Wall plug inventor Rawlplug adopts SLS 3D printing for end-use quality prototyping

Rawlplug may have over 100 years of experience within the power tool market, including the development of the world’s first wall plug, but the firm is always looking for opportunities to make its R&D projects faster, cheaper, and more efficient. 

In the past, the company’s tooling workshop conducted product QA testing via outsourced 3D printed mock-ups, before injection molding its end-use products. However, by switching to in-house prototyping and adopting Sinterit’s Lisa Pro system, Rawlplug has recently been able to ramp up its design iteration process, and rapidly test anchors, fasteners, and fixings that are more representative of the final product. 

“I can confidently say that nowadays 3D printing is one of the most important avenues for prototyping,” said Dominika Zarowna, Design Engineer at Rawlplug. “Due to the fact that we are able to check certain solutions on a printout, we need to create much fewer prototype forms. It saves a considerable amount of time, both for us and the tooling workshop.”

“We have experience with FDM and SLA 3D printers, but to print a lot of small elements, such as wall plugs, SLS is the best technology.”

From masonry to SLS innovation

Back in 1910, British inventor John Joseph Rawlings was contracted by the British Museum to affix electrical fittings to the walls of its buildings in an unobtrusive manner. In order to accomplish this, Rawlings created and patented a small and secure fixing device, which he nicknamed the ‘Rawlplug,’ but has now come to be known simply as the ‘wall plug.’ 

Arguably, Rawlings’ invention formed the basis of the modern fixings industry, and to this day, his legacy lives on through his firm which still bears the Rawlplug moniker. Over the last 111 years, the company has gone on to build a broad product portfolio of mounts, joints, and power tools, that have been deployed within the construction of buildings ranging from the Burj Khalifa to Wembley stadium. 

In that time, Rawplug’s prototyping workflow has also come on leaps and bounds, moving from traditional manual production into 3D printing, but until recently, the process had been outsourced to an external vendor, adding unnecessary cost, complexity and ultimately lead times to the R&D of its new products. 

“When I first came on board as a new hire, we used to outsource the printing to third parties,” explained Zarowna. “This often took a considerable amount of time. What we needed was a 3D printer of our own, in order to reduce the waiting times to a minimum. At the same time, we were on the lookout for new technologies.”

A cork board with several different mountings and fixtures attached.
Rawlplug now uses SLS 3D printing to prototype its latest mounts, joints and power tools accessories. Image via Sinterit.

A cost-friendly SLS entry-point 

For some time, Rawplug’s design engineering team wanted to bring prototyping in-house, but the initial expenditure required to adopt an advanced SLS 3D printer effectively priced them out of the move. Since then, however, the company has found Sinterit’s Lisa Pro to represent a more compact, cost-effective alternative to larger industrial machines, installing the system at its dedicated tooling workshop.

Leveraging their economical SLS system, Rawlplug’s engineers are now able to design new products and innovate upon existing ones at a more rapid pace than before, thus providing the company with the agility to quickly pivot, change design philosophy and continue to compete in what has become a crowded tooling marketplace. 

Sinterit’s Lisa Pro is also supported by a wide material portfolio, enabling the team to switch between powders and create products with vastly different functionalities in the same machine. Given that many end-use parts are produced using polypropylene (PP), the firm has found Sinterit’s new PP polymer to be an especially useful prototyping tool, in particular when it comes to making final part-quality mock-ups. 

Focusing on quality over quantity 

Before Rawlplug adopted the Lisa Pro, the team wanted to expedite their product design process, but not at the expense of part quality. As a result, prior to acquiring the system, the engineers put together a comprehensive test model, that assessed its accuracy and ability to incorporate nested elements, which wouldn’t have been possible using other machines. 

Since passing its initial assessments, Rawlplug has opted to install the machine, deploying it to produce around 95% of its products, and only outsourcing larger parts once or twice a year. Additionally, the firm has found that the system yields a reduction in the number of iterations needed to perfect each product’s design, allowing it to bring them to market more quickly and gain an edge over its competitors. 

“Lisa Pro is not quite the quickest 3D printer, but for us, that is not a big concern, because we reduced the waiting time for prints from 2 weeks to 2 days,” added Zarowna. “We have worked out a system, where we start printing on a Friday afternoon and the prints are already waiting for us on Monday when we come to work.” 

By collecting a weeks’ worth of projects from its designers, and producing multiple concepts at once, the company has also managed to streamline and minimize the cost of its overall R&D operation. What’s more, the quality of Rawlplug’s SLS-printed prototypes puts them on a par with injection molded parts, meaning that the firm can test their performance to the limit, knowing that if they pass, so will the final product. 

Ultimately, Zarowna concluded that Rawlplug’s market-leading product range is a result of the “good design” and “thoroughly thought-through testing” enabled by its Lisa Pro system, a machine which has also allowed Sinterit clients like Rotite Technologies to expedite its prototyping process, and will no doubt benefit others in a similar way in future. 

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Featured image shows a cork board with several different Rawlplug mountings and fixtures attached to it. Image via Sinterit.