X-bar with suction cup attachments.
Written by Humphrey Carter on May 7, 2020 in feature News

Increasing automated process speeds and efficiency through design of composite light-weight, stiff, high frequency structures with minimum section size. CompoTech has continually developed process and design to produce the optimal structures.

Published Articles.

Recently, Composite World and Metal Forming magazine published articles about the technology with front page images. These articles look at the application of composite in specific cases and show where the advantages are gained.

Developments in Automation Structures

CompoTech has worked on the application of composites within industrial automation for over 15 years.  Specifically, in automotive with our long-term partner, Bilsing Automotive, to produce boom and cross bar structures. These are used to manipulate the parts produced through automated press lines.  This usually means picking sheet metal parts and placing it between presses using a bespoke array of suckers. Fastening these suckers to a light weight and stiff structure allow a range of improvements to the whole process.

Throughout our corporation with Bilsing, CompoTech has developed and refined the design and production process, optimising to the specific set of requirements. The latest version of structural frame beams incorporates a new design section profile. This gives optimum bending to torsional stiffness and allows easy connection to inserts in the corner sections, integral to the beam. This means a range of frame connection designs are available to use. In addition, the beam production process is greatly improved.  With Robot Assisted Filament Laying (RAFL) and the precision press technology. The process technology has increased the surface quality and significantly reduced the machining and finishing required on the beams.

Composite T-boom used for hot-forming part manipulation

Over the last 15 years designers of automised production lines have realised the advantages the carbon composite structures. Specifically, with the ultra high modulus, graphite fibre, composite. Often disregarded due to the high cost, the material has shown it can bring process improvements that far outweigh the initial outlay due to the considerably high modulus properties of the fibre. These advantages present themselves in a number of ways:

  • Pick and place speeds increase due to the high natural frequency and improved damping of the whole structure.
  • The stiffness of the composite material means thinner profile beams , which in turn allows smaller opening of the press, shaving valuable time and energy from each pressing action.
  • The light weight structure has an impact on payload. Allowing smaller handling robots, saving significant cost over a project.
  • This in turn improves the lifetime wear and service of the moving parts, motors and actuators.

Cross Bar Profiles Comparison

Composite cross bar for press shop
Composite cross bar for press shop

Consider a comparison of materials for one of the most widely used profile in automotive automation industry – the Cross bar.  Used for sheet metal manipulation in press lines of larger parts like a side panel or bonnet. Bilsing has supplied our composite cross bars to customers such as: IHI, Aida and Strohthman which are providing press line to all major automotive manufactures. These cross bars are usually based on a standard 100mm square profile usually in length 4,5-5 meters.

For comparison of mechanical properties a profile was chosen with the same cross section 100x100mm and 8mm wall thickness made of steel, aluminium and graphite/carbon fibre composite.

Deflection comparison for Xbar over length
Deflection comparison for Xbar over length

As shown, the increased stiffness of Bilsing profile (lower deflection) compares to steel profile and significantly higher stiffness than aluminium. To compare the mass consider linear density:

  • steel profile is 23kg per meter
  • aluminium profile 8,2kg per meter
  • Bilsing Composite profile 5kg per meter.

The result for a 5 meter long cross bar shows the carbon profile is stiffer than steel by 10% and lighter than aluminium by 40%. The 42kg aluminium vs 25kg in carbon leads to potential of extra 17kg of payload which can be used.