What Is Offline Robot Programming (OLP), and How Is It Done?

The classic way to program a robot is to stop it and teach each point with the teach pendant. The robot does not produce in the meantime. Every new part and every new variant means doing the job again.

Offline robot programming (OLP) moves that work from the robot to a computer. The program is written and tried on a 3D model of the cell, while the robot keeps producing.

How it is done

1. The cell is modelled. Robot, fixture, part, conveyors and surrounding equipment are built in 3D. The part’s CAD model is used directly.
2. Paths are generated. Welding, cutting, gluing or surface-finishing paths are taken from the part’s geometry rather than entered point by point.
3. The program is tried in the virtual cell. Whether the robot reaches every point, whether an axis hits its limit, whether the robot collides with the fixture or another robot, and the cycle time are all checked on the computer.
4. The program is translated. A post-processor turns it into the robot maker’s own language: KRL for KUKA, RAPID for ABB, and so on.
5. The program is verified on site. It is loaded onto the robot, run at slow speed in the real cell and released to production.

Why can the model and the real cell differ?

The fixture in the model may not sit in exactly the same place as the one on the floor, and the robot’s tool may not measure what the drawing says. That is why a program prepared offline is verified on site. Where the difference is large, the cell is calibrated: the robot is taken to a few reference points and the model is updated to the real positions. If needed, a few points are corrected on site.

So OLP does not remove the final check on the floor. What it changes is that most of the program was prepared while the robot was producing.

When it pays off

• High-mix production: preparing the program for each new part on a computer instead of stopping the robot.
• Long, complex paths: taking welding or cutting paths with hundreds of points from the part’s geometry.
• A new cell investment: preparing the program before the robot arrives, and trying the robot model and the cell layout for reach and cycle time before buying.
• Cells with several robots: checking in the virtual cell that the robots do not collide with each other or with the surrounding equipment.

Which robot brands does it work with?

That depends on the post-processors the software supports. Visual Components states that Robotics offers 17 post-processors, including KUKA, ABB, YASKAWA and FANUC. The library used to build the cell holds more than 1,600 robot models from more than 70 brands. Visual Components also states that offline programming is ten times faster than programming by hand.

OLP and virtual commissioning

Offline programming tries the robot’s own movement. But the robot is not alone in the cell: it waits for signals from the PLC and takes turns with the conveyor and the other robots. When the same cell model is connected to the PLC, the robot program can be tried together with the cell’s control logic. That is called virtual commissioning.

How we work

Ono Teknoloji is the authorised Visual Components distributor for Turkey and the Middle East. We provide the Visual Components Robotics licence, training in Turkish and start-up support. For robotic cell investments, we run the process together with you as part of engineering consultancy, from the cell design to programming the robots.

If you would like to talk about a cell or a part, write to us.

Frequently Asked Questions

What is offline robot programming (OLP)?

It is preparing robot programs on a computer, on a 3D model of the robot cell, rather than at the robot. The program is tried in the virtual cell, translated into the robot's own language by a post-processor and loaded; meanwhile the robot keeps producing.

How does offline programming differ from teach pendant programming?

With the teach pendant the robot is stopped and each point is taught at the robot, so the line does not produce. With offline programming the program is prepared on a computer, and the robot stops only to load the program and verify it on site.

Does a program prepared offline need corrections on site?

The program is verified on site. Where the model and the real cell differ, the cell is calibrated or the points concerned are corrected. The difference is that most of the program was prepared while the robot was producing.

Which software is used for offline robot programming?

One of them is Visual Components Robotics. Visual Components states that it offers 17 post-processors, including KUKA, ABB, YASKAWA and FANUC. Ono Teknoloji is the authorised Visual Components distributor for Turkey and the Middle East.