Thornton’s
Rapid Manufacturing
Description and aims
To cut ‘Happy Easter’ into polycarbonate Easter Egg Moulds using a 5-axis waterjet.
About Thornton’s
Thornton’s was founded in 1911 by Joseph Thornton with the first shop established in Sheffield. It has since grown to become one of the UK’s largest manufacturer and retailer of specialist chocolate.
How the project is being undertaken
The School of Mechanical, Materials and Manufacturing Engineering joined forces with Rolls Royce, the East Midlands Development Agency (emda) and the Midlands Aerospace Alliance to establish Europe’s first state of the art waterjet machining technology centre.
The £1.1 million centre houses equipment that uses a six-axis computer controlled waterjet machine. The machine, which is one of the most advanced of its type in the world, produces a waterjet at pressures that are so high it can carve cavities and cut almost anything. The water comes out of the nozzle at 55,000 psi and speeds of up to 2,000 mph.
The waterjet, which can cut blocks of metal into three dimensional components, is an important resource for engineering and manufacturing businesses, making them more competitive within the global aerospace market. It also has some rather unexpected uses as this case study illustrates.
- Abrasive Waterjet Machining Capability
- Cut through many different types of material
- Large thicknesses
- Quick
- No recast layer or Heat Affected Zone
- Environmentally safe, not using any hazardous chemicals
Waterjets are also suitable for cutting the most difficult to machine aerospace grade materials, which are being developed to cope with increasing temperatures within gas turbines. Latest machines are also capable of machining to very tight tolerances.
- Advanced Waterjet Machining
- Coating and Recast Layer Removal
- Zero taper cutting of thick material
- Controlled Depth Milling
- Rotary Milling – eliminates hazardous fluids used in the chemical sizing of components
- Rough machining of bliscs
- 100 hours machining
- 10 hours cutting
No swarf, only more valuable lumps of metal
Impacts and benefits
To be one ‘cut’ above the rest Thornton’s formed an unusual alliance with experts at The University of Nottingham. After coming up with a unique spraying device to decorate their Easter eggs the Derbyshire based chocolatier went in search of equipment capable of cutting out the designs for their new polycarbonate moulds.
But no one could find a way of carving perfect shapes in the moulds without melting or damaging the plastic. As a last resort the chocolate maker turned to an institution renowned for its ‘cutting’ edge research and technology.
Thornton’s were immensely satisfied with the project. A laser could not cut polycarbonate as it burns and chars and the other attempts at waterjet cutting were not successful due to lack of the 5-axis capability. This was for their diabetic range and a new chocolate spraying process they are looking at.
Having proved the success of waterjet cutting further cuts were made on other polycarbonate moulds with less complicated geometries to enable some more chocolate spraying trials to be undertaken at Thornton’s.
For more information about the project
If you would like to hear more about this project, please contact Lucy Roberts, Business Development Executive, University of Nottingham.
University
Academic Lead
Prof Ian Pashby
Contact
0115 846 7814