What typical OEE improvements are achievable through shorter mixing times and faster cleaning?
OEE stands for Overall Equipment Effectiveness. The metric describes how much of the planned production time is actually used for manufacturing products that meet specification at the intended rate. It is calculated as availability × performance × quality.
Shorter mixing times and faster cleaning can significantly improve OEE where mixing, emptying, cleaning or product changes are relevant bottlenecks in the line. The actual improvement, however, must be derived from the individual time study and loss analysis; generic percentage promises are not credible without baseline data.
Improving availability
Shorter mixing, emptying, cleaning and changeover times reduce the proportion of planned downtime between two batches or product changes. This increases the available production time within a shift, week or campaign. In the OEE view, changeover, cleaning, tool changes, planned maintenance and quality checks are, among other things, recorded as availability losses, provided the plant was scheduled to produce during that time.
The lever is particularly large in high-mix, low-volume production, with frequent allergen, colour or flavour changes, and with formulations requiring wet cleaning. If, for example, a mixing and filling line runs ten product changes per day and each validated cleaning cycle is shortened by 15 minutes, 150 minutes of additional time result. This time can be used for production, maintenance, or a more realistic shift schedule.
A readily accessible, low-dead-space hygienic design can also improve the availability factor. It eases visual inspection, dry cleaning, wet cleaning and drying. Less build-up and extensive residual discharge additionally reduce the risk of unplanned re-cleaning, delayed releases, or the repetition of product changes. The effect should be measured using the real times for emptying, cleaning, inspection, drying and batch release.
Increasing performance
The performance rate describes how close a plant operates to its technically intended speed during its runtime. If the validated net mixing time is shortened with unchanged batch size and unchanged quality, the number of batches per shift can increase. This raises throughput, provided charging, emptying, filling, packaging and downstream processes can also keep up with this cycle.
What is decisive here is the entire batch time, not just the time with the mixing tool turning. It comprises charging, weighing, mixing, possible liquid addition, temperature control, emptying, sampling, cleaning, drying and preparation of the following batch. Shortening the mixing time from ten to five minutes, for example, only delivers the expected performance effect if the mixer does not then wait ten minutes for a filling station, a container, a laboratory release or cleaning.
Shorter and more reproducible cycles can additionally improve synchronisation with downstream filling and packaging equipment. The line then runs more stably, and minor stops, waiting times or intermediate buffers can be reduced. For a robust assessment, the real cycle time, batches per shift, waiting times and the capacity of all bottleneck units should therefore be compared before and after the measure.
Securing quality
Faster cleaning must not come at the expense of cleaning effectiveness. If an optimised cleaning procedure is validated, it can reduce cross-contamination, allergen carry-over, colour and flavour transfer, residual moisture and quality-related rework. This improves the quality component of OEE, which describes the proportion of flawless products in overall output. Scrap, rework and rejected batches directly reduce this metric.
A shortened mixing time can also improve quality if it was established as the result of a mixing kinetics study within a validated process window. Excessively long mixing can, with certain products, lead to particle breakage, fines formation, frictional heat, unwanted agglomeration, or subsequent segregation. The shortest robust mixing time can therefore improve yield, particle structure, homogeneity and process stability. A mere shortening without validation, by contrast, can cause off-spec batches and worsen OEE.
Calculating OEE correctly
OEE is usually calculated as follows:
OEE = Availability × Performance × Quality
Simplified, the following applies: availability is runtime divided by planned production time. Performance describes the actual production speed relative to the ideal speed. Quality is the number of good products divided by the total number of units produced. A value of 100 per cent means that the plant produces only flawless products without interruption and at ideal speed.
The multiplicative logic is important. If, for example, availability improves from 70 to 80 per cent, performance from 85 to 90 per cent, and quality from 96 to 98 per cent, OEE rises from 0.70×0.85×0.96=57.1% to 0.80×0.90×0.98=70.6%. This corresponds to a gain of 13.5 percentage points. OEE therefore does not improve through simple addition of individual improvements, but through their combination across all three factors.
Assessing implementation
Before any measure, the operator should record and clearly classify the actual losses over a representative period. At a minimum, the times for charging, mixing, emptying, cleaning, drying, formulation changes, waiting for raw materials, laboratory release, faults, maintenance, product changes and filling interruptions are useful. This makes it possible to determine whether mixing time or cleaning are actually the bottleneck and what OEE potential is economically achievable.
After optimisation, the same data should be recorded again. Quality signals such as mixing quality, residual discharge, cleaning verification, allergen analytics, scrap, rework, particle breakage and batch release time must additionally be observed. Only once cleaning and mixing performance demonstrably remain stable is the OEE gain sustainable.
How amixon® improves the OEE of powder mixing plants
OEE stands for Overall Equipment Effectiveness. The metric describes how much of the planned production time is actually used for manufacturing products that meet specification at the intended rate. It is made up of availability, performance and quality. amixon® improves these factors through short mixing and emptying times, a cleaning-friendly construction, high technical availability, and reproducibly controllable processes. The OEE improvement actually achievable is always determined based on the real formulation, batch size, changeover frequency, cleaning, production logistics and the bottleneck situation of the overall line.
Availability: durable and plannable
High technical availability begins with the construction. At amixon®, the mixing tool is supported from above; a lower shaft passage in the mixing chamber is eliminated. This avoids product-contact bearing points and potential wear or sealing problems in the base area. The comparatively low-speed operating mode, together with the limited number of product-critical wear parts, supports long service life.
