Fab Lab Rwanda · Group work
Computer-Controlled Machining
Our characterization plan separates the router, tool, material and workholding before choosing production settings. The aim is a repeatable account of alignment, runout, cut behaviour and joint fit.
Safety and workholding
We will begin with the lab's router safety training, approved tooling and machine-specific operating procedure. The setup must show how the stock is supported and restrained, where clamps sit relative to the toolpath, and how cut parts remain secured. Tool changes and machine access follow the lab's isolation procedure.
Before cutting, we will review the CAM simulation, stock thickness, tool length, work origin, safe heights and travel limits. A controlled clearance check should establish that the toolpath avoids the fixture.
Runout, alignment and fixturing tests
| Variable | Method | How to interpret it |
|---|---|---|
| Runout | Use a suitable indicator on a clean shank or test pin, following the spindle procedure | A milled slot width alone also includes deflection and cutting effects; it is not a direct runout reading. |
| Alignment | Cut and measure a test rectangle, its diagonals and corresponding edges | Compare with the CAD dimensions and repeat to distinguish systematic error. |
| Fixturing | Inspect support, restraint and cut-part retention on a small test | Look for movement, vibration or surface differences attributable to the setup. |
| Material thickness | Measure several locations on the actual stock | Use the range when selecting through-cut depth and joint tests. |
Feeds, speeds and toolpaths
We will identify the tool type, diameter, flute count and material before choosing a starting range from the tool and machine guidance. The nominal relationship is feed (mm/min) = spindle speed (rev/min) × flutes × chip load (mm/tooth). This calculation does not establish that a setting is suitable for our router or stock.
The test record should retain spindle speed, cutting and plunge feeds, stepdown, stepover, cut direction and toolpath strategy. Comparing chip formation, sound, edge finish and tool loading on a small cut helps us decide what to adjust before a larger job.
Joint-fit comparison
Our proposed comb test varies the slot around the measured sheet thickness. Each slot should be labelled in the drawing and on the physical piece. We will compare insertion, retention and damage after repeated assembly, with the same toolpath compensation and stock used for the final part.
Internal corners also need a deliberate solution: a dogbone, T-bone, different tool or revised joint. The selected relief should appear in the editable design and CAM files.
Available plotter drawings
The plywood plotter design supplies a base and paper-bed design as DXF and STEP. Its nominal stocks are 12 mm and 6 mm plywood. The actual thickness, tool access and fastening recesses must be checked during CAM preparation.
These are digital designs for a proposed build. They do not document that the router characterization or physical plotter parts have been cut.