Overcoming a problem with moulding small plastics balls, the smallest Tulip Ejector in the range was able to design a mould that allowed the plastics balls to be ejected successfully.
As well as being the UK's largest manufacturer of precision engineered standard components for use in injection moulding and die-casting tools, DMS-Diemould also exclusively distributes standard parts for a number of 'partner' companies, such as Barcelona-based Cumsa. The benefits of this arrangement were recently enjoyed by Ron Copleston Designs, a company run by semi-retired former Philips design engineer, Ron Copleston. A high profile London-based university recently approached RCD with an idea for a product, tasking the company with developing a viable method of manufacture.

While the intended application and specific design of the product are still under wraps, it can be described as containing a series of ball and socket joints assembled on a special lattice that allows the joints to bend up to 15 deg in any direction.

The balls are manufactured from a selection of thermoplastics materials (a critical factor in the design and application of the product) ranging up to tough polycarbonate.

The diameter of the balls measures just a few millimeters.

The difficulty for RCD was that the balls were not allowed to exhibit any material flow lines or seams and so could not be produced in a traditional two-half ball mould.

'The first thought I had was 'how on earth are we going to mould these balls?',' said Ron Copleston.

'Fortunately I have a relationship with DMS-Diemould stretching back over 25 years.

When I approached them with the problem they suggested I try Tulip Ejector from Cumsa, a product they distribute in the UK.' The close pitch also presented a difficulty, however, using the smallest Tulip Ejector in the range - the EE060175 - RCD was able to design a mould that allowed the plastics balls to be ejected successfully.

RCD's mouldmaker, Aylesbury-based Uniform Tooling, subsequently purchased three Tulip Ejectors from DMS-Diemould along with the associated die blocks, plates, pillars and bushes required to manufacture the necessary amount of moulds, each of which measured approximately 100mm square.

'The whole design of the mould revolves around the Tulip Ejectors,' explainedCopleston.

'They are probably best described as collet-type devices that spring open so that products with undercuts can be ejected without any difficulty.

They proved to be the perfect solution for this project.' Cumsa has been established in Spain for over 30 years and has evolved into a respected manufacturer of standard mechanisms for moulds.

Their patented designs permit the release of parts featuring small undercuts with minimal mechanical movement and a minimum footprint in the tool.

The Tulip Ejector is height adjustable and easy to install.

It is hardened to 45HRc and coated in Balinit C for low friction release action.

There are 12 models of Tulip Ejector available through DMS-Diemould, ranging from 6mm in diameter and 175mm in length, up to 12mm in diameter and 325mm in length.