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Best High Speed Machining is Dry Machining

May 18, 2016, 9:06 pm by Eldar Gerfanov (Admin)
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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.

A short preamble: 
I had to machine a 1080 steel component where chip clearance was an issue. Without programmable airblast and due to an unattended run of the machine I  decided to try and see how long the tool is going to last with the coolant turned on.

I calculated cutting parameters using HSMAdvisor Speed and Feed Calculator and came up with the following data:

Tool:  0.5" 4Flute High-Performance  End Mill from Kennametal
Depth of Cut:  0.8"
Width of Cut:  0.025" (5%)
RPM:  10000
Feed:  400 ipm
SFM:  1308
Chip Load:  0.010"

Because I had hundreds of parts to machine, I could get good sample data.

So I ran each tool for as long as I was comfortable with the noise level.

The results of the test surprised me quite a bit.
Yes, I knew tool life with coolant would be less than without, but I did not expect such a dramatic difference:

  Through Spindle Coolant.
Perfect chip removal.

Dry.
No Airblast - some chips re-cutting in the pocket

Number of Parts 45 pcs 400 pcs !! Could do another 400 easily.
Tool after the run

(Picture for demonstration only. The original file was lost.)

Comments

The run stopped when the tool was making a lot of noise and pushing too much burr up the wall.

Coating stripped from cutting edges. Lots of plastic deformation.

Tool survived barely touched! Finished the rest of the batch with the same cutter and could run the same amount easily.

No considerable wear on cutting edges and no built-up edge.

We got at least a 10-fold improvement in cutter life just by turning off the coolant.

Counter-intuitive, but that is High-Speed Machining for you. It does not have to make sense!

We know that the bad tool life is caused by the thermal shock of the tool coating and the carbide itself at high temperatures that are produced by high cutting speeds.
You can read more on the theory behind HSM in this article->How to: High-Speed Machining (HSM), CNC Milling
Here is a small excerpt from it:

Quote:
....Increased cutting speed makes the use of coolant not advisable.

As hot swarf contacts coolant, it may harden (in the case of tool steels) and when re-cut it will damage the cutting edges.
Also, contact of the coolant with the overheated cutting edge will cause thermal cracking and premature wear of the endmill.

Popular AlTiN and TiAlN coatings, for example, actually require heat to "activate" coating and make it work properly.

Airblast is required not to cool the tool, but actually to clear the chips from the cutting zone...

How about that gummy stainless?

I know what you are going to say: "Let's see you try no coolant with some 304 Stainless Steel"
And I agree with you. Sometimes when we are getting a lot of built-up edge on gummy tough materials we just have to use coolant. And that will negatively impact your tool life!

There are, however a few tips on dry HSM-machining gummy stainless:

  • Use less radial engagement (about 5%).
  • Use heavy feed.
  • As a result of the above, you can use a higher cutting speed

What this less radial engagement does, is it allows you to surpass the "no man's land" between 300 and 900 SFM where built-up edge forms on the cutting edge.
In addition to Chip Thinning our HSMAdvisor accounts for the SFM boost, you can get in that case. Just turn on the "HSM" checkbox! 

If you tried everything and you are still getting chip weld, you might have no other option than to turn on your coolant and suck up the bad tool life.

Some materials are just crap to machine and that's the end of it.

Happy Millin'!

6 ways to utilize your CNC spindle (and make your life easier)

May 10, 2016, 10:59 pm by Eldar Gerfanov (Admin)
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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!

Use a spring-loaded Sharpe to mark invisible features.

I came up with this method when guys in the shop asked me for a way locate vent holes on our moulds.

It consists of a two spring-loaded aluminium cylinders, one end of which goes into a tool holder and another one holds a Sharpe marker.

A program used to drill the back holes is rotated and hole locations projected to the surface of the mould. This way our tool does not try to go through the wall.

I tried to dig up a video of it, but it seems I lost it.

Give out a noise alarm

On one of my jobs I attached a simple whistle to a toolholder and programmed spindle air-blow M-code when the program was complete.

That's a noise you can not miss!

Do some side-milling with a right angle attachment

This spindle attachment adds one more faux axis to your 3 axis mill allowing you to do some work in a hard to reach place.

 

Increase RPM with a Spindle Speeder

Tiny endmills require crazy speeds to get optimal productivity and tool life.
Spindle speeders can solve the problem of near-zero cutting speeds for micro-machining.


