CoMoNeo, the latest injection moulding process monitoring system from Kistler Instruments, is helping South Wales-based injection moulding specialist, Waldon Ltd, to improve productivity and minimise rejects.
This is an addition to its Kistler CoMo Injection cavity pressure monitoring systems installed when the recession began to bite in 2009 as part of a programme to improve its production processes. At the time, project manager, now commercial manager, Richard Kempa said “There is no future in seaside buckets and spades. To succeed we must use the best available technology to achieve and maintain quality production both in terms of precision and minimum wastage.”
Now, success of the CoMo Injection systems over the past five years has given parent company, the Selectrona Group, the confidence to approve a £1M investment at Waldon, including the ComoNeo process monitoring system for cavity pressure-based analysis, optimization, monitoring and documentation of the injection moulding process. The new system builds on the original cavity pressure monitoring system being considerably more user-friendly whilst providing far more detailed information on the production process. In particular, CoMoNeo identifies rejects more precisely, including notification of which cavity produced the reject, and delivers them automatically to a robotic handling system for recycling. The high level of process control and monitoring provided by the new system allows Waldon to run its injection moulding machines “lights out” for 24-hours a day, six days a week with any problems being advised to the duty maintenance engineer by mobile phone.
According to Richard Kempa, a major benefit of the CoMoNeo system is that it can compensate in real time for variations in the operating environment, such as temperature fluctuations caused by external doors being opened or changes in the external air temperature, which can increase reject rate, especially at the tight tolerances adopted by Waldon. The precise control over the entire injection phase delivers a CPK, the measure of process capability, of better than 1.33 to be achieved consistently. But perhaps the major benefit brought by CoMoNeo is the dramatic reduction of rejects which has gone from 20% to less than 3% and is forecast to be zero ppm shortly. This improvement is due, according to Richard Kempa, to the CoMoNeo system providing a “window” into the cavity which provides feed-back from individual cavities, not just the machine. Compared with the CoMo Injection system, which was not as user friendly and was often difficult to set-up, the CoMoNeo system is exceptionally easy to monitor and set-up. The system monitors the profile of cavity pressure in real-time with graphical display making it easy to identify process fluctuations. Integrated data storage allows recording of curve histories with at least 50 000 cycles. Curve superimposition and a host of other useful functions (changeable colour schemes to display curves, cycle comments, cursor functions, etc.) allow detailed analysis directly on the injection moulding machine. Production mode includes clear displays showing production progress and scrap rate, as well as intelligent mechanisms (e.g. automatic detection of interruptions to production and declaration of a defined number of cycles as scrap on restarting). As well as part quality, ComoNeo can monitor process stability and give warning signals in case of process fluctuations.
The design of the software is predicated on operational simplicity by using advanced technology to minimising the need for manual input. Typically, the integrated software automatically generates and positions the monitoring boxes for good/bad evaluation which, in the past, had to be set manually whilst an Evaluation Assistant systematically helps the operator to define the evaluation types and the relevant limits quickly and accurately. In addition to making the initial setup faster and more accurate, this approach ensures that the production process is continually monitored with high precision, false rejects reduced and faulty components eliminated from the production line. Reducing false rejects and eliminating out of spec products are the two most crucial factors in cutting production costs and increasing productivity in the injection moulding process. As Richard Kempa says, “The user-friendliness of CoMoNeo means that the systems benefits are achievable without heavy dependence on a senior, experienced engineer. In fact, they are now accessible to good semi-skilled technicians.
Automatic mould identification reduces tool change times and prevents errors on the interface between the mould and the CoMoNeo system to maximize production efficiency whilst the new hardware and software allow more cavities to be monitored bringing automatic product quality assurance to large, multi-cavity operations whilst the new optimised touch screen display provides a comprehensive interface that can be adapted to meet specific operational needs. Waldon plans to expand the system using the CoMo DataCenter to network all the CoMo devices allowing data to be viewed in real-time or as archived historical data and add the MultiFlow option to provide automatic hot runner balancing based on cavity pressure.
This improvement in reject detection is allowing Waldon to expand its marketing to high precision sectors such a medical products where customers demand a guarantee that every moulding delivered is within specification; rejects are just not tolerated. In addition, an existing customer has been so impressed by the precision and reliability of the new production process that it has placed orders for three new mission critical components of automobile sensing systems.
CoMoNeo is very easy to use, provided the system is integrated with the machine control systems. Here, according to Richard Kempa, the success of the new system could not have been achieved without the support of the Kistler engineers. As he says, buying the equipment is easy but the key to success is having the right technical expertise on hand to ensure that the system is up and running without any problems now or in the future.
