Pocket strategy should be chosen from the surfaces the customer will measure or see. Compare offset and raster clearing with the same cutter and stock, then judge wall size, floor variation, entry marks, chip behavior, runtime, and cleanup instead of relying on a CAM default.
Map the Pocket Before Choosing a Clearing Pattern
Start by separating functional surfaces from sacrificial ones. A pocket that locates a bearing may be released from wall position and diameter, while the floor only needs clearance. A presentation tray reverses those priorities. Put the requirement on the setup sheet before comparing paths so that a shorter cycle does not win by solving the wrong surface.
Offset Clearing Follows the Pocket Boundary
Boundary-following motion can keep the cutter engaged in a predictable relationship to the wall, but narrow corridors and islands may force tight turns or full-width encounters. Inspect the generated engagement map rather than assuming every offset loop is gentle. If the software offers smoothing or minimum cutting radius controls, verify their effect in the actual posted path.
Raster Clearing Makes Direction Visible
Raster direction should be treated as a visible design variable. A pass parallel to grain may disguise floor lines in wood yet make reversal bands obvious on a coated panel. Rotate the same coupon ninety degrees without changing the remaining conditions; if the appearance rotates with the toolpath, the pattern is process-driven rather than a stock defect.
| Evidence | Offset-led result | Raster-led result |
|---|---|---|
| Visible floor | Check island swirls and corner transitions | Check reversal bands and scan direction |
| Finished walls | Measure allowance and wall pass separately | Do not infer wall size from floor appearance |
| Total labor | Add cleanup to observed cycle time | Add cleanup to observed cycle time |
Two pockets can require opposite choices
Consider a shallow recess for a visible instrument panel and a deeper pocket that locates a purchased component. The panel is judged under raking light, so a consistent floor pattern may outweigh a few extra seconds. The locating pocket is released from wall position, corner access, and depth; its floor only needs clearance. A single shop-wide preference cannot serve both.
Score the coupon against weighted requirements before looking at runtime. If wall size is critical, a dimensional failure disqualifies the path even when its floor looks better. If the floor is the product surface, record the lighting and cleanup used for acceptance so later operators do not approve a rougher appearance from a different viewing angle.
When neither pattern satisfies both surfaces, split the work intentionally. Use one strategy for efficient clearing, leave measured wall and floor allowance, then apply dedicated finishing operations only where required. This is different from adding cleanup paths by habit: every added operation should correspond to a failed measurement or visible criterion on the coupon.
Separate Wall Allowance From Floor Allowance
Wall and floor allowance need separate inspection points. Measure the rough pocket before the finishing operation at several depths and around islands. If the wall already reaches final size in one region while another carries heavy stock, no single finishing pass can cut consistently. Correct the roughing handoff before evaluating the finishing strategy.
Run a Matched Pocket Coupon
Use identical pocket geometry placed close together on the same stock, with the same tool projection, origin, stepdown, and workholding. Keep entry position and finish allowance documented. Photograph and measure the coupons before any sanding, then repeat the planned cleanup on both; this reveals whether hand finishing reverses the initial ranking.
Release the Strategy From Measured Results
Release a strategy with two decisions, not one: whether the dimensions pass and whether the visible surface passes. Record cycle time together with deburring or sanding time. An offset path may be the dimensional winner while raster is the cosmetic winner, and mixed work can legitimately use one for roughing and a different final floor operation.