As far as I know there are 3 kinds of spindle speeders:

  • Meachanical, where rotation of the spindle is multiplied using gears.
  • Air-driven, where air is used to rotate a little turbine, that in turn rotates the tool.
  • Coolant-driven (like on the picture above). Same as air-driven, but the pressure of the Coolant-Through-Spindle is used to rotate the turbine.

Coolant and air-driven speeders offer highest speeds, while mechanical ones give the most torque and more constant RPM values.

Use your CNC with a Spindle Probe as a CMM to measure features right on the machine

Sometimes i had to measure huge parts with pretty tight tolerance requirements and taking them out of the machine was not an option. Instead i elected to write a little macro, that would tell the machine to probe the features i needed and write numbers into unused work offsets.

All that remained after that was to check if the numbers stored in offsets lay within the tolerances.

What else can you use your spindle for?

 

Combating Chatter: 4 reasons to NOT reduce your feedrate

April 30, 2016, 6:58 pm by Eldar Gerfanov (Admin)
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We all have heard hundreds of times that when chatter is happening during machining, we should reduce our feed rate. The same advice we also hear for compensating for extra-long tools and unstable setups.

Let me explain why I think this is mostly incorrect.

Let’s list  the effects of reducing the feed rate:

  1. Reduces tool life.
  2. Reduces productivity.
  3. Increases deflection.
  4. Causes chatter.

Let me explain from my own experience and research I have made each of these points and a simple way to avoid chatter's adverse effects.

Reduction in chip-load reduces tool life.

This may seem counter-intuitive, but the tool gets the best cutting edge life only within a narrow window of chip-load range and cutting speed.

Reduce your chip load below a certain value, and you will be hurting your tool life a great deal.
Yes, your tool may run longer, but it will do a lot less work before it gets dull!

Reduction in productivity

This point follows right out of the previous one. Not only your tool now moves slower, thus reducing the material removal rate, but you also have to replace it more often. That adds extra setup time cost too.

Increase in deflection

Cutting action is a fine balance between a cutting edge plowing through the material, rubbing and shearing it. We want to do as much shearing as possible and less plowing, and ideally, no rubbing.

I recently did a test cutting 6061 Aluminum plate with a 1” long .25” dia Grooving tool and measuring its deflection at different chip-loads:

You can clearly see how below 0.0005” chip load (X-axis) bar deflection is double of what it should be if you were to follow the light-blue trend line. Here, we are getting 0.001” deflection!

Then once we increase the chip load to 0.001”, the tool is not rubbing anymore, and we get 0.0015” deflection - not double, but only 150% of deflection increase for 200% increase in chip-load.

The line continues steadily until we hit 0.003” chip load, and then it almost takes a dip!

Between 0.003” and 0.004” chip load, we get just 0.001” increase in deflection instead of projected 0.002”.

This means that the perfect chip load for the boring bar I was using is between .003” and .004” because right after the sweet spot, at .005” chip load, we get a sudden spike in deflection up to 0.010.”

As cutting edge (ideally) shears off a slice of the material, it hardens the work-piece right underneath. This layer of material will be sheared off by the next (or the same in case of a single flute) cutting edge.

If our chip-load is too low, we will be cutting right through the work-hardened surface, thus decreasing tool life (see point one) and actually increasing the cutting pressure.

Also, the cutting edge is not ideally sharp. It has an edge radius, half of which will be pushing the material up and the other one - down. So you will be having a lot of plowing and rubbing action too.

Because one image is better than a thousand words:

The red surface on the picture is the work-hardened layer. The green one - workpiece with the regular hardness. We want the cutting edge to shear off underneath the hardened layer.

Induces Chatter

In many cases, a lower feed rate may actually be the reason for chatter in the first place.

Have you ever heard an experienced machinist tell somebody to “load-up that tool” to prevent chatter?
You are most likely such a machinist, and you have noticed that increasing the feed rate may actually reduce chatter.

Why does chatter occur?
It is a combination of the above mentioned factors such as an increase in cutting pressure causing deflection and unstable cutting conditions.

The tool deflected by the cutting pressure tries to return to its original shape, and lack of chip load allows it to do so unobstructedly. The tool pretty much vibrates freely. When that happens thousands of times per minute, you get your tool singing.

