PREVENTIVE MAINTENANCE ON CNC MACHINES:
Maximum attention should be paid to preventive maintenance and other types of maintenance in CNC machine tools. In addition, negligence and mistakes to be made cause the machine to be out of service.
Some aspects of preventive maintenance must be strictly followed. Healthy working parts should not be tampered with and their settings should not be changed. Any signals or messages sent must be strictly adhered to. Incoming signals and messages are usually related to corrosion, loose connections and dirty contacts.
Parts required for preventive maintenance should be carefully lubricated. Never use too much oil. Excess fat is more harmful than lean. Diagnosis and testing should be in accordance with the instructions. Damaged parts should be replaced with a new one instead of repaired. Preventive maintenance has three main functions;
1-Cleaning 2-Lubrication 3-Checking
MAJOR FAILURE AREAS IN CNC MACHINES:
The main fault areas and their locations in CNC machine tools are as follows;
Machine tool axis drives
Hydraulic and pneumatic elements
Measuring and transfer systems
digital data processors
Input / Output (Input / Output) units
IDEAL WORKING ENVIRONMENT AND CONDITIONS FOR CNC MACHINES:
In order for CNC machines to work properly, environmental conditions with a high degree of cleanliness are needed. Ideal working environment conditions recommended by bench manufacturers;
These issues should be taken into consideration as they are affected by changes such as heat, light, humidity, vibration and voltage in the bench control units. The working environment temperature and humidity ratio should be between the values recommended by the bench manufacturer. Vibration should be below 0.5 grams. Any voltage changes must be + 10%, – 10%, voltage drops must be a maximum of 2.5 waves (20 MS). If the working environment conditions of the bench do not comply with these standard values, the manufacturer does not fulfill its obligations regarding maintenance.
MAINTENANCE OF LUBRICATION SYSTEMS:
Another system that needs maintenance in CNC machines is the healthy operation of the lubrication system.
The most common maintenance process is to change the oils when the periodical period expires, to complete the missing oils and to clean or replace the filters. The lubrication processes of the components related to the closed internal systems of the machine are performed automatically. In some small-sized, educational CNC machines, the lubrication of the registration-slide systems is done manually.
Another point to be considered in lubrication is to avoid excessive lubrication. Along with excessive lubrication oil waste in CNC machines, it covers the outer surfaces of especially sensitive electronic circuit elements and prevents their healthy operation. In addition, the level lines must not be exceeded in the completion of the depleted oils.
PROTECTION OF THE BALL SHAFT AND REGISTRATION-SLIDING SECTIONS:
Ball Screws, which are motion transmission elements used in CNC machine tools, and record-slide systems are enclosed in closed enclosures. These enclosures are vinylex or spiral protectors.
MAINTENANCE OF HYDRAULIC AND PNEUMATIC EQUIPMENT:
As with the elements mentioned above, hydraulic and pneumatic equipment should be maintained at periodic intervals. In addition, since the elements apply pressurized force, it should be checked whether the continuous working pressures are in ideal values and if any, malfunctions should be eliminated. Otherwise, they pose a great danger to the machine, the operator and those working in the environment. Estimate that the pneumatic bench chuck is not clamping the workpiece sufficiently, the cutters are not securely attached, and the resulting accidents.
TOOL SELECTION FOR CNC MACHINES:
One of the most important features of CNC machines in preventive maintenance in CNC machines is that they have very high metal removal rates. Add to that an industry-less set-up time and an automatic tool change job that takes about five seconds, and we better understand why production engineers think tools are the most critical issue in numerical control machining.
Sintered carbide (Carbide) tools are generally used in CNC machining, although high-speed steel (HSS) tools are used for small-diameter drilling, tapping, reaming, center drilling, and key cutting.
The tools to be used in these benches are at the beginning of the physical properties required, and the hardness and toughness of the material at the metal cutting temperature is felt up to 600°C. High-speed steels are tougher than sintered carbide, but not as hard. Therefore, intensive research is being carried out to develop new carbide types that can meet the requirements of high speed metal removal techniques. In order to understand how successful these researches are, it is enough to watch CNC machines in action.
Efficient use of expensive CNC machines