Spot welding robot has improved accessibility

Citation

(2003), "Spot welding robot has improved accessibility", Industrial Robot, Vol. 30 No. 4. https://doi.org/10.1108/ir.2003.04930dad.002

Spot welding robot has improved accessibility

Spot welding robot has improved accessibility

Keywords: Spot welding, Robots

Conventional robotic systems for spot welding, with their trailing external dressing hoses and cables, are restricted in their ability to access confined spaces such as car interiors and have the downtime associated with the external cable changes. Not so with the new SMART H4 system from Comau, which routes all air, water and electrical supplies entirely inside the robot from inside its base through the forearm right to the point of welding (Plate 2). In this respect, the robot is believed to be the world's first.

Plate 2

Apart from improved dexterity, two further benefits of the design are particularly noteworthy. First, the overall dimensions of the robot are reduced and more exactly defined (without external cable loops), making it easier and quicker to prepare programmes off-line. Previously, predicting the cable motion made off-line programming problematic. This allows a model change to be downloaded and run satisfactorily without manual touch up of points.

Second, there is no risk during welding of the workpiece snagging the hoses and cables, a constant source of wear normally. Confidence in the product is expressed in that the internal harnesses are guaranteed for 3 years working round-the-clock. For the same reason, downtime for maintenance is virtually eliminated.

The six-axis articulated SMART H4 can support 200 kg on the wrist to its nominal reach of 2.4 M. The robot is also available in "L" (long reach) and "SHELF" (work envelope below robot base - underneath the robot) versions. Repeatability is ±0.3 mm with the fast movements, which vary from 110°/s for the first three axes to 205°/s for the gun, the innovative hollow wrist having no external rotating devices. Electric or pneumatic gun actuation are standard options, with the further option of integrated weld timer as a standard board in the robot cabinet as a function package.

Several of these robots have been sold and installed (actually more than 1,200 in recent months) – one particular order was from Volvo for 297 robots for their new plant in Gent, Belgium, where the S70, V70 and S80 models are to be assembled.

Comau, part of the Italian Fiat group, has a pedigree unrivalled in the supply of robotic welding systems to automotive companies. More than 20 vehicle manufacturers use Comau equipement in 78 facilities throughout Europe, America and Asia. One out of three car bodies worldwide is spot welded on Comau lines, which execute over 72 million welds per year.

Comau's SMART H4 has all cables and hoses within the robot elements, allowing better access to awkward areas such as car interiors.

For further information, contact: Comau Estil, Harlescott Lane, Shrewsbury, SY1 3AS. Tel: 01743 453 800; Fax: 01743 453 810. Contact: Robert Lewis, Operations Manager. E-mail: robert.lewis@comau.co.uk