Have you ever wondered how much tool life can deteriorate when using coolant with High-Speed Machining (HSM)?
Or maybe you never really saw the boost in tool life when using HSM techniques because you had to use coolant?

Well, here is a test result I just got from running the same tool at the same Speed and Feed with and without coolant.

Latest advances in tool technology make milling of high carbon and tool steels as reliable and predictable as benign aluminium alloys.

In this video a large 4140 steel component is being roughed out at 2700RPM and 600 inches per minute.
While achieving  impressive material removal rate (20 pounds of steel machined off in a matter of half an hour!) the tool life puts the old school square shoulder endmills to shame.

Yes, it could(and should) have been machined using a bigger cutter, but I wanted to put the tool to the test.
And it performed beautifully: Was able to surpass the recommended starting speeds and feeds by at least 170%!

Look for the HSM machining of the round central pocket in the beginning.
Here we have a 12mm 6 flute Coated hi-performance endmill, cutting 1" deep at 0.047" (10%) rWOC.
at 10000 RPM and 300 ipm feedrate. the chipload works out to be 0.005". Material is 4140 pre-hardened steel.

Impressive isn't it?
Those results have been achieved with uber-expensive BlueSwarf tap-test technology.

This is one video that caught the eye of one of my HSMAdvisor trial users:

Being a geek and wanting to help the user make the right decision I immediately punched the numbers into my HSMAdvisor app.

Here is what I've got:

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

FSWizard:Online has a new feature.

Thanks to a suggestion made by Kennis on Suppport Forums we now have basic thread milling speed/feed online solution.

Take it for a spin guys.

If you have anything else to say regarding this feature, or maybe some suggestions please reply to this forum thread http://zero-divide.net/index.php?page=forums&shell_id=170&article_id=4280

And keep your suggestions rolling!

Out Company used to have somebody else plasmacut cutting anvils for us.
This was expensive, plus heat generated by plasma caused already unstable anvils to warp like crazy making them very hard to grind flat.

So when foreman told me to machine one on CNC i immidately asked him to buy one of those nifty Hanita TiALN coated Varimill cutters.
Too bad they are too expensive. So the company bought same style of cutters made by Niagara. 0.5" end mill there is x3 cheaper than hanita's. Plus i believe cutting tools made to the same specs, out of the same materials are performing identical.

The machine we ve been using for this is really shaky and busted, so dont laugh at speeds and feeds that we came up with.

So basically, Specs Are:

• Material: Hardox pre-hardened steel Rc 45-50
• Cutter: 4 Flute, Stagger Flute TiALN coted 0.5" Micrograin Carbide End Mill, 2.5" Overall, 0.625" Flute Length, 1" overhang
• Operation: Slotting
• Speed: 1200 RPM
• Feed: 4.8 IPM
• Depth OF Cut: 0.125"
• Plunge method: 2.5 Deg Ramp/Helix, Or Plunge into 0.281Dia pilot hole at 3 IPM
• Coolant: Airblast + Oil