Circular saws are the most popular and technologically advanced sawmill equipment. They are used for sawing logs, logs, boards and slabs. In sawmill industry they are used for longitudinal and cross cutting. In woodworking, they are used for sawing at an angle in the direction of the wood fibers.
The circular saw equipment is structurally simple. All inertial forces are balanced. High cutting speeds and feed rates ensure quality surface finishes.
Circular saw machines consist of a saw part with a feed mechanism. On a metal frame the saw and feed mechanisms are mounted. The equipment has a rail track with driving drums and blocks to move the cart by means of a steel cable. For quick securing of a log and its lateral feed the cart is equipped with special devices.
All circular saws are divided into two types:
- For sawing medium and large wood;
- For sawing small-sized timber.
The equipment of the first type is also capable of sawing thin-diameter logs. Generally speaking, circular saws for sawing medium and large-sized woods are equipped:
- One large-diameter saw with which logs up to 60-70 cm in diameter can be sawed;
- Two saws set in one vertical plane one above the other, thanks to which it is possible to saw 90-100 cm logs.
- The saws have a diameter of 1000-1650 mm.
Log feeding scheme in the circular saw machine is identical to that in the band saw machine. Although circular sawing machines are much simpler than band sawing machines in terms of construction, equipment and saw care. However, circular saws give a fairly large kerf, due to the fact that a stable saw position is achieved with a sufficient saw thickness, which is 4-6 mm. In addition to circular and band saws, saws with inserted teeth that make an even larger kerf are used. Common large-diameter saws, for example, have a kerf of 6.4 – 7.2 mm and claw-insert saws have a kerf of 6 – 9.6 mm. Therefore it is more reasonable to use such machines according to the scheme: obtaining thick bars on circular saws – cutting of bars into boards on dividing machines with small kerf, band-saw or sawing frames. With such a scheme, the yield rate of boards increases considerably.
The main difference between a circular sawmill and a band sawmill is the presence of a circular sawmill disc saw. According to the scheme of the device and work these machines are similar. The log is also fixed on the cart and is sawn in the same way as a band saw. The circular saw is generally easier to maintain than the band saw because of the slower feed speeds.