In the field of metal sawing and processing, when users face the choice of sawing and processing methods, they often ask a question: "Which processing method is best for my situation? Choose a band saw or a circular saw?" The business development or cost control may be affected in the long term.

Band sawing has always been regarded as the main processing method of metal sawing. Over the years, many subdivisions of this sawing technology have made great progress, such as:

✦Bundle sawing technology, feed control technology using servo drive

✦Adopt gear motor to realize low speed and high torque sawing main drive technology

✦CNC technology for repetitive work

✦High-precision high-speed hard alloy band saw blade manufacturing technology

✦High-precision sawing processing technology for difficult-to-cut materials

The above items only represent some of the functions and advantages of today's band saw technology development.

If the circular sawing machine is used with a good quality cold saw blade, it has the characteristics of high sawing precision and high sawing efficiency.

The most basic manual circular sawing machine can be used for simple and small batch sawing of a variety of materials, while the automatic closed circular sawing machine is very suitable for large-scale production, and the material specifications and processing types are relatively single application scenarios.

A few years ago, it was easier to choose the answer between a circular saw and a band saw. High-volume, high-volume applications may require the use of circular sawing machines, and if workpiece accuracy is not critical, then a cheap band sawing machine may be sufficient. But today, due to the development of band saw technology, the answer is not so clear.

What is certain is that in some application scenarios, the circular sawing method is more economical and effective, especially where high processing accuracy and high efficiency are required. Although this equipment is expensive, circular sawing with cold saw blades with carbide tips can significantly improve sawing efficiency.

However, from the current development trend, the application fields between these two sawing technologies have begun to cross each other. Disc heft can still provide high-speed and high-precision sawing; in the long run, the initial investment of band saws is less, and it has greater flexibility in sawing capacity, multi-layer sawing and bunch sawing methods, and currently A high-quality carbide band saw blade coupled with a good-performance band saw machine may also meet or exceed the workpiece accuracy and production efficiency indicators that only circular saws could achieve in the past. For example, in the application of sawing and processing of aluminum ingots, the current trend is to gradually replace sawing by circular saws with high-speed band sawing.

1

Influence of material type and material specifications on two sawing methods

Ask yourself the following questions first:

What is the diameter of the sawing material?

Types and grades of materials to be cut?

Which material is most commonly sawed?

Saw solid heartwood or pipe or both?

Will future projects change demand?

Are you planning to provide other material models and specifications for the new market?

Generally speaking, the maximum diameter of circular sawing machine is between 100 and 150mm. If the diameter exceeds 150mm, whether it is measured from the perspective of function or cost, the band sawing machine should be selected for processing.

Workpieces with a diameter between 25 and 100 mm can be processed using either a band saw or a circular saw. The method chosen depends on various influencing factors. In the cold cutting process, if the workpiece needs to be fast-in and fast-out, some common steel types such as medium and low carbon steel, low alloy steel, tool steel, easy-cut stainless steel, and aluminum are more suitable for processing by circular sawing machine, because these materials It is cut quickly by the circular saw, and it will not affect the machining quality due to excessive heat and friction leading to premature wear of the cutting edge. However, for difficult-to-cut materials such as nickel-based alloys and titanium alloys with low cutting efficiency, more heat and friction will be generated during cutting. When using a band saw with a much larger number of tooth tips (a conventional type of belt) The saw has 300 ~ 400 teeth, and a circular saw only has dozens of teeth to hundreds of teeth). Because each tooth tip has a longer "rest" time during operation, this processing method is more conducive to control The temperature of the tool, so this difficult-to-process material is more suitable for cutting with a band saw.

2

Production demand analysis in history, present and future

You need to know the following information in this regard:

Hourly, daily, weekly or monthly?

Are these long-term, production-oriented, short-term or accidental cutting? Will production demand shift to mass production in the future?

In any case, what is the size, grade and quantity of material to be cut?