When you increase the feed rate, you may actually create more stable cutting conditions and eliminate chatter.

So what should I do if I am already getting chatter?

First of all, make sure you are using proper speeds and feeds, to begin with.
Call your tool vendor to get proper numbers for your particular case, or try our HSMAdvisor- Advanced Speed and Feed Calculator.

HSMAdvisor will suggest you perfect starting speeds and feeds, and also it will suggest you proper Depth and Width of cut for your particular workpiece material and tool configuration.

If you used HSMAdvisor, chances are you are not going to get any chatter at all!

If you did not and want to go with your tool vendor' numbers - fine - try their speeds and feeds on your machine.

Did it help? If not, here is the simple solution:

Reduce the Depth of Cut!

While a reduction in chip-load leads to more rubbing, it does not reduce the cutting pressure in the same way the DOC reduction does.

For example. We might only need to reduce the DOC (and thus cutting pressure) by 20%, and the chatter will go away. The same effect would require us to reduce the feed by 50% or so if we are lucky. If we are not lucky, even further reduction in feed rate will not eliminate the chatter.

So in conclusion:

Whenever you are having chatter issues, get proper Speeds and Feeds and reduce that DOC!

Best Regards

HSMAdvisor is moving to the Rolling Release model

April 21, 2016, 7:33 pm by Eldar Gerfanov (Admin)
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From this point on, all holders of valid HSMAdvisor licenses will be eligible to free Life-Time updates and upgrades to their HSMAdvisor product.
Likewise there is not going to be a big functionality jump between the version 1.99 and 2.0 like in some other software products.

This release model is called "rolling release" and it is becoming the new industry norm.
It offers smoother transition and no steep learning curve for existing users. It also helps prevent unavoidable bugs when a large amount of changes is introduced all at once.

Hence the second piece of the news: 

The sale of the old HSMAdvisor "Permanent License" package has been discontinued.

A couple of days ago we stopped selling the old "Permanent with 1 year of free updates" license package, that had been selling for more than two and a half (sic!) years.
For a while it was the only available package and it sold great! Now, however, it is being outsold by our Floating Licenses.

There is a number of reasons for this decision: 

  • Because even though a version has become obsolete, I still have to support it.
  • Newest cool Cloud features (being implemented right now) require most of the users to be more or less on the same version.
  • I just hate the though of a user somewhere being stuck on an old and obsolete version of my software.
    Yes, I know it works fine for you like it is (from time to time i see people with 1 year-old version), but I would like all customers to have the latest and the greatest.
  • To disallow updates for licenses with expired maintenance would require significant investments of time from my side. Which would involve creating new product code, following by the need to update license keys for ALL seats sold to this date.
    Instead of making my users (and mine too) lifes harder, I would rather spend the time adding new features to our products.

In light of the above-mentioned reasons the only available Permanent license type is now the new "Permanent License" that includes Life-Time Updates. It is just like the old Permanent License, but the maintenance on it never expires.

I am assuring the holders of the old Permanent License packages that nothing is going to change in the way they own and operate the software. My customers never get the short end of the stick and you will be taken care of.

More details on this are to follow when we are ready to move to HSMAdvisor 2.0

Regards.

Hi-Feed Milling at 600 ipm!

April 8, 2016, 10:19 pm by Eldar Gerfanov (Admin)
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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%!

It is a 1" dia 5 flute Tungaloy DoFeed hi-feed cutter that Tom Muller (Toronto Tungaloy tool rep.) set me up with.
I bumped into him the other day at the office. He recognized me as one of his LinkedIn contacts and asked me how it was going (I do envy people's ability to have such a good memory for faces). At the time I was programming the steel component you see on the video and asked Tom if he had anything that would help us effectively remove the bulk of material.

Turns out we had one of his amazing feed-mills all along. So he suggested starting cutting parameters (which were very much in line with HSMAdvisor's recommendations) and even waited until I finish setting up a test cut to make sure the endmills work as advertised.

The next day I had more time to play with it and found out that the cutter appeared a lot quieter at slightly shallower DOC (0.030" versus 0.035") and a much higher cutting speed and feed rate (0.044" per tooth versus 0.028).

I also was able to use a much higher cutting speed than recommended because the mfg's recommendations (unlike HSMAdvisor) do not consider the actual alloy but a wide group it belongs to. So the speeds tend to be in the middle of the road (too high for tough stuff. too slow for mild one).

