Our company has been quietly involved in an R&D project with a major aerospace company for the last three years to figure out how to design a machine tool to cut the new triple-nickel titanium materials. Alongside cutting tool manufacturers, we have learned a great deal, and we continue to learn every day—not just how to cut titanium (you can do that with a file), but how to cut it more productively and economically. We are building these machines and taking orders, but the process of perfecting techniques for machining titanium 5553 is ongoing. That’s why I’m cautious when I hear a company claim they have the “quintessential titanium” or “heavy metal” machine.
In this limited space, I’ll cover the key areas to discuss when your sales engineer or “titanium machining expert” comes calling:
- Low-frequency machining: The machine must be structurally designed to operate at low frequencies, specifically below 350 Hz (especially at 20, 90, and 320 Hz). A machine made for low-frequency machining reduces chatter at the necessary low rpm for cutting these materials. Less chatter significantly extends tool life.
- Tool taper interface: Buyers should ask, “What is the moment load that will separate the tool from the spindle taper?” For general-purpose machines with a BT/Cat 50 taper, it’s around 8,500 in-lb. A 7-inch long, 1-inch diameter, four-flute cutter removes approximately 1.2 cubic inches of 5553 titanium per minute before the tool separates. To remove more material, the load will exceed 8,500 in-lb. If you’re aiming for 25 cubic inches of material per minute in 5553, contact me.
- Machine stiffness and material elasticity: In heavy metal machines, all materials must stay within a specific range of stiffness in the modulus of elasticity curve. Stiffer materials cost more, making the machines more expensive, but necessary. The machine must bend consistently under heavy loads. If it doesn’t, the machine’s volumetric accuracy and tool life suffer.
- Big power: To cut heavy metals, machines need ample spindle horsepower, torque, and large servomotor drives on fine-pitch lead ballscrews. These power elements need to be designed carefully to avoid influencing low-frequency vibrations.
Of course, there are other considerations like chip control, coolant, and cutter types, but these four factors are at the core of optimizing heavy metal machining.
Here’s the important news for contract shops: OEM aerospace companies don’t plan on cutting all of these special alloy titanium parts themselves. While they used to keep such proprietary technologies in-house, they will now rely heavily on their top-tier suppliers. Titanium 5553 and about 18 similar grades are coming your way. Be prepared.
For those machine tool companies and salespeople claiming they have the answers for machining 5553, I urge you to do your homework. You can’t just slap a geared spindle on an HMC and call it a titanium machine. In the early days of high-speed machining, many machines were sold without the right capabilities, damaging the reputations of machine tool vendors. Let’s not make the same mistake with heavy metals. Please educate your customers properly on the true capabilities of your equipment.
At Mitsui Seiki, I know what we’ve invested in this research, and I understand how far we’ve come with help from the biggest OEM research departments in the industry. Heavy-metal machining requires deep knowledge. Get the facts straight.