Robot Applications

 Cutting Applications:

Robots are the perfect tool for many cutting jobs. Laser, plasma and water jet cutters are often used with robots. Due to the dangerous nature of these technologies robots are the obvious choice. Usually the cutting tool is placed on the robot and the part is presented to the robot by conveyor, turntable or manipulator. A second option is to have the robot hold the part and move it while the cutting tool is fixed. A robot can have hundreds of cutting paths programmed into it and on later models cad data can be fed directly to the controller. The excellent accuracy and path following capabilities give precise results time after time, in three dimensions and with greater flexibility than many dedicated cutting machines. As with many applications the ability of the robot to communicate with the tools with which it is interfacing is all important- the use of I/O or bus communications allow the robot, for example, to control the power of the cutter or change its own speed as required. Typical robots for cutting applications have payloads of between 7 to 40 kg, or sometimes more if the part is being moved by the robot. In general terms we would advise to use of the newer - 1994 and later robots as this is when accurate path following became the norm. Robots can be mounted over the workpiece on a gantry if needed to increase the effective working area.

 De-burring, Grinding, Polishing, Linishing and Finishing:

By using the flexibility of 6-axis robots it is possible to grind, trim, fettle, polish and even clean almost any part, in any material and achieve an consistent excellent finish. Robot technology allows a large number of different programs and hence parts to be adapted to by one installation. As with Cutting there are two main approaches, either the robot holds the part or the robot holds the tool. Also it is possible to have two robots working together for ultimate flexibility: one holding the part, one holding the tool. The starting point of designing a cell of this type is often the manual process it is to replace, although often using a robot will allow the use of new or different technologies. It is easy to use a multi-purpose tool to the end of the robot, for example in a mobile phone case finishing application an ABB IRB 2400 was fitted with an end effector with two sorts of router, a circular sander and a rotating wire brush, all air powered. If the part is picked up by the robot precise 3D positioning allows the part to be presented to a grinding wheel for example, with repeatability that ensures that the product is identical time after time. With the heath and safety regulations governing the use of finishing equipment ever tightening and claims for RSI a constant concern a robotic cell an offer a fast ROI while guaranteeing a consistent quality finish.

 Handling:

Due to the huge array of technologies available and through years of experience, we are able to offer solutions to most handling applications. By using both proved systems from specialist manufacturers and bespoke products we can meet your requirements. Robots have not only power and speed but also accuracy dexterity and sensitivity. They are regularly used in a variety of industries for the manipulation of a plethora of of items from car doors to eggs, from springs to champagne. A typical large robot will be able to handle a load of 120kg at speeds of 2500 mm/s. Sensor systems including vision systems can allow for variables in part position and type. Grippers are available in a huge array of types, payloads and many applications will require the fabrication of a bespoke gripper. The actuator units themselves - usually pneumatic but also electromechanical - are available from many manufacturers as are suction cups. There are also other gripping devices such as electromagnetic grippers.

Handling covers a very large range of applications, dedicated pick and place such as the ABB IRB 340 are designed specifically for very fast and accurate work often coupled to a vision system. They are often used in the food industry for jobs such as picking chocolates from a moving conveyor and placing them into boxes in given positions at speeds of over 150 picks per minute. Handling can also include machine tending. Robots are excellent for working with injection moulding machines, blow moulders, CNC mills and lathes, spark eroders, presses etc. By automating with robots machines can be worked much more efficiently and even through the night and weekends to give the best return on what is invariably very expensive hardware.

 Palletizing:

Palletizing is a type of handling application but owing to the huge number of installations that directly involve the use of a pallets this has become a subset of its own. ABB and other manufacturers have even designed specialist palletizing software packages and even palletizing robot arms although in practice these are not often needed. The principle is simple, the robot picks part or parts from one or more positions and the places them in sequence. This is usually on a pallet, stacking for example bags of cement, in such a way that will stop the stack from easily falling over. This could also mean placing parts into a stillage or other rack but the most important part is that the robot keeps count of the position to which it has gone and must go to next. Count functions were one of the first logic functions included in robot controllers and are probably one of the most used.

In a palletizing job the robot will often pick the part, box or bag from a conveyor either using conveyor tracking or more simply at a fixed point and then put the parts in order until the pallet is full. The pallet can either be changed by hand (with the robot stopped or working in another area) or the full pallet can be carried away on a second conveyor for wrapping etc. If needed the robot itself can pick a pallet from a stack and start palletizing again saving operator time and effort.

Dedicated palletizing robots such as ABB's "Flexpalletizer" and Fanuc M420iA are usually simpler than a full 6 axis robot, often only having 4 or 5 axis and are designed to be simpler and cheaper. However because 6 axis machines are made and installed in such large numbers (largely in the car industry) they are actually often cheaper than a dedicated palletizer. In addition parts are not as widespread and therefore we would often suggest the use of a standard 6 axis robot such as the ABB IRB 6400. We have sold robots for a multitude of palletizing work, including palletizing potatoes, frozen fish, furniture, pipes, masonry, even live worms for the long-line fishing industry.

