, and machine rigidity.
The physical and chemical properties of the materials will also influence bandsaw blade life by modifying stability and wear rates.
Blades are designed for high heat, abrasive materials, and entry/exit shock, and ironically, these are the very things that help to reduce blade life.
Other variables to shorten or prolong bandsaw blade life include:
The operator — the one with at least basic knowledge of all the other life-span variables. The person operating the bandsaw machine can work to either shorten blade life or help maintain it depending on knowledge, skill, and interest in quality output.
Proper break-in will prevent stripping and assure longer blade life. With any new blade, first reduce the normal feed rate by ½ and then gradually increase the band speed until the desired cutting rate is achieved.
Horsepower (hp) rates will determine the band’s ability to cut through certain types of materials.
Blade quality varies depending on the manufacturer and type, including carbon, bi-metal, or carbide-tip bandsaw blades.
Buyer beware and you get what you pay for both apply in this instance.
Tooth style choice for the materials being cut is important.
- Standard (regular) teeth have a zero-degree rake angle and are featured on constant or straight-pitch blades. They should be used for general-purpose cutting of solids and ferrous materials.
- Skip tooth is similar to the standard in application usage, but the skip tooth has double the gullet capacity for larger chip clearance.
- Sabre teeth have a ten-degree face rake angle and are used primarily on soft materials that generate large chips.
- Si-pitch has a regular tooth pattern that is broken up in order to reduce noise by producing less vibration and chatter. These blade types are well suited for a wider range of cutting materials.
Tooth set choice is just as important, and they include regular, wavy, every tooth, and si-pitch designs.
- Raker teeth mean that one tooth set is to the left and one tooth set is to the right, with a third raker tooth unset or straight. Their primary use is in general-purpose cutoff and contour cutting.
- Wavy teeth are set alternately left and right in a wave-like pattern. This design is meant to help reduce strain on individual teeth. Their primary function is for use in cutting thin stock on a variety of shapes.
Tension needs to be ideally set in order to achieve straight cuts throughout. Using a tension meter will help. Most blades work best at tension set to a minimum of 25,000 p.s.i. and a maximum of 32,000 p.s.i.
Proper band speed will influence blade life and needs adherence throughout the cutting process.
- The rate at which the blade moves across the work is measured in feet per minute (fpm) or meters per minute (mpm).
- Excessive speed on hard materials results in friction and premature dulling of teeth.
- Insufficient speed causes ineffective production, resulting in crooked cuts and stripped teeth.
It is always best to refer to the manufacturer’s recommendations prior to cutting.
Proper feed rate results in the smooth steadiness of the head of the saw as it drops onto the material being cut. Erratic or choppy is bad.
The use of coolants during the cutting process helps to wash chips out of blade gullets, reduces heat damage, and lubricates to prevent friction heat.
Brushes aid in the cleaning of chips from the blade gullets to prevent tooth stripping and achieve a smoother cut surface. The ends of the brush filaments should touch the bottom of the deepest gullet and not constantly rub the sides of the blade.
Checking for wheel alignment along with the bearings and flanges. Assure that the wheel flange isn’t rubbing the back of the blade and causing back cracks. Worn-out bearings and gullet cracks need to be addressed. Idler wheel adjustment should be set for proper blade tracking.
Machine condition (old, new, and well-maintained models) influences cut results. Bandsaw machines need regular maintenance for optimal performance.
Tightly clamped materials that are also set square to the cut will offer the best end results. If the material is capable of movement then the teeth are more likely to strip.
Guides support the band and should barely be able to turn by hand.
Sled are better than roller or disk when applying high pressure. They are also better at spreading the cutting force over a larger area; eliminating back-of-blade mushrooming.
Guide arms should be as close as possible to the material and firmly secured.
If the adjustable guide arm is set too far from the work, blade damage occurs.
Material hardness will reduce blade life. Materials vary in regard to machine-ability, with one type being much harder to cut than another.
Knowing the right blade for the right materials will help extend blade life while offering satisfactory production output.
A Rockwell of 40 has a machine-ability approaching 0.
Material hardness influences cutting performance.
Continuous or intermittent blade use. Different operating conditions and procedure will help to determine the right type of blade for use in such conditions in order to help achieve blade longevity.
Room temperature will modify the machine’s hydraulic fluid. Bandsaw environment affects many aspects of performance. The hydraulic fluids and heat are known enemies.