Tips for Generating Clear and Effective Laser Motion Programs Using Delta Motion Software

Delta motion control software is used to program motion on Amada Miyachi America laser welding systems. Many of the terms are standard G&M codes, which can be applied to other CNC style motion programming. Here are a few tips for using the software to program nearly every type of weld joint configuration. In this post, we are just hitting the highlights to get you started on the right “path.” Full instructions on essentials for each configuration type can be found in Quick Start Guide to Programming in Delta Motion.

A quick look under the hood – G codes and M codes

Delta motion uses a combination of ‘G’ and ‘M’ codes to generate a program that executes the desired weld path and events on your laser welding system.

G-code is the common name for the most widely used numerical control (NC) programming language. It is used mainly in computer-aided manufacturing to control automated machine tools. M-code (machine code) is a computer program written in machine language instructions that can be executed directly by a computer’s central processing unit (CPU). Each instruction causes the CPU to perform a very specific task, like open a laser shutter, turn on cover gas, or actuation of external tooling.

Follow these basic programming steps

1. Start by initializing the program.
2. Set a feed rate (speed the table or rotary chuck will move).
   • Speeds are usually called out in inches per second or millimeters per second, and rotary movements are called out in degrees per second.
3. Specify if you want the machine to read absolute coordinates, or incremental coordinates.
4. Input commands to move each axis a set distance either in a positive or negative direction.

The diagram shows the universal coordinate system.

Weld programs available

Examples of common weld joint styles and their sample programs include:

Learning by example – stitch program

Here’s an example of Delta motion programming for a butt weld using the stitch program, which is especially useful for welding in a straight line regardless if the part is straight to the laser head. The beginning of the program zeros out at the weld starting point. There is then an optional stop in which you then track to the end of the weld joint. When you start the program again, it will return to absolute home, welding the whole way back.

Advanced programming tip

What if you need a more advanced programming technique, for example welding a pattern of parts laid out onto a flat plate? If so, use the built-in variables and logic commands to create an effective program. Go to the ‘Loops.NC’ program and use the variable called out on line 12 (p299=x), which is a counter for how many times you wish to run the loop. To start the loop, type in while (P299>0), which tells Delta Motion to execute all consecutive lines up to the endwhile function, after which it will return back to the first line.

How to use position-based firing

Rather than using the pulse rate set on the laser panel, position-based firing uses a set overlap variable for center to center spacing of the weld spots. After you set a feed rate, the motion program adjusts the pulses per second on the fly by modulating the laser’s frequency to accommodate table slowdowns on corners and sharp edges. This will ensure the overlap is the same on all areas of the weld.

Position based firing is initiated by using the code m149 s1 dx – where x is the center to center spot overlap.

Calculating the right feed rates

To calculate the proper feed rate, you will have to input a few variables to get accurate speed and shot count.

For pulsed style lasers, use the Weld Calculator tool. Enter:

1. Pulse rate (Hz) at which you want to pulse the laser during welding operation
2. Overlap desired
3. Weld diameter
4. Part diameter

The Amada Weld Calculator will then calculate and read out:

5. Linear speed in inches per second.
6. Rotary speed in degrees per second.
7. Estimated process time in seconds to complete weld.
8. Spots needed for complete joint coverage.

Linear welding (X, Y) feed rates are a bit more flexible with continuous wave style. Feed rates for rotary welds rely on a simple equation to calculate laser on time to ensure you are going around the weld joint 100 percent of the circumference. Laser on time is preceded and ended with a small ramp up and ramp down of 0.2-0.5 seconds to reduce crater cracking and spit holes.

Converting linear and rotary motion.

If you ever need to convert linear motion (inches per second) to rotary motion (degrees per second) or vice versa, use these formulas:

Linear to rotary

C=360(A/( πB))

Rotary to linear

A=πB(C/(360 ))