Robot offline programming 

What is offline programming?

Robot offline programming (OLP) in essence is the programming of a robot in isolation, thereby allowing the robot to be continually utilised as an asset while programs are being generated. Traditionally robot programs require the steering of the robot through the required path physically and so the robot becomes ‘out of action’ through this process. Complex offline programming can take many hours or days to create in this way and so the robot can be down and not generate income for considerable time periods. This document is aimed at providing more detail on OLP, how it is used and where it can add value.

Robot Programming

Robots have been around for many years and are becoming increasingly advanced in terms of their programming, accuracy, capabilities, and many other things. The hydraulic robots of the 1950’s and 1960’s which were little more than lifting aids have given way to highly versatile manipulators that can be used in many applications ranging from welding through to complex surgery. 

Traditionally robots have been programmed by recording positions and saving the positions to the robots memory. This requires the user to move the robot manually to the required position and then saving this point. This needs to be done for every point in the programme. Today’s complex programmes can have hundreds and even thousands of points. A complex machining tool path may have 10,000 points. If you were to move the robot to 10,000 locations and it took 20 seconds to move to each location, it would take over 1100 hours (nearly 28 weeks, using a 40hr work week) to programme all the points and your asset is unavailable for this whole period i.e. not generating revenue for your business. On the other hand if you need only move to a few locations for a program, for instance if you are programming a straight weld and so you only need program the start a stop points then manual teaching may be quite adequate.

Robot programming remained this way for many years but in the last two decades there have been a number of developments mostly along the lines of ‘codeless’ programming and offline programming. Robot programmers used to require extensive knowledge around the programming language to make a robot do anything useful. Modern developments in software have eroded this barrier considerably making robot programming simple and easy to pick up. Cobot’s (Collaborative robots) like the UR10 can be made compliant at the push of a button, and then literally pushed into position physically by hand. Other programming commands can be simply dragged into place to make a full usable robot program.  This concept of ‘no code’ programming has, and is, developing in many forms currently with new advanced software and hardware coming to market. The ultimate target of no-code programming is likely to be a common simple platform that has the capability to program any robot, no matter its make or type.

OLP has developed alongside no-code programming over the last few decades. The major driver for OLP software has been the development and capability of computer aided design (CAD) software. CAD packages have become capable of accurately modelling a robot and its surrounding cell. This has led to the capability to complete programming in this virtual environment. Further to this, tools have been developed that can automatically select featured and create paths in line with modelled parts. This environment makes the programming of robots much easier and faster whilst at the same time allowing it to happen offline.

When does it make sense to your business to use offline programming?

Your robot cell in likely to be a sizable investment that is used to add value to your manufacturing processes, if it can be continuously operated in this manner i.e. there is sufficient work for the cell to work continuously then down time needs to be kept to a minimum. Using OLP can save many hours of downtime due to programming. With OLP the bulk of the programming work can be completed offline (while your robot cell continues working) with only a small time needed for verification and minor tweaks. 

If your robot cell is very complex with many axes and, or robots, then programming manually will be a very big job. Complex robot cells can have multiple robots each with several additional axes especially for large jobs. OLP can make the task of programming complex cells much easier. Many movements can be automated in the software, points can simply be clicked, and speeds and feeds can be changed en masse.

Robot programmers are hard to employ and can be expensive. If you want to maximise the efficiency of your programmers, then OLP can make a lot of sense. As a business it may be the difference between one or two programmers, or experienced prolonged robot downtime waiting for programs to be written.

If you have several different robot brands and want one common means of programming, then OLP can also make sense. Generic OLP software allows programs to be created that are then run through a post processor to generate the robots specific code. This type of OLP software can help minimise the effects of multiple robot brands with multiple programming languages for you robot programming team.

When does it not make sense to your business to use offline programming?

If you never or seldom program your robot i.e. it carries out the same operation permanently then OLP makes no sense.

If your programs are very easy to create and downtime isn’t an issue, then again OLP makes no sense.

How do you roll out OLP within a business?

The first step is to obtain the software. Virtual Components offer a month’s free trial so that it can be evaluated. After this period, we can offer a quote for purchase.

All the components within the cell need to be modelled accurately, or as accurately as possible. Models of the robots are usually available within the software, or online, but bespoke tooling and end effectors will need to be drawn in CAD unless models already exist.  This can be a time-consuming process and so needs to be evaluated.

Once all the components are available as CAD, they need to be pulled together within the OLP software as a ‘virtual twin’ of your robot cell. This usually takes a few hours, but it depends on the complexity of the cell.

All the cell components need to be aligned in accordance with the robot’s coordinate system. Once completed the cell needs to be verified to ensure everything aligns accurately and is a good ‘digital twin’ of the real cell. The cell now needs to be saved and can be used for OLP purposes. Note that any changes to the real cell will need to be reflected in the digital cell moving forward.

Summary

OLP software can offer some major advantages to robot users but it depends on how your robot cell is used. If your cell is (or could be) fully utilised, you very frequently change programs and or write complex programs, or you have to deal with multiple robot languages then OLP could be of benefit.