In this tutorial we are going to explore different options and techniques when programming cutter movement.

Lets begin with a simple part shown in a drawing below.

Basically it is a rectangular piece 4.00x2.00
For the purpose of simplicity lets make the depth of our profile (z- dimention) 0.75"

We are going to use a 0.5" dia endmill, again because it is a very common size and is easy to do basic math with.

I took a liberty of puting locations for our part/toolpath, so it is easy to extract numbers from the drawing just by looking at it.

Notice the green rectangle. This rectangle represents the path that the center of the tool will have to take to produce the part with required dimentions.
The thing is: because endmills have certain diameter, the center of the tool must be always offset by its radius.

There are two ways of doing that.Read More 

We all love getting positive feedback on anything we do.

For example hearing "good job" from our bosses. Or "nice work" from our co-workers....
Okay, Okay bosses do not normally tell anyone "good job", but anyway that would be nice!

I also like reading e-mails which people all over the world send thanking me for my work on FSWizard and HSMAdvisor calculators.
Telling their success stories and suggesting new features.

Most seem very surprised when they send a question on weekend and receive an answer withing a couple of hours.

Often people send pictures of their work and links to their own web sites.

It is nice that more and more professional machinists are using my software, but seeing it help create a work of art is a special feeling.

One of recent customers Daniel Gentile, uses HSMAdvisor to calculate cutting parameters for his custom knife production business.

Here is what he has to say:

HSMAdvisor enables me to efficiently do the math that saves me not just a lot of time as I can confidently often use higher speeds but also a lot of money, as I tend to break less of those expensive 2 and 3mm carbide tools that see a lot of use on my folder production. Also because I work with a dozen different materials - from D2 steel to Titanium to Bronze - and a lot of different cutter types and finish requirements it's just nice not to have to work with "guess-work" for the feeds and speeds.

Daniel Gentile, owner of FERRUM D Gentile, custom Knives & forging classes.

Here is a link to his web site.
https://www.dgentile.com/

Here is a link to his portfolio page filled by pattern welded forged blades and katanas!
https://www.dgentile.com/portfolio.html

If you are a fan of old school forging, custom knives and basically anything to do with knives and blacksmithing, you have got to check it out!

HEM is a relatively new term.

It means High Efficiency Milling. It only became available when constant tool engagement toolpahs became almost standard on most of the CAM software.

Unlike HSM that utilizes chip thinning effect, HEM relies on much larger widths of cut and thus chip thinning does not occur. What gives it its name is much higher material removal rate that would normally be possible.

When you are machining a pocket you are most often only milling at about 50% WOC. But nevertheless you need to calculate speeds and feeds based on the fact that the very first move and every corner will be full slotting action. Which means that the whole pocket needs to be machined at lower feedrate.

HEM uses constant engagement toolpths to make sure that this never happens and that Width of Cut remains optimal. Tool never needs to make a full slot so you can ramp up the feedrate as if you were doing outside profiling.

Here is a video of a 1/2" 3 flute endmill machining a 5/8" deep pocket in aluminum at full depth. Normally this pocket would have been machined in 2 steps at 150 inches per minute.

Using Constant Tool Engagement toolpaths we can go full depth at 0.175" stepover and 275 inches per minute.

The advantage of this method is obvious- Higher Productivity.

HEM is not ideal for all cases and each application merits its own method of machining, but its always nice to know more than one way to do your job.

Lately there have been a lot of really interesting HSM topics on PracticalMachinist forums.

In one of them a guy who owns his own resharpening business posted a video of his endmill milling a block of D2 hardened to over 60 RC.
The forum topic is located here First try on D2 62Rc(video)

Here is his post so you know what we are talking about:

In the ensuing discussion i posted my own take on how and why HSM works

HSM works in many ways.

1) Reduced cutting time per edge per revolution allows it to cool down more.
2) Chip thinning allows to increase chipload (advancement per tooth per revolution)
3) Increased depth of cut combined with shallow radial positively affects deflection. Tool bends less as it is more rigid towards the tool holder.
4) Higher cutting speed actually reduces cutting forces as heat generated in the cutting zone makes it easier to shear off a layer of metal. Yet because the time of contact is so small, most of the heat is carried away with the chip.
5) Higher RPM also allows to get rid of hot chips faster thus further reducing heat transferred to the tool.
6) Higher feedrate actually reduces relative cutting speed.
7) At high axial engagements more than one flute is in contact with the workpiece at different points along the axis of the tool. This too helps combat vibrations and chatter.
8) You are using more of the tool than just its tip, so technically you can do more work with one tool before it gets dull.
9) lastly it looks cool as hell and is very impressive. Whenever we know visitors or bosses are coming we try to make sure some HSM is going on even if application does not merit that
I am not sure if the air that is moved by the endmill is doing much, but i suspect he didn't mean exactly that.

Check this video out.

The whole thing is pretty impressive, but the best part starts closer to the middle of the video. At around 3:20 you can see the size of the machine. Truly amazing.

Note: TURN YOUR VOLUME DOWN

I have been asked to create a tutorial on how to work with the tool library, so here it is.

myCut Tool Database is quite a unique thing.

It not only contains all of your tools, but also each and every tool can have multiple operations or "Cuts" attached to it.

Everything is very simple.

Database contains Libraries

Libraries contain Tools

And Tools contain Cuts

Each entity behaves according to specific rules and "knows" specific kind of data.

Please read more to learn how it all works.Read More 

I have just uploaded a new release of HSMAdvisor.

I have decided to extend trials every time major releases come out.

This will happen every several months or so.

This release is pretty big. So every one who has not purchased yet gets 30 days more to play with it.

We have material cross-reference tool.

It allows you to quickly figure out material group for a large number of materials. Around 1000 of them.
You can access it by pressing "MORE" button next to material drop-down list.

Here is it looks:

Second Big thing is new tool life estimator.

It allows to show you how tool life reacts to changes in speed, feed rate and depth of cut.

It is a percentage based on normal shoulder milling cut that should equal 100%

Nobody else has this feature- it is absolutely unique to HSMAdvisor and that is in part why i decided to extend trials this time.

Besides tool life gage there is a new tab in results area.

It is called Gages.

It shows important information like what percentage of deflection, torque and machine load we are running at the moment.

It helps to figure out at a glance if something is out of whack.

As always feedback is welcome.

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 Read More 

This video was uploaded a couple of days ago and has sparked fierce debates on PM forums about its feasibility.

There is no official information yet, but some are already wondering how accurate and cheap it is going to be.

.....and this is why they are so heavy.

I have stumbled upon this video the other day.

It shows a very good reason to keep those doors closed at all times when runing your machine.