Manufacturing a new filter for a 1934 Lagonda.
Utilising reverse-engineering to fabricate a filter element for a classic car.
Custom
Designed
Metal
3D Printing
Community
Spirit
Croft Filters is incredibly proud to be sponsoring the Croft Carnival once again this year. It is an honour to support such a fantastic family event, which has been bringing the community together for well over a century. The carnival is not only a highlight for many people in the village and surrounding areas, but also raises valuable funds for local charities, organisations and clubs throughout the year.
For more than 10 years, Croft Filters has manufactured custom metal 3D-printed medals, which are presented to the winners of various competitions held throughout the day, including the world-famous Egg Throwing Competition.
These medals are produced using Croft’s Selective Laser Melting (SLM) additive manufacturing machines, more commonly known as metal 3D printers. In this case, the medals are manufactured from Stainless Steel 316L powder.
The process begins with a CAD (Computer-Aided Design) model, which digitally represents the part to be manufactured. A common misconception is that metal additive manufacturing is as simple as pressing a ‘Print’ button, much like printing a paper document. In reality, there is a significant amount of engineering work required before the machine can begin manufacturing.
Once the design has been optimised, it is imported into specialised build preparation software. Here, the component is orientated on the build plate within the machine’s build chamber. The orientation is critical, as it directly affects build quality, surface finish, build time and the amount of support material required.
Support structures play a far greater role in metal additive manufacturing than many people realise. They are essential for preventing distortion caused by the intense heat generated during the build and for anchoring the part securely to the build plate. During this stage, engineers aim to minimise the amount of support material while ensuring that any supports used remain accessible for removal after manufacture. As a general rule, overhangs greater than 45 degrees will usually require support structures.
Once the orientation and supports have been finalised, the CAD model is sliced into individual layers just 50 microns thick—approximately half the thickness of a human hair. These medals consist of approximately 933 individual layers, each of which must be manufactured separately.
The additive manufacturing machine is then prepared for the build. This involves reducing the oxygen concentration inside the build chamber to create an inert atmosphere, preventing oxidation during the melting process. The Stainless Steel 316L powder is loaded into the machine, and the build file is transferred using the appropriate process parameters.
The Build Can Now Begin.
A wiper spreads an even layer of stainless steel powder, just 50 microns thick, across the build plate. A high-powered laser then selectively melts the powder according to the CAD data, forming the first layer of the build and the initial support structures. Once the layer has been completed, the build plate lowers by a further 50 microns and another thin layer of powder is spread across the surface. The laser then melts this new layer it to the previous one. This process is repeated layer by layer until all 933 layers have been completed, gradually building the finished medal from the bottom upwards.
Once the build is complete, the parts and their support structures remain buried beneath the loose, un-melted powder. This unused powder is vacuumed from the build chamber and recycled for future builds, leaving the completed parts attached to the build plate by their support structures.
Post-processing is another stage of additive manufacturing that is often overlooked. Unlike many plastic 3D-printed parts, metal support structures can be strong and cannot simply be snapped away by hand. A combination of snips, saws and chisels are first used to separate the support structures from the build plate. The remaining supports are then carefully removed before the parts are finished using files, rotary tools and tumblers to achieve the desired finish. This labour-intensive stage often takes as long as the build itself and is frequently underestimated, even within the manufacturing industry
For these medals, the finishing process includes filing, tumbling and polishing before the ribbons are attached, ready to be presented to the winners at the carnival.
Last year marked the 100th anniversary of the Croft Carnival, so Croft Filters wanted to do something special. The medals were gold plated to commemorate the milestone. Croft reached out to Karas Plating, who very kindly not only accepted the work but also supported the local community by carrying out the plating free of charge. Their generosity added a unique finishing touch and helped create a truly memorable keepsake for such a significant occasion.
Everyone at Croft Filters is looking forward to this year’s carnival and is proud to continue supporting such an important event within our local community. We wish all of the organisers, volunteers and competitors a fantastic day and the very best of luck.
Croft Filter Refurbishing Service
For more than 20 years Croft have been re-meshing and refurbishing filters for a customer operating within the Chemical industry.