- Boring mills used in steel operations require that every minute the chip must receive 1 horsepower for every cubic inch. This rule is a basic standard to make sure that the machine can provide adequate horsepower. If the horsepower is not adequate then it is suggested that the speed is reduced or the cutting is changed from balanced to ‘stepped.’
- For structural steels that have low carbon, the insert to be used should be ordinary and triple coated. With this insert, the speed will be within the range of 600 to 750 while the chip loads will be from 0.007 inch for every cutting edge. For structural steels with medium carbon, be it alloyed or not, the insert should be normal and triple coated. With this insert, it could have a speed of around 550. For structural steels that possess a higher strength, it is best to consult the manufacturer regarding the material used before performing any operation.
- When boring aluminum there is a speed limit which is often caused by the maximum revolution per minute of the machine, the boring bar’s stability, how the work piece is fixed and the machine itself. With this material, speed higher than or equal to 1,000 is acceptable because aluminum requires higher speed for better operation. The recommended chip load when roughing aluminum is within 0.010 and 0.020 inch for every cutting edge. While the feed rate depends on the required surface finish.
- Interrupted cuts may be encountered while boring and is should be rectified by maintaining a higher speed, reducing the cut depth and lowering the chip load.
- If the bore is quite deep, machining should be done by using moderate speed so as to avoid tool wearing. While for a long bore, cutting edge might be compromised.
- To avoid any confusion while operating, do not change the speed and the feed rate at the same time.
- Decide at what starting speed can the machine operate and cut safely while preventing vibration and overload.
- For desired short chips or C-shaped, it is suggested that the chip load must be in inches for every revolution.
- The boring bar’s projection ratio must be maintained at 4:1 or even shorter if possible.
- Do a cutting test and make sure that chip form is at its optimum. If not, alter the chip load as needed.
- The cutting speed must be at its most effective to generate ideal cutting conditions. This can be accomplished by regulating the chip load.
- Choose inserts depending on these factors: cutting forces at minimum, chip is controlled well and the chip evacuation is not impeded.
- Always the inserts before it wears out completely and change it right away.