Digital quality inspection with Power Apps in precision machining

Technical design and clickable mockup

Before implementation, I wrote a technical design. It defines the target architecture, MVP scope, deliberate exclusions, roles, operating model, and error and cancellation handling, and names platform limits such as delegation in Power Apps and the 5,000-item threshold in SharePoint. A questionnaire clarified outstanding issues with quality assurance.

For functional alignment, I built a tablet mockup in HTML, CSS, and JavaScript that loads real JSON inspection plans and demonstrates the inspection trigger, characteristic filtering, sorting, and deviation recording. The feedback from quality assurance went directly into the app.

• MVP scope excluding measuring machine integration, Power BI, and CAQ features
• Analysis of the Q-DAS transfer format (DFQ) and design of a lean intermediate JSON format
• Device and UI strategy based on the existing production hardware

Responsive canvas app for guided inspection

In nine screens, the canvas app guides users from the selection through the characteristics overview and the individual inspection steps to the results overview and inspection history. When the operator selects a machine, the app loads the part currently running there from the machine status in SQL and suggests it. The layout is based on auto-layout containers and switches to a smartphone layout below a width of 700 pixels.

• Preselection of the part currently being produced per machine from the machine status view
• Load inspection plans as JSON via a flow and convert them into local collections with ParseJSON
• Automatic OK/NOK evaluation for unilateral and bilateral tolerances, required information for NOK
• Multiple inspections when several parts must be inspected per characteristic
• Interim saving via a timer and resuming at the first open or incomplete inspection step
• Catalogs for 45 measuring instruments, 8 deviation causes, and 7 actions

Inspection triggers, interval logic, and tool change groups

The inspection app distinguishes between interval, restart, tool change, and group change inspections. The inspection interval is read per characteristic from the inspection plan and compared with the number of parts produced since the last matching inspection, that is, the current part counter minus the part counter at that inspection. From the interval onward, a characteristic counts as due, from 80% as due soon. For a tool change, only the characteristics of the selected tool positions are queried, each as a last-part and first-part inspection.

• A separate basis for determining when each characteristic is due, rather than one for the entire inspection
• Completed tool change and group inspections with a part counter count toward the interval
• Sorting by production logic: first/last part, then measuring instruments in inspection plan order, and then characteristic number

Power Automate flows for storage, roles, and notification

The background business processes run on cloud flows with the Power Apps trigger (V2). Each flow has separate processing and error scopes. The error scope filters failed actions, sends an error email, and returns a defined code to the app.

• Create or update the inspection result as a JSON file and set metadata
• Role determination via membership in three Microsoft 365 groups
• Quality assurance notification by HTML email for NOK, controlled by trigger conditions and a sent flag
• Uniform flow configuration for environment and tenant as an object variable

Closing a production run without changing historical counters

For a new production order, the part counter was to start over without rewriting old inspection data. I solved this with a production run: a flow with 77 actions checks required information and permissions, looks up the open records of the machine-part combination, requires exactly one unique run identifier, and blocks the closing as long as an inspection is still open. Only then is the run closed, with every step recorded in a log list.

• Separate return codes for success, open inspection, no open run, ambiguous run, missing permission, and technical error
• Pagination up to 5,000 records and parallel processing when closing
• Available only to quality assurance and administration

Automatic archiving to stay below the SharePoint threshold

As the number of inspection results grew, the queries approached the 5,000-item threshold. For this, I built an archiving flow that moves completed inspections into a separate archive library after two months. It runs on Sundays between midnight and 6 a.m. in 10-minute steps with 50 files each and also checks itself whether the time window is active.

• Analysis mode, which only counts and logs candidates, and archive mode
• Log statuses STARTED, COMPLETED, COMPLETED-WITH-ERRORS, and FAILED with cutoff date, quantities, and batch identifier
• Errors per file handled separately from overall technical errors, with quantity reconciliation at the end

Solutions, environments, and permissions

The inspection app and all flows are in one solution with connection references. Between March and October 2026, 30 solution versions were created and deployed as managed solutions to test and production. During the rollout, I worked with IT to set up run-only access, connections, and flow permissions so that operators do not need maker or administrator rights.

Migration plan for an existing production app

For the existing production app with modules such as placing parts on hold and scrap, machine status and OEE, fault reporting, shift handover, and group planning, I prepared a technical pre-assessment and a strategy and migration paper with 33 chapters. I analyzed the app file with 26 screens, 11 embedded flows, 7 Dataverse tables, and several SQL databases.

The paper describes the target state, solution strategy, managed and unmanaged solutions, the design for connections, identities, and service accounts, environment variables, permissions, initial licensing guidance, data lifecycle, App checker findings, a risk register, and test, cutover, and rollback plans. Management then confirmed the target state with three environments and manual solution deployment.

Integration with Business Central

I am currently building Power Automate flows to connect an app built with Power Apps to Microsoft Dynamics 365 Business Central. The SQL integration and app development are handled by the client's internal IT or development staff.