Part of the PCB manufacturing process is the UL test. In this article we will firstly outline what is involved with the UL test, before moving on to discuss’ Hi5’s accreditation for performing that test.
UL recognition of metal substrates (in terms of the base material used in PCB manufacture) has become increasingly important in recent years, particularly as it is fundamental in LED lighting. Once the preserve of science fiction films, LED lighting has now become ubiquitous in the consumer market – starting in the US but quickly transferring to the UK, where it has found favour in a marketplace ever keen for new energy saving ideas.
In terms of manufacturing a printed circuit board, the manufacturer (in this case, Hi5), needs to evaluate the properties of that board and is, in fact, legally obliged to do so. If the end use of that board is purely for connection to a low-energy circuit, the interrogation of the base material needs only be tested by its flammability. In these cases, the danger of electric shock or other injury to anyone using the board is not an issue.
In other cases, however, there are various factors that need to be born in mind when investigating the base material. These will include moisture absorption, ignition resistance to electrical sources, insulation resistance, dielectric strength, mechanical strength and combustibility. In addition, you will need to assign a temperature index and make sure there is resistance to distortion and creeping at the temperatures the PCB is likely to experience in its end use, as well as resistance to arc-tracking. What you are looking for is that the integrity of the base material is not compromised beyond what might be expected by, for instance, the results of aging.
Further, you need to interrogate the conducting properties of the PCB and its conductor forming process. Such tests will include solder limits, minimum width and maximum ground plane area, and shape of the PCB.
In essence, then, there is quite a lot involved with the UL test, so in 2013 Hi-5 undertook a project that lasted many, many months to apply for – and ultimately achieve – fresh UL recognition and thereby boost our manufacture of printed circuit boards. After winning this recognition, customers can be assured that such tests can be conducted by Hi-5 under their own auspices, and by their own engineers, thereby assisting the logistics of the process by keeping the whole process under one roof, rather than the associated costs of out-sourcing such tests.
This new recognition particularly applied to an extension of Hi-5’s IMS PCBs. And if that seems like an acronym too far, let’s further unpack it by extrapolating that it relates specifically to insulated metal substrate boards, sometimes known as metal-backed PCBs.
This recognition means that HI-5 can now manufacture laminate on the premises, and our PCBs can be UL marked. And that’s a huge boost to our own business and our ability to help our customers. Outsourcing the process always meant longer lead times on special aluminium thickness or copper weight. Following the recognition, Hi-5 have been able to undertake UL marked, PCB manufacture on aluminium thickness, from prototype through to volume orders. In the year and a half since the award, we have found the approval has helped both our own designers, through to our customers, who have benefited from a low order minimum and fast turn around times.
And anything that expedites the process is, of course, very welcome news.