Technology for design ambitions
UV Bonding technology is being used by glass processors across a wide range of applications from furniture to retail display cases. What is notable is that there has been a definitive shift across sectors towards larger installations.
“This creates an immediate challenge,” Amanda Carr, Bohle’s UV bonding specialist, said. “The pressure applied through the sheer weight of the glass used can mean that adhesive is pushed out from the joint, something which can lead to failure.
“Bohle has created a specially developed range of UV bonding adhesives designed to support glass processors in achieving the optimum bondline, guaranteeing the structural integrity of the bond in display cases and larger glass furniture.”
Bohle’s MV760 UV bonding adhesive system delivers a sheer strength load capacity of 25 newtons/mm2. It does this using spacer technology, which employs transparent 90 micron spacer granules to achieve the optimum bondline gap by preventing the pressure exerted by glass weight in larger bonds from forcing adhesive from the joint.
This was employed by Halsall Glass in its fabrication of four specialist retail display cases for fashion outlet the Design Retail Centre in York. Measuring 2m x 2.5m x 1.3m, the display cases were designed to accommodate full sized manikins, making them too large for offsite manufacture.
This meant that Halsall Glass had to develop a solution involving on-site manufacture, as Rob Halsall, founder and managing director of Halsall Glass, explained.
“The display cases were simply too large to fit through the door which meant on-site assembly was a pre-requisite to the job,” he said.
“To UV bond in a site environment requires a lot of specialism. Lifting and handling large 10mm toughened glass was just one of a number of logistical challenges.
“The other major challenge was the sheer weight of glass we were using and the pressure that that put on the joints.
“The use of Bohle’s MV760 spacer bonding adhesive was a critical element in delivery, allowing us to achieve a consistent bond-line along the joint.
“We also used Bohle lifting and handling equipment, its suction holders and clamps, plus Bohle’s clamping and UV lamps to cure the bonds on site.”
This included use of Bohle’s Verifix Pro Angle Suction Holders, which optimises the thickness of the adhesive layer to within a tenth of a millimetre.
Halsall Glass also used Bohle’s new UVA Star UV bonding tube lamps, which deliver higher quality cures while reducing energy consumption.
Part of Bohle’s leading-edge Verifix UV bonding range, the new UV lamp range is can be used to bond lengths of glass of up to 1,410mm. The new ‘T8’ tube technology creates a high UVA output with a wave range of 315nm-400nm, operating from a power source of just 230 volts.
This high ratio of output to power, is achieved using a new electrical transformer, which is integrated in the housing. This also reduces flickering, significantly improving the curing of acrylate adhesives. It’s also fitted with special filter disks to prevent damage to the eyes, skin and to avoid stresses in the bonding.
“Having vacuum clamped the unit, we bonded it a metre at a time, 5m per joint on the largest joint between the top of the case and the sides, to deliver a consistent cure and even set on both sides of the joint,” Rob said.
Another critical element of the design was an access door and opening. This was hinged using Bohle hardware and locking mechanisms.
“We used Bohle technology across the board from hinges and hardware to the preparation, handling an installation of glass,” said Rob. “We see this as an area of growth, although one which requires some area of specialism, as there are lots of handling and health and safety implications along the way.”
