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CAQ-Software at MTG: Moulding a Quality Network

The plastics industry creates objects in all shapes and sizes and colours of the rainbow – products without which our everyday life would most probably be unthinkable. It applies techniques such as injection moulding in order to shape synthetic or semi-synthetic organic solids into any form imaginable and thereby fulfil varying criteria regarding plasticity, hardness, elasticity, or durability. One rock-solid factor must, however, never be underestimated when dealing with such an incredibly flexible material: quality.

Over 100 Years of Tradition

CAQ-Software with direct ALS-interface at Thermoplastik Erich Müller
CAQ-Software with direct ALS-interface at Thermoplastik Erich Müller

Müller Technologie Gruppe (MTG) in the German town of Dieburg is a company that has always laid great importance on ensuring the quality of the parts it produces and it can prove this passion for quality with a tradition that dates back over 100 years. The company that today covers every facet of contemporary plastics engineering from development and planning to production has its origins in the manufacturing of woodturning parts at the Müller family’s mill in the town of Brensbach. From the initial woodworking business the company subsequently moved on to cutting thermosetting plastics. This change to a new material eventually led to the acquisition of the first manual injection moulding machine in 1962 and a subsequent shift of focus toward the thermoplastic materials that the company deals with today.

From Plastic Granulate to the Finished Product

MTG was founded in 2009 and today consists of three main companies that each covers a different area of operation. Hamburg-based MULTIKunststoff GmbH is a raw materials trading company that offers a wide range of technical thermoplastics/commodities, Thermoplastik Erich Müller GmbH produces plastic injection moulding parts and assembly groups for the automotive industry, and SkyEngineering GmbH produces said parts for application in the aerospace industry.

All of this together provides the company with direct control over all steps of the production process – from the selection of the most suitable granulate and the product development phase with 3D-CAD and simulation software all the way to the actual injection moulding procedure. In order to consistently monitor and control the quality of its products, the Quality Management Software CAQ.Net by CAQ AG Factory Systems was implemented in all facilities of the company in the year 2011.

One Quality System Replaces Isolated Applications

Prior to the introduction of CAQ.Net, quality matters at MTG were executed via isolated applications such as control plans in MS Excel and SOPs in MS Word. This meant that it was not easy to e.g. conduct cross-inspection chart evaluations or analyses, because all necessary data needed to be complied by hand. This, in conjunction with tightened regulations by some key customers regarding specific quality documentation criteria, led the company to assess the market of Quality Management Software providers in order to find someone that met their strict requirements. After a painstakingly accurate market analysis, they eventually found everything they were looking for and more at CAQ AG.

Integration into Peripheral IT-Systems

Conjoint development of the ALS-interface by the companies Arbug, Müllertechnologie Gruppe, and CAQ AG
Conjoint development of the ALS-interface by the companies Arbug, Müllertechnologie Gruppe, and CAQ AG

Apart from being convinced by the great range of functions available in the CAQ.Net software family, MTG was also persuaded by the high degree of the software’s bidirectional integratability into existing IT-structures such as ERP/PPC/MES or MDA/PDA system environments. MTG was particularly interested in one of the latest additions to the range of interfaces available in CAQ.Net, which facilitates the interconnection of the CAQ-system and the ARBURG ALS master computer system. Once installed, this interface can directly exchange all process parameters from ARBURG’s electrical, hybrid, and hydraulic injection moulding machines with the CAQ-system.

Solutions for All Quality Matters

The modular CAQ toolset meant that a tailor-made software solution could be put together for MTG that covered all relevant aspects of quality management with one system. Hence, the system was able to achieve a significant decrease of the manual effort involved in maintaining quality-related data in the company. All production processes from supplier management and incoming goods inspections to in-process inspections and complaint management are today almost entirely executed via CAQ.Net. Because the entire software solution at MTG runs in a virtualized environment (a private cloud on a terminal server that is accessed via clients to which gauge interface boxes are connected), this can all takes place simultaneously across each and every one of the company’s facilities.

In-Process Inspection

As mentioned previously, the third software besides the ERP-system and CAQ.Net that is utilized at MTG is the ALS master computer system by ARBURG. The 18 injection moulding machines in Dieburg are all linked to the ALS system via Ethernet, which – in turn – is connected directly to the ERP system. All production orders containing the operation sequence “Injection Moulding” are automatically transferred to the ALS system. The data that is transmitted includes the article number, order number, target quantity, tool number, default cycle, and material requirements. The process parameters per shot (e.g. melt cushions, injection pressure, temperature control) are then transmitted to CAQ.Net via a direct interface.


As soon as a production order is started at a machine, the ALS-system prompts the relevant inspection event in the CAQ-system
As soon as a production order is started at a machine, the ALS-system prompts the relevant inspection event in the CAQ-system

As soon as a production order is started at a machine, the ALS-system prompts the relevant inspection event in the CAQ-system. Here an advanced approval procedure is executed by quality assurance. At this point, the utilized raw material batches are allocated in the CAQ-system and can subsequently be tracked from here. The in-process inspection is conducted at a fixed interval throughout the entire production batch. All gathered values then serve as basis for the execution of evaluations across any number of production batches.

