Recommendations on the choice of machines
Since metalworking machines were invented several centuries ago, only the principle of their operation has remained unchanged. The design has changed beyond recognition. A great many modifications of machines have appeared:
- Desktop machines – weigh 13-100 kilograms, power – up to 400 watts. They are placed on a table or workbench, used in private workshops and car services.
- Semi-professional machines with a power of up to 1000 watts. This category includes combined machines that combine the functions of turning, drilling and milling equipment. They are used for small-scale production.
- Professional metal machines with numerical control – differ in large weight and power, equipped with a CNC system.
The main differences between the machines of different groups are only structural. Although all the main elements are the same and are present in each:
Numerical control machines are a separate type of equipment. Human participation in the processing process is minimized – the operator is responsible only for the removal of finished products. The machine performs everything else according to a preset program, prepared in advance by a specialist. The processing accuracy is the highest. The machine performs a wide range of work.
A group of CNC machines, developing, combined the capabilities of drilling, turning and milling machines in one high-tech machine, received the name processing center (Figure 1), gradually erased the line between classes of equipment. However, this does not make it any easier to choose when buying a machine.
You can just get lost in this abundance of equipment on the market, and this is not surprising — it can be difficult even for professionals to choose the best CNC machine if they do not follow the novelties of the market, the range of which is constantly expanding and improving.
Figure 1 – Processing center.
Choosing a machine is one of the most important and difficult tasks. It is difficult to establish firm and precise machine selection rules for each processing case. However, when choosing a machine, it is necessary that the selected equipment provides:
- obtaining the required processing accuracy and surface cleanliness;
- compliance of the machine performance with the specified program for the production of parts;
- matching the power of the machine to the power required when processing;
- matching the dimensions of the working area of the machine to the dimensions of the machined parts;
- ease of processing on the machine (ease of machine operation, chip removal, etc.);
When choosing a machine, they are not limited to the above parameters only, but take into account its purpose in production. For example, if the production is focused on the production of large batches of the same type of products, a CNC machining center and a tool shop are best suited. Especially if the part will need to be processed with several tools at once.
But if the choice of equipment is being carried out for the repair shop of an enterprise or a garage for repairing cars, universal machines with manual or semi–automatic control system are suitable.
Choosing any equipment, and especially such high-tech as a processing center, it is necessary to think about the prospects for the development of production. In such a situation, immediately buying a machine in the maximum configuration is not just expensive, but also very risky - you can never use the purchased option. Any investment should be recouped, and preferably in the shortest period of time.
The selection of the machine begins with determining the basic parameters: the maximum size and weight of the workpiece, its material, the number and complexity of the operations performed.
The larger the dimensions of the workpiece being processed, the more production area the machine will occupy. In the case of working with rod-type parts, do not forget about the size of the spindle bore during turning. The workpiece surfaces to be processed and the tools used also affect the necessary movements along the axes. The material of the workpiece determines the value of the rotational speed and torque on the spindle. That is, if you plan to process blanks made of cast iron or alloy steel, then high torque will be a priority, and for aluminum, the spindle rotation speed is more important. The basic equipment offers a high cutting speed.
In general, the basic parameters are limited to this. Next, you need to select the complete set of the machine according to your technological requirements. The options allow you to expand the technological capabilities of processing centers, increasing their productivity, accuracy, convenience and safety to the maximum. Of course, if there is a financial opportunity, you can purchase a processing center in the maximum configuration, but most likely, you simply will not have to apply the entire arsenal of technical solutions in practice. Processing centers are multifunctional equipment, and based on this, their basic equipment is very impressive.
Each equipment manufacturer has a recommended list of options to ensure optimal operation of both equipment and personnel.
The operation of the machine, especially in heavy cutting modes, is associated with a large consumption of coolant (removal with chips and transition to a vaporous state). To extend its service life and maintain quality, an oil separator is installed in the coolant. It collects excess oil, maintaining the recommended composition and reducing the rate of bacterial reproduction and, as a result, the appearance of an unpleasant odor in the shop.
The oil mist extraction system (Figure 2) is designed to organize safe working conditions in the workshop. The oil components included in the coolant and their emulsions tend to form an oil mist during processing, which often causes occupational diseases of personnel. In addition, the forced and effective removal of harmful substances makes it possible to reduce the downtime of the machine associated with the natural dispersion of vapors, thereby increasing productivity and eliminating contamination of both machine components with oil film and other workshop surfaces.
Figure 2 - Oil mist extraction system.
Modern contact measuring systems for machining centers can significantly reduce the tool setup time. Products from such global brands as Renishaw and Hexagon allow you to fully automate the process of measuring the instrument, entering corrections of its size and finding breakdowns. This makes it possible to eliminate errors related to the human factor, reduce the percentage of defects and replace broken and worn tools in a timely manner.
Regardless of the presence or absence of experience in selecting the necessary equipment and tools, it is logical to contact the technical specialists of the equipment supplier, they will help with the selection of equipment, a set of options and answer all your questions. Also, a technical specialist will be able to develop the manufacturing technology of the part and order a cutting tool and tooling for the part being worked on with the machine.
List of sources used:
1. Internet resource – "https://ru.wikipedia.org/wiki/Nartov,_andre_
Konstantinovich".
2. Internet resource – "https://top3dshop.ru/blog/how-to-choose-cnc-machine.html".
3. Internet resource – "https://habr.com/ru/company/top3dshop/blog/397221/".