Product: Software

Fixture Offset Calculator

Developed by Michael Braun

Horizontal Machining Center Users!

  • Reduce setup time and make programming easier!

  • Calculate fixture offset values at the click of a button

Calculate fixture offset values and generate G10 commands in seconds!

What does this spreadsheet do?

If you have a machining center with a rotary device, and if your programs work on several sides of a workpiece (or workpieces), you know how difficult it can be to determine program zero assignment values.  You must either calculate them while programming (assuming qualified and predictable fixtures) or your setup person must measure and enter them at the machine during setup.  Both methods are time consuming and error-prone.  And of course, multiple measurements made at the machine are especially wasteful.  (Consider measuring values for 10 fixture offsets - thirty values must be measured!)


Provided in Microsoft Excel format, the Fixture Offset Calculator spreadsheet will instantly calculate fixture offset values based upon some simple input .  And it will automatically create G10 commands that enter fixture offsets.  This provides at least three important benefits:

  • For the programmer: Programmed coordinates will be simpler to calculate - all coordinates will be specified from a central location that is right on the workpiece (click here to find out how).

  • For the setup person: Program zero assignment will be more fail-safe.  There will be fewer chances for mistakes during fixture offset measurements and entries.

  • For the setup person: Less time will be spent during setup to determine and enter fixture offset values.  With predictable, qualified setups, the task of program zero assignment will be completelyeliminated.  At worst (non-qualified setups), just three values must be measured during setup (compared to three per fixture offset).


Admittedly, the benefits of this spreadsheet may not be immediately obvious, especially if you've been left to your own to figure out how to assign program zero for your four-axis machining centers.  While you may be pretty comfortable with your current methods, there might be a better way.  Given the great potential for improvement, you owe it to yourself - and to your company - to learn how this spreadsheet works.  


Your input

Most - possibly all - of these input values can be entered long before the job hits the machine. Indeed, you'll probably fill in this data while programming. So when the job does hit the machine, your fixture offset values (G10 commands) will be ready.

The spreadsheet makes it easy to determine which values you are expected to enter, showing them in yellow boxes.  So whenever you see a yellow box, it is a value you must provide.

Machine data


From a list that you create (based upon your own machines), you'll choose the machine you intend to use for the job.  You can create up to 12 machines.

The data related to each machine includes four values:

  • Machine name

  • Distance from machine reference position (zero return) to center of table index in the X axis

  • Distance from machine reference position (zero return) to table top in Y axis

  • Distance from machine reference position (zero return) to center of table index in the Z axis


Here is some sample machine data:














Entering this data (on sheet3 of the spreadsheet) automatically creates the machine buttons in the spreadsheets working area (sheet1).  This data need only be entered one time.  You may find this data in the machine tool builder's manuals, or you can measure it at the machine.

If the job must be run on a different machine some day, just click the appropriate machine button and all fixture offset values will be updated! 

Known fixture values (yellow boxes below)


This includes just the values in the yellow boxes.  These are the distances from the center of index (table center) to the fixture's datum surfaces (program zero) in X and Z - and the distance from the table top to the fixture's datum surface in Y.

These values, of course, tell the Fixture Offset Calculator the location of program zero for a known side of the fixture, which is also a value you can specify (Known B Index in yellow box above).  Fixture offset values for all other sides will be calculated based upon these values and the specified angle of rotation.

With qualified and predictable fixtures, these values will come right from the fixture drawing.  This allows the G10 commands to be created long before the job hits the machine.

With unqualified fixtures - or qualified fixtures that are not predictable) these three values must be measured at the machine during setup.  This is not an obvious benefit, so please think about for a moment.  The worst case scenario is related to unqualified fixtures.  Your setup person will have to measure these three values at the machine during setup.  Compare this to having to measure three values for every fixture offset!

The values in the orange boxes (above) come from your machine selection.  Again, they are the distances from the machine's reference position to the center of index in X and Z, and to the table top in Y. 


The values in the green boxes (above) are the program zero assignment values for the known angle.  They are calculated for you.  If your program will be working on this index angle, these values will be included in one of the G10 commands.

Fixture offset numbers and corresponding angles of index


Based upon which sides of the workpiece you'll be working on, you specify the corresponding fixture offset numbers.  Again, this can be done long before the job hits the machine.  You enter only the values in the yellow boxes (fixture offset number and index angle).


The values in green boxes will be automatically calculated for you.  These are the program zero assignment  values to be placed in fixture offsets.

Note that any angle can be entered - not just right angles.  This is especially helpful when you must machine a surface that is at an odd angle - say 306 degrees.

Other preferences you may need to set

The Fixture Offset Calculator spreadsheet is pretty flexible, allowing you to set up for a variety of special choices:

  • Extended offsets - When checked, this will create G10 commands for Fanuc's extended fixture offset option. When not checked, it creates them for machines with only six fixture offsets (the L word value in the G10 command is different based upon which style of fixture offsets a machine has).

  • Overwrite sheet 2 - Sheet 2 of the spreadsheet provides you with a place to store fixture offset data for future use.  When you check this box, the corresponding data on sheet 2 will be overwritten.

  • N numbers - When checked, G10 commands will be created with sequence numbers.

  • Append B0 - When checked, G10 commands will include the word "B0".

  • Add external - When checked, a G10 for fixture offset number zero (G53) will be created.  This will ensure that the machine's reference position is the point of origin for fixture offset entries.

  • Okuma format - When checked, G10 commands will be created in Okuma format (if this box is not checked, Fanuc format will be used).


The output

The Fixture Offset Calculator spreadsheet is dynamic.  That is, it will constantly and immediately display current fixture offset data as you enter your values.


