Engineering Solutions Live took place at the British Motor Museum in Gaydon, Warwick, in March. The show brought delegates and exhibitors under one roof to identify new technological solutions and learn about new techniques and technologies, whilst also providing a range of seminar content on engineering materials, PCB (printed circuit board) design and fastening and assembly solutions.
Additive manufacturing company Stratasys has been working in the field of 3D printing for more than 30 years. In simple terms, additive manufacturing is the industrial production name for 3D printing, a computer-controlled process that allows users to create three dimensional objects by depositing materials, usually in layers.
Senior applications engineer Matthew Jones explained to delegates the benefits that additive manufacturing technology can bring in terms of light-weighting, parts development and metal replacement by detailing a range of use-cases from across different sectors within industry. “This presentation is heavily focused on FDM (fused deposition modelling) because the plastics and properties of the material lend themselves very well for metal replacement parts,” Jones said. FDM builds parts layer-by-layer by heating and extruding engineering-grade thermoplastics. Highlights of some of the use-cases presented follows.
Delegates were first presented with an example from US car manufacturer Ford and its Mustang production line, whereby operators were using a “cumbersome” window alignment tool that featured vacuum suction cups to place the window glass inside the vehicle doorframe.
Jones explained how the original device was unergonomic because the handles were in the wrong position, meaning that operators would grab the corners of the tool and risked damaging the device, vehicle and themselves. Furthermore, the tool was expensive to make and the connections for the vacuum lines would come off and get damaged.
To combat such issues, the decision was made to 3D print the window alignment tool from FDM Nylon 12CF material, which Jones described as “a nylon 12 base material with 35% chopped carbon fibre on the inside”. However, rather than building the whole thing as a solid part, light-weighting was also taken into consideration. Reinforcement, via honeycomb structures on the inside of the tool (see box out), was only applied to areas that needed reinforcing. “You are light-weighting that part, but you are still regaining the stiffness,” delegates were told.
Other ergonomic considerations were also incorporated into the 3D printed tool, such as moving the handles and the on/off switch. “You could even make texture displacement [and] put a textured grip on there as well,” Jones explained, to aid operators if there was oil or grease on production line, for example. In addition, the vacuum hose routing was simplified and made more durable, and a hanging hook was designed, so that the tool could be hung up when not in use.
“There was a 15% weight reduction in this actual part (4.83kg final weight),” Jones added. “To start off with, metal was chosen, because that's what they had inhouse, and that's what they wanted to use. Replacing that big heavy metal fixture with a lightweight carbon fibre part, with new features for the operator, saves a lot of time and money and they're able to replicate that down the production line.”
The tool also won the ‘Additive Manufacturing Award’ at the SPE (Society of Plastics Engineers) Automotive Innovation Awards in 2018.
Another company to work with Stratasys is Airbus. The multinational aerospace firm presented the challenge of finding a material that could meet aerospace requirements, including FST (fire, smoke and toxicity) compliance, as well as reduce weight of components and replace traditional manufacturing methods. “We have more than 1,000 FDM parts printed and flying in planes,” Jones told delegates.
Stratasys announced in 2017 that it had been chosen by Airbus to produce 3D printed polymer parts for use on the A350 aircraft, such as brackets and other parts used for system installation, using FDM material ULTEM 9085. Jones also highlighted a topology-optimised aerial mount for the back section of the plane, which is made from ULTEM 9085 material and is FST compliant with aerospace and military specifications, as well as certified under EN 45545-2 for rolling stock vehicles for trains and trams.
Furthermore, delegates heard about the development of a Nylon 12CF material drill guide, in partnership with a UK service provider, to help the firm drill the holes on the wings of the aircraft. Jones explained how the original drill guide was made from metal that was “very heavy, very cumbersome, and easy to drop and damage”. Key benefits of switching to FDM were said to include weight savings, lead time reductions, and improved health and safety.
Obsolescence is an issue that has affected industry for years. Parts and components may no longer be available, and a decision needs to be made around what to do. Printing parts that are no longer available is one option, as highlighted by Operations Engineer in 2018.
Jones also picked up on the obsolescence issue during Engineering Solutions Live, giving a real life example whereby Stratasys, UK train leasing specialist Angel Trains and engineering consultancy DB ESG Rail worked together to help address the issue of obsolete parts, reduce whole life rolling stock costs and enable vehicles to remain in passenger service for longer.
These goals were focused on four components, including an arm rest, grab handle and seat back tray table.
The project focused on four components, including an arm rest, grab handle and seat back tray table. Credit: Stratasys/Business Wire
Citing the grab handles as an example, Jones explained how they were typically made in aluminium, had a 10-week delivery time, and a cost of €566 each with a minimum order quantity of 10. However, printed in-house on an F900 printer system with a certified grade material and all the post-finishing resulted in the part costing €250 each.
One of the final examples highlighted to delegates involved a company that was not named working within maritime and heavy industry, which presented Stratasys the challenge of printing a functional propeller in Nylon 12CF materials to replace a metal propeller.
The part was designed to operate in the sea off the coast of Canada and was used to circulate water. “This propeller can basically shift the same amount of water in an Olympic-sized swimming pool in 46 minutes,” Jones said.
He added that tests were carried out to ensure that temperature build-up on the outside would not cause any damage to the plastic. The part passed a functional test at more than 2,600 rpm. Weight savings and lead time reductions were also achieved.
“Metal replacement with plastic is becoming very common, typically because metal has been used as a standard but it isn't actually required,” Jones concluded. “You have to start at the top and say, ‘look, there are two routes [that] we can go down – the traditional or an additive route’. It [the additive route] will do exactly the same job for you.”
NOTE: Engineering Solutions Live took place before the UK Coronavirus lockdown. On arrival, all visitors were heat-scanned and had to confirm that they had not travelled to.from the worst-affected countries.
|BOX OUT: SOFTWARE IS KEY|
During his presentation, Jones explained that software is “key” for light-weighting parts and replacing metal parts. This is because software, such as Stratasys’ GrabCAD, allows the user to determine what areas of the part being created need to be thicker than the rest (for reinforcement purposes).
“Really, it's applying an almost composite manufacturing mentality to producing 3D printed parts,” Jones explained. “In the software, you get different fill patterns, so you can do sparse, sparse dense, different honeycomb structures or solid structures.”
Furthermore, software allows the user to change the infill angle. “If I wanted to increase the stiffness of the model to stop twisting, [then] every 10 layers we will alternate the angle to counter the torsion in the actual plastic by putting the stiffeners in in the middle.”