WOODWORKING & BUILDING. technical information

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1 WOODWORKING & BUILDING technical information

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4 14 - TECHNICAL INFORMATION TECHNICAL INFORMATION PAGE SAFETY STANDARDS CUTTING MATERIALS QUALITY CUTTING SPEED FEED SPEED ROTATION SENSE WITH RESPECT TO THE FEED ROTATION SENSE AND WORKING POSITION CUTTING SENSE WITH RESPECT TO THE GRAIN OF THE WOOD CUTTING EDGE GEOMETRY ADDITIONAL RECOMMENDATIONS

5 ACCIDENTS PREVENTION WITH WOODWORKING CUTTING TOOLS The use of the woodworking cutting tools is potentially dangerous due to the high spindle rotation speed and the large cutting angle of the blades. The prevention and the reduction of the accidents during the machining with the cutting tools is a permanent objective for the machine and for the cutting tool manufacturers, and has been obtained by means of the use of: SAFETY STANDARDS Concerning this last paragraph, the CEN (European Committee for Norms) has established the series of norms EN 847, part 1 to 3 Woodworking cutting tools Safety technical requirements referred to The minimum requirements to consider safe the tool according the most updated technologies are in two types: design to reduce the backward movement. By limiting the size of the slitting and the projection of the blade with respect to the body, the TOOLS FOR HAND FEED Manual feed is understood when the feeding is generated manually, even if mechanical clamping devices are used. During the manual feed works, on spindle moulders and similar machines, the backward movement of the parts is particularly dangerous. By measuring the backward speed, after a large number of tests, the backward speed of the wood and Vs the cutting speed of the tool. There are two type of tools which meet these conditions: 1) Tools for hand feed with a limiter or counter-blade. Max 1.1 Smax 2) Tools for manual feed without a counter-blade (round shape). Max 3 In accordance to the European Standard EN 847 all tools suitable for manual feed are marked with the MAN sign.

6 SAFETY STANDARDS TOOLS FOR MECHANICAL FEED Mechanical feed is understood when the feeding and the movement of the parts are completely mechanical, without the intervention of any operator. The manufacturing characteristics of these tools are as follows: In accordance to the European Standard EN 847, these tools are engraved with the MEC sign. CIRCULAR SAW BLADES For the circular saw blades equipped with hard metal inserts and with a cutting width of less than 4mm, these differences about the feed system do not apply, as the performance of a circular saw blade is different at the cutter. The circular saw blades can be used for either manual or mechanical feed.

7 CUTTING MATERIAL QUALITY The ideal cutting material is the one that at the same time is very hard and tough. Being these characteristics on the opposite side, the cutting material has to be selected, based on the working material, among a different range of qualities, from the soft and tough ones (alloyed steels) up to the fragile and hard ones, as the diamond. These are the characteristics of the main qualities of the cutting materials: HL SR Steel for high alloy tools (more than 5% alloy). Used for blades and mono-block tools. The sharpening is done with borazon or corundum grindstones. HSS High speed steel with cobalt, chromium, molybdenum and vanadium alloys. It is not suitable to be used with abrasive wood or chipboard panels. The sharpening is done with borazon or corundum grindstones. TN The tantung is a material with a high cobalt content (45-50%). Its characteristics are in the middle between the HSS and the HM. It has the toughness of the HSS and is nearly as hard as the HM. It is suitable for hard and semi-hard woodworking. woods. Dueto its high cobalt content, very good results have also been observed in tools for copying machines. The sharpening is done with borazon or corundum grindstones. HM-HW HARD METAL The hard metal or tungsten carbide is a high hardness sintered material to be used to machine all type of materials, due to the different hardness of the several HM qualities. The main component and the one that the hardness comes from are the tungsten carbide grains The evolution of the qualities of the hard metal in the last years come from the grain reduction (micro- increased hardness. Nowadays, the hard metals are suitable for a wide range of applications, from the soft woodworking with knots to the panels. of binder, in order to obtain a greater lifetime, from 2 to 6 times in materials like the MDF, agglomerate, Due to this wide range, it is very important, when the HM tool are demanded, to let us know the type DIA-DP POLYCRSTALLINE DIAMOND substrate. It is mainly used to work on abrasive materials (wood derivates, plastics and aluminium). It is suitable, also, for knots free solid woods. By means of the variation of the size of the grain, the toughness and the resistance to the wearing greater to the one obtained with hard metal inserts, according to the type of work and the material to be machined.

8 CUTTING MATERIAL QUALITY CUTTING MATERIAL QUALITY MKD DP-DIA Material de corte ideal Dureza Metales duros de granos ultra-finos Tantung (TN) Metales duros (HM) HS (HSS) Tenacidad/Resistencia a la flexión

