Know-how, or procedural knowledge, is what separates STL from most other SME engineering businesses. In this article we delve deeper into the source and evolution of STL’s Multistrip press tooling know-how.
What is ‘Know-how’?
According to Wikipedia, “Intellectual property (IP) is defined as a category of property that includes intangible creations of the human intellect. There are many types of intellectual property, and some countries recognize more than others. The best-known types are patents, copyrights, trademarks, and trade secrets. The term “intellectual property” began to be used in the 19th century, though it was not until the late 20th century that intellectual property became commonplace in most of the world’s legal systems.”
STL is an SME engineering business with a very long history of IP but in the informal manner, or as Wiki puts it, ‘trade secrets’.
Trade secrets can also be known as “know-how”, something which STL excels in, again to quote from Wikipedia “procedural knowledge (also known as know-how, knowing-how, and sometimes referred to as practical knowledge, imperative knowledge, or performative knowledge) is the knowledge exercised in the performance of some task”.
Examples include metal stamped parts of very different thicknesses and compositions, welding the un-weldable, stamping asymmetric pitched parts on conventional presses, producing edge bonded and rolled metal strips and so on.
One of the latest developments was the creation of cold clad bimetallic strip using copper and aluminium and now a new concept of assembly using press-tooling as the basis.
Was this patented?
No, because we don’t want to give away the recipe, and this is what is known as know-how.
The origins of our Multistrip Press-Tooling know-how
Our example starts some years ago with a well-known maker of household switches, who had a single piece earth-strap for their twin gang switched socket.
This was a splendid concept, as a single piece could easily be stamped and placed by an AA machine directly into the back moulding at a decent speed. All the components were designed to be auto assembled.
New concepts of poka yoke or “mistake proofing” were introduced and design became both technical, for the electrical currents, socket pull out forces and so on, and driven by production engineering for automation.
Their new concept of accessory was made with nicely rounded corners, less materials, less numbers of parts and all made by a few technicians and an expensive piece of automation capable of running 24/7. The customer’s know-how on switched sockets is legendary but less well known was their know-how on JIT, supply chain & inventory management, subjects STL subsequently learned well on this project.
Then along comes STL hungry for more work, innovative and looking for a new challenge. Over coffee and biscuits at our customer’s premises the conversation moved to value engineering. The earth strap came up as the most expensive metal part within this assembly, but what can be done?
The BS 1363 regulations state that the contact parts including the earth socket shall be of non-ferrous materials, and although the earth contact and cable is not normally current carrying, in extremis it can become live, thus the stamped and folded part was made in relatively expensive phosphour bronze.
It has to perform a consistent contact “grip” function which excludes cheaper non-ferrous alloys and the idea of plated steel is also verboten. This ensured that the regulations are followed and the socket as safe as it can be. This very clever design facilitated a one piece stamped part which was a brilliant innovation both technically, and for the AA machine too, as one piece only needed to be assembled.
However, the scrap element was said to be around 70% due to the great complexity of the part when “flattened” out. Yes, the scraps are recyclable and much of the original cost recovered, but any contamination of the scraps and they become almost worthless, so good factory hygiene and know-how is essential. Thus, we can see that the part is both very clever as it’s only one piece, but expensive as it’s large and wasteful and all made of the expensive material.
Years ago the business of feeding three strips into one press-tool had not been done by STL or our customer before, and when machinery suppliers were asked, not by them either, so know-how here was lacking and had to be learnt.
Nowadays of course STL considers this to be relatively normal. Today STL adds tapping into press tools, welding, soldering and other contacts and other parts too.
For example, a new re-shoring project is running at STL whereby parts made in the UK are assembled in a cheap labour country and then returned to the UK. They do it by hand, however the entire sub-assembly can be done by STL for a fraction of the price and hassle, never mind the CO2 , time and inventory costs wasted. With clever automation and know-how STL can do it all, including soldering, within one press line. This will also include camera technology to ensure that each part is complete, recorded and correct.
For STL the sub-assembly and automatic inspection of stamped metal parts is not unusual, all we need is decent volumes and budgets and STL can provide the know-how to find the right solution.
Back around the coffee table chatting over this earth strap all those years ago STL suggested that the contact part be made of the existing material, so no change there, but the rest (where all the scraps are generated) could be made of cheaper steel.
In 2025 prices the phosphor bronze is around £12.00 per kilo and galvanized steel around £1.50 per kilo. At one eighth of the cost, could this be made to work? The complexity of the part was now suddenly made far worse by the need for three strips with different pitches to be fed into a press machine running at over 100 parts per minute. This had never been done before by our customer or any of their suppliers, nor by STL.
So, a project was born, a team developed and prototypes made and tested. The testing and prototyping took months of optimisation and STL decided early on not to use any conventional fasteners or pre-formed parts, due the added complexity of placing additional loose items into an already fancy presstool design running quickly.
A semi tubular “rivet” was extruded from the base steel and a gas tight joint made. Here the boffins at STL used know-how from the connector industry and our customer was impressed.
Less impressed however, were the STL tool designers who were faced with getting very small, delicate pins to work in large press-tools complete with side action and three strips at once. Make the pins too hard and they snap like carrots and can cause collateral damage in a complex prog tool, make them too soft and the maintenance is forever an issue, then there is the question of the hole size to the extrusion size, and so on. The camera tech STL uses is now in it’s second generation such is the progress of the devices and the application of continuous improvement at STL. We can proudly say, much know-how on presstool design and development is chez-nous at STL.
The STL suggestion was to use plain mild steel, after all sockets are not meant to get wet or need salt spray testing. However the customer said no, it must be plated and it must look cosmetically good too – as the earth strap pressing is visible on the back of the socket. So, more sampling, more know-how in finding the right suppliers, and because we had a long and complex press-tool design with many stages, we needed very good steel (thin wide, accurate, and with very precise gauge control).
This is always difficult to source so STL know-how again came into play; only with a very good supply chain would this project work.
Additionally, much like our customer, we too have limited space for inventory so kan-ban JIT principles applied with weekly call offs normal. To present day, the STL original steel and non-ferrous suppliers remain in place producing product now with press-tooling and a dedicated work cell dating back over 20 years, demonstrating the first time right approach coupled with great know-how all round. The moral of the story is, vendor assessment is not a simple price driven exercise, but a much more nuanced multifaceted understanding and assessment of know-how.