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### Author Topic: CNC machine - Parametric programming - Before we start  (Read 9272 times)

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#### stamatis

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##### CNC machine - Parametric programming - Before we start
« on: September 01, 2008, 20:12:43 PM »
Parametric programming – Before we start

As seen before, using G-Codes someone can make anything that can be done with a CNC machine. There are of course much more G codes but this is not subject of my tutorial. This tutorial is mainly to explain the philosophy and the applied geometry for making parametric programs. The G-codes already explained are far enough for our examples.

I have chosen to use G-codes for the examples, not to make you suffer more and not to cause you a headache. The reason for this is that, more or less they are pretty straight forward and can be converted easily to be used by any machine, regardless if it uses G-codes or not. I might have chosen a specific controller of software for my tutorial, but hey, I write it for free and i mean to do no advertisement to no one.
If you read my previous articles describing G-codes, you will be able to convert the examples to your machines GUI. For example, it is not hard to understand that:

Code: [Select]
G1 X100 Y100
means a line to point X 100mm and point Y 100mm and translate it to your machines software.

Before I start, I should first declare some things that will be common to all the programs that will follow and should be declared in order to avoid problems.

1. All dimensions are mentioned in millimeters. For example, X150 means 150 mm (in G-codes this would be G21)
2. The Z axis zero point lays directly on the table of the machine. Positive values will drive the Z axis higher and negative values will drive them lower than the machine table. A value of Z3 for example means that the cutter will be 3mm over the machine table.
3. The cutter will follow the centerline of our drawings. This means that the cutter axis of rotation will follow exactly the drawing line and will have NO offset to the right or to the left. In many machines, a programmable offset may be added. In our example machine, no programmable offset can be added.
4. There is one program zero point that we use for programming and reference values. We really do not care where this point is.
5. All dimensions are absolute dimensions and not incremental. In G-codes this would be G90
6. The spindle is already equipped with a cutter. The dimensions of the cutter do not really bother us.
7. Over the table there is already a panel. The type and size of the panel do not really bother us***

Within the next posts I will start explaining what many people may need years to understand, if they ever do. I will try to be as straight forward as possible. Of course soma basic mathematics will be a tool in your hands, but if something you miss to understand... hey, you are in a forum that has also a board for math and geometry... Post there your questions.

*** of course the panel size is reasonable. A panel size of 6x10 mm is not really reasonable.
« Last Edit: September 01, 2008, 20:16:12 PM by stamatis »

#### spic0m

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##### Re: CNC machine - Parametric programming - Before we start
« Reply #1 on: September 04, 2008, 03:54:19 AM »
If i have time, (right now we start the insatllation and training on a machine, you know how time consuming this can be  ) , i'll try to gather and post on the math section the basic trigonometric functions for everyone to refence.

#### kam

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##### Re: CNC machine - Parametric programming - Before we start
« Reply #2 on: September 04, 2008, 18:32:17 PM »
If i have time, (right now we start the insatllation and training on a machine, you know how time consuming this can be  ) , i'll try to gather and post on the math section the basic trigonometric functions for everyone to refence.
You will find time spicom. Tell your boss that you need to send topics to a forum... Ask for holidays. A day off maybe...

#### spic0m

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##### Re: CNC machine - Parametric programming - Before we start
« Reply #3 on: September 04, 2008, 18:37:44 PM »
You don't know what installing a machine means. The customer is always in a hurry because he wants to start production and your boss is also in a hurry to finish this and go for the next one. And of course, as always, murphfy is walking around the corner. Stamatis understands.

#### stamatis

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##### Re: CNC machine - Parametric programming - Before we start
« Reply #4 on: September 05, 2008, 18:18:57 PM »
You don't know what installing a machine means. The customer is always in a hurry because he wants to start production and your boss is also in a hurry to finish this and go for the next one. And of course, as always, murphfy is walking around the corner. Stamatis understands.
And also, you should add the parameter "learn-ability" of the people you must train for this machine. or you do not make the training yourself?

#### spic0m

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##### Re: CNC machine - Parametric programming - Before we start
« Reply #5 on: September 05, 2008, 19:27:38 PM »
That is a key parameter, if the others willing to learn i also train, if not, i leave it to my partner who is more patient than me. This time is his turn  .

#### zolotas

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##### Re: CNC machine - Parametric programming - Before we start
« Reply #6 on: June 05, 2009, 20:50:10 PM »
Before we start we finished allready.
Stamati you will not right again?