HM circular saw blades are specially manufactured for the accurate and economical cutting of materials.
The sharpening duration is 200 times higher than conventional blades in high-speed steel (HSS).
It greatly reduces the loss of time caused by the change of the blade and gives you the best production continuity.
The precision and quality of cutting finishing is optimized in a way thatit doesn't need specific adjustments or retouchings of custom-made cutting.
How we make circular blades
The tungsten carbide tipped blade is a high quality product. The body of the blade is made with the best hot-laminated steel, hardened in oil to enhance its mechanical qualities.
With following mechanical operations the body blade is toothed, according to the type of use (see the paragraph "choice of the teeth") and grinded on both sides of the circular blade.
The next step is to level and tension the body to give to the blade a perfect circularity and rotation stability, in order to reduce oscillations on centesimal tolerances.
The toothed and finely worked body blade is ready for the "loading" of carbide inserts (tips).
The cutting is performed exclusively by tungsten carbide, created around 1920 in German laboratories: it is a sintered product composed of approximately 92% of Wolfranio powder and 8% of Cobalt powder, although other types of metal powders (eg. titanium) can be integrated in some different applications.
The choice of the hard metal for the production of the circular blade is made according to the characteristics of the material to be cut: the metal must be sufficiently tenacious to counter the hardness of material to be cut and resist to the "impacts" which each tooth is subjected.
Another main aspect of the circular blade is the perfect balancing and tensioning of the body blade.
The circular blade must be perfectly balanced, in order not to have "unbalanced masses" during the rotary motion, which would that could cause negative vibrations for quality and sawing machine's functioning cutting.
The geometry of the teeth is of various shapes, chosen according to the mechanical characteristics of the material to be cut.
For the choice of cutting angle (positive / negative) you can use the following guidelines:
Choose the number of teeth
- Negative cutting angles: Suitable for manual feed cutting. The negative angle of the tips "rejects" the material, consequently the cutting is carried out by "compression" of the tooth on the material, because of the manual feed. In this way dangerous recoils on the tooth are avoided, since the cutting edge is not "wedged" in the material.
- Positive cutting angles: Suitable for automatic feed cutting. The positive angle of the tip wedges into the material, the automatic feed allows a stable speed without "tears", as in the case of manual use, allowing a greater finishing of the cutting quality.
When it's time to choose the number of teeth you have to consider different elements:
Modality of blades' use
- Type of cutting: If the cutting is done manually, a distance of 13 - 15 mm between the top of the teeth (tooth pitch) is sufficient. If the cutting is done automatically, perpendicularly to the material, the distance of 9 - 13 mm between the teeth is the most suitable. According to what stated above, the choice of the circular blade depends on the material thickness and feed speed.
- Feed speed: If you cut perpendicularly to the material and you want the less splintering or burr, it is valid the following rule: high feed speed requires a bigger number of teeth, although it is important to not increase the total cutting pressure choosing a blade with too many teeth. In any case the number of teeth can't be too limited, otherwise it would be a very high pressure per tooth which might cause the breaking of tooth itself or give the blade vibrations that could compromise the cutting surface.
- Thickness of the material: When it's time to choose the number of teeth in relation to the thickness of the material, you can use the following rule: blades with a lot of teeth for thin materials, a smaller number of teeth for thicker materials.
Listed below there are some elements that bring to a better use and best performance of the blades:
- During the assembly of the blade check that the flanges are perfectly flat and clean from any deposits of chips. The flanges must not have an eccentricity higher than 0,02 mm.
- When the feed is automatic, it must be continuous and without sudden shocks, otherwise it would damage the blade and also would compromise the quality of cut.
- The material to be cut must be firmly placed on the working table (so it won't bend) and must be held on the table by special presses.
- The perfect feed is neither too slow nor too fast. You can use a high feed for small sections with a thickness from 0,8 to 1,5 mm, and a less fast feed with sections from 1,5 to 3,0 mm.
- Handle the blade with care: never hit the edge against hard objects, do not place the blade on an iron table or on iron objects, do not cut iron objects or any other material not provided.
- When you cut soft and pasty materials, the blade must be cleaned frequently.
- For a perfect cut it's essential that the circular blade is well lubricated, in order to facilitate the sliding of the chips from the tooth groove. You must follow the technical reccomendations given by the sawing machine manufacturer, about the modality and the type of lubricant indicated.
- Let the blade speed up before start cutting. Do not stop the engine before the piece is completely cut.
- When you see that the blade has lost the "cutting edge", proceed with the re-sharpening of the same.
The re-sharpening is an important operation for the perfect maintenance of the circular blade: when perfectly re-sharped, the blade performance will be very similar to it first use.
A correct sharpening can be evaluated according to the following rules:
- The surface of the cutting edges should be symmetrical, without "scratches" and without splinterings.
- Broken or missing teeth affect the blade performance.
- The original cutting angles of teeth must be accurately followed by the sharpener.