A few years ago, Chris Freshman (pictured) — R&D director of the Torus Group (www.torus-group.com) — set himself the challenge of making 3-D printing an indispensable part of the bespoke measurement and testing business by exploring its benefits for all aspects of day-to-day operations.

The group now produces its own doorstops and whiteboard erasers by 3-D printing, but the high point of its additive-manufacturing adventure so far is the development of a unique part that is helping it to meet the stringent demands of its internationally renowned clients.

After experiencing problems with reliability and functionality in the past, Torus looked at how it might use 3-D printing to produce a redesigned filling assembly for its top load and volume gauge machine.

The assembly is a complex construction of channels, inserts and electrodes that allow water to flow in and out during bottle volume and crush-resistance testing.

It is printed on the group’s Stratasys Objet260 Connex3, which was supplied by Derbyshire-based SYS Systems (www.sys-uk.com).

Mr Freshman said: “We make machines for quality and inspection.

“With the top load and volume gauge, a customer will want to know, when they are filling a bottle to a set height, that the right volume of liquid has been dispensed.

“Previously, the filling assembly involved stock tubes that we would machine, but they were a nightmare in terms of reliability.

“We thought they could be improved by using 3-D printing, and that has certainly been the case — they are now 100-times better.

“Four separate parts have been combined into one sturdy structure, without any support materials required.

“The fact that we print the parts means they’re easily replaceable, but they only fail if you break one — we haven’t yet had to replace one worn out by general use.

“Compared with the old method of producing the parts, I’d say 3-D printing has saved us three days of labour per machine, factoring in the production problems that have now been removed.”

The manifold and nozzle for the new filling assembly took less than a week to design, and each complete part can be printed in 19hr (to an average accuracy of 50µm) using VeroClear — a rigid material that provides excellent detail and dimensional stability.

The 3-D printer runs unattended overnight.

Nozzles can now be produced to a width of just 9mm, compared to 18mm using traditional manufacturing methods; this helps Torus to cater for customers producing smaller bottles.

Where faster fills are required, the part can simply be scaled up.

Mr Freshman said: “The assembly structures have been specifically designed for 3-D printing, and I don’t know of any other way they could be manufactured.

“We’re pushing real 3-D printing applications as far as we can for the benefit of our customers, and it is an ever-growing area.

“You have to think and design differently, but what you get out of it at the end is a lot better.”

The Connex3 range of 3-D printers offers design freedom with a wide range of material properties, from rigid to flexible, transparent to opaque, neutral to vibrant, standard to bio-compatible and durable to high-temperature.

It is possible to incorporate dozens of colours into one model, from vivid opaque to stained-glass-like translucent, with hundreds of blended hues in between.

Rob Thompson, sales manager at Derby-shire-based SYS Systems, said: “We love the challenge of working with customers on new and innovative 3-D printing applications, and Torus continues to break new ground.

“They are setting the industry standard with their filling assemblies, and it’s inspiring to see how they’ve embraced the power of additive manufacturing.”