29
29
Breaking in a Saw Blade
Important:
A new blade requires a break- in period, during which time about half
the normal feeding speed should be used.
Sharp cutting edges with extremely small edge radii are required for high cutting capacity. To
achieve the optimal tool life we recommend breaking-in the blade accordingly. The correct
cutting speed is determined by the material being cut and its dimensions. It is very important
that the new blade is first used with only 50% of the determined feed rate. This will avoid micro-
breakages of the blade because of too large chip thicknesses. New saw blades may tend
toward vibrations and vibration sounds. In this case a slight reduction of the cutting speed (feed
rate if the saw is a single rpm machine) is helpful. With small workpiece dimensions
approximately 300cm² of the material should be cut for breaking-in. If large work piece
dimensions are to be cut we recommend a breaking-in period of about 15 minutes. After
breaking-in you may slowly increase the feed rate up to the determined value.
Coolant
The cooling fluid ensures that the blade teeth and material in the area of the cut do not
overheat. The fluid must be an excellent lubricant so as to prevent abrasion of the teeth and
welding of the chips to the teeth (seizing).
Blade structure
For non-ferrous metals, it is common to use circular
saws with a brazed hard metal HM cutting edge,
consisting of a disc made of alloy tool steel (71Cr1) on
which the shape of the teeth and the seats for the
cutting edges are made of Widia K10. These saws have
shown excellent wear resistance but low resistance to
impact, which is in any case a minor problem with non-
ferrous materials.
Types of blades
In addition to the size and pitch of the teeth, the blades also have different geometric
characteristics in accordance with their particular use:
tooth cutting angle
– may be negative or positive
tooth sharpening
– may be BW with an alternate raked tooth or C with a roughing tooth raked on
both sides and a non-raked finishing tooth
tooth pitch
– the distance between the crest of one tooth and the crest of the next tooth (tooth
pitch = T)
