Often times CNC programming tutorials only teach you how to create the tool-paths and not enough attention is paid on showing how to properly hold parts being machined.

At the same time efficient workholding is an art in it self and mastering it could drastically improve shop productivity and accuracy.

Without further ado let's jump into the workflow.

Step 1. Analyze the Drawing and the Model

We would have to look at the drawing, tolerances and the CAD model to develop the machining strategy.

This particular part has tight (+/- 0.001) tolerances between the features located on the top and the bottom sides. In addition to that it has a 2.5 degree draft angle on external walls.

Thus I decided to not use the soft jaws approach and machine it in a fixture. Soft jaws are generally OK for tolerances down to +/-0.001" but because of the draft angle the part would always want to pop out of the jaws.

1. Finished Part 2. First Op: Before 2. First Op. After 3. Machined Fixture 4. Second Op: Bearing Seat 5. Third Op: Finished Part

Update: I have received emails saying that lots of people's purchasing and accounting departments were closed during this time, so the sale has been extended by one week until January 12!

7 Years in Business!

The only deal of the year starts on December  28 and will last until January 3 (Extended till January 12)

Only during these 5 days you will be able to save 50% on any and all HSMAdvisor and/or FSWizard packages, sold on our https://HSMAdvisor.com store!

Do not miss the only deal of the year!

Merry Christmas and a Happy New Year!!

TiAdvisor (Tool Inventory Advisor) is a new feature under development within HSMAdvisor.

Unlike most cases when developers design a standalone product and then go through a laborious work of integrating it into existing software products, i decided to go the other way.

TiAdvisor will be developed as an integral part of HSMAdvisor and then, once complete, will be moved into a separate standalone product. This will make for seamless integration between our software products.

What TiAdvisor does

• Keeps track of inventory levels.
• Automatically add tools that are low in stock to Purchase Request List
• Generate and print Purchase Request form
• Add tools to stock when they are received

More functions are being worked on.

Download TiAdvisor bundled with HSMAdvisor over here: http://zero-divide.net/index.php?page=forums&shell_id=170&article_id=4776

TiAdvisor Workflow

Did you know there are three ways you can touch off your tools?

Because of how Machine Offsets add up, there are several ways CNC machinists can set their Tool and Work Offsets.

This is especially true for Tool Length Offsets.

Tool Offsets can be either Positive or Negative.
Depending on your Machine Shop equipment you should use one or the other.

Regardless of how you set your tool length offset, you apply it the same way.
Right after the tool change and after turning on your spindle and moving to your X Y position above the part.
The very first absolute Z movement should be the line where you apply the tool length offset.

Positive Tool Offsets (gage line tool length offsets)

In the case of Positive Tool Offsets, the offset represents the Length of the tool measured as a distance from the Gauge Line of the spindle (typically spindle nose) to the tip of the tool. The longer the tool, the larger your Tool Length offset will be.

Before we run any G-Code program, we need to tell the machine where our part zero is.
A Part Zero is simply a bunch of numbers that offset the axis to give the machine a new coordinate point to work from.

Work Offsets is one of the most basic pieces of knowledge any machinist must-have.

Let us account for all the basic coordinate systems and definitions, available in a generic CNC machine

• Machine Home and (Absolute) Machine Coordinates
• Work Offset Coordinates
• Tool Length Offsets

Machine Home and Machine Coordinates: G53

Machine Coordinates (or Absolute Coordinates) is the absolute and constant representation of the machine axis position.
These coordinates never change between Machine Restarts and must remain such. In fact, there is often no way for an operator to adjust the Absolute Machine Axis Home position.

Machine Home is simply that magical place where all Machine Coordinates should become Zero.

To Home the Machine is to start a machine operation, that will move all Axis to their soft limit position where X, Y, and Z-axis reading will be set to zero.

Homing must be done every time you restart your machine. Without it machine does not know where is the position of its table or spindle.

When homed your machine coordinates will read X=0 Y=0 and Z=0 and it is going to look like this:

The point where Machine X and Y intersect is called Table Home Position and the one where the Machine Z-axis starts from is called Spindle Home.

Now, there is no agreement between machine tool manufacturers on where the machine home should be.

Canned cycles are used every time we need to drill, ream or tap holes on our CNC machine

Standard Fanuc G-Code language supports more than a dozen canned cycles.

The most common cycles that will cover 99.9% of your g-Code CNC programming work are:

Subsequent holes

You can drill additional holes After your canned cycle has been initiated.
Any line with X Y position will be treated as another hole position.

Each position can have its own Retract value, feed rate and retract height modifier.

G80 - Canned Cycle Cancel Code

After all the holes of the canned cycle have been drilled, it is required to call G80 code in order to cancel the current cycle.

A couple of days ago I helped a gentleman by answering a few questions about using HSMAdvisor Speed and Feed Calculator to machine a 310 Stainless Steel piece using HSM techniques.

Today he created a post on PracticalMachinist forums walking us through his experience.
And he even took a video of the part being cut!

Endorsements like this is the best thing any software developer can hope for.

I always welcome any feedback regarding my software and never mind helping anyone, whether he is a novice, experienced machinist, my customer or not.

Thank you Sebastien, good luck to you!

Yesterday I uploaded another update to FSWizard:Mobile app.

Apart from the newest materials and coatings that are already present in HSMAdvisor PC calculator, i also added Socket Head and Imperial Flat head screw reference.

You can download the updated app on Google Play appstore

FSWSHCS.PNG FSW82degFHS.PNG

A few days ago one of FSwizard:PRo users questioned me over how FSwizard works.

The way SFM calculates seemed off to him.

As a result i made a quick sketch for him, that i thought i would share here.

Omar was asking me how come SFM seemed wrong for a 1" dia ball-nose cutter when making shallow depth cuts.

The sketch above shows exactly why.

On the left part we see a cutter engaged into the material to the depth equal to its corner radius.
At that depth the maximum effective diameter is achieved. So an old good RPM=4xSFM/Dia formula would apply.

But at shallower depths, effective diameter of the cutter is reduced.

At 0.1" depth of cut, effective diameter would only be around 0.6"

In fact it goes to zero at the very centre. So a higher RPM will be required to achieve the recommended cutting speed.

In the same thread i also explained how DOC/WOC balancing works.

So if you are interested - read on.

Here is the thread http://zero-divide.net/index.php?page=forums&shell_id=170&article_id=4590

Here are some samples of nested parts i did recently

In both cases back of all pieces were machined at the same time, dowel holes milled so that there would be a way to align top and bottom.

Ealot of material was lost, but it was a scrap anyways, so all i gained was alot of saved man-hours.

And here are 4 more pictures: