Posted by diegoroman17_2 on Jan 03, 2012; 12:23am
URL: https://forum.librecad.org/LibreCAD-modified-for-the-interface-of-a-laser-machine-tp5113327p5115734.html

Hi Tin-Pot and R. van Twisk,

Thank you for your answers.
Indeed it is developing a system similar to a CNC machine but not in its entirety.

The main difference is that G is not managed code to specify the movement to "machine controller".

Below I will specify the characteristics of the system as best you can in the order flow data:

1. As you say what is wanted manufacture is constructed in a CAD program such as VectorWork, AutoCad, Illustrator, etc. There are many options on the market ... This is stored in dxf format (This software design is totally outside the scope of the project, the user has complete freedom to choose their favorite software to develop their design, the only constraint is given which must necessarily save your design in dxf format).

2. The user enters the design into the laser cutting machine through its USB port or via ethernet or any means of income you have the mainboard that is within the laser cutting machine. Let's talk about the mainboard and S.O:

           2.1 It is a computer mainboard with a Core 2 duo. Within this is installed Ubuntu 10.04 which will install a real-time kernel with the features offered by RTAI (Real Time Aplication Interface). RTAI install a real time subnucleus which manages the processes and interruptions by giving higher priority to real-time processes.

3. The design is modified LibreCAD opened by which a more general tools that are available in the normal version will have:
- A text box called primitive element.
- A text box called cutting power.
- A start button.
- A stop button.
- A button machine specifications.
All these elements will be in a new toolbox

4. When you click with the mouse on a line, circle, spline, etc in the box "primitive element" will be the name of the selected primitive in the text box "power cut" power will be written to that should cut this primitive, this process will be made with all primitives in the design.

5. When you click on the button "Machine Specifications" will open a window which is set minimum and maximum speeds, maximum and minimum accelerations, etc..

6. When you click a button "Start" LibreCAD placed in a position of  memory all modified primitives with its information. It is ilustrade with the following example:
If we have a line from 0, 0 to 10, 1 and a circle of center in 15, 1 and 10 radius we want to cut respectively 20W and 50W, memory information will be placed in the following

line 0 0 10 1 20
circle 15 1 10 50

7. Below LibreCAD open another application developed in C language This application has the characteristic of being developed as a real-time application which took control from now on.

8. This will read the data from the machine specifications and data for each of the primitives located in memory, will make the process of generation of trajectories (interpolation) of the current primitive and will result in the number of steps to be taken each step-motor the next millisecond.

9. The numbers of steps of each step-motor and the power of the laser is sent via USB to a card of control that read the data received and transformed into pulses to send drivers for stepper motors each axle and Power Controller laser.

10. 8 and 9 will be repeated until it is finished cutting all the primitives.

This is what the system should do. As you said LibreCAD actually be only one user interface. Hard work will the application developed in C.

Can not save a file from libreCAD then be read by another application and that it would take too long to read data from disk and dimensions as the sample rate is 1 ms. That is the whole process of interpolation must be made within this range.

I hope I was explicit enough about the project. sorry with my English, this is very bad. I know your can help me with my project. Thanks in advance

Regards Diego