DESIGNING AND BUILDING THE IDEAL SAWING MACHINE (Italian version published by tecnologie meccaniche, giugno 2022)

ISTech’s metal cutting solutions are well known in the industry, but not everyone knows how they come into being: analysing the path from design to delivery provides insight into what sets this manufacturer’s solutions apart.

UNDERSTANDING REQUIREMENTS

The design of a new sawing machine always starts with an analysis of the customer’s requirements.
Whether it is an ‘ideal type’ of customer, in the case of the sawing machines which will eventually become part of the catalogue, or a real client for custom-built systems, ISTech always starts with the question: what requirements should the machine satisfy?
The answer to this question is the result of a process of continuous interaction with the customer.
ISTech’s engineering design department examines concrete needs and specific requirements, maintaining a continuous dialogue with the customer throughout the design phase.
ISTech’s attention to the customer’s needs brings benefits on both sides: in some cases this dialogue has led to the identification of construction solutions which have then become part of the ISTech offer. Examples include the improvement of the user panel interface ( which has become increasingly rational and intuitive), the management of the cutting head feed for hardened bars, or the approach of the brush to the blade according to its degree of wear.
There are many aspects which will influence the design and appearance of the ready-to-use cutting system.
Depending on whether the sawing machine is intended for the production of small batches or large series, and on the frequency with which the type of machining will have to be changed, the solutions proposed during the design phase can change a great deal.
The intensity of use to which the machine is likely to be put will lead to different designs depending on whether the sawing machine is intended for occasional prototyping or automated, continuous production.
Another element influencing design choices is the type of material to be cut; ISTech sawing machines are very versatile and lend themselves to cutting all types of metal, but knowing from the outset whether the metal to be cut will vary frequently or whether it will always be the same will lead to different solutions.
The size of the parts to be cut is also fundamental, as it will determine not only the characteristics of the part of the plant intended for the actual cutting, but also the solutions adopted for loading and unloading the parts.
The centrality of continuity in production will lead to the implementation of measures aimed at guaranteeing reliability and minimising machine downtime.
Finally, the standards to be met by the customer in terms of cutting quality will be decisive.

A PROJECT AIMED AT PERFORMANCE

Once the customer’s needs and expectations have been clarified, ISTech designs the sawing machine accordingly.
Specifically, for machines that work according to a 4.0 logic, customisation of the software is fundamental; for plants, in addition to the IT aspect, it is also important to customise the mechanical solutions for the management of incoming and outgoing material.

For sawing machines intended for unmanned use, it will be crucial to automate process control activities as far as possible.
For this reason, it is important to include sensors in the design phase to verify that the process is stable.
A blade deviation sensor, which allows the quality of the cut to be evaluated during the process, will, for example, avoid cuts which do not conform to quality standards, correcting and self-adjusting; if the deviation proves impossible to correct without operator intervention, the sensor will interrupt the cut, avoiding the creation of non-conforming pieces which would entail a waste of the metal being processed.
Other sensors (unloading cells) evaluate the cutting pressure; it is also possible to check the power absorption of the blade motor. If these parameters are exceeded, the machine is able to introduce corrective measures, signal the anomaly or, in the event of a deviation that could damage the workpieces, interrupt the process.
Another aid in the case of unmanned machining is the automation of the positioning of the motorised chip cleaning brush. The brush is subject to wear; a fixed positioning would mean a very rapid reduction in effectiveness, but the automated positioning system brings the brush closer to the teeth of the blade as the brush itself wears down, keeping the cleaning constantly accurate.

FOR EVERY SITUATION, THE IDEAL SOLUTION

The characteristics of sawing machines also vary, of course, depending on the material to be processed predominantly or exclusively.
For aluminium, for instance, cutting is much faster than for stronger materials; therefore, the gearbox first of all changes, but not just that.
The cutting speed means that many more swarf will be generated in a given time frame, so the chip conveyor is designed with a higher capacity.
Furthermore, aluminium being the light metal par excellence, it produces chips which float; the coolant filter system must therefore be designed with this in mind.
If the material to be machined is cast iron, cutting generally takes place without the aid of coolants, but this can lead to overheating of certain parts of the machinery; to overcome this problem, minimal lubrication systems can be studied or, alternatively, the sawing machine can be designed with materials able to withstand high temperatures without losing efficiency. For certain uses where the use of liquids is not possible due to the complexity of decontaminating the waste, such as  nuclear power plants, air cooling systems can also be studied.
Other arrangements can be studied to optimise cutting efficiency and quality in the case of very delicate materials such as chromium-plated metals.

In addition to the hardness of the material, the size of the workpieces to be machined can also lead to different design choices.
In the case of automated systems which cut large workpieces, the automatic loading of bars is certainly a great advantage, but if in the morning operators have to unload all the production of the previous shift, they can take hours, not to mention the hard work.
An in-depth study of the process of unmanned plants also allows the unloading and palletising of cut pieces to be automated; the operator thus finds everything in order and proceeds to the next machining operation seamlessly. The reliability of cutting times is much greater and the company is able to meet last-minute requests on time, with an excellent return in terms of image as well.
Depending on whether the focus of production is on cutting speed, the ability to handle the transport of even very heavy bars, or other aspects, the adjustments to be made in the design of the system will lead to machines which, although similar at first glance, in reality incorporate very different technologies, customised for each situation.

