On electronic scales and not only
Unfortunately, the traditional view of a band-saw machine as a rough and very imprecise instrument for initial treatment prevents many entrepreneurs to look at all of its features. But cutting can and should be rational and economical, especially today, when every penny counts. Precise primary wood cutting allows us not only "cut out a couple of extra plates from billet", but also reduce the production cycle, eliminating some entire stages of production (such as additional processing with gauge machine or thicknesser before the finishing stage of processing).
Electronic scale can and should be used to improve accuracy and increase the effectiveness of the band-saw bench. A device allowing upright positioning of cutting mechanism to height specified by operator with certain accuracy and monitoring the process visually is called electronic scale among woodworkers. However, not all scales have high accuracy and identical functionality. Completely different devices are called with one term. Therefore I would like to explain in this article in what case it is rational to purchase machine, equipped with an electronic scale, and what to look for when choosing a machine.
Many woodworkers consider that a simple power-saw bench, without any additional electronic devices, is the most reliable. Let me disagree with such single-variant thought. Because none of you would use a hand screwdriver instead of more convenient electric one, on the grounds than there is nothing to break in it. Dear readers, the reliability of electronics and mechanical devices, hydraulic and pneumatic appliance components depends on many factors: it is the quality of components and the method of their installation, the operating conditions of power-saw bench, as well as many other factors. When you choose a band-saw machine don't be feared of electronics installed on it. You just need to balance all pros and cons while purchasing machine, like in any other cases. Therefore, we will not discuss the electronic scale as a reason for the breakdown. However, purchase of power-saw bench even equipped with quality electronics is not quite rational (purely in terms of payback) in the following cases:
- If you will operate a power-saw bench personally, carefully controlling the size of the boards sawn off and spare no time for positioning, since performance in your case is not important.
- If precise positioning of cutting equipment is not important for you, inasmuch as +\- 5 mm (sometimes more) on the board for you does not matter. If you are a representative of this category of producers - you are a business genius - because you are able to find absolutely unpretentious customer, arrange the delivery of cheap raw materials and obtain such a great profit that disappearing cubes of wood per month - is nothing worth your attention.
- Woodworking is not the main activity for you, it serves only to maintain and ensure the proper functioning of the main production, so the band-saw machine accuracy and performance is not important.
- It is not possible to operate the band-saw machine equipped with an electronic scale in foreseen conditions. Such conditions may include significant voltage drops in the network to which you connect equipment, machine operation at very low temperatures, etc.
- Current financial situation does not allow purchasing the machine with an electronic scale.
The representatives of the above mentioned categories of woodworkers need reliable, economical and ergonomic band-saw machine without unnecessary options. But if you do not belong to their category, the right choice is to purchase band-saw machine with electronic scale.
However, as mentioned above, all scales are different.
Depending on functionality, the electronic scales can be divided into several conditional groups:
The first group includes scales, working with which the operator himself adds thickness of cut to the desired size, sets the value obtained on the display and presses the button with the direction of the saw mechanism motion. These lines practically do not increase performance and help avoid operator error minimally. It is fair to say that this is really quite a simple device and it is found very rarely.
The second group includes scales with set cut thickness value during their functioning, which is automatically added to the board thickness.
Size is exposed for each board separately. Productivity increased is very slight, because the operator usually does not perform the calculations in his mind, and uses a table, but the decline of the human factor is present.
The third group electric scales have all the advantages of second group appliance, but other than the above, it has a function of forecast - entering the desired thickness the operator will see how many boards of a given size (already with given cut) can be obtained from the work piece blank (the current position of the saw mechanism assumed as absolute altitude).
For operator only remains to specify machine tool the number of boards to cut off - an electronic scale will lower the cutting mechanism in the right place as many times as needed. Operator does not need to set the size every time, resulting in increased productivity of power-saw bench, and declined ability to make a mistake.
The fourth group includes the most advanced electronic scales in terms of the functionality. They remember the so-called cutting map for the whole log - how many boards of specified size and in what sequence to saw off. Cutting maps are stored in the memory of electronic devices, a name (like a file in your computer) could be given to each map for convenience. The operator selects the desired map not wasting time and effort, thereby increases his own productivity and minimizes the chance of making a mistake.
The smaller features have the electronic scale, the cheaper it is. The cheaper electronic scale, the less money its owner will save.
