Generating robot paths direct from CAD files

robot
cad-cam

In the past it has been very expensive and complex to convert CAD files into robot movements. Part of the problem has been that such systems were only possible using the latest machines often with a lot of optional extras. Another problem has been the cost of the software. At Global Robots we have found solutions that bring this technology within the price range of many more customers.

Applications Include:

  • Milling
  • Profiling
  • Deburring
  • Waterjet Cutting
  • Plasma Cutting
  • Polishing
  • Laser Cutting
  • Prototype Model Making
  • Plastic Part Trimming
  • Sign Making
  • Wood Working
  • Rapid Prototyping (RP)
Essentially the process is as follows:

CAD File - This is drawing of the part being worked on

CAM Path - This is the toolpath, this is generated by the CAM software using what are called strategies, these define how the path is generated perhaps working from the inside out or in strips. This is usually output in G-code.

Robot Language Post Processor -This takes the G-code and converts it into robot language instructions. It will define things like the size and mass of the tool being used, the orientation of the robot to the part. The system should be modeled to check for collisions.

Robot controller - The robot controller uses the instructions to move the arm to the series of points. These will be very small linear moves, often many thousands of them depending on the complexity of the part and the resolution specified by the CAM software. One major issue is the size of the robot controller memory. Either is must be able to handle 20+ MB of data or it must be fed this data as it works.   

There are two usual types of CAM file path generation: 3 axis and 5 axis (both use a full six axis robot arm). 3 axis controls the robot in X Y and Z axis and allows "2.5D" forms to be milled, cut, etc - this is an entry level system. 5 Axis path generation requires different software and allows full 3D forms to be made. One of the main benefits of the system is the size of the robot's work envelope, a CNC with the same capacity is huge in terms of physical size and indeed cost. As mentioned we have developed the system to work with robots going back to the ABB S4 M94 controller. This is because we can sell very good quality S4 robots at remarkably low prices and for many applications they are as effective as the latest robots. However these systems are easier to set up when used with later S4C and S4CPlus ABB robots and robots of different sizes and types, from the diminutive IRB 140 to a 3m reach IRB 6400.

It should be noted that if customers already use CAD-CAM milling software on CNC machines that they can make some saving by utilising this to output suitable paths (such as G-code) and then just using a post processor to convert this into robot code. Some CAM software packages such as Delcam and Mastercam have robot post processor modules available. 

CAD-CAM programs can run to many thousands of lines depending on the resolution used. This is because when it comes to curves the CAD-CAM software will usually split the curve into many short linear movements. This in turn can mean that there is a lot of program data to be fed into the robot. In these cases we recommend an ABB M98 S4C controller (or later) fitted with an Ethernet board. This allows the connection of a PC to "drip feed" programs into the controller essentially allowing infinite program size.


For more details please  contact us  by phone or email.

Specification

Control S4 or S4C or S4CPlus
Capacity: 120kg (using standard IRB 6400)
Reach: 2.4m (using standard IRB 6400)
File Types: .crv, .dxf, .epf, .ai, .stl, .3ds, .asc, .obj, .sbp, .txt, .wrl, .lwo, .v3m, and .pdf