Regular inspections and preventive maintenance help convert unplanned downtime into plannable maintenance windows. Depending on the project, condition monitoring and predictive maintenance concepts can be integrated. amixon® develops and manufactures the apparatus in Paderborn with a high level of in-house manufacturing and can support the long-term supply of spare and wear parts. Selected critical parts can also already be provided as an on-site spare parts stock at initial delivery.
Fast, reliable emptying also contributes to availability. SinConvex® and SinConcave® mixing helices produce controlled, three-dimensional product movement and support discharge. ComDisc® elements sweep across the vessel base during the final emptying phase and guide product residues toward the outlet. This can reduce the residual quantity, simplify product changes, and prevent cleaning times from being unnecessarily extended by remaining product build-up. amixon® describes ComDisc® as providing extensive residual discharge that is low in segregation with suitable products.
Performance: shortening every cycle phase
The performance of a batch mixing plant is determined by the entire batch time: charging, mixing, possible liquid addition or temperature control, emptying, cleaning, drying, and preparation of the following batch. amixon® can optimise several of these time shares simultaneously.
The vertical twin-shaft mixer HM uses two superimposed product streams and, with a suitable formulation, can enable short mixing times. The KoneSlid® mixer KS produces active, three-dimensional forced restratification. The entire volume can be restratified once after about four tool revolutions; depending on the formulation, the desired mixing quality can be achieved after approximately 20 to 30 revolutions. The actual mixing time must always be validated with the original product, a defined fill level and the required homogeneity target.
SinConvex® and SinConcave® mixing helices support product-appropriate flow-through and extensive emptying. MultiPlane® can be used where sensitive particles, coatings, granules or agglomerates are to be homogenised with particular gentleness. Product movement can thereby be oriented toward low mechanical stress. This helps limit particle breakage, fines formation and unnecessary heat input. Where agglomerates need to be specifically broken up, cutting rotors or HighShearBlades can be switched on for a limited time, without permanently subjecting the whole batch to high stress.
DosiFlap® combines the functions of a low-dead-space, gas-tight closure fitting with a metering discharge function. The fitting can close against the still-flowing product stream and thereby supports the controlled filling of big bags, IBCs or other containers. In conjunction with weighing technology, defined fill quantities can be targeted. This can reduce waiting times in the filling process and stabilise the cycle of downstream packaging. amixon® describes DosiFlap® as a fitting that closes free of dead space and gas-tight, and which can be closed against the product stream.
Cleaning and product change
With frequent formulation, allergen, colour or flavour changes, cleaning time is often a decisive OEE lever. amixon® combines extensive residual discharge with good accessibility of the product-contact areas for this purpose. Large CleverCut® inspection doors with OmgaSeal® seals are designed to close permanently tight and constructionally low in dead space, close to the mix. This eases visual inspection, manual dry cleaning and inspection after cleaning.
OptiClean® stands for a hygiene concept that puts the readily accessible, fully drainable and cleaning-friendly construction of the mixing plant at its centre. The aim is to reduce product residues, hard-to-reach areas and the cleaning risks that result from them. The specific cleaning design, however, always depends on product adhesion, fat and sugar content, allergen or active-ingredient risk, water compatibility, microbiological requirements, and the cleanliness limit to be demonstrated.
WaterDragon® supplements this concept with automatable wet cleaning and drying. Programmable target-jet lances with rotating wash heads introduce cleaning water into the mixing chamber in a targeted manner. The nozzles cover different directions while the lance and the wash heads reach the intended areas. After the wet cleaning cycle, a large volume of dry warm air can be blown in to rapidly dry the mixing chamber, internals, discharge fittings and cleaning equipment. WaterDragon® can thereby standardise cleaning procedures, improve reproducibility, and reduce the time to release of the following batch. amixon® describes WaterDragon® as an automated system for wet cleaning and drying with rotating wash heads and three-directional nozzles.
Cleaning, however, must never be shortened solely for the sake of a desired cycle time reduction. Cleaning cycles, drying duration and release criteria must be validated for the specific product, the worst-case product change and the relevant contamination limit. Only demonstrably effective and reproducible cleaning creates a sustainable gain in availability and quality.
Quality and batch safety
The quality component of OEE improves when scrap, rework, faulty batches and quality-related interruptions decrease. amixon® mixing principles are designed for reproducible, three-dimensional product circulation. With appropriate design, they can achieve a technically ideal random mixture. Whether this holds for a specific formulation across a fill level range of approximately 10 to 100 per cent of the usable volume must be checked with the original product. With low-dose components, large differences in bulk density or particle size, cohesive powders, or liquid additions, the suitable process window can change.
PLC-based recipes ensure repeatable adherence to critical process parameters. These include mixing time, tool rotational speed, fill level, raw material sequence, dosing quantities, liquid additions, temperature control and discharge sequence. Barcode or RFID capture as well as an ERP connection can seamlessly link formulation, raw material batch, process values, operator interventions, cleaning status and batch release. This supports traceability, deviation management, and rapid root-cause analysis when quality data falls outside specification.
Calculating OEE potential robustly
Robust OEE potential cannot be promised in blanket percentage points. It results from the difference between the actual current state and the real, measured process times of the target plant. Mixing time, emptying, residual discharge, cleaning, drying, product changes and, where applicable, downstream filling should therefore be examined with the original product.
In the amixon® pilot plant, these times and quality characteristics can be determined with a realistic fill level, formulation and process control. The results form a basis for selecting the size, designing the periphery, capacity planning and a robust comparison with an existing plant. A complete OEE calculation takes into account, at a minimum, planned production time, planned and unplanned downtime, real batch time, good quantity, scrap, rework, and cleaning and release times.