A customised cold welding system developed by British company PWM in partnership with US manufacturer Virtus Precision Tube (formerly Luvata) has streamlined and improved the process of copper tube production.
The system has improved uptime, reduced costs and created a better working environment for operators, according to Joe Napier, VPT’s Engineering Program Manager.
“We produce over 40 million pounds of roll-and-weld copper tube each year, in sizes from 1/4" to 1/2", he said. ”The cold welding system we have developed with PWM is part of our continuous improvement program. It supports our on-going drive to develop high-performance tubing solutions for the HVAC and refrigeration heat exchanger markets.
“Copper strip is supplied in large narrow rolls and approximately every 20 minutes, the tail end of one roll has to be joined to the head of the next roll. The new cold welding process is more straightforward than the crossweld process we used for a decade, and works the first time, every time. It’s faster, easier to standardise, requires less operator input and training. Most advantageous of all, the new weld is stronger and capable of handling the tensions we place on the strip during tube production.”
Before approaching cold weld specialists PWM, VPT also tried alternative methods of joining strip such as brazing, dovetail profiles, lap joints and laser welding.
PWM successfully test welded VPT’s strip using a portable ST40 cold pressure welding machine, capable of joining copper strip as wide as 45mm wide and as thin as 0.2mm. Precision engineered to create reliable permanent welds stronger than the parent material, the ST40 enabled VPT to reduce the operational scrap rate on the line by 15% during production trials.
PWM has now supplied VPT with three ST40 welders that run full-time in production.
Adaptations such as automatic flash trimming and annealing of the weld (to soften it and make it less brittle), and automation of the weld cycle and die opening system have been developed to streamline the process. VPT will field the new system across all tube mill production lines and currently has four more ST40 units on order with more to follow.
“Technical assistance from PWM, particularly from its Chief Design Engineer, Ivan Turner, has been incredible throughout,” said Joe Napier. “Any problems we had during the development and early fielding of the units were quickly resolved. For example, we went through four design improvements to arrive at our current tooling.”
Steve Mepsted, Managing Director of PWM, said: “This has been a fascinating bespoke project to work on. VPT shares our commitment to quality and innovation and together we’ve created a customized welding solution that significantly improves business performance. We’re delighted with the outcome.”
British company PWM, leading manufacturer of cold pressure welding equipment for over 30 years, is launching two new cold welding machines at wire 2016 (stand 9B41).
The ST40 air/hydraulic strip welder is designed for joining non-ferrous strip and tape used on armouring lines. The machine, for strip and tape up to a maximum width of 45mm (1.772) and a maximum cross sectional area of 33mm² (0.0514²), produces strong, reliable bonds stronger than the parent material without loss of electrical integrity. No set up time is required, and, like all PWM welders, the ST40 is low maintenance, simple and cost effective to operate. Mounted on a trolley, the ST40 can be wheeled easily to the work area, saving effort and reducing downtime.
The new HP180 air/hydraulic cold welder is a versatile machine for wire sizes 0.30mm to 1.80mm (.0118” to .071”). Supplied on a trolley, it can also be hand-held (within the limit of the air supply pipe) if required. Quick and easy to use, the HP180 enables the operator to produce strong consistent welds without effort.
Also on show will be PWM’s powerful energy-efficient electro/pneumatic and electro/hydraulic rod welders for joining large rod sections from 5mm to 30mm (.197” to 1.181”), and its comprehensive range of manual cold welders, for wire sizes 0.10mm to 5.00mm (.0039” to .197”). This includes lightweight hand-held machines, as well as larger portable models which can be used on a workbench or with a trolley.
British company PWM (Pressure Welding Machines) Ltd celebrated 30th years of service to the wire and cable industry on stand 9B41 at wire 2014 on the 8th April 2014
PWM, based in Kent, England, designs, manufactures and supplies high-performance cold welding machines and dies to wire and cable manufacturers worldwide.
PWM’s first machines were small, manually operated cold welders for joining fine wire and strip. The M10, M25, and M30 models for wire sizes 0.10mm to 1.80mm, are all still produced today.
Over the years, PWM gradually expanded its range and introduced larger, powered cold welders, including the P1500 rod welder for joining large rod sections up to 30mm diameter. Recent innovations include the portable air/hydraulic powered HP100 and HP200 machines, which provide effortless welds on wire and strip 1mm to 5mm and 2mm to 6.50mm. All PWM machines and dies are precision engineered in-house to stringent quality standards by PWM’s own team of skilled engineers and technicians.
PWM now employs 19 people in the UK and has a worldwide network of experienced agents who, together with the UK team, provide fast and effcient on-site support with full back-up and after-sales service.
PWM’s on-going research and development programme ensures that it continues to offer wire and cable manufacturers the most advanced and comprehensive range of cold welders in the world. To explain the cold weld process, the company recently developed a series of videos demonstrating the technique, which can be viewed at www.pwmltd.co.uk .