Flexing into new die manufacturing territory

IN JUNE, ROTOCON began full-scale commercial production of the ECOFLEX range of flexible dies from its Johannesburg-based manufacturing facility in Longmeadow Business Park South to satisfy the needs of customers who require international standard quality performance and a quick turnaround time of 24 to 48 hours.

Director and project manager, Patrick Aengenvoort, explains that ROTOCON realised its long-term ambition of local flexible die production after Covid-19-related supply chain interruptions and challenges made its customary 48-hour turnaround times impossible for the imported versions.

‘When we first discussed the idea many years ago, the number of orders and the level of capital investment and commitment required to finish flexible dies locally to high tolerances wasn’t warranted,’ he reports. ‘However, 2020’s supply chain landscape and import delays changed this scenario. That December, we decided to go ahead and we received a positive response to our enquiry from an engraving machine supplier. We then started researching different equipment suppliers, sent some test plates over to Germany for engraving, conducted our due diligence on the other machines required, and placed the necessary orders.’

Patrick notes that the management team also had to overcome several logistics and customs stumbling blocks before it could kit out the ECOFLEX operation, which consists of a chemical etching department and an engraving department. The latter houses a high-performance CNC engraving machine, a high-tolerance grinding machine, and a die testing station. ‘We transferred our best rotary die engraver to head up the flexible die engraving on the CNC machine and employed two new operators for the etching and grinding work,’ he states.

In March, an expert consultant – who is based in Australia and has worked for many international companies – spent two weeks helping to set up the etching, engraving, grinding and testing equipment, as well as training the operators and the production and operations manager. ‘When we started this project, we thought it would be a lot easier because we had experience with cutting tools and the manufacturing of rotary dies. However, we soon discovered that flexible die-making is quite an art,’ Patrick reports

From an etching process point of view, the consultant assisted the team with setting up the equipment and taught them how to get the process 100% correct to ensure that they can create a good cutting edge later that isn’t too thick when it goes on the engraving machine. Additionally, he showed them how to achieve the right base plate thickness. The rule of thumb generally is that the smaller the magnetic cylinder, the thinner the base plate needs to be to stick to the magnetic cylinder.

In terms of the engraving process, the consultant taught the team how to set up quickly to achieve high productivity rates, the correct angles to use with the different die materials, and how to achieve the right cutting edge heights.

The ECOFLEX team started small-scale production as soon as the consultant left to ensure that they could maintain the tolerances and obtain consistent cuts, even on difficult materials such as thin liners. They put samples to the test during five customer trials. The positive feedback they received confirmed that the flexible dies deliver high tolerances and quality cutting results and that the nickel coating applied to dies destined for Durban and Cape Town provides protection again rust and makes the die slightly harder.

‘These positive results confirmed that we can continue to meet customers’ expectations and ensure that the flexible dies we send into the market reach the highest standards that the ROTOCON brand is well known for,’ Patrick enthuses.

Maintaining quality control

THE die testing station consists of a magnetic cylinder with 276 teeth (ensuring that ROTOCON can accommodate various sizes of ECOFLEX flexible dies with the right repeat lengths), the international standard undercut/air gap of 0.48, and two adjustable pressure gauges.

Director, Patrick Aengenvoort, explains that the ECOFLEX team prefers customers to supply a piece of the material that they will run. In that way, the team can achieve a one-to-one result, which will show the customer exactly what the flexible die will do on the printing press. ‘We start by creating the cutting image that the customer will have on the printing press and ensuring that it’s on the line. Then we strip the material off, take the cut cavities off, check that the impression is 100% (and not too deep), and inspect the die closely to ensure there are no knicks on it.’

Supply chain issues have forced ROTOCON to step over into new flexible die manufacturing territory. Installing the well-trained ECOFLEX team along with top-notch equipment is just one of many examples of how ROTOCON evolves with the times so that the company can continue to provide timely and quality service to its customers.

PDF of article»» as featured in PPM

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Michael Aengenvoort (ROTOCON group CEO), Benny Friedman (Rebsons Labels managing director), Carlton Motolla (machine operator), Linda Madonsela (supervisor), Norman Maja (die-cutter) standing next to the CHROME RDF 340.

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