In the case of particularly difficult machining operations, in order to preserve materials from damage which could be caused by cutting errors, the plant may be equipped with automatic systems to stop machining before the damage occurs, so as to minimise waste and maximise the efficiency of the production process.

If the cut pieces have to meet particularly stringent quality requirements, the adoption of sensors can safeguard the quality of the processing: for example, laser measurement systems allow the positioning of the piece by checking its size and congruence with the cut and stopping the machinery in the event of deviations beyond a predetermined limit.

THE ELEMENTS OF THE SAWING MACHINE

What are the main elements of the sawing machine and what characteristics of these elements can influence the performance of the finished system?

Let us start with the base frame: the study of this part of the sawing machine is very important as this is where chip management takes place. In high-speed cutting systems, where chip generation is very intense, studying a base which allows the chips to be conveyed to disposal in an efficient manner is fundamental.

Sliding columns are also fundamental to give solidity and rigidity to the cutting head: compared to linear guides, double columns of large dimensions made of chrome-plated metal minimise vibrations and guarantee a more precise cut.

Regarding blades, they are able to make the difference in terms of the quality of the semi-finished or finished product: this is why it is important to be able to choose from a wide range of blades.
There are many types of blades on the market, but two main categories can be distinguished: bimetallic blades, which are the most common, and blades with carbide tipped teeth, which allow the most difficult materials to be cut at high speed.
In order to preserve the service life of saw blades with inserted teeth, ISTech sawing machines have a mechanism which pushes the material away as it rises after the cut, greatly reducing the risk of the teeth becoming damaged at this stage.

Another fundamental element to bear in mind when designing the ideal sawing machine is the operator interface.
The solutions created by ISTech for its sawing machines allow the parameters of the cutting operations to be programmed, executed and memorised for future use, thus achieving, after a rapid learning curve, perfect and repeatable results.
In this respect, ISTech has been a pioneer in realising systems compatible with the principles of Industry 4.0, starting well before this production model became widespread: logging of cutting parameters for the company’s automatic sawing machines has been offered for a long time. The automatic logs are able to retrieve the history of the cuts made, indicating the type of blade used, the processing time and the number of square metres cut up to that moment, in order to assess the efficiency of the machinery and intervene in good time when the blade needs to be replaced or other maintenance operations need to be carried out.
ISTech sawing machines can be seamlessly integrated with company management systems, so that very extensive databases can be accessed and machining processes can be optimised.
The interface of the ISTech automatic sawing machines also allows many operations to be carried out remotely, such as the change of cutting programs, and also to carry out various maintenance operations: this allows the machinery to operate without the continuous presence of the operator and to intervene only when necessary, maximising efficiency and productivity.

A CONCRETE EXAMPLE

In order to clarify how the combination of the different design variables leads to an optimal design, it may be interesting to consider the example of the system realised for a major railway wagon manufacturer.
The company required an automatic system for cutting the axles of trains; these must be cut from forged metal bars which are usually not perfectly cylindrical, tending to taper at the ends.
The bars therefore have differences which can make each of them more suitable for turning into a particular type of axle (there are several hundred types). For each bar, once the type of axle best suited to be made from it has been identified, the optimum cutting point can be determined, thus maximising productivity. Recognising the type of bar is therefore essential to proceed with machining in the most efficient way.
Bar selection has historically been done manually, based on the experience of the operators, who would then manually transport the part to a sawing machine to cut one end of it; this operation would be followed by cutting the other end.
ISTech’s solution has made this process faster and more efficient: a laser system scans the profile of the bar along its entire length (which is usually about 4 metres), recognises which type of axle it is best suited to and identifies the optimum cutting points at the ends.
At this point two cutting heads work simultaneously, one at each end of the bar, to speed up time and reduce material handling.
The finished axle is then transported by an automated shuttle to the correct position in the storage area. Compared to the manual option, the scrap reduction and time savings are clearly considerable.

A COMPLETE SERVICE

The customer was very satisfied with the equipment provided by ISTech, which allowed his productivity to increase considerably. They were also able to appreciate the excellent level of service, with well-trained and helpful staff able to resolve any doubts with practical advice in a very short time.
ISTech thus confirmed that the ideal sawing machine for every company’s needs exists, and if it is not yet available on the market, it can be designed and manufactured with excellent results.

For over 25 years, ISTech has offered standard and customised solutions for every metal cutting requirement. Innovative design and flexibility in manufacturing allow ISTech to create tools which integrate perfectly into production cycles, offering high mechanical cutting capabilities and contributing to process automation.

For more information on ISTech solutions you can contact the company by phone (+39 02 93548545) or email (info@istech-segatrici.com) or visit www.istech-segatrici.com