Lesson 1Key process steps: setup, roughing, finishing, inspection, deburring, cleaningThis part breaks down the CNC process into main steps like setup, roughing, semi-finishing, finishing, deburring, cleaning, and inspection, explaining goals, inputs, outputs, and equipment used in each stage for Zambian workshops.
Pre-setup staging and job preparationMachine setup and workholding verificationRoughing operations and bulk removalSemi-finishing and feature definitionFinishing, chamfering, and edge qualityDeburring, cleaning, and final inspectionLesson 2Data to gather before redesign: volumes, batch size, order variability, supplier lead times, floor space and workforce capabilitiesThis section outlines operational data needed for redesign, including demand volumes, batch sizes, order changes, supplier times, space, staff skills, and shifts, ensuring practical improvements for Zambian manufacturing.
Demand volumes and product mixBatch sizes, lot sizing, and changeoversOrder variability and demand patternsSupplier lead times and reliabilityAvailable floor space and layout limitsWorkforce skills, shifts, and flexibilityLesson 3Typical workflow for precision aluminium housings from billet to finished partThis section follows the full workflow for precision aluminium housings, from receiving billets to programming, setup, roughing, finishing, inspection, and shipping, noting information flow and documentation in Zambian settings.
Billet specifications and incoming inspectionCAM programming and process planningSetup, workholding, and zero referencingRoughing strategies and toolpath selectionFinishing passes and in-process checksFinal inspection, packaging, and shippingLesson 4Typical part assumptions: sizes, wall thicknesses, tolerances, surface finish requirementsThis section describes common aluminium housing features, like sizes, wall thicknesses, tolerances, flatness, surface finish, and how these affect process choices and risks in Zambian production environments.
Common housing sizes and aspect ratiosWall thickness ranges and stiffness limitsDimensional and geometric tolerance bandsFlatness, perpendicularity, and positionSurface finish and cosmetic class levelsCritical features and datum structuresLesson 5Quality issues and failure modes: geometric tolerance stack-up, surface integrity, burrs, residual stress, coolant contaminationThis section discusses common quality problems in CNC aluminium housings, such as tolerance issues, surface errors, burrs, stresses, and contamination, which can lead to rework or failures in Zambian factories.
Dimensional errors and tolerance stack-upsForm, position, and runout nonconformanceSurface integrity, chatter, and tool marksBurr formation, removal, and missed edgesResidual stress, distortion, and warpageCoolant contamination and cleanliness risksLesson 6Root causes of high cost and lead time: machine utilization, cycle inefficiencies, long setups, tool life, material removal ratesThis section pinpoints reasons for high costs and delays, like poor machine use, inefficient times, long setups, tool issues, and removal strategies, relevant to improving Zambian manufacturing efficiency.
Machine utilization and OEE shortfallsCutting vs non-cutting time breakdownSetup duration, changeovers, and SMEDTool life limits and unplanned breakageMaterial removal rates and chip loadScheduling, queues, and waiting lossesLesson 7Primary manufacturing metrics to collect: cycle time, takt, throughput, scrap, first-pass yield, cost-per-partThis section explains key metrics for CNC housings, including cycle time, takt, throughput, scrap, yield, and cost per part, and how to measure them for better performance in Zambian operations.
Cycle time components and measurementTakt time, demand, and line balancingThroughput, WIP, and bottleneck analysisScrap, rework, and defect categorizationFirst-pass yield and rolled throughputCost per part and cost driver breakdownLesson 8Common machine types, tooling, fixturing, coolant and chip managementThis section reviews typical CNC machines, tools, fixtures, coolants, and chip handling for aluminium housings, connecting choices to rigidity, accuracy, and maintenance in Zambian workshops.
3-axis vs 5-axis machining center choicesSpindles, holders, and aluminium toolingWorkholding, vises, and custom fixturesCoolant types, delivery, and filtrationChip evacuation, conveyors, and binsMaintenance and reliability considerations