Here you can see the screenshot of the HSMAdvisor's calculation I used to make the cut:

As I saved the tool into the HSMA database, I also saved this successful cut, so that there is no need to guess the next time when using this wonderful tool.

Back to the question of tool life: After about 30 minutes in the cut I did not see any (and I mean ANY) wear on the cutting edges.

At this rate we can easily get 6 hours of cutting edge life!

Some more photos:

By the way. If you are using a Speed and Feed calculator other than HSMAdvisor, does its developer have access to real manufacturing equipment to continually cross-check the data his calc outputs with reality?

HSMAdvisor's does!

One Case of HSM Machining: HSMAdvisor vs. All

April 2, 2016, 6:41 pm by Eldar Gerfanov (Admin)
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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:




Not too bad huh? My Speed and Feed calc suggests almost the same chip-load.
But because it is caring about your tool life, HSMAdvisor suggests slower cutting speed. 4464 RPM versus BlueSwarf's 10000 RPM

Now, if we wanted 15 minutes of tool life (what the tool on the video is probably going to have)
We could have entered 10000 RPM and voila!

We are getting almost the same feedrate at the expense of tool life.

86% of Tool Life versus 18% - You decide which is better. HSMAdvisor gives you that ability.

You can also decide whether super-expensive technology like BS is really worth the hype and the money spent.

But we are not over yet.

Let us try another calculator. The HSMAdvisor's direct competitor.
Introducing the G-Man(real name hidden).

This series of screenshots was sent to me by a user of that software, who showed me the okuma video to try and make sense of his results.

He entered the same tool numbers with the same material to see what the Goliath of the S&F business suggests:

All the tool data is absolutely the same.

We can see that G-Man really cares about his customer's tool life because his RPM is really low.
However his Feedrate seems kind of HIGH....

How high - I do no know. What's the Chipload? 0.003" or 0.005".....hmm OK.....

Then the user set RPM to 10000 like in the Okuma Video at the top of the article:

HOLY FLYING CUPCAKES!

10000 RPM and 650 IPM !

Why is the Feedrate so high?
Isn't there something in the calculator that should prevent the machinist from leaving the Endmill inside the pocket once the E-Stop is pressed and Z-Axis is retracted?

Yes, everything is set to "Rigid" and "Rough" but you would not normally expect such mild words to cause much trouble, would you?

I am starting to realize that something is very very wrong here.

In the last screenshot his Chipload(IPT) shows 0.0108". Please note in the previous screenshot he has 0.003".....

How does a mere fact of changing the RPM change the Chipload so much?

I am going to the previous screenshot and start doing some math. Something that G-Man should have done for him:
185.9ipm / 6 flutes/ 2640 RPM = 0.0117" Chipload.

Where does 0.0117 show on that screen? Nowhere!

Whelp. Perhaps before "...considering over 60 variables..." G-Man should get his basic math in order?
Or a program workflow. I don't know - I am not an accredited IT engineer to advise on that.

Also note that aside from the Deflection nothing shows us how hard we are really pushing the Endmill.

What if I told you that the endmill in question WILL NOT survive 0.004" deflection at all?

How does my HSMAdvisor know it? Math. Not even some hard-core science. Just a high-school level.

Does G-Man know it?

Dohis customers it?

HSMAdvisor users learned to trust the Limits I have put in place to protect their tools.
If it says "Can't do it" there is a really high chance that you really should not!

What do other people who run HSM machining toolpaths for a living say?

Here I assembled the cuts posted for 4140 PH or similar steel with a similar tool diameter on Rizzo's Dynamic Database :

Chipload: 0.007" 0.0068" 0.007"

At the bottom of each column I calculated the actual chipload the comparable tools were making.

These results by real people are in fact more in line with HSMAdvisor's default suggestion than with the Okuma Video.

And shure as hell none of them goes any close to 0.011" per tooth in such situation.

It is not my job to point to my competitors mistakes (though he probably should thank me for finding them).
But it is a word of caution for those who use Speed And Feed Calculators, that do not consider the endmill's strength and do not show you how hard you are pushing your tools and machines.

A user who does not see what he is doing is bound to break something.

So the big question everyone is having: Is G-Man plain wrong?

