Star Rapid is a low-volume manufacturing and 3D metal printing company specialising in rapid prototyping, rapid tooling and manufacturing of custom parts using a range of traditional and additive technologies. Formerly known as Star Prototype, the company finalised a rebrand at the beginning of the year, coinciding with a $2.5 million investment and expansion of its facility based just outside of Hong Kong, to bring in new cutting-edge plastic injection moulding, CNC and inspection equipment.

                                                                  Impeller printed in titanium with weight saving lattice

Chloe Kow, Manager of Direct Metal Laser Sintering at Star Rapid, has been with the company since 2015. Born and raised in Malaysia, Chloe began her career studying materials and manufacturing engineering. With a masters in advanced engineering from Sheffield Hallam University, Chloe spent over five years in R&D focusing on metal 3D printing, working with The Manufacturing Technology Centre (MTC) and The Welding Institute (TWI), both in the UK, where she focussed on the aerospace and automotive sectors before moving to Star Rapid where she now manages its metal 3D printing services.

I asked Chloe a few questions about leading a team in one of the industry’s most exciting growth areas, the need for AM manufacturers to become educators, and what she believes needs to happen in order for the wider AM industry to progress. 

                                          Chloe Kow, Manager of DMLS at Star Rapid with the Renishaw AM250 system       

TCT: Can you talk us through your role at Star Rapid? What does an average day look like and which technologies are you working with?

Chloe Kow: As a manager, part of my role is being a problem solver and educator. The general lack of design-for-additive manufacturing knowledge in metal 3D printing from customers leads to a lot of trial-and-error, as well as technical issues arising during the build process, which I help address. This is also why part of my role includes teaching customers how to design parts using additive manufacturing in addition to general counsel.

At Star Rapid, we use a state-of-the-art Renishaw AM 250. For a typical build, I first work with the 3D CAD files provided by the customer on Materialise Magics software to fix the part, determine part orientation optimisation and the support generation. Support generation is a very important part of the software preparation as it is needed to hold the part securely to the build platform and allows for heat dissipation. If the part is not sufficiently supported, it might distort from the build plate due to the internal stress that is induced during the repeated heating and rapid cooling or the part might fail due to the molten area that, without supports underneath, will be wiped off by the wiper. Once the support generation is completed, the part with the supports will be sliced and hatched by providing the correct process parameter and laser scanning strategy in the Renishaw Build Processor prior to sending the files to the AM 250 machine for printing.

Once a part is built, metal 3D printing usually requires some form of post-machining to provide features that 3D printing alone cannot provide. I use our in-house AddSub service, where material is removed by a 5-axis CNC machine to improve the surface finish and tolerance.

You have spent over a decade researching and working in advanced manufacturing - what are some of the biggest changes you’ve seen so far? 

Over the last decade, I’ve seen 3D plastic printing become widely embraced within the industry, while metal 3D has remained uncommon. Although a few metal machines have been on the market, they have, until recently, been mainly for research purposes. In the past two years, a great deal of metal machine manufacturers and metal powder manufacturers have started to emerge – a trend I expect to continue. With increased adoption and competition, the machines and materials costs will gradually become more affordable.

Many universities have started to teach courses and conduct research in metal 3D printing as well, although opportunities are limited. Right now, the use of metal 3D printing is centralised to the aerospace, automotive and medical sectors, along with some very niche applications such as jewellery making. In the coming years, metal 3D printing techniques will advance in terms of speed, quality and the improvement of post-processing. More companies will begin adopting metal 3D printing processes to manufacture parts and end products. With the continued emergence of simulation analysis software in metal 3D printing, the intensive build process will be more controllable, thus reducing the amount of parts that fail. I’m also looking forward to the emergence of more hybrid systems, especially in powder bed fusion technology.

                                                                          The Star Rapid factory floor

Having worked in AM in both the UK and in China, have you experienced a difference in the rate of development and adoption across the two?

During these two years working in China, I have seen a massive step forward in the development of the 3D printing industry, especially in metal 3D printing. This might be due to the Chinese government’s unveiling of the “Made-in-China 2025” plan in 2015, which was an initiative to propel the manufacturing industry forward and upgrade standards to match those of Germany or Japan. The Chinese government has accelerated the development of AM technology with new facilities, by supporting new applications and by establishing the AM Innovation Centre. This effort in recent years has led to boost in local AM machine manufacturers and powder manufacturers.

What do you think is stopping companies from adopting AM for series production and what needs to happen to change that?

As mentioned, there is a lack of education around designing for metal 3D printing that is stopping companies from adopting this process for series production. It’s a time-consuming, costly process, so if the need for lightweight and high strength parts takes priority over time and cost, then metal 3D printing is the ideal process.

At Star Rapid, we work closely with our customers on how to design parts for production and provide design guidelines to assist them through the process. Once the customer is able to understand the fundamentals of the design guidelines, they are able to fully utilise metal 3D printing, without sacrificing creativity. To further support our customers, we also offer free online videos focused on how to design for additive manufacturing and limitations of the process and are offering in-person metal 3D printing workshops at our factory in November and March 2018 to provide hands-on training. More manufacturers in the industry need to become educators in the sector and make metal 3D printing training a core part of their business initiatives.

Terry Wohler’s commented last year that metals were the industry hot trend - do you think that’s true?

Absolutely! Metal additive manufacturing allows the industry to create finished parts with complex geometries that are otherwise unachievable by other processes. That makes it an incredibly sought-after process. I’ve attended the TCT event in Shanghai the last few years and the number of metal and plastic AM machines on display have grown year-after-year.

What advancements would you like to see happening in the industry to push it forward?

Although there is software on the market that can provide simulation analysis on part deformation during metal 3D printing process, I’m still looking forward to a more stable, mature and accurate software in the next few years that can accurately predict the thermal behaviour and microstructural change on each layer during the metal AM process.

It is very hard and complicated to predict the microstructural change of metal AM parts due to the layer additive nature of the process - a complex thermal behaviour that involves re-melting and rapid cooling on each layer underneath. If this complex microstructural evolution were successfully studied and fully understand, this would make the metal AM process more controllable during the build, resulting in fewer failed builds and massive time savings.

Source:TCT Magazine