Solid carbide router bits are generally associated with straight cutting applications and traditionally less common in profiling applications. Solid carbide compression tools and other straight tooling have optimized machining speed and cut quality for many years. Historically, profiling operations are generally performed with carbide insert or diamond tooling solutions, as solid carbide does have some limitations. However, there are specific applications where solid carbide profile tools can provide optimal performance and value.
BENEFITS
Most solid carbide profile router bits can be designed with helical geometry, which provides optimal tool performance premium cut quality at high feed rates. Carbide insert tools are convenient, and diamond profile tools provide optimal tool longevity. However, neither option will provide cut qualify equivalent to solid carbide helical cutting edges.
Solid carbide tooling solutions are very effective in smaller diameter tools to machine intricate profiles and details. Due to design constraints, diamond tools cannot be made under 1/8 of an inch at the small diameter, so smaller profiling is not possible in many cases. Even if tip of diamond tool can be made at an 1/8 inch, the cut quality results are often limited due to geometry constraints. Carbide insert tools can be made in smaller diameter at the tip of tool; however, the necessity to use screws to fix inserts onto the tool body make it impossible to manufacture small diameters for the entire tool. Furthermore, carbide insert tools are generally limited to single flute geometry, which limits feed rates and cut quality results. Solid carbide routers outperform carbide inserts and diamond tools in the following applications.
Image 1 shows a solid carbide router bit, which is designed to machine the top and bottom radius of wood or plastic components. This tool will cut both top and bottom radius, and the flat edge of the part in a single pass. Notice the smaller diameter and narrow cutting edge under the part to allow minimal contact with the spoil board in nested applications.
A common nesting challenge is machining under the part and dealing with spoil board design. In some situations, the parts can be elevated on pods, but in many scenarios a spoil board is preferred to improve hold down of small parts. Tooling design is a critical factor as the tool body below the part must be as small as possible. Although channels are often pre-cut into the spoil board, there are still limits on the size of tool. Brazed diamond or carbide insert tooling are often difficult to design with narrow geometry, because it is impossible to get enough support behind the cutting edge.
Solid carbide profile tooling is the best option in this scenario, because flute geometry is ground from a solid carbide rod, and no brazing or insertable cutting edge is required. Therefore, a narrow flute can be produced to cut below the material.
Image 2 shows a solid carbide 45-degree v-grooving tool. Angle tools are manufactured in carbide insert and diamond. However, solid carbide will provide the most accurate point geometry resulting in the best possible cut quality. Carbide insert tools are effective, however it can be difficult to maintain accuracy on the point of the cutting tool. Accuracy is dependant on knife set up and tool body tolerances to ensure tools perform, which is difficult to maintain. In addition, carbide inserts are normally limited to single flute, especially in smaller diameters, which can further limit tool performance.
Diamond tools are another option for V-grooving applications. But due to the nature of diamond manufacturing, it is impossible to achieve a sharp point geometry equivalent to solid carbide. Cutting edge clearance can be difficult to achieve, and durability has substantial limitations when cutting edge comes to a sharp point.
Solid carbide V-groove tooling provides the absolute best point geometry accuracy. It is available in multi-flute design to ensure optimal feedrate and best possible cut quality at the point of cutting tool.
Image 3 shows a multi-step compression tool manufactured from solid carbide rod. Step drills are commonly made from solid carbide to achieve optimal cut quality and efficiency in a variety of applications. The same concepts can be applied to solid carbide routers to machine multi-step profiles. Helical solid carbide geometry is used effectively to provide cut quality superior to PCD or brazed carbide.
Image 4 shows a solid carbide ball nose or cove tool, which is very common in multiple applications to produce a variety of products. Fluted posts, MDF doors, 3D carving operations, and many other products all require this type of tooling. Traditionally brazed carbide tipped tools were standard and more recently diamond tools have become common, but solid carbide tools outperform both options. The helical flute geometry of solid carbide provides superior chip evacuation and surface finish.
CHALLENGES TO CONSIDER
Solid carbide profile tooling is the best option for many applications. However, there are some important factors to consider before purchasing. Tool diameter is restricted to 40 m or smaller. Solid carbide raw material is produced in rod form and cannot be produced cost-effectively in diameters over 40 mm. Therefore, it is impossible to manufacture profile tooling over 40 mm diameter, which does limit the use of solid carbide profile tools as many profiles require larger diameter.
Cost is dramatically increased as diameter of tool increases. Solid carbide is produced in rod form at various diameters from 1/16 to 40 mm. Diameters under ½ are relatively in expensive, but as diameter increases from 5/8 to 40 mm, there is a sharp increase in raw material cost. Furthermore, 5 axis grinding cycle times are increased in conjunction with raw material diameter. The performance benefits of solid carbide tooling does justify the premium cost but consider using smaller diameters whenever possible.
Solid carbide profile routers are complex to design and manufacture, which makes them very difficult to sharpen without proper machinery, software and knowledge of design. It is impossible to sharpen on manual grinding machinery, so 5 axis CNC machines are the only solution for re-grinding accurately. Improper sharpening process will dramatically decrease the level of tool performance or make tools unusable.
CONCLUSION
Solid carbide profile tooling is not a viable solution for all profiles or applications. However, there are specific applications which can be optimized by using solid carbide routers. The cost of solid carbide profile routers will be higher than other options, but the value-added benefits can be realized through cycle time and cut quality improvements. Solid carbide profile tools are an investment which can be wasted if improper sharpening procedures are implemented. If designed and serviced properly, solid carbide profile tools will ensure optimal machine performance.
