Machine vision and robotics combine for materials handling solution

Citation

(1999), "Machine vision and robotics combine for materials handling solution", Industrial Robot, Vol. 26 No. 5. https://doi.org/10.1108/ir.1999.04926eaf.009

Machine vision and robotics combine for materials handling solution

Machine vision and robotics combine for materials handling solution

Keywords Cognex, Machine vision

The addition of a heat treatment station to help improve cast quality of V6 aluminium engine blocks at Ford's Windsor, Ontario, plant posed a material handling challenge. Each engine block weighs 25kgs and has to be moved from a bin to an overhead conveyor.

The material handling engineers had to choose between a manual or an automated solution, bearing in mind that they also had to meet plant safety, stringent quality and cost saving criteria.

Manual handling was ruled out quickly - not only was there a very real risk of injury to the operators moving the blocks, there was also the problem of quality control if a block was dropped.

Ford decided to install an industrial robot, with an accompanying machine vision system. Previous robot installations at Windsor had handled parts without vision control, simply moving between pre-programmed points. However, as the engine blocks are not in a fixed position in the bin and need to be located precisely, whatever their orientation, machine vision is essential for the engine block manoeuvring.

Having evaluated several systems, Ford opted for a Cognex Checkpoint machine vision system running PatMax software on an MMX-based Pentium PC (see Plate 8). In operation, the vision system processes an image of the block acquired from a standard RS-170 camera mounted on the arm of an ABB IRB6000 robot. The PatMax software then carries out image analysis using its geometric feature analysis technique. The block is thus located, whatever its orientation, and the machine vision system then transmits the X, Y and Z coordinates of the block, over a direct serial link, to the robot. This ensures that the robot can locate and grip the block to within +/-2mm accuracy.

Plate 8 Ford has been impressed with the cost savings produced by the robot/machine vision solution, in terms of improved quality, improved uptime and less manpower

Thus far, the system has been able to locate the engine blocks at any angle, despite varying light conditions.

The Cognex system also adds value to the inventory control system, by reading binary-coded ID tags on the steel bins as they enter and leave the material handling station; and also verifies that each bin is empty before refilling commences - preventing significant equipment damage and operational downtime.

Ford has been impressed with the cost savings produced by the robot/machine vision solution, in terms of improved quality, improved uptime, and less manpower.

Ford's engineering project manager at the Windsor plant, Geoff Steel, concludes, "Much of what Ford plants do worldwide is insert and remove parts from containers and the ability to locate and robotically grip unfixtured parts may prove to be one of the most significant tools as manufacturing moves into the twenty-first century."

For details contact Colin Graves: Cognex UK, Chancery House, 199 Silbury Boulevard, Milton Keynes MK9 1JL, UK. Tel: +44 (0) 1908 206000; Fax: +44 (0) 1908 392463; E-mail: salesuk@cognex.com