Selection of tooth pitch, tooth profile and band saw blade product series for thin-walled pipe sawing

The blanking of thin-walled pipes can be processed by sawing. Since the sawing incision is very narrow (compared to the grinding wheel, it reduces material loss by 60%), and it can be automatically sawed in bundles, so sawing is used. The processing method is an economical and high-efficiency pipe cutting processing method. However, how to choose saw blades and how to choose sawing parameters to reduce sawing costs are problems faced by every customer.

Because the geometry of the workpiece is very complicated, pipe sawing cuts solid material when it enters the knife, and when it comes out of the inner wall, it is hollow. Its intermittent cutting frequency is much more than that of solid wood, and it is produced during sawing. The vibration is several times greater than that of solid wood, so sawing thin-walled pipes consumes more saw blades than solid materials of the same material.

When we use the saw blade, if we pay attention to the reasonable selection of the saw blade series and the reasonable selection of the parameters and the installation of the saw blade, the sawing cost can be reduced.

1. Tooth pitch selection
Tooth pitch selection: If the tooth pitch is too large, it may cause teeth pulling, tooth tip bending and deformation, and tooth tip bluntness in advance. But if the tooth pitch is too small, then the distributed load of each tooth is too small, or they may not be able to cut in, or the cutting amount is small, the sawing efficiency will decrease, and because some materials have a tendency to work hardening, If the number of teeth is too large, the processing performance of the material may be reduced, and the selection of the tooth pitch may also cause chip removal failure. For reasons such as the above, the manufacturer generally recommends the principle of 3~24 teeth contacting the workpiece at the same time (if it is a tensile tooth series, the principle of more than 2 teeth can be used). Within this range of the number of teeth, the vibration is within the range that the saw blade can bear, the cutting depth of each tooth is relatively deep, and there is a large enough chip space.

2. Tooth shape
If the tooth pulling is severe during sawing, you should choose a tooth profile with better tensile resistance (tooth resistance to impact), or choose a relatively small tooth pitch. In Taijia’s typical product series, there are the following tooth shapes to choose from:

This series doubles the strength of the weld by extending the weld between the tooth material and the backing material. When a tooth is pulled, it will not cause the subsequent tooth to fail like a domino effect at the same time. The tooth profile is distributed as follows:

The vibration generated when cutting pipes, I-beams and profiles with a band saw blade that saws solid heartwood will greatly shorten the service life of the band saw blade and reduce the cutting area. The strengthening of the welding seam strength between the tooth material and the backing material enables the tooth part of the band saw blade to withstand the overload operation caused by the vibration caused by the discontinuous cutting, and can effectively prevent the phenomenon of tooth pulling. Its special tooth division method It also reduces the vibration in sawing and prolongs the fatigue of the band saw blade.

If the customer’s sawing site is equipped with well-equipped fixtures, the phenomenon of tooth pulling is not common, and cutting is a common failure method. You can also choose a small pitch product with a 0 degree angle for sawing.

The weld strength of this tooth profile is not as great as the first two tooth profiles. Since a smaller tooth pitch is selected, the number of teeth on the material to be sawed by this tooth profile can be greater than that of the above two tensile teeth. Therefore, the vibration during sawing is reduced to varying degrees. At the same time, because the clearance angle is larger than the former two, the tooth wear resistance will be strengthened. This tooth profile is easy to wear to the tooth tip, and It is a better choice for situations where it is easy to cut diagonally. Some customers who saw thin-walled stainless steel pipes and alloy steel pipes prefer this type of tooth profile. Note that when choosing this tooth profile, the tooth pitch should be one or two smaller than the tensile tooth. For example, if you use 4/6 anti-tension teeth, this kind of tooth profile uses 5/8 teeth or even 6/10 teeth. The rough reference data for choosing this tooth type is as follows (because there are too many series, it is impossible to provide like the two tables above).

3. Selection of brand series and consideration of product stability
The choice of brand series is closely related to the cutting efficiency you expect. If you are not so demanding on sawing efficiency, you only need 15-20 cm2/min efficiency for the average 5mm thick Q235 pipe, then you can choose the economical PROCUT-FT (the anti-tension tooth in the original Feiju series) ) Yes, if you require high-efficiency sawing, or the material to be sawed is difficult-to-process pipes such as stainless steel pipes, it is recommended to use a series with higher back edge strength such as PROCUT-EX (formerly Taiju series tensile teeth) or PROCUT -AA (formerly A series anti-tension tooth) series (the former has higher performance than the latter).Another very important potential factor affecting the cost of brand series selection is product stability. If the geometric accuracy of the band saw blade is not well controlled in the production and processing, it will cause the tooth load to fluctuate or the amount of tooth division is unstable. When sawing, there will be phenomena such as failure of the pull tooth or a significant reduction in the life of the band saw. Therefore, when choosing a band saw brand, users should pay particular attention to the good and bad discrimination of the band saw blade manufacturer.

4. Sawing speed
The sawing speed must be set to match the workpiece and tooth profile. Too fast belt speed may cause tooth tip overheating, reduce tooth tip hardness, premature passivation, and cause cutting problems when sawing high strength materials or workpiece hardening . A too slow speed not only reduces the sawing efficiency, but may also increase the cutting depth of each tooth, causing the workpiece to rotate, and the phenomenon of tooth pulling is likely to occur. The sawing speed needs to be adjusted appropriately according to the material material and the size of the sawing workpiece.

5. Feed force
Feed force is one of the decisive factors that determine cutting efficiency. Insufficient cutting force may reduce sawing efficiency and may also cause work hardening. If the feed force is too large, the result will be the same as slow speed, and it will easily cause the workpiece to rotate and cause the saw blade to pull teeth. For sawing materials with different wall thicknesses, in addition to adjusting the sawing speed according to the material material, the thinner the material is sawed, the lower the sawing speed and efficiency are used, and the thicker the material is to be sawed. Slightly higher sawing speed and sawing efficiency.

In addition to the above factors when cutting thin-walled pipes, attention should be paid to the correct use and maintenance methods of cutting fluid, sawing machine, and jigs. For other cutting knowledge, please contact the sales engineer of ANTS MACHINE EQUIPMENT.