The values in green boxes are the fixture offset values.  Enter a new fixture offset number and B index angle (yellow boxes) and a new set of fixture offset values will be immediately displayed.


Writing data


When you're ready, you can output your data in two ways.  Clicking the Write to Sheet2 button will store your data on sheet two of the spreadsheet.  When you save the spreadsheet, these values will also be saved. 

This is important when you know you'll need your input data again some day.  Possibly you'll be running the job on a different machine in the future.  When it's needed, data from sheet2 can be recalled to the spreadsheet working area (sheet1).  Here is the format for sheet2 for our example data:





















Each time you click the Write to Sheet2 button, all of the data in the current working area (sheet1) will be placed on Sheet2.  The illustration above shows two jobs on Sheet2.  You man easily make notations on Sheet2 to clarify which job each set of data is for (part name, program number, etc.).

You can write to Sheet2 as many times as you wish, saving data for every job you run.  If necessary, the data for a job can be written back to the working area on Sheet1. 

Write to text file

This is what actually creates the G10 commands.  When this button is clicked, a text file including your program zero assigning G10 commands is created.  Here is the G10 text file for the example data shown above:


Once created, this file can be copied and pasted into the program and transferred to the machine using your DNC system (or it can be transferred by itself).

Sheet2 can also write a single group (or multiple groups) of fixture offsets to a text file.  Simply double-click a cell, select Write to Text File button, enter the Start row number and End row number and click OK.

Example of multiple groups of offsets (This example is for a part on pallet A and a part on pallet B using 2 separate fixture origin points):


  • N10G90G10L2P0X0Y0Z0B0

  • (B0)

  • N20G90G10L20P23X1.75Y-23.8895Z-40.9413B0

  • (B180)

  • N30G90G10L20P24X-1.75Y-23.8895Z-37.7913B0

  • (B0)

  • N40G90G10L20P25X0Y-20.5285Z-34.6423B0

  • (B90)

  • N50G90G10L20P26X-4.724Y-20.5285Z-39.3663B0

  • (B180)

  • N60G90G10L20P27X0Y-20.5285Z-44.0903B0

  • (B270)

  • N70G90G10L20P28X4.724Y-20.5285Z-39.3663B0

  • (B54)

  • N80G90G10L20P29X-3.8218Y-20.5285Z-36.5896B0

  • (B306)

  • N90G90G10L20P30X3.8218Y-20.5285Z-36.5896B0

  • (B80)

  • N100G90G10L20P31X-4.6522Y-20.5285Z-38.546B0

  • (B280)

  • N110G90G10L20P32X4.6522Y-20.5285Z-38.546B0


Download a demo of the Fixture Offset Calculator

We hope you've seen enough to want to know more. With our demo of the Fixture Offset Calculator, you'll be able to view the user interface. Admittedly, the demo is limited, but it should help you determine whether this product will suit your needs.  You can also download the instructions (a .pdf file) which provides detailed descriptions of all entry/answer fields. If you still have questions, please call call us (847-639-8847) before you buy. We cannot provide a refund for this product.

Special note:  The Fixture Offset Calculator uses Excel macros, so macros must be enabled within Excel in order for the Fixture Offset Calculator to work.  To enable macros in Microsoft Excel, click the Toolsmenu, then Options.  From the dialog box that appears, click the button named Macro Security.  We recommend the Medium setting, which will prompt you to enable or disable macros each time you load a file that has macros.


Limitations of the demo:

  1. Maximum of 50 file openings

  2. Only 2 index angles permitted (licensed version allows 40)

  3. G10 text file cannot be created

  4. Cannot edit Sheet2 (saved fixture offset data) or Sheet3 (machine data)

  5. Cannot create new machine data


Order today!

If you've been manually calculating and creating G10 commands and then pasting them into your programs, you'll find the Fixture Offset Calculator to be a dramatic improvement. Worse, if you've been having your setup people measure and enter fixture offset values at the machine, the Fixture Offset Calculator will help you dramatically reduce setup time.  It's price can be easily recovered with the first job you run! Order The Fixture Offset Calculator today!

The Fixture Offset Calculator is a Microsoft Excel file.  It will run on any computer that has Excel.   But if you're worried at all about compatibility issues, be sure to download and run the demo. If the demo runs on your computer, so will the licensed version.

Delivery Options

You have two delivery options to acquire the fully licensed version of the Fixture Offset Calculator.

  • Delivery by download - Once your order is processed, we'll email you a link to an FTP site where you can download the Fixture Offset Calculator (be sure to provide us with a working email address). Notification emails are sent during regular business hours only (not holidays, weekends, or evenings). Even so, this delivery method will save you time and money.

  • CD-rom version - While more expensive, we can deliver the Fixture Offset Calculator to you on a CD-rom disk. Again, there is an extra charge for the CD-rom and for shipping.


Delivery by download: ** Again, download orders are only processed during regular business hours (not holidays, weekends, or evenings).

SW-FOCD ~ Fixture Offset Calculator Single License~ $100.00 

Delivery by CD-rom (shipped to you):

SW-FOCC ~ Fixture Offset Calculator Single License ~ $125.00

Additional licenses

Need more than one license? We offer a substantial discount for each additional license for the Fixture Offset Calculator that you purchase. You must, of course, purchase the first license at full price to qualify for the discounted price.

SW-FOCA ~ Additional License (download) ~ $50.00 

Special five axis version of Fixture Offset Calculator is also available ($169.00).  Please call to order (847-639-8847).

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44 Little Cahill Road

Cary, IL  60013

Ph: 847-639-8847

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