There is another pitfall worth attention. For clarity, give an example: one of our client, to the moment of our acquaintance has already become a "happy" owner of the power-saw bench with an electronic scale, to my question about the quality of the saw mechanism positioning said that in order to get 20 mm board thickness, they expose the electronic scale size of 22 mm. Do the math - 10 boards, he lost one, 20 - 2 30 - 3 boards due to scale errors. After such an answer becomes clear why did the entrepreneur not address the band-saw equipment producer he already knew (who when buying a second machine probably would offer a discount).
Therefore, it is important to underline the information about the so-called simple electronic scales that are proposed to be easily (?) installed on any band-saw machine - both new and used.
RPA GC "MAGR" has strong division of electronic engineers who have experience in producing both self designed encoder (!!!) and use of industrial controllers. And, drawing on their years of practice, we can confidently say: hardly simple (and frankly, not very) methods can achieve acceptable accuracy of vertical positioning. It is impossible to install electronic scale able to position the cutting mechanism with an accuracy of at least 0.5 mm without significant adjustments of machine electrical scheme.
But perhaps the talented guys could figure out how to overcome all difficulties well-known to our company' electronic engineers? We will not guess, we will only recommend: purchasing such a device, be armed with measuring tools, and do not hesitate checking the positioning in all cases. Also, try to move with the proposed device to values 0.1, 0.5 mm, and if it is impossible, then what precision is?
In conclusion, I want to acquaint the reader with another kind of electronic equipment for band-saw machines. In my opinion, for woodworkers interested in improving profitability of their production the best option is equipment of power-saw bench with automatic cutting control system. An industrial controller, which combines features of multifunctional electronic scale and cutting intension stabilizer, operates with this machine.
This combination allows you to organize a full automatic cycle of blank cutting, converting power-saw bench into almost program-controlled machine. As an example, I want to bring band-saw machine "Umka", various modifications of which are produced by Research-and-Production Association "Group of companies "MAGR" since 2004 Е
Industrial controller made by famous Austrian company "Bernecker & Rainer" operates band-saw machine "Umka".
All the parameters that characterize machine functioning are displayed on a three-inch display and allow the operator to control power-saw bench working process. The controller menu use is intuitive and similar to mobile phone menu use. Therefore, fears that band-saw machine operator "may not cope with sophisticated electronics" are absolutely groundless.
Saw mechanism vertical movement procedure is reduced to typing movement amount and cutting direction on controller keyboard. Thus positioning occurs rapidly and precisely, additional refinement is not needed. Cutting equipment positioning accuracy on a vertical is 0.1 mm.
In the automatic mode all changes to saw mechanism altitude are made by machine with cut thickness correction, which is given by the operator at the beginning of work and saved at after machine is off Е
The carriage moving speed during cutting cycle is automatically regulated up to maximally allowed for specific conditions, such as wood density, the presence of knots, changing the work piece diameter, the state of saw blade and etc. This feature allows you to operate the machine in a sparing mode, obtaining the best performance.
Operating in automatic and semiautomatic modes, the band-saw machine can cut the workpiece on the boards of three (and in some cases four) different sizes. An operator sets the required board thicknesses and their number.
The control system allows the machine to memorize up to 16 typical workpiece cutting maps - or, technically speaking, profiles. Each of the profile can be customized to your version of cutting and a name to profile can be given, and then, when changing tasks, you can select the correct one.
Profile settings are saved when power is off.
Not only a three-stage cutting network but also parameters such as automatic mode cutting intension, the cut thickness, the minimum altitude etc can be configured and saved in profiles.
Due to this there is no need to perform the setup process each time when changing different types of wood. It is enough to press a few buttons and select the desired profile.
With "Umka" machine example I would like to emphasize all advantages of band-saw machines with automatic control system, and to see respected woodworkers have ceased to be afraid of complex electronics in the design of a band-saw bench and did not consider such tools as a waste of money. Full automation of cutting cycle with the automation of the cutting modes will significantly reduce the human impact on the quality of the finished product. Especially, this is important when processing expensive kinds of wood, when each operator error significantly impacts the machine owner's finances. In addition, the significant reduction of operator's burden can allow operating several machines simultaneously by minimum personal that reduces payroll costs and makes the business more profitable.