TPT November 2019

AR T I C L E

Advanced Machine & Engineering I AMSAW

for each time when the blade is re-tipped, for a total of 40 regrinds for the life of a blade. On average, five tips must be replaced for each regrind, because the teeth are damaged beyond repair. Approximate cost of regrind (re-sharpen) carbide-tipped saw blades 24" diameter, 60 teeth saw blade:

The cost of a new blade at 24" (610mm) x 60 teeth

$390

4 times re-tipping 60 teeth = 240 tips at $3.50/tip

$840

Tool life and power consumption based on tool wear

40 x 5 teeth replacement = 200 tips at $5.35/tip (cost per tip is more due to a lower quantity)

With a new blade, the sharp edges wear more quickly at the first cuts, but later the wear of the teeth becomes more gradual. If one tooth breaks, the next one has to take a double load. If the second tooth breaks, it is a domino effect: they will break in sequence and will destroy the tooth seats, thus destroying the blade body. While every aspect points to the advantage of replaceable tipped blades, the key is the proper maintenance. This type of blade could be the most cost efficient on larger blades if it can be sufficiently protected from damages beyond normal wear. The above is basic information for quick comparisons. If you really want the best solution, more information is needed: 1. What machines are available (HP, RPM, stiffness, etc)? 2. How experienced is the saw operator? 3. What material will be cut (chemical composition, hardness, shape, etc)? 4. What are the stock sizes and length? 5. Quantity of cuts, per day, per week; and number of shifts? 6. Is the shop location close to a good blade repair shop? 7. What are the shop environments (quality of maintenance, operators, etc)?

$1,070

40 times regrinding at $54

$2,160

Re-tensioning and other general maintenance at each regrind process 40 x $10/blade (approximate cost $10 per regrind)

$400

Total cost for a blade (Assuming free shipment by the blade repair shop)

$4,860

Average tool life 15,000 square inches (9.7m 2 )/blade for one usage. Total tool life for the life of a blade =

$0.008/ square inch ($12.637/m 2 )

15,000 x 40 = 600,000 square inches (384.6m 2 ) Average cost per square inch of cut for 24" – 60 teeth re-sharpened saw blade ($4,860/600,000)

Approximate cost of one-way blades A one-way 24" (610mm) diameter saw blade has less chip load per tooth; therefore it will have more teeth (about 80) to get a better performance. The gullet size also shrinks, and chip breakers are used to avoid problems with jamming. More teeth and a smaller chip load result in a better surface finish and less burr.

8. What is the required cutting rate? 9. Is the machine fully automatic? 10. Unattended operation required? 11. Operator controlled production? 12. Is material loss due to wider kerf critical? 13. Is a new saw needed?

Approx. cost of a 24" – 80 tip 0.12" (3mm) kerf (tooth width)

$461

Tool life is much higher due to the coating, and is about 50,000 square inches (32m 2 ) The cost per square inch is ($461/50,000)

$0.009/ square inch ($14.4/m 2 )

An in-depth discussion with a saw expert will give you the best answer.

Although the basic cost for a one-way blade is more expensive, the convenience of easy handling justifies the higher cost. The cost advantage with smaller blades is in favour of one-way blades. Approximate cost of replaceable carbide-tipped circular saw blades Replaceable carbide-tipped circular saw blades are generally much more expensive. The best justifications for these types of saw blades are the savings of shipping and handling costs, and the higher tool life due to the coated teeth. Small blade sizes with replaceable teeth are too expensive for most applications because of the more expensive blade body and material waste due to the wider kerf.

Advanced Machine & Engineering I AMSAW – USA 2,500 Latham Street

Rockford, IL 61103, USA Website: www.amsaw.com

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NOVEMBER 2019