High Speed Machining has become a catch-all phrase for several specific tool programming strategies that have unique characteristics.  By now, almost all shops are trying to use one or more of these techniques to increase efficiency and be more profitable.  Beginning machinist may hear some of these terms and not know exactly how they are applied or how they are different from each other.  Our friends at Harvey Tool have published a fantastic guide that fully explains these terms and how they can be applied.


Harvey HEM Guidebook


First lets talk about High Efficiency Milling (HEM).  HEM is a roughing solution that is characterized by the tool having a lower radial engagement combined with a high axial engagement.  This program allows the heat load to be spread evenly across the tool and not concentrated at the tip.  Typically HEM uses 7-30% of the tool diameter for radial engagement and up to double the diameter for axial depth.  This is then paired with increased feed rates to produce much higher productivity than conventional milling.

High Speed Machining (HSM) is also highly productive but uses a different strategy.  Unlike HEM, High Speed Machining uses a very low axial or depth of cut combined with a much higher radial component.  This is then combined with a very high spindle speed.  The process normally requires several step-down passes to complete the operation.  By using contour or ball radius tools the program can create 3 dimensional curved surfaces down to a final (or nearly final) shape.

Trochoidal Milling is a program strategy that produces a slot wider than the tool diameter.  Trochoidal Milling normally uses the same methods as HEM by using low radial engagement together with a higher axial engagement.  The tool path is then set as a series of circular movements within the workpiece to produce the slot.

There are many more considerations that go into using any of these methods.  Your CNC’s capabilities and program features are key to successfully running at higher metal removal rates.  Another factor to consider may be chip thinning and preventing tool wear.  You also have to be sure your setup is stable and that the tools you want to run are designed to produce good results using “high speed” machining.  If you would like to learn more please download the guide from Harvey Tool.  Also, take a look at all of the tools that Harvey can provide.  Harvey Tool is a unique company that provides many tools as off the shelf standards that other companies can only make as a special.  They also specialize in miniature tooling used in drilling and milling applications

Please feel free to contact us or ask your local Tool Crib representative if you have an application for high speed machining you would like to explore.