I seriously, do not know. His calculations seem just too wonky to be even sure this is the intended result.
Here is what I have when I try to simulate G-Man's results:

It is possible! With Torque Limit almost at its maximum (190% is no joke)

For a minute or two! Then you will likely hear an unmistakeable sound of the endmill snapping.

Only a mad man would run his tools like that. I mean who has the time and the money to replace his tools like that?
Unfortunately for his customers G-Man does not tell them that kind of information.

What did I advise the customer? I sent him a link to this article, so he can decide.

Regards.

Tesla Model 3: Is This The End?

April 2, 2016, 12:04 pm by Eldar Gerfanov (Admin)

There have been purely electric cars long before the Tesla Model 3.

But Tesla has made it cool. Sort of like how Apple made the iPhone cool, Tesla made not just gas-free, environment-saving cars. It made cool high-performance vehicles that are fun to drive.

And nobody really cares that Chevy Volt has already been available for years for a comparable price. Couple of days since its unveil, the new Model 3 has already outsold the Volt. Not a small feat, considering, they are only going to start delivering in about a year!

But Tesla, like Apple, like Amazon is in many ways a disruptive technology.

This technology will eventually leave some people without jobs.

And I am not only talking about  all those dealerships, car mechanics and alike - all those people who are directly being affected right now because the business model of Tesla does not permit independently-owned dealerships, nor third-party mechanics. Just like Apple that will not allow any other apps to run on their iPhones, other than the ones bought in their iTunes store.

I am also talking about the huge industry of gas or diesel engine and transmission producers.

See. I work for a company, that specializes in just a small (but important, like everything else) business of power transmission within the engine. All those timing sprockets, pulleys, automatic AC clutches, vibration-silencers and a bunch of other stuff that rotates. It is a 2 billion business for the company.

I work in a prototyping department. And I can see the writing on the wall.
Once car manufacturers realize that the future has come, they will stop investing money into developing the old engine technologies.

For the time being, while transitioning to all-electric cars, they will still produce the engines, but nobody will spend a dime on all those obround-shaped sprockets (for example) company I work for specializes in.

And then eventually they will not need even that any more!

Would I buy a Tesla, thus by a tiny bit nearing the end of my job in engine manufacturing?

Yes, I would.

Once a new technology sweeps in. All those who were reliant on the previous one will have to adapt or die off.

Just people who used to operate elevators- new technology will force lots of people to go their way.

Can't stop the evolution.
But it really helps to see where its heading, so we don't get ran over by it!

Me? I don't see my current position within the current company existing any more in about 5 to 10 years.

Cheers!

We are announcing a New Product!

April 1, 2016, 5:01 pm by Eldar Gerfanov (Admin)

I would like to announce the launch of a brand new product called HSMCode.

HSMCode combines the power HSMAdvisor speed and Feed calculator, its advanced Tool and Cut Database and the new functionality of HSMCode into one seamless product!

What does HSMCode Do?

HSMCode allows you to create ToolPaths from imported CAD or Solid geometry with ease.

All you need to do is pick features that need to be machined and HSMAdvisor will pick the most suitable tool, calculate proper speeds and feeds and then HSMCode will generate the G-Code for your machine

As simple as that.

You can also create additional geometry using an in-built CAD designer and Simulate your Toolpaths to verify the correctness of your work.

The sales will begin in a couple of months on June 31 2016!

Please contact me if you would like to test the early demo version, affect the development of the software and (depending on the value of your input) receive your Lifetime Subscription for free!

Cheers!

Mind the Gap!

March 29, 2016, 3:22 pm by Eldar Gerfanov (Admin)

Don't you hate when "that guy" cuts your stock a little too short?

Holding on to just 0.060" here. The part is 1.5" tall made out of 4140, which helps it stay in place and not collapse under machining pressure. Pretty sure it would have moved if it was made out of mild steel.

PS. Did I eay I love those CR vise? I do. Can't lift that jaw with a lift truck.

FSWizard:Mobile 1.47

March 29, 2016, 8:43 am by Eldar Gerfanov (Admin)

There have been reports of troubles our FSWizard users were having after updating to Android 6.0

I issued some hotfixes before but they did not help.

So I would like to announce that with the latest update all the problems have been fixed. There were also minor updates in the UI, but nothing major.

Cheers!

 

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