New generation of rapid manufacturing equipment

Paul Boughton
Significant advances in producing large numbers of parts simultaneously at speed and with high accuracy have been made using a radical new exposure system. Ole Hangaard reports.

Stereolithography (SL) was first introduced in the late 1980s, and since then Huntsman Advanced Materials has been actively involved in pioneering SL resin development.

This year sees the start of a new period for industrial development in rapid production. Many systems have been developed over the years such as SLS, FDM and 3D printers offering users a range of choices. As a consequence of these technology developments, the global additive fabrication market has evolved into three major segments, with a clear distinction in what customers are looking for:

- 3D Printers for Concept Modelling: Low cost and marginal performance material with small build envelope which has led to high numbers of unit sales in this segment.

- Mainstream Rapid Prototyping System: New machine sales in this segment have probably reached a plateau because of the limited progress in laser based technology in recent years.

- Rapid Manufacturing Systems: Customers are looking for reliable and reproducible systems that offer accuracy and mass manufacture for personalised products. This is where the future lies.

Over the past 20 years, global companies have changed their global manufacturing strategies, which have laid the foundations for what many in future years may call the 'rapid prototyping renaissance'. This renaissance now leads the way into real time rapid manufacturing of numerous and complex parts with great accuracy and cost savings.

Rapid manufacturing will change the way things are made. It will increase the degree of customisation that can be produced to match end user's requirements, while still enabling mass production to eco-friendly standards. Customised parts can be produced by anybody in almost any part of the world - the fabrication of the future will not necessarily be in industrialised areas. The industry can only grow over the coming years.

Rapid manufacturing will inevitably lead to a much larger range of possible applications across a range of markets. A few examples of markets that will be affected by new rapid manufacturing technology are equipment and parts for the automotive, general industrial, food manufacturing, building and health sectors with items ranging from hearing aids to complex surgery. The list is endless.

There is always pressure to bring new designs to market as quickly as possible. This is one of the main drivers behind the work of design engineers and their prototyping partners.

A team of engineers and chemists have been working closely together to develop this brand new machine and complementary photopolymer. Combined with a strong history in UV chemistry this integrated system enhances the total offering to customers.

New exposure system

At the heart of Araldite Digitalis are the MLS MicroLightSwitch modules. Based on entirely new MEMS (micro-electro mechanical system) technology, which is neither based on lasers nor on light reflecting MEMS technology as used in 3D printers, the MLS MicrolightSwitch makes Araldite Digitalis superior to any other radiation curing technique on the market.

A laser is only able to expose one point at a time, drawing line by line with the illuminating angle varying depending on where the laser irradiates. The MLS MicrolightSwitch operates at 90°, which makes it able to expose 40,000 light pixels at a time with high accuracy, thus offering the potential of much faster manufacturing of even very complex parts and making it fundamentally different from any existing stereolithography technology.

The MLS MicroLightSwitch module enables micron-size spots of radiation to be selectively irradiated onto a resin surface via a shuttering mechanism built into silicon MEMS chips. The exposure system traverses across the build in x direction and the building plate goes down and the recoater applies the fresh resin onto the surface to build parts layer by layer.

The key benefit of this system is that it enables a large surface area of radiation curable resin to be selectively exposed via a computer controlled micro shutter system

MLS MicroLightSwitch is a transmissive technology, making it different to other MEMS systems.

The width of y axis of the build is determined by the numbers of MLS MicroLightSwitch modules used. Araldite Digitalis consists of the 16 modules which give 370mm y build.

Bigger or smaller build envelopes are obtained by increasing or decreasing the number of MLS MicroLightSwitch modules still maintaining same resolution and accuracy all over the building platform due to the 90° vertical exposure angle.

This transmissive modular exposure technology offers a great flexibility in the resolution, the size and the complexity of the build, as compared to lasers and reflective technologies.

Araldite Digitalis opens the way to a much greater range of applications and what will be a new era in the development of rapid manufacturing. It has the potential to reduce production times and thereby costs and further it is also easy to use and maintain. The competitive benefits of Araldite Digitalis grow exponentially as the number, size and complexity of parts produced increases.

Initial tests at customer sites have proven the enormous potential of the new AralditeDigitalis technology. It is not just a machine, but a complete development philosophy, combining the best of chemistry and physics.

Experts estimate that the rapid manufacturing market is currently worth around US$1.2 billion.

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Ole Hangaard is Project Manager for Araldite Digitalis, Huntsman Advanced Materials, Basel, Switzerland.