Just found a very good video of testing a table-top gantry router cutting mild steel.

YouTuber named "Breaking Taps" used speeds and feeds generated by HSMAdvisor to get a starting point.

To see where exactly he was in the calculations I decided to reproduce all of cuts in HSMAdvisor.

A couple of assumptions i made:

1. Tool Type: Solid End Mill. It is not recommended to use the HP/Roughing tool type on such light machines, so i assumed this is the tool BT used.
2. Tool Stick-out looked like about 3/4" so I used that number.
3. Material was set to A36 Hot rolled steel.

Test 1) Minute 4:52

Good, slow and very safe starting point.

Test 2) Minute 6:20

Twice as aggressive as before, but we can still push it further.

Test 3) Minute 7:10

Here we can see the lack of machine rigidity starting to show. But at 65% feed rate it is still alive.

Test 4) Minute 8:30

This last test did not go well at all.

The machine has finally hit its limit and the endmill broke at all S&F overrides at about 100%

Was this fault of the software? Not really!

If that were a heavier machine, the last cut would not even be considered that difficult.

Here is a full slotting cut on a Matsuura VMC:

And here is the calculation that was done using HP/Roughing End Mill tool type:

If i were using the "Solid End Mill" tool definition, i would have to dial the feed override to 176% to match the 45ipm feed rate!

So what can users of light machines do in order to not break taps end mills?

First of all make sure the spindle torque curve is built and enabled in your machine profile settings.

The easiest solution is to de-rate the spindle. There is "Warning at" level in machine profile settings. Set that to 50% for starters and it should save you from exceeding the machine's capabilities.

Overall this was a great test of this little machine's capabilities and of the great help that software like HSMAdviasor can lend in discovering them.

Please head over to Breaking Taps YouTube account and subscribe.

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:

Here is a video of a 3 flute Hi-performance endmill slotting aluminum 0.75" deep per pass.

Well, not entirely slottimg, more like pocketing, but the very first move is a full width slot.

Stepover is 0.4"

First i calculated the cut on HSMAdvisor.

Used 6061 aluminum as material and HP endmill at a tool type.

Tool torque and deflection limits were both set at 100% and performance slider was at maximum.

This is what it came up with:

S9127 RPM 125 IPM.

Full slot, 0.75" deep.

45 in^3/min mrr.

Looking at how easy it went i think i should allow for more load in my calculator.

If you have not yet tried HSMAdvisor, make sure you do.

You will be amazed at how much productivity you have been missing out on.

The best online cnc speed and feed calculator FSWizard is now available as an app for iPhone and Android.

CNC Milling and Turning Speed and Feed Calculator For Machinists on the palm of your hand!

Go To FSWizard Online Calculator

Note: Certain HSMAdvisor Licenses Include FSWizard PRO For Android for Free!!
Check out our HSMAdvisor Web Store for Details

Absolutely the best handheld CNC machinist's speed and feed calculator around.
Calculate cutting conditions simply by choosing your work and tool material.
No need to know any numbers. 
FSWizard will automatically use recommended cutting speed and chipload.

* Made by a machinist for machinists * 

Improve productivity and optimize cutter life.

* Milling, Drilling, Tapping and Turning
* Suggests optimum cutting depth and balances cutting parameters.
* Supports Chip thinning and HSM machining.
* Required Power estimation, Recommended Depth/Width of Cut for extra-long cutters.
* Built in tap drill calculator to calculate not only cutting speed and feed , but also drill dia in accordance with desired thread engagement.
* Drill and Tap charts for both imperial and metric systems.
* Oblique Triangle Calculator
* Fillet Calculator will find tangent points to a circle and two lines
* Machinists Bolt Hole Circle and Line Calculators

It just does it all.

*Milling Tools: Solid EndMill, Indexed End Mill and FaceMill, Solid and Indexable drills
*Drilling Tools: Jobber Drill, Hi-Performance Parabolic Drill, Spade Drill, Reamer
*Turning Tools: Profiling and Grooving

Please try the Free FSWizard Lite first to confirm your device capability.
Also huge thanks to those who go through the trouble and leave a review.
Good reviews mean more sales and more incentive for me to further improve on this app.

FSWizard Lite and FSWizard PRO are iPhone/Android machinist calculators that do not require internet connection.
PRO version has all the latest material lists and speed and feed technology.

Lite version has all the same features, but it only has tool steel, mild steel and aluminum in its material list. It still has all the tool types and tool materials found in online and standalone versions
Both Lite and Pro  versions have unlocked tapping data.

Lite versions have limited geometry calculators.

This app is intended not to replace but to complement my much more powerful standalone Windows application called HSMAdvisor.

