For the past 33 years, I've been working closely with on-site machinists on every continent, helping them to be successful in their most challenging projects. One question I often hear is: "What's the benefit of a flange facer having the tool head mounted behind the machining arm instead of in front of it?" In this article, I'll explain the science behind this unique design and the advantages to the user.
Deflection or "play" refers to the clearance or compliance in any machine related to movement. When there is more deflection or play, the tool can "bounce" up and down, and that's why you get chatter. All metal bends, and everything deflects; the extent simply depends on the distance you are cutting from the support. The farther you are from the support, the more the system deflects. Even if you hang an 8-inch (203-mm) bar out 4 feet (1,219 mm), it will deflect some amount. You can find deflection in any system, whether it be the chuck jaws, the arm, the main body, the tool head or any clearances.
So, when the tool is pushed, that deflection goes into the workpiece, and when the tool is pulled or dragged, that deflection goes away from the workpiece. For example, a broom or rake, when pushed, will catch on every crack or surface inconsistency as the force pushes the straws into the crack. When the broom or rake is dragged, there is less resistance created, making it easier for the operator to perform the task.
Ironically, most flange facers you'll see in the marketplace are designed with a tool head placed in front of the tool arm. But when the tool head is pushed, it becomes evident the deflection goes right into the workpiece. It's much more advantageous to use machines that drag the tool head to accommodate for metal deflection, ensuring a better and more consistent result.
When pulled or dragged, if there is any tool deflection due to cutting forces, the tool moves slightly away from the workpiece as shown by the curved arrow in Figure 1, reducing the deflection and stabilizing the system.
Pulling or dragging the tool is unique to certain designs. I recommend selecting flange facers that are engineered to minimize the amount of force it takes to hold the tool to the workpiece and that allow users the flexibility to successfully use a wider variety of tooling.
For more information, visit www.climaxportable.com or call (800) 333-8311.
