| Process fit | Suitability for the product’s viscosity, solids content, batch size, and required mixing result. | A written process review, proposed mixer configuration, and test results using a representative material or documented equivalent. | Prefer a supplier that explains the selection and its limits, rather than recommending a machine based only on tank volume. |
| Mixing technology | Whether the proposed agitator or mixer type matches the operation—for example, blending, high-shear dispersion, or powder incorporation. | Impeller or rotor-stator drawings, speed range, power information, and an explanation of the expected flow pattern or dispersion duty. | Check that the stated duty matches the process; a single mixer design is not suitable for every material or mixing objective. |
| Capacity and scale-up | Working volume, batch size, vessel geometry, and how performance is expected to change when production is scaled up. | A dimensional drawing, usable-volume range, motor and drive specifications, and documented scale-up assumptions. | Confirm working volume—not just nominal vessel volume—and verify that the proposed machine fits the site and process sequence. |
| Product-contact materials | Material grades and surface finish for product-contact parts, selected for the product, cleaning method, and operating environment. | Material certificates, surface-finish specifications where applicable, weld documentation, and a product-compatibility review. | Stainless-steel grade alone does not establish compatibility; assess chemical exposure, temperature, cleaning, and contamination requirements. |
| Fabrication and quality control | Manufacturing controls, inspection stages, traceability, and handling of nonconformities. | Quality-management documentation, inspection and test plans, calibration records where relevant, and sample inspection reports. | Check whether quality records relate to the equipment being quoted; a quality-system certificate is not a substitute for product inspection. |
| Safety and compliance | Machine guarding, emergency stops, electrical design, operating instructions, and any applicable site or market requirements. | Risk-assessment documentation, electrical drawings, safety-device list, manuals, and relevant conformity documents for the destination market. | Confirm requirements for the installation location and process, including hazardous-area needs where applicable; do not assume one certificate covers every requirement. |
| Controls and automation | Control functions, speed regulation, interlocks, recipe handling, and compatibility with the plant’s electrical and automation systems. | Control-panel drawings, component and signal lists, operating sequence, and a clear scope for integration and commissioning. | Identify which controls are included and which require plant-side work, programming, or additional equipment. |
| Cleaning and maintenance | Access for cleaning, disassembly needs, seal and bearing arrangement, and routine maintenance requirements. | Cleaning instructions, maintenance schedule, recommended spares list, and details of seals and other wear parts. | Evaluate cleaning against the actual process and hygiene requirements; a “cleanable” design does not automatically mean validated cleaning performance. |
| Testing and acceptance | Factory testing, inspection scope, acceptance criteria, and any process-performance test before shipment. | A mutually agreed test plan, completed test records, inspection checklist, and defined process-performance criteria where measurable. | Agree on measurable acceptance criteria, responsibilities, and remedies before placing the order. |
| Delivery and project management | Drawing approvals, manufacturing milestones, packaging, shipping scope, and coordination with installation dates. | A project schedule, scope-of-supply list, packing details, shipping terms, and a named project contact. | Compare the complete delivery scope and dependencies, not just the quoted equipment price or stated lead time. |
| Installation and commissioning | Availability of installation guidance, startup support, operator training, and commissioning responsibilities. | A service scope showing included days, travel or site costs, customer prerequisites, and training deliverables. | Clarify support arrangements and site-readiness requirements before confirming the purchase. |
| After-sales support | Warranty terms, technical response process, spare-parts availability, and escalation for service issues. | Written warranty conditions, support contact details, spare-parts list, and stated service response arrangements. | Compare documented commitments and exclusions; do not rely on verbal assurances alone. |