At present, the band sawing technology has developed advanced multi-layer sawing and bundle sawing functions, which can realize high-efficiency and high-precision sawing of small-sized workpieces. If multi-layer sawing technology is used, then the band saw can be comparable to the production efficiency of circular saws. On a standard circular sawing machine, it takes only 10 seconds to cut each piece of Q235 round steel with a diameter of 50mm, but if five 50mm Q235 round steels are placed on a band sawing machine, the band sawing machine can also process within 70 seconds After completion, this cutting efficiency is almost the same as the efficiency of the circular sawing machine, and may also meet the production needs. If a high-quality band saw blade is used to set the band saw tension higher on a double-column band sawing machine with good rigidity and stability, and a constant control technology for the cutting load per tooth is used for sawing, the workpiece tolerance and consistency can also be It has been greatly improved.

Through multi-layer or bundle sawing, the feeding time can also be greatly reduced. If you are using bundle sawing, please carefully consider the fixture design. In fact, by using special jigs, circular saws can be bundled and cut, but only for sawing small diameter workpieces. As for sawing larger diameter workpieces in a bundle, band saws are still the only option. Saw cutting of bundles of square or rectangular tubes may only require horizontal clamping, while sawing of round bar stock will require clamping in both vertical and horizontal directions, which in some cases will reduce the sawing capacity because The fixture will occupy part of the space in the work area, while leaving less space for the material itself. Nevertheless, the best clamping method is to use both horizontal and vertical fixtures to reduce vibration during sawing, because excessive vibration will greatly shorten the life of the tool.

3

Analysis of the accuracy requirements of the processed workpiece

What are the tolerances for the length, flatness and consistency of the final product?

Is secondary processing required?

What are the quality specifications of the finished product?

If the accuracy is improved, can secondary processing be cancelled, thereby saving processing costs?

If a circular sawing machine uses a cold saw blade of good quality, the surface of the workpiece cut by the saw is very smooth, and the burrs on the edge of the workpiece will not exist. But compared to the current band saw technology, this may not have any obvious advantages. Now, some high-end band sawing machines use servo-driven ball screw feeding instead of traditional hydraulic feeding, and are also very precise in length tolerance and repeatability control. These ball screws on high-end band sawing machines enhance the precise positioning of materials by improving the machining accuracy during sawing and eliminating backlash after sawing.

4

Cutting type analysis

Does the material need to be corner cut or bevel cut? If so, how much angle do you need to reach? What percentage of the workpiece to be angle cut and bevel cut? Do you need to control these processes automatically?

If a large number of corner cuts are required, multi-layer sawing or beam sawing is not feasible in conventional horizontal band sawing machines. At this time, the cutting efficiency of the circular saw and the band saw can be compared piece by piece. If the number of corner cut workpieces is limited, you can choose a horizontal angle miter band sawing machine suitable for small-sized workpieces.

5

Long-term solution

Try to review the current and future sawing needs. Management and procurement personnel may consider current expenses, while manufacturing and operations personnel may consider the long-term productivity of the machine, both of which are important. Based on the company's current financial situation, it is important to consider whether it is important to control the initial purchase cost or whether the machine's long-term financial investment returns.

If the input and output of a fully automatic band sawing machine is compared with a fully automatic circular sawing machine, the cost of the former is significantly lower than the latter. The most scientific cost evaluation method is to use a cost calculation formula instead of simply comparing equipment prices. When calculating the cost, it is necessary to consider whether it is a single piece of sawing or a bunch of sawing? How many classes do you have every day? What is the daily output? Is the circular saw blade reground? A large amount of empirical data shows that the cost per square meter of material cut by a band saw is relatively low. Taking Q235 material 50mm bar sawing as an example, the cost of band sawing is about 492 yuan per square meter, while the cost of circular sawing is about 793 yuan per square meter. However, if the circular saw blade regrind is considered, the unit cost of circular sawing will gradually decrease with the number of regrinds.

The cost calculation must consider the operating cost (including power consumption) and the cost of single sawing (labor and consumables), as well as the preparation time. Based on the number of processes and other factors mentioned above, it is possible to calculate how long it will take to compensate for the initial investment of the equipment by improving production efficiency and the cost savings per saw

In the calculation, it is necessary to understand the production demand trend, so that the calculation result will be a good help in measuring what kind of sawing processing method is used to process the product.