Three Methods for Restarting Programs

When programs need to be restarted on a Mazak laser, operators can utilize three different methods to efficiently resume laser-cutting

by Joe Fiorito, Applications Engineer at Mazak Optonics Corp.

During laser-cutting operations, laser users may run into a scenario when a program needs to be restarted. A situation may occur after stopping the machine to check for cut quality or after a collision. Depending on the situation there are multiple ways operators can efficiently resume a program on a Mazak laser. The three most effective methods laser operators can utilize to perform a program restart are through the FEED HOLD, RESTART function, or the GOTO method.

Standard FEED HOLD Method

The simplest and most common way to restart a program is simply through the  FEED HOLD  and  CYCLE START  buttons. At any point in the program, an operator can press the  FEED HOLD  button and the laser will stop in its place no matter where the cutting head is located or what operation it is performing. Now, the operator can open the access door to evaluate inside if needed.

Laser operators can also move the cutting head up and down in the Z-axis but be careful not to travel too high and cause a +Z OVERTRAVEL alarm to signal. When finished, make sure that the machine is in AUTO mode then simply press  CYCLE START  and the laser machine will pick up where it left off.

RESTART Function Method

There are situations, whether by choice or not, laser operators will have to terminate a program. This is achieved by pressing the  RESET  button.

If there is a red alarm, operators cannot press  CYCLE START  to resume cutting where the laser left off. An instance when a red alarm might occur would be if operators get an OVERTRAVEL alarm. If a red alarm does appear, laser operators are also unable to press  CLEAR  followed by  CYCLE START .

In these cases, the operator will have to perform a program restart. In order to restart the program, first put the machine in AUTO mode and then press the   CTRL MENU  button on the control. At this point a popup window will appear. On the top row of this popup window, operators will have an option for   RESTART .

After pressing  RESTART , a popup window will show the operator exactly where the program left off.

O Nodenotes the program number, N Nodenotes the sequence number (number of cuts),B Nodenotes which block, and finally, L is which repetition of the program laser operators are on if looping the program.

The operator can now press  SET  and the NC will figure out where it needs to go. Once the RESTART menu disappears, press  CYCLE START  then the cutting head will move into position and the  CYCLE START  button will start flashing. Press  CYCLE START  one more time and the laser will resume cutting where it left off.

GOTO Method

As an alternative to using the RESTART function, operators can use the GOTO method to restart a program.

A GOTO statement jumps to exact points in the program, most often where the program stopped.

Once the program has stopped, operators can view where cutting was interrupted by going to the  SBR  tab on the   COMMAND  screen. Similar to the RESTART function, operators can see where laser-cutting left off in the program via the sequence number and block number.

However, while using the GOTO function, operators only need to see the sequence number (N No). Operators can type in GOTO followed by the sequence number in the program. Once the program reads that line it will adjust to that sequence number. Typically, laser operators can type this line in right above N1 in the original program.

Although, there are instances where operators need to take some additional steps in order to properly restart the program. One example of this is if operators are utilizing Edge Detection.

If a program needs to be restarted that used Edge Detection to set the program’s coordinates, operators do not want to re-run Edge Detection again when restarting. This may cause the program to not come up with the exact same coordinates.

Instead, laser operators can recover the edge detection measurements by inputting M98P77 into the program. Operators can then restart the program where it left off by block deleting the edge detection with a //, typing in M98P77 underneath it to recover the measurements, and finally, type in the GOTO statements underneath this to enable the cutting head to move to the location laser-cutting needs to resume.

Another example of when additional steps are needed to properly restart a program is when using Nozzle Start programs.

These are programs where the program origin is set by the location of the cutting head when pressing  CYCLE START .

In order to properly restart this type of program, laser operators must return to the location where the program began to restart it. To begin this process, press the  MDI  button on the control. Operators can then close the  MDI  screen by pressing the  MDI  button in the popup window so the new code can be entered. Once on the  MDI  screen, type in X0.Y0., then press  FIX , and finally press  CYCLE START .

Always make sure that the cutting head is retracted and will not interfere with anything while it is moving back into position.

By using the Standard FEED HOLD method, RESTART function method, or the GOTO method, operators can restart programs on their Mazak laser. These methods will help laser users resume laser-cutting operators quickly and efficiently.

For additional assistance, please contact the Mazak Applications Department at 1-888-MAZAK-US.

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About Mazak Optonics Corporation

Mazak Optonics Corporation is a major supplier of laser-cutting systems, offering 50 laser models and leading the industry in the implementation of emerging laser technologies. The company’s 50,000 sq. ft. North American Headquarters are located in Elgin, Illinois, and feature a 30,000 sq. ft. laser technology center housing up to 18 machines for demonstrations and training. Mazak Optonics is part of Yamazaki Mazak Corporation (Oguchi, Japan), the global leader for the manufacture of machine tools and systems for the precision machining of metal parts, including CNC turning centers, horizontal and vertical machining centers, Multi-Tasking machining centers, turnkey cells and software solutions. The North American Headquarters for Yamazaki Mazak are located in Florence, Kentucky. For more information on Mazak Optonics’ products and solutions, visit, email or call 847.252.4500.