9 CUTTING SPEEDS (V) The cutting speed is related to the diameter of the tool and the spindle rotation speed of the machine (r.p.m.). For manual feed tools, the cutting speed range is between 40 and 70 m/s. For less than 40m/s rotation speed, the backward increases, with the consequent additional risk. The attached diagram relates these three concepts. By means of the two selected parameters: the diameter of the tool (D=mm) and the cutting speed (Vc=m/s), we obtain the spindle rotation speed (r.p.m.). By means of the two selected parameters: the spindle rotation speed (r.p.m.) and the cutting speed (Vc=m/s), we obtain the diameter of the tool (D=mm). The diagram curves are based on the following formulas: Recommended cutting speeds (m/s): CUTTING SPEEDS (V) Cutters and Cutter Heads Saw Blades HSS HM-DIA HM-DIA Soft wood Hardwood Agglomerated panels M D F HPL and veneered panels Hard plastic panels Solid aluminium Al, Mg, Cu alloys D= Diámetro en mm v = Velocidad de corte en m/seg Example To determine the diameter of a cutter for tropical hardwood: Selected cutting speedy: 50m/seg. Machine: spindle moulder, at r.p.m. Answer: 160 mm. D Diameter in mm. n = Rotation speed in r.p.m. v = Cutting speed in m/ sec. n= Velocidad de rotación en r.p.m.

10 FEED SPEED CUTTERS AND CUTTERS HEADS (r.p.m.), the number of teeth (Z) and the feed per tooth Sz (mm) parameters. U=Sz*n*Z/1000 The attached diagram relates these three concepts for cutters and cutter heads. Recommended Sz: Finishing: 0,8 2,5 mm. Roughing: 2,5 5 mm. Sz= mm. Avance por diente 3,0 2,5 2,0 1,5 1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,15 0, U = Velocidad de 60 avance en m/min n= Velocidad de rotación en r.p.m Z= Número de dientes

11 FEED SPEED SAW BLADES (r.p.m.), the number of teeth (Z) and the feed per tooth Sz (mm) parameters. U=Sz*n*Z/1000 The attached diagram relates these three parameters for saw blades. Recommended Sz: Longitudinal softwood: 0.2-0,9 mm Cross softwood: 0.1-0,2 mm Hardwood: ,15 mm Panels: ,25 mm Al, Mg, Cu Alloys: Sz= mm. Avance por diente 0,30 0,20 0,15 0,10 0,09 0,08 0,07 0,06 0,05 0,04 0,03 0,02 0,015 5 U = Velocidad de avance en m/min n= Velocidad de rotación en r.p.m Z= Número de dientes

12 ROTATION SENSE WITH RESPECT TO THE FEED COUNTER-FEED ROTATION This is the main utilized system: the tool rotates against the feed, obtaining a long, thickness increasing chip, and it is the only way to work with manual feed. The advantage is that the cutting edges of the tools last longer. The disadvantage is that splintering is produced working against the grain. FEED-WISE ROTATION It is only used with mechanical feed. The disadvantage is that there is a lot of wear on the cutting edge, due to the greater contact time with the material. The feed is carried out with less strain, and higher feed ranges can be utilized, obtaining the same surface quality as working on counter-feed rotation. As the feed-wise rotation need a larger cutting angle, it is necessary to specify in the order that the machine spindle will rotate with feed-wise.

13 ROTATION SENSE AND WORK POSITION A) DRILL BITS ROTATION SENSE Drill bit rotation is either clockwise or counter-clockwise as indicated below. DCHA. IZDA. RIGHT Right-hand thread Clockwise turning, looking from the upper part. LEFT Left-hand thread. Counter-clockwise turning, looking from the upper part. CUTTERS AND CUTTER HEADS Mistakes are quite often made when indicating the sense of rotation of a tool. This type of errors will be minimized if we take the direction of rotation looking at the tool from the drive (where the motor is). This means: However, and in order to eliminate confusions, these are the most usual working positions: Counter-clockwise rotation. Bigger diameter down. Regular position in vertical spindle moulder. Clockwise rotation. Bigger diameter down. Counter-clockwise rotation. Bigger diameter up. Clockwise rotation. Bigger diameter up. Giro contrario a las manecillas del reloj. Posición normal en máquinas de eje horizontal. Clockwise rotation. Position to rebate panels in horizontal spindle machines.

14 CUTTINGSENSE WITH RESPECT TO THE GRAIN OF THE WOOD For solid wood milling, there are four ways of cutting with respect to the grain of the wood: A1: Along grain longitudinal cutting. Favourable cutting A2: Counter grain longitudinal cutting. Unfavourable cut- B: Grain cross cutting. Favourable cutting conditions. C: Cross cutting. Unfavourable cutting conditions. Rough

15 CUTTING EDGE GEOMETRY A: CUTTERS AND CUTTER HEADS H = Cutting width B B: SAW BLADES H = Cutting thickness D B

16 ADDITIONAL RECOMMENDATIONS be observed: MACHINE of the saw blade THE CUTTING TOOL glues adherences and the interfaces between the machine and the tool, prior to the assembly, by using solvents that does not affect the tool, in order to maintain the concentricity and the precision. If deep detachable cutting edges that reduce the attack angle, avoid the right chip relief and damage the quality surface. the tool. has to be controlled. utilized without a reducer ring. and more wearing.

17 MODIFYING MODIFYING HOLES AND SHANKS. KEYWAYS The prices for modifying holes and shanks and machining keyways on the Tools are as follows: INCREASING HOLE SIZE CUTTERS AND CUTTER HEADS: CIRCULAR SAW BLADES: REDUCING SHAND SIZE KEYWAYS (unit) CUTTERS AND CUTTER HEADS: CIRCULAR SAW BLADES:

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