Circular saw blades are an integral part of every sector of the woodworking industry, from forestry to the manufacture of timber framed housing and windows. They come in a wide variety of sizes and tooth geometries but all have one thing in common – they all need regular sharpening to keep them performing at their best.
In 1996 the German company Walter introduced its first saw grinding machine, the NC3, and has subsequently developed a range of machines for the automatic, CNC-controlled grinding of saw blade teeth.
Central to this development is the Woodtronic CNC 5D which can produce or regrind circular saw blades of 80mm to 1000mm diameter, up to 12mm thick and with tooth pitches of 4-125mm. The CNC 5D can be fed from a three spindle loader, expanding the machine’s grinding capacity to between 100-120 blades.
Automatic running
Once programmed, the machine can then run an automated, unmanned saw blade grinding operation – even overnight if required. If the sensors on the machine identify a problem with a particular blade during unmanned operation – either an unexpected diameter or wrong tooth geometry, for example – the blade is returned to the loader and the next blade is selected. When the operator returns to the machine the cycle has not been stopped but he can see which saw blades, if any, have not been reground. Details of the blade’s reference code and the problem are displayed by the software package.
Because side face cutting has a significant effect on the cutting ability of a saw blade, Walter has developed the Woodtronic CNC 6F for the specialist production of side faces. Up to five Woodtronic CNC 5D tooth face/top grinders and Woodtronic 6F side face grinders can be linked using the company’s production loader facility to allow the automated processing of any type of saw blade tooth geometry.
Each saw blade is first processed on the CNC 6F for side face grinding and is then transferred to the CNC 5D for tooth and top grinding. This system offers carbide-tipped circular saw blade manufacturers an innovative solution while at the same time keeping production costs to a minimum. The saw blades are loaded onto trolleys which are located at the front of the machines, and transportation of the blades from the loading trolley to the grinding machine is handled by a four-axis robot system. All the machines, in whatever combination has been chosen, are controlled from a single, Siemens-based, CNC control panel running Walter Window Mode software.
While the Woodtronics are supplied as standard with a series of software programs covering the major tooth blade geometries, the system additionally features a free programming facility which allows operators the option of creating their own programs for any tooth shape or combination of shapes for any blade diameter. Programming can be carried out while the machine is performing another task, as is to be expected these days, and a modem link is also available if required for remote programming or maintenance.
Low-cost measuring
Accurate, low-cost measuring of any rotating tool has long been a priority in many industries and Walter has responded to this demand recently with the launch of the Heli Tool-check. This simple-to-operate, non-contact measurement system can handle tools up to 300mm diameter and 500mm long and gives a repeatable measuring accuracy of ±2 microns in both manual and automatic mode.
With X, Y and Z axes of 310mm x 290mm x 600mm, and 60 rpm in the rotational axis, the machine is designed for the measuring of cylindrical and conical shank-type cutters and drills. Resolution in all linear axes is 0.2 microns and in the rotational axis, is 0.0025O.
The Heli Toolcheck uses a pair of CCD matrix cameras to measure tooling via direct/incident light. Direct light is used for measuring external contours and for defining end geometry, land width and radial angle, while incident light is used for cutting edge position and definition of flute depth. The Toolcheck’s Quick Check software allows the automated production of a measuring program, enabling users to measure tools without set points. All parameters are shown and selection of the desired geometry automatically generates the correct measuring program.
