Cutting speed, pass depth and travel speed are the most
important parameters for all types of machining; indications for
the ideal values will be given with reference to the specific
tasks.
From a general point of view, it has to be remembered that the exact setting of the right cutting speed is one of the most important things to do when working with titanium, because if speed exceeds even by just a little the correct value, it will greatly reduce the tool`s working life.
lnexpert workers often think they can make the tool life longer by making more, shallower passes instead of fewer, deeper passes.
Because of work hardening and heat conductivity, the most common cause of excessive tool wear is working with chips that are too small and thin. Shallow cuts cause the tool to slide along the surface, with high pressure on cutting and heat.This fact must be noted for the last pass, which must not be too thin, because, in this case, the material would tend to refuse the tool and make the operation impossible.
On the other hand, titanium accepts deep cuts with a thick and well defined chip. Limits may be posed by high torque rates and consequent high power input requirements.lt is therefore useful to break chip into smaller pieces, especially during roughing passes.ln such cases, the chip-breaker is necessary as it considerably reduces the pressure on the cutting edge.
Turning
The tool should protrude as little as possible in order to avoid deflection to stop as far as possible titanium from scraping against the side of the tool.
Use tips with big radius (1.2) for the first cuts.
To obtain a good surface finishing, use tools with tips with a wide radius, but remember that such tools tend to increase work piece deflection. We recommend tips, Sandvik H13A or similar.
The tool should be kept constantly supplied with a strong flow of cutting fluid, directed towards the contact zone between the work piece and the tool.
A water solution containing 5% sodium nitrate, or a 5% oil emulsion in water is used. For turning, live centres should be used because the dead centres cause the tool to seize up.
Front milling
The working life of tools used for front milling can be prolonged by always using a device for compensating play on the feed screw.
The titanium chips tend to weld to the cutting edge of the milling tool and when the cutting edge enters the metal, chips are dislodged and take with them part of the cutting edge. This is especially pronounced with carbide tools.
As a result, the increased cutting speed that can be obtained with carbide tools compared with high-speed steel tools does not always make up for the additional costs of wear; it is therefore advisable to try both types of tools to find out which is more suitable for the different cases. We recommend the same tips as used for turning. Sandvik H13A or similar.
Milling with feed screw play compensation produces a fine chip when the teeth of the cutting tool leave the work piece, thus reducing the tendency of the chip to weld to the cutting edge.
As in all titanium machining operations, sharp tools must be used in order to reduce rubbing and welding. The bottom rake angle or front milling clearance angles must be greater than those used for steel. Use a water-based refrigerant.
From a general point of view, it has to be remembered that the exact setting of the right cutting speed is one of the most important things to do when working with titanium, because if speed exceeds even by just a little the correct value, it will greatly reduce the tool`s working life.
lnexpert workers often think they can make the tool life longer by making more, shallower passes instead of fewer, deeper passes.
"With titanium, it is true.... the opposite."
Because of work hardening and heat conductivity, the most common cause of excessive tool wear is working with chips that are too small and thin. Shallow cuts cause the tool to slide along the surface, with high pressure on cutting and heat.This fact must be noted for the last pass, which must not be too thin, because, in this case, the material would tend to refuse the tool and make the operation impossible.
On the other hand, titanium accepts deep cuts with a thick and well defined chip. Limits may be posed by high torque rates and consequent high power input requirements.lt is therefore useful to break chip into smaller pieces, especially during roughing passes.ln such cases, the chip-breaker is necessary as it considerably reduces the pressure on the cutting edge.
Turning
The tool should protrude as little as possible in order to avoid deflection to stop as far as possible titanium from scraping against the side of the tool.
Use tips with big radius (1.2) for the first cuts.
To obtain a good surface finishing, use tools with tips with a wide radius, but remember that such tools tend to increase work piece deflection. We recommend tips, Sandvik H13A or similar.
The tool should be kept constantly supplied with a strong flow of cutting fluid, directed towards the contact zone between the work piece and the tool.
A water solution containing 5% sodium nitrate, or a 5% oil emulsion in water is used. For turning, live centres should be used because the dead centres cause the tool to seize up.
Front milling
The working life of tools used for front milling can be prolonged by always using a device for compensating play on the feed screw.
The titanium chips tend to weld to the cutting edge of the milling tool and when the cutting edge enters the metal, chips are dislodged and take with them part of the cutting edge. This is especially pronounced with carbide tools.
As a result, the increased cutting speed that can be obtained with carbide tools compared with high-speed steel tools does not always make up for the additional costs of wear; it is therefore advisable to try both types of tools to find out which is more suitable for the different cases. We recommend the same tips as used for turning. Sandvik H13A or similar.
Milling with feed screw play compensation produces a fine chip when the teeth of the cutting tool leave the work piece, thus reducing the tendency of the chip to weld to the cutting edge.
As in all titanium machining operations, sharp tools must be used in order to reduce rubbing and welding. The bottom rake angle or front milling clearance angles must be greater than those used for steel. Use a water-based refrigerant.