What benefits does a modular mixer design bring for companies with frequently changing recipes?
A modular mixing plant can make product changes and new process requirements easier, provided that connections, cleanability, control system and safety functions are prepared for this. Modularity alone, however, guarantees neither short set-up times nor consistent product quality: what remains decisive are the specific product, the cleaning strategy and a controlled change process.
Flexible process adaptation
Additional or interchangeable functions can be adapted to different recipes, for example liquid additions, sensor technology, temperature control, vacuum, discharge devices or, where applicable, de-agglomeration tools. Exchanging mixing tools or product-contact components can be sensible, but it changes mixing intensity, energy input, heat generation and possible particle stress. Every configuration must therefore be assessed for the product, batch size and quality objective.
Not every material class can be processed economically on the same base machine. Very cohesive, abrasive, moist, reactive or highly viscous products may require different geometries, drives, seals, containment or cleaning strategies. Where the differences are fundamental, a separate plant can be more robust and economical than frequently converting one mixer.
Set-up and cleaning
Standardised connections and readily accessible components can make changeovers easier. Actual set-up times, however, include dismantling, cleaning, inspection, reassembly, functional testing and, where applicable, quality release. The time saving should therefore be assessed on the basis of the real changeover procedure.
Interchangeable product-contact parts or separate vessels can reduce the risk of cross-contamination. However, they do not eliminate it automatically. Hygienic design and cleaning must be adapted to the product, soiling, allergens, active substances and the intended cleaning process. The FDA expects written procedures for different cleaning cases, as well as documented validation where this is required; for critical product changes, acceptance limits and suitable sampling and analysis methods must be established. EHEDG likewise emphasises that plants that are poorly accessible or unfavourably designed are difficult to clean effectively and thereby increase contamination risks.
Cleaning in place, abbreviated CIP, refers to cleaning in the installed state. Cleaning out of place, abbreviated COP, means cleaning removed components outside the plant. Sterilization in place, abbreviated SIP, refers to sterilisation in the installed state. Which method makes sense depends on the product, the hygiene objective, the design and the operating procedure. CIP or SIP capability is not automatic confirmation of cleaning effectiveness or validatability.
Extension and operation
A modular plant can start with a base configuration and later be supplemented with dosing stations, liquid modules, temperature control, vacuum technology, sensor technology or digital interfaces. This works particularly well where installation space, connection nozzles, utility supply, cabinet reserves, control system and safety functions were already taken into account in the base planning. Otherwise, retrofitting is often feasible, but comes with additional engineering, downtime and, where applicable, changes to hygiene, explosion-protection or qualification concepts.
Replacing the unit with a larger or smaller mixer size is not a modular extension but a capacity adjustment. Recipes, mixing times and process parameters cannot simply be transferred, because fill level, flow, energy input, heat transfer and discharge can change.
Shared components can simplify spare-parts holding, training and maintenance. Higher plant availability, however, only results where maintenance access, spare parts, staff, buffers and, where applicable, redundancy are in place. A module change during ongoing operation is only possible with mixing plants if process and occupational safety, containment and production logistics permit it.
Control system and quality
A modular control architecture can structure recipe changes, batch documentation and operation. New modules require unambiguous process phases, setpoints, alarm limits, interlocks and safe states. The Module Type Package, abbreviated MTP, can make the software-side integration of suitable process modules easier. MTP describes a module's automation functions and interfaces in a machine-readable, vendor-neutral way; the VDI/VDE/NAMUR 2658 series of guidelines describes the corresponding modular automation. MTP, however, does not replace a review of material flow, safety, hygiene or product quality.
Recipe flexibility and retrofittability at amixon®
amixon® mixers can be designed on a project-specific basis for frequently changing recipes and batch sizes. The basis is the user requirement specification, abbreviated URS. It defines products, process tasks, cleaning requirements, automation and possible later extensions. Where retrofit options are considered early, spare connections, free installation positions, installation space, utility supply and control-system reserves can be prepared by design.
Depending on the machine design, mixing intensity can be adjusted via mixing time, speed, tool configuration and additional process devices. Mixing programmes with dosing sequence, temperature profile and other parameters can be managed in a programmable logic controller, abbreviated PLC, and run reproducibly for each batch. With recipe changes, this supports controlled process management, provided that recipe versions, permissible operating ranges and releases are clearly defined.
For new recipes or process requirements, amixon® can integrate or retrofit, among other things, liquid dosing with addition lances or two-fluid nozzles, additional sensor technology, temperature-control jackets, vacuum connections, washing lances, cleaning functions, cutting rotors, and discharge devices such as DosiFlap®. An adaptation is matched to the product, process objective and existing plant design. For example, cutting rotors can support de-agglomeration or the incorporation of liquids, while temperature-control jackets can be helpful with heat-sensitive or thermally controlled processes.
The benefit of every addition is assessed with the actual product before implementation. According to amixon®, more than 35 test machines are available in Paderborn; additional pilot plants are located in the USA and several Asian countries. Trials allow mixing quality, liquid distribution, product stress, energy input, dischargeability and cleanability to be checked. This means that retrofits and recipe changes are designed on the basis of documented trial results, not on general assumptions alone. amixon® manufactures most components – with the exception of motors and gearboxes – itself at the Paderborn site.
With frequent product changes, cleanability is particularly important. Depending on the design, amixon® mixing chambers can be executed with a mixing tool supported at the top, readily accessible inspection doors, low-dead-space sealing concepts and washing lances. These features can make inspection, cleaning and product changes easier. The actual cleaning effectiveness and suitability for critical recipe changes, however, must be demonstrated for the product, soiling and cleaning method.
A project-specific connection to enterprise resource planning systems, abbreviated ERP systems, and manufacturing execution systems, abbreviated MES, can link recipe, batch and process data. An ERP system supports materials management and order management, among other things; an MES supports production control and batch documentation. Barcode-based material identification can supplement traceability. These functions support recipe changes, OEE evaluations and a traceable batch history, provided that the data model, time stamps, user permissions and downtime reasons are regulated within the overall system.
For regulated areas, amixon® provides qualification-relevant technical documentation and supports Design Qualification, Installation Qualification and Operational Qualification, abbreviated DQ, IQ and OQ. The plant can be aligned with project-specific requirements such as EU-GMP, FDA 21 CFR Part 11, EHEDG, 3-A Sanitary Standards, ATEX or ASME. Regulatory responsibility for change control, cleaning and process validation, and the validation of electronic systems remains with the operator.
amixon® accompanies mixing plants over their life cycle with commissioning, maintenance, modernisation, retrofitting and spare-parts supply. The high manufacturing depth in Paderborn, the technical documentation and the pilot-plant trialling create a reliable basis for adapting mixing plants to new recipes and process requirements.