In-Process Inspections for the Aerospace Industry

The SkyEngineering department of MTG produces and assembles parts for the aerospace industry – primarily for installation in the cabin / interior of the plane. All assembly processes are planned and executed in accordance with production orders from the ERP-system. As soon as a production order has been approved, the direct ERP-to-CAQ interface automatically prompts the relevant inspection procedures. These inspection orders then appear right on the workstation that is installed at the applicable production point on the shop floor. The inspection plan in the case of SkyEngineering is similar to a route card that contains the ATP (acceptance test procedure) criteria that were agreed upon with the customer. All dimensional, visual, and functional inspections are documented in the CAQ-system. The completed and “OK” assessed route card later serves as documentation of a successful final inspection and thus approves shipment of the product.

Gauge Management

As the reliability of information is determined right at the point of its initial collection, perfectly functioning gauges are essential for successful quality assurance. MTG uses CAQ.Net’s gauge management module in order to ensure that the employed gauges are always correctly calibrated and in sound working order. The module furthermore organises the acquisition, application, and maintenance of all gauges. It replaced the existing MS Excel spreadsheets and automated the monitoring of gauges and calibration dates – tasks that were previously executed by hand. Ever since the gauge management module was implemented, there has not been a single query regarding gauges during customer audits at MTG.

Supplier Management

The reliability of shipments and the quality of acquired goods are initial aspects that set the course for the subsequent value chain and are some of the most important factors in any production process. At MTG, the CAQ-system retrieves all supplier and customer data directly from the ERP-system. A unique identifier thereby defines which suppliers should be transferred to the CAQ-system. Data gathered in previous incoming goods inspections along with additional information is used to execute the fully automated supplier evaluations in the CAQ-system. The CAQ.Net document management module also plays a role in the supplier management process, as it is used to administrate supplier certificates (with fully automated validity reminders), supplier contracts, and supplier agreements.

Incoming Goods

The interface between the two systems ensures that every incoming goods registration in the ERP-system automatically prompts an appropriate goods inspection in the CAQ-system. Within this process, the information regarding the article number, target/actual quantity, target/actual date, and batch is transmitted to the CAQ-system. In the case of drawing parts, variables inspections via gauge boxes and/or coordinate measuring machines will be prompted. The sample size is determined according to AQL-tables with appropriate dynamizations. Depending on the error frequency, the individual sample size is adjusted by the CAQ-system.

When MTG acquires plastic granulate for production processes or onward sales, the specific test report of the supplier is compared with the product data sheet. If the comparison of the two entities identifies deviating criteria that lead to a negative inspection verdict, a supplier complaint is prompted automatically. The data that is gathered in these processes forms the basis for subsequent supplier evaluations regarding quality and quantity/due-date reliability of shipments.

Initial Sample Inspection

Suppliers conduct initial sampling processes to provide evidence that their products meet the quality parameters required by the customer. In order to create and manage their initial samples, MTG uses the initial sample inspection module of CAQ.Net. It provides them with everything they need for planning, executing, inspecting, maintaining, and printing initial sample inspections.

Document Management

 Product-accompanying documents such as specific test reports, packaging instructions, operating instructions, or inspection orders
Product-accompanying documents such as specific test reports, packaging instructions, operating instructions, or inspection orders

At MTG, all product-accompanying documents such as specific test reports, packaging instructions, operating instructions, or inspection orders are controlled and approved via the document management module of CAQ.Net. The module also facilitates the automated publication of relevant documents in the ERP-system and directly at the PDA-terminals on the shop floor.

The Full PDCA-Circle

The complaint management module of CAQ.Net is essentially the final element of the quality management circle that is implemented at MTG. It is used to process all complaints and – via continuous improvement processes and “lessons learned” – lays the groundwork for comprehensively optimizing the overall production procedure. In view of future developments at MTG, the training management module of CAQ.Net will also be playing an increasingly important role in the company. Once it has been fully implemented at MTG, it will be used for planning, managing, and controlling all training and qualification matters. Hence, it will allow the company to fulfil key documentation duties within the framework of ISO 9001 and create an expressive and easily maintainable qualification and training database.

Designing the Future of Quality Management in the Plastics Sector

The far-reaching cooperation between the companies MTG and CAQ AG over the past few years – especially during the process of linking CAQ.Net with ALS – has led to a technological partnership that addresses the optimization of quality management in the plastics industry with great passion. The target/actual comparison between CAQ.Net and the requirements that MTG faces on a day-to-day basis means that the software can be easily adjusted to meet even the most current and demanding challenges of the plastics industry. This ongoing technological partnership is, for instance, also manifested in the latest project that the two companies are working on. It aims to facilitate the process data transferal between CAQ.Net and ALS in a manner that allows the direct analysis of the measured values of parts and the process data in CAQ.Net. This type of evaluation means that, in future, the process limits of the machine can be restricted to a precise point at which faulty parts can be immediately identified and directly discharged right at the machine.

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