Charles (Chuck) W Hull is the co-founder, executive vice-president and chief technology office of 3D Systems, whose business is based on the stereolithography process Hull invented in 1986. This was the first ‘solid imaging’ or 3D-printing process. Stuart Nathan spoke to him (and his wife) at the recent European Inventors’ Award ceremony in Berlin, where he won the Industrial Award
Chuck Hull invented 3D printing on Wednesday 9th March 1983 at 8.39pm. His wife, Anntoinette, remembers it distinctly; ‘and she has a much better memory than I do,’ he says.
The invention was aimed at speeding up the prototyping of plastic parts, he says. ‘Back in those days it was very difficult between when you had the idea and the blueprints to get the first part: It could take six weeks to two months; it was very slow,’ he says. ‘And when you got the prototype it was usually wrong; but you couldn’t start iterating and improving until you got it.’
At the time, Hull was working for a company which made ultraviolet lamps which were used for curing coatings on tabletops. ‘I saw those coatings as thin pieces of plastic,’ Hull says, ‘and I thought that if I could stack those up to make a solid shape, it might be a way of solving the prototyping problem.’
’I saw those coatings as thin pieces of plastic and I thought that if I could stack those up to make a solid shape, it might be a way of solving the prototyping problem
3D stereolithography works along those lines, using UV light to polymerise and cure a layer liquid resin, creating a thin solid sheet on top of a motorised platform. Successive layers are cured on top of this as the platform sinks into the vat of liquid resin, eventually making a solid form. It’s the basis for all other forms of additive layer manufacturing used today, whether they use UV or lasers to cure liquid resin or to melt powdered plastic or metal.
Hull’s first 3D printed part was a simple cup-shape, based on an eyewash applicator cup; Anntoinette habitually carries it in her handbag. It’s a humble start to such a transformative process, but the first thing it transformed was the Hulls’ life. ‘I had been working with a patent lawyer and as soon as I got the machine working he wrote the patent and I submitted it,’ he said; the working of that patent covers any material that can be caused to change physical state as the printing material, as Hull immediately realised that it wasn’t limited to liquids. ‘When the first patent was issued I knew I wanted to commercialise it. The president of the company I was working for said they didn’t have enough money to do that, so I suggested starting a new company to raise new capital, and he could have part of the company, so I started 3D Systems in 1986.’ He and his former boss – now partner – raised $5.5million. ‘It was hard, but it was enough money to hire engineers and take us to the next stage,’ Hull recalls.
Hull says it was obvious to him that the technique would be hugely versatile. ‘I saw it was just the beginning, but I couldn’t anticipate what we have today,’ he says. The amateur maker movement is providing a lot of new knowledge and broadening the understanding of what 3D printing is capable of, he says: ‘We’re seeing new applications every day; but we still need better materials and faster, more accurate processes.’
The most surprising application for Hull was the use of 3D printing in surgical planning. ‘Conjoined twins is particularly notable,’ he says. The surgery can take 20 hours and up, and the surgeons spend a long time practicing. They make a 3D printed model of the case they’re about to work on, so they know what they will encounter during the surgery and how to cope with it. That was a huge surprise to me.
Hull isn’t overly concerned about the use of 3D printing to make weapons: ‘There’s a lot better ways to make weapons than with a consumer grade 3D printer,’ he says. But the loss of manufacturing jobs is a concern. ‘It does change the skills; it puts a new emphasis on design, so in that sense it creates new jobs. We can’t predict how it will affect things into the future; it’s far too early. But yes, it will certainly eliminate or change beyond recognition some jobs in manufacturing; where those jobs would be is something else we can’t say.’
Although Hull is now 74, he has no intention of retiring. He continues to work on 3D printing, and also holds patents in ion optics.