Techspex

Nov 2017

Techspex provides metalworkers free research and analysis tools to help them find the right machine for their job.

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T H I N K I N G A B O U T F I V E - A X I S C N C M A C H I N I N G ? 4 rotated one of the axes. Today's cutter- compensation software will keep the tool center point right on the surface, no matter which axis is moved or rotated. Offline simulation software contained in a high-quality CAM software package can be extremely helpful to verify a five-axis machining process and avoid collisions, as it can be difficult for a programmer to mentally visualize all possible collision points among the tool, fixture and part when working in five axes. Selecting the Right Machine Not all five-axis machines are alike. Here's where the application for which they will be used must be considered. You need to know what cutting speeds you're going to run, for example. The type of spindle, the arrangement of rotary axes, rapid traverse rates, feed rates and available horsepower are other major considerations. Do you primarily intend to machine aluminum, stainless steel or titanium? How rigid does the machine need to be? What surface-finish quality do you require? What part accuracy are you trying to achieve? These are all questions you'll need to answer in order to select the right machine for your application. If you're primarily machining aluminum, you may prefer a spindle capable of higher speed, such as 20,000 rpm, with higher rapid traverse rates, especially if you're using smaller-diameter tools. Likewise, if you're machining stainless or alloy steel for complex mold surfaces, you will likely be using small tools and high spindle speeds to achieve exceptionally smooth surface finishes. Be aware that some machines are designed for cutting only aluminum. Others are suitable for steel and tough alloys, which require more rigidity, higher horsepower, lower spindle speeds, slower rotary speeds, higher torque and stronger box ways to make deep cuts with bigger tools. Machining different grades of steel, titanium alloys or even harder materials may require a heftier machine, however, this hefty machine would need to rotate the table excessively fast to achieve adequate surface speeds for cutting aluminum. The result might be disappointing. When specifying out a five-axis machine, obtaining the expert advice of an experienced engineer is recommended. Horizontal or Vertical Five-Axis Machines Horizontal five-axis machines are normally equipped with an automatic pallet changer (APC) ready to be installed on the shop floor. If you're machining aerospace components that have deep pockets or waffling designed to reduce finished-part weight, the high volume of chips will naturally drop into the conveyor. In addition, horizontal five-axis machines tend to be heavier and more rigid, which helps when cutting steel and titanium. In contrast, vertical five-axis machines tend to be more agile for processing smaller parts. VMCs tend to enable better operator access and can often take heavier cuts, but clearing chips can be inconvenient. High-pressure, through-the-spindle coolant delivery comes in handy to remedy chip accumulation. Swiveling-Head or Trunnion Style There are pros and cons to different types of machine designs. If you're loading heavy parts, the non-tilting table on a swiveling-head When specifying out a five-axis machine, obtaining the expert advice of an experienced engineer is recommended.

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