 Sealing and Gluing:

From an installation point of view sealing applications are very closely related to arc welding. The most important ability for the robot is to follow a path accurately with good control over speed. Automated sealing has been very difficult to get right in the past, a process that works very well at one speed may run into problems if it is accelerated. Over many years the problems have been ironed out and now sealing systems are not only very advanced but also have a great deal of connectivity with the robot so a good even bead of sealant will be applied. Robots are frequently used for sealing applications in the car industry using RTV to seal in windows, keep out water etc. There are two basic setups, either the sealant head is fixed and the robot moves the part or the part is fixed and the robot moves the sealant head. There are a few robots that are designed more or less specifically for sealing like the ABB IRB 3400L which has a very low payload but a very long reach and a slender arm that could access a complete car body. However any standard robot can be used for sealing it is just a matter of selecting the right reach and payload for the job.

 Spraying, Painting, Coating:

Paint spraying was one of the first uses for industrial robots. The volatile and hazardous nature of solvent based paint means that it is best to minimise human contact and robots give an excellent and consistent finish. Painting robots have been developed that are impervious to paint shop conditions and present no hazard when in proximity to flammable compounds or explosive atmospheres. There are two types of painting robots explosion proof and non-explosion proof. The former are sealed units and the arm is pressurised with air to prevent the ingress of explosive solvents. Pressure sensor are used to monitor integrity. Non explosion proof robots do not have the pressurised system but the do have the other features specifically for painting. Paint robots typically have quite thin arms as they do not have to carry much weight and access is important. They are also capable of very fluid movements as they have to mimic a skilled human painter.

Painting robots often have a controller that has been designed specifically for the job. Not only are paint related controls needed but also the way in which the robot moves may be different from a standard type robot. Some painting robots can even be programmed by actually moving the arm directly, by hand, rather than using a joystick or buttons. In this way the robot can be taught very "organic" movements that may otherwise be difficult to achieve.

 Welding:

Welding can be split into two areas; seam welding (including MIG, TIG, arc and laser) and spot welding. Both applications have been robotised for many years and the interface between the robot and welding units are highly evolved. Welding robots can be very highly specilised: For example "poke welding" robots are spot welding robots that use the arm itself to generate the mechanical force needed. CO2 laser welding robots are fittedwith a complex system of mirrors to take the laser to the end of the arm. Having said this MIG, YAG, TIG, ARC and normal spot welding use standardised machines that are widely available.

Seam welding will require a robot with excellent path following and precision. MIG and TIG systems are very frequently fitted to small robots of around 5 to 10kg payload and with a reach of less that 1.8m although it is possible to use bigger robots such as the 2.4m reach ABB IRB 6400. Robots often have weave functions to give a fantastic quality of weld - probably better than that of a skilled human welder. They can also control many of the welding parameters such as power, wire feed, gas flow etc. By using "service stations" that combine torch cleaners and "bullseye" or a centring device it is possible to maintain production 24-7 without the need for intervention. As arc welding is hazardous with fumes as well as the blinding light from the arc itself a robot is a sensible choice from a heath and safety standpoint. Arc welding cells obviously have screens around the work area and manipulators are often used to present parts to the robot to prevent anyone getting too close and to keep production rates high.

Pictured are four ABB IRB 1400 robots equiped with ESAB MIG welding gear. The wire feed units are the black boxes mounted on the top of the arms. In this case the robots are welding a car chassis. The robots will be connected so that they are aware of each others location to prevent collisions. The orange Y shaped stands between the robots are the bullseyes used to calibrate the robots.

Spot welding robots will generally carry a complete spot weld gun and power pack on the end of the arm. As these frequently weigh in excess of 100kg it is not surprising that this a task to which robots have been applied since the early days. In fact Kuka were spot welding specialists for many years before they started making robots. Using spot welders by hand is a very difficult job indeed and trying to manoeuvre such a heavy-weight piece of kit accurately is near impossible. A spot welding robot will on the other hand position a spot gun with remarkable dexterity and speed. J -guns, G - guns and some truly monstrous scissor guns are often equipped to robots. The robot will also require a substantial loom to carry services to the welder (air, water and power as well as sensor information) so the robot is designed to bear a substantial supplementary load to do this. The weld timer is closely linked to the robot and this allows a robot to respot a point if the welding process has not occured as it should. Tip dressing stations are usually fitted in a spot welding cell so that quality of weld can be consistant.

The ABB IRB 6600 pictured is a very heavy weight spot welder and it is carrying a scissor gun which could easly reach most of the way across a car body. Other robots frequently used for spot welding include the ABB IRB 6000 and 6400 models, Fanuc 420, 430 and R2000 models and Kuka KR125, and KR150's. Most major robot manufacturers have at least one robot designed for spot welding.