We all know what the CNC Milling Machine spindle is used for - to hold the tool. But it is old and boring. Everybody does that.

Here are the 6 interesting and maybe less common ways to utilize machine spindle, increase productivity and solve some problems you never thought you had.

Use your Spindle as a fan to blow chips and coolant off of your work-piece, table and fixturing.

I saw this little gadget at a local IMTS show and it was quite cool. It is installed into a tool holder like a regular cutting tool would be and at the end of the program you can call the it up and run a little table-cleaning program to make your work a lot cleaner!

We have finally reached version 1.00!

Here is a list of new and improved features:

What's New

• Material Drop-Down list now shows 'X' on the row when the current Library Tool has Custom Surface Speed and Chipload settings.
• Load Tool dialog box now has Tool Type Icon. The same column shows a readable Operation Type Icon for finishing, roughing, etc.
• Drilling Tool Types now allow user to enter a custom Pecking value
• Milling Tool Types now have Editable Plunge RPM and Plunge Feedrate
• Milling Tool Types' updated Circle/Ramp Dialog now allows to specify whether ramp settings apply to Plunge feedrate of Milling feedrate

What's Improved

• Custom Speeds and Feeds tab on Edit Tool Dialog was improved with new buttons to reset custom Surface Speed and Chipload settings
  Glitch with certain diameters in metric mode being missed is fixed
• Load Tool/Cut Dialog box' Search was improved
• Load Tool/Cut Dialog box now features much improved tool and cut list with better readability and usability
• Ballnose Tools have been improved to better show changing effective diameter for different depths of cut.

Now, because a picture is worth a thousand words, here are some screenshots as well.

Updated and Improved Load Tool/Cut Dialog:

Note new Tool Type and Cut type Icons in the third column.

Since surface milling is more than half of what i do for a living, I decided to share some of my tips on that topic.

Generally you want to create a continuous toolpath that does not change directions too often.

Changing directions slows the machine down and reduction in feedrate affects deflection of the cutter. Different deflection means you get gouge marks on your surfaces.

When you have a long narrow piece its better to go along the long side to save on time and machine wear.
Also going along the longest side reduces the number of direction changes you will have to make

When milling cavities you need to first rough, then semi-finish then finish.

Leave 15 thou after roughing, 3 thou after semi-finishing and finish to zero. All with progressively smaller tools.
5 thou stepover will give you very good finish on most ball mills
3-5 thou chiploads are very common for surface finishing.

Ball mill will always give bad finish on shallow areas- the center is not cutting, but dragging around.
Also straight portion of the flute acts as a wiper and reduces scallop that the ball portion creates.

This is why going from top to bottom is safer and yields better surface finish.

The closer the wall taper angle to the taper of the flutes the better finish you will get.

There is another reason for always trying to go from top to bottom.

When taking material top to bottom you engage stock closer to the tip of the tool.

It makes cut more stable. It is more safe because you are less likely to bury the tool in stock unexpectedly.
Do not go from climb milling to conventional UNLESS you need to save some rapid time.
Pick up only climb milling and you are good to go.
Changing from climb to conventional will cause tool to deflect away from the work on climb and into the work during conventional pass. You will see zebra marks all over your surfaces.

If you are working in mold-making, prototyping or even in a job shop you have had to use unusual form tooling before in your life.

Form tooling is often used to machine undercuts and other features on regular 3 axis machines that would otherwise require a multi axis machining centre or are not machinable o at all.

The classical example of a form tool is a tear-drop ball mil, also known as a "lollipop". It has a tip with a certain diameter and a much smaller shank that produces enough clearance to machine undercuts on straight walls. It can also be used to regular surface finishing and 2d milling.

Another example is a T-slot cutter that is used to produce key-ways and t- slots

The main thing to consider when machining with reduced shank end mils is deflection and torque.

While deflection is especially dangerous for long tools, torque becomes much more important for tools with severely reduced shank.

Torque required to break a tool is directly proportional to the diameter of its shank.

And when shank diameter is much smaller than the tip diameter it does not matter how short that weak portion is: unless you compensate for it you will snap the tool.

The first thing that crosses the mind in many such cases is "I gotta run this tool very slow". It may take forever, but in many cases job gets somewhat done.

Contrary to that many experienced machinists have been proponents of different approach. Instead of reducing feed rate to the point of rubbing and below, it is much more productive to reduce cutter engagement if possible and leave feed rate settings largely unchanged.

Trying to keep proper chip load is even more important when machining work-hardenable materials like stainless steel and titanium. In those cases rubbing is not just unproductive, it leads to a very premature, in many cases instantaneous tool failure.

Just how much of a cut is possible to take in each particular case is the black magic that separates beginners from seasoned pros.

Not to worry though

Here is an example