Manufacturers commonly buy CNCs because these flexible machines promise to replace several manual machines and dramatically improve the capabilities and efficiency of the production shop. This transition is, of course, very achievable, but because of inaccurate tooling and application choices, many buyers are missing out on fully optimizing their CNC machine performance.
When key machining principals such as proper part fixturing, achieving ideal cutting velocity and chip load are overlooked it can significantly affect process efficiency and ROI. Developing strong relationships with your router supplier and qualified tooling experts will prevent catastrophic errors and expedite the integration and optimization of this critical machine technology.
Utilizing existing hand routers and shaper tools
Many first-time CNC buyers will continue to use their inexpensive carbide-tipped tools on their new high-tech machine. These brazed carbide tools may “work,” but are generally not rigid, precise, balanced or durable enough to provide ideal CNC performance. Brazed carbide tools are, by necessity, much softer and less wear resistant than solid carbide or carbide insert tools. Tools designed around the CNC’s operational specifications and your output will yield more efficient and higher quality results.
Solid carbide router options
Solid carbide tools are also available in a range of hardness and durability levels that cannot be differentiated by eye. Carbide is essentially tungsten particles held together with a cobalt binder. Softer, less expensive routers are formed with 10% cobalt glue; harder more durable carbides generally have 3% cobalt concentration and may also include trace elements which resist thermal or mechanical dulling.
CNC operators may inadvertently settle for “softer/less durable” solid carbide tools because they’ve broken harder versions. Understanding why these higher quality tools broke (vibration, part movement, improper chip load, etc.) and addressing the issue will help you extend tool service-life and lower annualized tooling expenses.
Coated carbide tooling
Carbide coating options that improve surface lubricity, heat deflection, or increased cutting-edge hardness offer the next level of enhanced performance. These coatings are relatively inexpensive and generally provide much greater value to the user. Depending on how the tool must be sharpened, these coatings can sometimes provide extended performance over multiple service cycles.
Polycrystalline Diamond (PCD) routing tools can provide the lowest tooling cost per unit of production, but the higher initial tool cost and risk of damage can be intimidating. We recommend transitioning to diamond tools only after you are comfortable with the operation of your CNC and are enjoying problem-free routing with solid carbide tools. We also recommend forming a partnership with a PCD tooling supplier who can guide you through the proper utilization and care of these delicate yet durable tools. The baseline cost comparison for PCD vs. solid carbide routing tools is generally less than 7:1, but the average performance comparison should exceed 15:1. Used correctly, PCD tooling will dramatically reduce tooling inventory and required tool changes, while maximizing machine uptime and process efficiency.
Tool holding generally drives most CNC processing issues. Machine tooling start-up kits generally include basic collet chucks in one of three common collet versions (ER32, ER40 or SYOZ25/RDO35). Collets provide dimensional flexibility, allowing an operator to hold cutting tools with 1/8” to 1” diameter shanks in the same chuck body. Collets are, however, the first weak-link in an otherwise very rigid and precise machining process. The multi-directional torque applied to the collet when tightening or releasing tools can push the tools out of concentricity, and slight rotation or slipping of the tool will create internal damage which compounds tool run-out. Even the premium SYOZ25 collet system, which due to its 52mm grip length and 2.5-degree taper is the most precise option, can induce tool eccentricity and allow tool deflection. Collet systems also require significant maintenance and wear out over time, but issues which lead to poor tool performance are not always easy to visualize.
There are several collet-free chucking options available, but the easiest and most effective is Leitz ThermoGrip heat-shrink chucking system. ThermoGrip uses the thermo-mechanical properties of steel to grip tool shanks under tremendous pressure, effectively yielding a one-piece chuck and tool. Leitz ThermoGrip CNC chucking system provides the most rigid and precise CNC tool holding possible, optimizing cut quality, throughput and safety, while conservatively yielding $15,000 in annualized savings per machine shift. ThermoGrip ensures perfect tool concentricity under working loads, resulting in greater than 25% increase in tool life and at least 10% improvement in machine throughput at optimal finish quality.
We challenge customers to test their existing top running router bit style with the ThermoGrip. Once installed, their operator will immediately report:
- Much quieter cutting
- Outstanding cut quality
- The ability to increase feed speed, without degrading the quality
- Significantly longer tool life
Ultimately, this test is eye-opening for most customers, and a major step in optimizing the efficiency of their routing processes.
In order to optimize your CNC-based manufacturing process, you must be aware of available cutting tool related technologies and understand how to properly implement and utilize the technology. Tooling is the single machine accessory which can either limit or optimize your manufacturing efficiency and success. Having a knowledgeable tooling partner, with a worldwide perspective, will greatly enhance your ability to continuously improve your internal processes and keep your company at the forefront of the industry. How can Leitz help you?
Talk to your Leitz Representative about a partnership for continuous improvement. Fill out the form below or call us at 800.253.6070.