The Next Generation of Coatings is Here!
SurfTech® is here, being the first to introduce Nano scale Multilayer coatings in 1995 for commercial use. Next Generation? To fully understand the significance of this statement, one must first understand the differences between Multilayer coatings and SurfTech’s Multilayer coatings. (Fig. 1 & Fig 1.1) Our coated surfaces are both harder and reduce friction far more effectively. As a result, tool performance and tool life improve dramatically. The obvious advantages of SurfTech® coatings have led to their increase in popularity not only for cutting tools but also for wear parts. In the area of machining, SurfTech® coatings have: 1) increased production by reducing machine down time [due to build-up material on edges of tools or tool breakage], 2) reduced tool breakage, 3) reduced scrap rate by holding the close tolerances and finishes, 4) reduced tool cost by using Carbide in place of PCD and HSS in place of Carbide, and 5) increased productivity by increasing speeds and feeds by as much as 50% in some cases.
What we mean by next generation coatings is that we build multilayer coatings. (Fig. 1.3) We build a sandwich in which we control the thickness of each layer to; 1) make the coating more lubricious, or 2) make the coating harder, or 3) make the coating to dissipate heat, or 4) make the coating more abrasion resistant, depending on the application. This not only holds true for cutting tool applications but for wear components as well. SurfTech® can also produce multilayer coatings by combining any of its current lists of coatings.
How SurfTech Coatings are Applied
SurfTech’s approach to our coating process is very unique. What takes place in the coating chamber is considered widely to be the most critical step in a coating process. However, if tools and/or parts are not properly cleaned and prepared, the coating quality can be compromised. SurfTech starts with incoming inspection of the components. Once we have properly performed our incoming inspection and assessed the condition of the parts, then we perform our unique cleaning procedures. Our parent company ERC has developed cleaning specifications for all the different types of materials we coat. They include multiple ultrasonic baths to remove all oils, dirt or residues, which may inhibit proper coating adhesion. After the components have been received, inspected, cleaned and fixtured they are then loaded into our equipment where they are “re-cleaned” under vacuum by use of “ions” to assure that the components substrate is absolutely clean for proper coating adhesion.
The coating process we use is called (PVD) or Physical Vapor Deposition with an ion assist or (IBAD) Ion Beam Assisted Deposition. The equipment we use and the processes we employ, enable us to apply our coatings at temperatures BELOW 200º F. This assures that there will be no annealing or softening of the substrate and no warpage to effect the dimensional stability of the component. It also allows us to control our coating thicknesses to a tighter tolerance as well as assuring greater uniformity of the coating applied, thereby maintaining the fine sharp cutting edges on tools, as well as the fine details of components coated. Our processes and coating also do not effect the surface finish of the substrate material.
How SurfTech Coatings Increase the Life of Cutting Tools & Components
The most critical time of any component is the early stages of use, or break-in period. Once this “pattern” or footprint is established, it continues but at a much reduced pace. Tooling or components that are coated usually have a much higher wear period well beyond that of an uncoated tool or component. The advantage of coating cutting tools, is that it takes fewer tools, the speeds and feeds can usually be increased thereby increasing production, decreasing machine down time by alleviating frequent tool changes, and the finished part quality is generally improved.
How SurfTech Coatings Reduce Wear (abrasive as well as adhesive wear)
Abrasive wear is the most familiar type of wear. It is caused when a tool or component comes in contact with hard particles. Our coatings supply a surface that has more lubricity and hardness to protect against this type of condition.
Adhesive wear is caused when small particles weld or gall themselves to the tool cutting edges or the face or contact point of a component. As these particles break away they leave a rough cratered type condition which helps promote this condition but at an increased rate.
A build-up edge is formed (a) on the edge of a cutting tool which changes during the cutting operation allowing it to become torn and imbedded in the work piece, leading to poor finishes and/or tolerances. (Fig. 1) A galling condition is formed on a wear component (b) which causes excessive wear, higher torques to operate and eventually component seizure or catastrophic failure. (Fig. 2)
The added lubricity of the coating provides protection from this condition. In a cutting tool, the coating improves chip formation and reduces chip welding and build-up on the edge.
Coating adds lubricity to the cutting edge allowing the chip to slide off the cutting edge more quickly, thereby reducing heat build-up and chips being welded to either the tool or the cutting edges, leading to better finishes. (Fig. 3) A galling condition or excessive wear condition are also prevented on wear components by reducing friction and adding lubricity. (Fig. 4)