FSWizard LITE Free
FSWizard PRO $49.99
FSWizard PRO $39.99 Multiplatform License for iOS and Android Purchase through PayPal

2013-07-06_15-51-40.png 2013-07-06_15-51-50.png 2013-07-06_15-52-04.png 2013-07-06_16-03-27.png 2013-07-06_15-52-51.png 2013-07-06_15-52-27.png Fillet Calculator Oblique Triangle Calculator Pipe Taps New Layout Bolt Hole calc Bolt Hole Line Calculator Bolt Hole Particial Calculator SHCS Reference 82Deg FHS Reference

HSM or High Speed Machining is becoming more and more popular each day.
Many of us have seen those youtube videos where endmlls remove large amounts of material at high speeds/feeds.

While definitions of HSM may vary between tool manufacturers and even individual shops, the physics behind it remain the same.

In this article i would like to explore flat endmills.

HSM is not about ramping up your speed/feed overrides to 200% and puling out your smartphone to record another youtube-worth video.

What is HSM?

HSM is a complex of programming, machining and tooling techniques aimed at radical increase of productivity.

Programming

The cornerstone of HSM is low radial and high axial engagement of an endmill with the workpiece.

There are many CAD/CAM systems that allow you to create HSM tool-paths. Mastercam's Dynamic milling and SurfCAM's Truemill are some of them.

When radial cutter engagement with the material is smaller than the radius of the tool an interesting thing happens.
Chip load- the distance the tool advances per cutter revolution per tooth- does not equal the actual chip thickness anymore.
Chip thinning mainly happens at radial engagements below 30% of the diameter.

In order to get compensated chipload you need to multiply recommended by manufacturer chipload by the chip thinning factor.

Usual Radial Engagement for HSM toolpaths however is between 5 and 15%.

Axial depth of cut varies depending on geometry, but

Radial Chip Thinning HSMAdvisor Screenshot

Some time ago an unknown colleague had borrowed an end mill from me.

Have i had been there i would have stressed that it was aluminum specific cutter and that it should not be used on steel.
Unfortunately i was not and it did not occur to him to ask somebody who would have known better.

Next time i look into my drawer i see this.(first picture)

Now we have a tool and cutter grinder to sharpen the OD of an end mill, but chips were so big, i would have to grind off maybe 20 thou of the diameter on order to get rid of them.

Our TC grinder does not allow to re-flute end mills, so i had to do it holding end mill in my hands.

First i picked up correct angle, and then i slide end mill upwards, turning it at the same rate as to follow flutes.

It came out better than i thought.
I was not planing to use it for finishing anyway.

And it lost only 5 thou in diameter after this hack-regrinding.

Before during after

Sometimes people ask me: "I tried your calculator, and i liked it, but it seems to me a little too aggressive...do you actually do any testing?"

Well, to those I say that not only i do testing, but i run production jobs 100% calculated with my own HSMAdvisor.

Many machinists say that nothing beats an experienced operator holding his hand on feed hold button and playing with speed and feed override trying to find the "sweet spot" where cutting speed and feed rate are maximized and chatter is eliminated or reduced.

And it is correct, but not any machinist is experienced or actually knows what he is doing.
Many machinists also finish their apprenticeship program and never learn a single thing about new tooling types and materials since. They bag years of experience, but their knowledge is stuck on a level it was when they first got their license.

Also not a single person can possibly know cutting conditions for hundreds of materials and remember all of the jobs he had ever ran.

This is where tool database comes in.

Not only can you save tools to cut down and in many cases eliminate entering parameters for every calculation.
But you can (and should) save cutting data for each particular case.

A single tool entry can contain an unlimited number of cuts attached to it, so machinist never has to remember everything.

Here is a i made video of slotting D2 with variable helix hi-performace endmill.

Material: D-2 Tool Steel 200-250 HB
Tool: 0.500in 4FL Carbide TiAlN coated Solid HP End Mill
Speed: 360.0 SFM/ 2751.6 RPM
Feed: 0.0023 ipt/ 0.0094 ipr/ 25.76 ipm

Engagement:  DOC=0.330 in   WOC=0.500 in

Speeds and Feeds by HSMAdvisor (FSWizard)
Material: A-36 Hot Roll Steel 160-220 HB
Tool: 0.500in 4FL Carbide TiAlN coated Solid HP End Mill (WIDIA Metal Removal Maestro)
1" Stickout, 0.625 Flute Length
Speed: 528.0 SFM/ 4035.7 RPM
Feed: 0.0028 ipt/ 0.0114 ipr/ 46.00 ipm
Chip Thickness: 0.0028 in
Engagement:  DOC=0.250 in   WOC=0.500 in

Recenty ordered a 3Flute High Performance End Mill From NIAGARA.
Was very glad and slightly surprised that when punched in all of the endmill's data into my Calculator nothing broke down.I had a rason: At 5000RPM and 3/8" Deep slot cut. The feed came to around 92.0IPM. Chips were making this nice ringing noise that sounds like money.

Setup:
HAAS VM-3
Hudrolic Tribos Holder
3/4" 45DegHelix 3Flute 1.625FluteLen, 2.375"Overhang TICN HP End mill

S:5000RPM
F:92.0IPM
DOC: 0.375" Slotting
Coolant:FLOOD

The calculation was pretty much dead on.