The implementation of the retrofit measure for sand processing control system in the Dutch Aluminium Gieterij Oldenzaal in Oldenzaal

by Wolfgang Ernst (datec GmbH), January 2021

During discussions on the scope of renewal, all existing electrical equipment was placed under scrutiny. "We wanted to take a big step forward because what used to be sufficient is no longer good enough," Dennis Eekers, CEO at Dutch Aluminium Gieterij Oldenzaal in Oldenzaal, not far from the German border near Rheine, explained the motive for the investment. "No more disruptions and downtime, better sand quality and less waste, as well as much more transparency in the processes, and saving energy."

The beginning for the new control package Sandplant_control by datec GmbH was a new PLC, because the one still in use had long since been discontinued by the manufacturer. A new control cabinet was also envisaged, since contactors that are about 30 years old have a high probability of failure. At the same time, the manual operation system was completely renewed, as the central manual operation previously in use no longer corresponds to the current safety philosophy. Decentralised control boxes with a direct view of the aggregates being worked have significantly increased safety. A special failsafe concept also prevents the automatic control from being switched on centrally if the manual control is switched on decentrally.

The central manual control was replaced by local control boxes. It can only be operated in sight of the aggregates.

The core of the modernisation and quality improvement is state-of-the-art measuring technology. The two scales were equipped by datec with new electronics for more accurate dosing. Overrun optimization and automatic taring, as well as high resolution in the analog-to-digital value conversion, are the key features for improved dosing technology, especially for a binding material scale that is intended to weigh quantities of around 300 to 400 grams.

The scale electronics are part of the entire PLC network and are addressed directly via the PLC program.

"We now have a lot more data to help us with analytics and give us the visibility we need." A comprehensive batch report documents the large number of measured values and a special evaluation report helps with the analysis. With the use of statistical process control methods, the process can be analysed in detail and then also evaluated.

All relevant measured values, intermediate calculations, and menu values are documented in the batch report.

The evaluations are carried out from the large volume of data from the batch report, which is stored in a database for one year. With the eight-channel multi-diagram, 8 freely selected channels can be displayed simultaneously.

The EVA (Event Analysis) program is used to evaluate all fault messages in the archive. The primary concern here is the duration and number of faults. This information will help maintenance decide which problem to address as a priority.

Display of how often and how long in total which aggregate was in malfunction.

Display of how often and how long in total which aggregate was in malfunction.

In-house construction of the new control cabinet.

The continued use of the almost 30-year-old control cabinet was ultimately rejected because the probability of failure over the years was quite high and there were also gaps in the documentation.

"Of course, we pondered whether to go for a smaller or larger solution. We chose confidence - because things are looking up after the crisis and we then want to work through the orders without a handicap."

Energy efficiency

Initially, those responsible did not consider an energy efficiency control system, which automatically shuts down the sand preparation system when idling, to be necessary.  But after a reference visit, the opinion changed, because then it was also seen at home how even with a foreseeable longer idle time, the system was not stopped manually. The system used to continue running through the break. Now the system switches off automatically and energy is saved. Energy consumption is recorded via a meter and later processed for sand production in an index calculation - kWh / 1 t moulding sand.

Hourly display of the sand quantity, energy consumption and the indicator kWh / t moulding sand.

You will find more information about our retrofit here.
You will find more information about the company Aluminium Gieterij Oldenzaal here.

Dutch aluminum foundry Gieterij Oldenzaal invests in sand processing

by Wolfgang Ernst (datec GmbH), January 2021

30% higher sand throughput after retrofit of controls

A comprehensive renewal of the PLC control, the power unit and also the measurement technology resulted in significant improvements in the sand processing of the Dutch Aluminum Gieterij Oldenzaal in Oldenzaal, near the German border.

“Our controls were getting on in years and individual devices were no longer working properly. We had to act. ”Danny Vreriks, Process Engineer and Planner, explained the investment measure. “A repair was no longer worthwhile - we had switched off the moisture measurement / water metering and added the amount of water manually using a fixed value. The weighing of the used sand was too imprecise and we always had too much sand in the mixer and had to significantly reduce the batch weight. "

After it became clear that the innovation reserves for sand preparation were in the control and measurement technology package Sandplant_control, the company decided on a large and comprehensive solution with us, the company datec.

Managing director Dennis Eekers wanted to implement 4 goals:
• Safe, state-of-the-art control
• Significant improvement of the sand quality through even sand values
• Reduction of electrical energy consumption
• Traceability and evaluation of the sand values through long-term storage of the batch values with the help of SPC programs

The exchange of the control could of course not be accomplished like a tire change, because it was a clear improvement and the latest technology should be used. Not only was the latest PLC and a completely new power unit installed, but the weighing technology and moisture-dependent water metering with our datec system akwa_mix were also renewed. An important step towards improving quality was the installation of the ROTOCONTROL RTC 107 on the mixer for online molding material testing in the mixing cycle with direct correction of compressibility and compressive strength.

With DView, the operation and display was relocated from the old control room to the molding system. The most important operating states and measured values are displayed online with a sufficiently large screen visualization. The molding machine operator can change the recipe himself very quickly when changing models. Faults in sand processing are displayed immediately and can be remedied from there.

Even with an older mixer, the investment is worthwhile

Hardly any modifications were made to the system itself during the investment; the new electrical equipment alone enabled significant improvements to be achieved. The original batch weight of 200 kg could be increased to 260 kg and at the same time the uniformity of the sand could be increased. The compressibility fluctuates only slightly, namely 1.5% in the 1st standard deviation.

In the spirit of the general energy-saving discussion, sand processing was also implemented with the Energy_control program module. An operating mode that automatically stops the sand processing when idling is detected and starts up again when sand is required. Although there are no long-term secured data with reliable findings, a conservative estimate is based on savings of at least 10%.

Key number chart

Dennis Eekers (li) and Danny Vreriks(re) ahead of the RTC at the Speedmullor


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