Machining characteristics of medical titanium and titanium alloys

Titanium 6AL-4V ELI is the standard product for the fabrication of hip joints, bone screws, knee joints, plate bones or organs, dentures and surgical devices. However, cobalt-chromium alloys are being used more and more often because of their strength, tighter grain size, and cleanerness than titanium. Machining titanium alloys requires only slightly greater cutting forces than machining steels, however, the metallurgical properties of titanium alloys make them more difficult to machine than steels of moderate hardness. Titanium has a titanium work-hardenability that eliminates consolidated metal (hemming) in front of the cutting tool. This helps to increase the shear angle in machining, thus forming a thin chip that touches the cutting tool surface in a reasonably small area. Because of this work-hardening, the feed should not be suspended during the tool-workpiece motion contact. The large supporting force that occurs during machining, combined with the frictional force generated by the chips in the touch area, causes a large increase in heat in the tool part area. The heat generated by cutting titanium does not dissipate quickly because it is a poor conductor. Therefore, most of the heat is concentrated on the cutting edge and tool surface. The large bearing force and heat form a crater near the cutting edge, causing the tool to be damaged quickly. To make matters worse, Titanium Alloy Threaded Rod have a strong tendency to fuse with the products in the tool to form alloys or revive chemical changes at the working temperature of the tool. damage. These difficulties are multiplied when tools begin to break, so tools used to machine titanium and its alloys should be carefully monitored to ensure sharp edges and replacement before they become dull. The experience of machining titanium and titanium alloys is that if you see any changes during the machining process, you should change the tool immediately, because the change means that the tool will become dull. Another reason to insist on sharp knives is that titanium can catch fire when cutting with a damaged or damaged tool. When incinerated, the metal generates oxygen, so the fire will spontaneously ignite. Therefore, many workshops that process titanium do not report fires, and they are equipped with rescue systems on their machine tools.

Titanium has a moderately low modulus of elasticity and is more elastic than steel and therefore tends to defy the cutting tool when machined unless it is to be cut robustly or used as a proper support. Slender parts tend to deflect under tool pressure, causing problems with tool chatter, tool friction, and tolerance. Through the processing experience, it is believed that the rigidity of the entire system of the tool is very important, and the sharp and accurate shape of the tool should be used. As a result of these pressures, new technologies have been introduced to help shops that make medical parts cope with the competition, and the machining performance can produce these complex parts with very high precision; many innovations in EDM have enabled the production of high-quality parts faster, eliminating many old machining techniques inherent topics.

As a new type of product, titanium has only been developed and used in China's pharmaceutical industry, medical equipment, human implants and other fields for nearly two decades. However, it has achieved great success and achieved significant social and economic benefits, shortening the gap between China and the advanced countries in the world. The use of titanium equipment in the production of many commodities not only solves the equipment corrosion problem that has seriously plagued the company's production and development, but also greatly improves the quality of drugs.