Feeds and Speeds….Help is here!!

NEW WEBSITE: http://www.worldofcncmachines.com

Feeds and speeds are one of several variables that play an important role when setting up CAM software and ultimately start machining your chosen material. Getting feeds and speeds correct can really make all the difference between a perfect finish and smoke…literally!

Generally speaking in our world feed rate is the rate at which the cutter will be moving around when actually taking a cut (i.e the cutter is in the material). This should not be confused with rapid feed rates which are the rate at which the cutter will be moving when it is relocating above the material (i.e. when not cutting). Coupled with feed rate is plunge rate which as the name suggests is the rate at which the cutter will ‘plunge’ (down movement on the Z axis) into the material. Care should be taken with plunge rates as some cutters have a sharp point to them whereas other cutters may have a flat bottom and might need to be plunged slower. All this is generally referred to as feed rate or just “feeds” and is usually set inside CAM software.

Spindle speed or “speeds” is the speed at which the cutter will be rotating and is usually measured in revolutions per minute (RPM). Spindle speed may be controlled via CAM software if your spindle is connected to your machine control software via your controller however more often with machines at the lower end of the market, spindle speed will either be set on an inverter, in the case of the 3kW spindle or on the spindle itself, in the case of the Kress range of spindles.

Feeds and speeds are two of several variables that are linked together and finding the balance is paramount! Choice of cutter and the material itself and the cutter requirement itself are the other main factors to consider when trying to workout your feeds and speeds.

A little guidance is often provided on the cutter manufacturer packaging or documentation. Some cutters need to used at a certain feed and speed to prevent them from burning or leaving a poor finish. That’s fine when we are talking about large scale sheets of wood however there is less guidance available when we move away from wood and start looking at plastics and even soft metals.

This is where the CNCCookBook comes in!

Having had several of our customers find it of their own accord and report back that it had been an invaluable tool and at such great value for money of course we had to take a look and see if this was something we should recommend and point our customers towards for more specialised help in this minefield of figures and variables.

To summarise, we highly recommending the CNCCookBook downloadable product for great assistance (it gives you the answer) when calculating feeds and speeds. The CNCCookBook website itself has a lot of free important information regarding general CNC machining including various bits of technical documentation as well as general advice and pointers that is well worth a thorough read for everyone and in particular those new to machining.

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