Dave Kingston, Group Training Officer at Aspen Pumps, says choosing the right tools can help achieve the perfect joint.
Traditionally, the method of joining two pieces of copper tube together is by using a standard tube expander and brazing the joint. When expanding a tube, ensuring that the result creates a straight clean expansion, means less chance of a sloppy fit and the joint falling apart during assembly. By expanding one end and sliding the other tube into it, there is only one join to braze; this results in less chance of a refrigerant leak.
With standard tube cutters, spinning the cutter round the tube and turning the handle periodically tends to crush the cutting wheel into the copper and this is the only way to increase the cutting depth. However in the process of this that crushing affect tends to deform the edge and tapers in towards the centre, creating an internal burr. This is perfect lead in for a cut tube to slide into an expanded piece. Sliding an expander straight into the end of a cut tube is impossible due the deformation and burr. An internal reamer will cut out the burr and most expanders have a step that can be used initially to expand the burr and restore the diameter; both allow the expander to slide in properly.
Whichever processes is used it cannot rectify the crushing effect of a standard cutter and it’s this that causes the rim edge to work harden. Immediately any tube expander is brought into play that small amount of hardening is all that’s required to start the edge cracking; resulting in a full split down the length as the tube is expanded.
The JAVAC EDGE tube cutting range eliminates the requirement for tube reaming or any pre-expansion to remove a burr, simply because of the unique way it cuts the copper tube. The patented adjustable tension setting eliminates the tube edge from being crushed by automatically increasing the adjustment in a controlled way. This maintains the internal tube diameter and in turn protects the cutting wheel from excess pressure and keeping it sharp for much longer than a conventional wheel cutter.
By combining the use of the EDGE tube cutter, set at the correct tension, and an EDGE tube expander, a perfect joint can be created every time; something the refrigeration industry has not been able to consistently achieve previously.
This makes the whole process easier, faster and eliminates possible breakdowns due to poor joins. It also makes assembling pieces of tube prior to brazing much easier, due to a perfectly tight joint every time.
The JAVAC EDGE expander is precision machined from high grade materials so its accuracy and repeatability is guaranteed. Simply compressing the handles until they stop is enough to create a perfect expanded joint.