3.3 Depanelization Choices
V-score,Separating
router,boards laser—mechanicalfrom stress,their fiber dust, and edge quality without drama.
Depanelizationpanels is the finallast mechanical hurdlestep betweenbefore a well-builtproduct panelis truly finished, and ait shippablecarries board,more andrisk it’sthan whereit poorappears. choicesThe wrong depaneling method can cracksilently introduce cracks in brittle components, marleave edges,edges out of tolerance, or contaminate worksurfaces areas.with fiber dust. V-scoring isdelivers fastspeed at the cost of higher stress, routers trade dust for cleaner outlines, and cheaplasers butoffer introduces higher bending strain, making it risky for fragile parts near the edge. Routing with mousebites offers cleaner edges and lower stress, though it generates glass fiber dust that must be managed. Laser cutting—especially with UV—yields the cleanest, lowest-force separation and excels in tight geometries, but it’s slower and more expensive. Fixture design, tab placement, and part keepouts all influence how well each method works, while dust extraction, ESD control, and strain checks keep quality and reliability intact. By matching the method to the board’s stress tolerance, geometry, and cosmetic needs, panels can be separatedprecision with minimal riskstrain but higher cost. Success depends on aligning method with board fragility, cosmetic requirements, and maximumthroughput consistency.
3.3.1 The problem in one minute
You’ve got good panels. Now you need good singles—without cracking MLCCs, snowing the room with fiberglass, or chewing ugly edges that won’t fit bezels. The right depanel method depends on stress tolerance, edge spec, throughput, and what debris your product can tolerate (none, ideally).
3.3.2 Three main methods (what each is best at)
Rule of thumb: if components are close to the edge or you’ve cracked MLCCs before, move away from snap-heavy V-score toward router or laser.
3.3.3 Design knobs that make any method easier
- Keepouts from final edge
- V-score: fragile parts (MLCCs, crystals) ≥ 2–3 mm, robust parts ≥ 1.5 mm.
- Router/laser: you can live with ≥ 1.0–1.5 mm; more for tall/heavy parts.
- Rails & tabs
- Add breakaway rails so machines grip panels, not products.
- Mousebites: 0.30–0.50 mm webs, hole Ø 0.5–0.8 mm, pitch 0.8–1.2 mm. Tabs every 50–75 mm along long edges; avoid corners and connectors.
- Put robber tabs where cosmetics don’t matter; plan to sand/polish after.
- Score geometry (if V-score)
- Blade angles 30°/45° common; residual web 0.30–0.50 mm.
- Straight lines only; don’t score into cutouts or tight radii.
3.3.4 Router setup (stress low, edges nice)
Hardware & bits
- Spindle: 40–80 krpm typical.
- Bit: 0.8–2.0 mm single-flute (O-flute) carbide for FR-4; larger for aluminum/MCPCB.
- Kerf: ~bit Ø (plan clearances).
- Vacuum extraction at the nose; add ionized air to knock down static.
Feeds & speeds (starter)
- Feed: 50–150 mm/s depending on thickness and bit Ø.
- Step-down: full-depth for thin boards; two passes for ≥1.6 mm or heavy copper.
- Climb cut finish pass for cleaner edge.
- Fixtures: vacuum table or pin fixture with top clamping fingers to stop chatter.
If edges fuzz/burr: new bit, slower feed/finish pass, check Z height; add deburr brush station for mousebite stubs.
Safety: router dust = glass fiber. Enclose, vacuum, HEPA. Ground the spindle and use ionizers—static can zap boards.
3.3.5 V-score separation (fast, cheap, but mind the strain)
Tools: manual snap fixture, rolling “pizza” cutter, or pneumatic foot-pedal separator.
How to reduce strain
- Use a rolling blade rather than hand snap; it keeps the board flat.
- Add hold-down rails and support fingers under the seam.
- Don’t score over big inner copper pours without thermals—it makes the seam hard and raises force.
- Measure bend strain during NPI (simple strain gauge or electronic strain checker near the edge). Many teams aim <500–700 με at risk parts.
Typical failure tells: cracked MLCCs near the seam, hairline fractures at BGA corners on thin boards. If you see them, switch the method or move parts back.
3.3.6 Laser depaneling (cleanest edges, lowest force)
Pick the wavelength
- UV (355 nm): crisp edge, tiny heat-affected zone; best for FR-4/flex and close-to-edge parts.
- CO₂ (10.6 µm): faster bulk removal, more soot/amber edge; OK for mask/FR-4 but watch cosmetics.
Programming
- Multiple light passes > one heavy pass (keeps HAZ small).
- Assist gas (N₂) and vacuum at the cut keep char off.
- Leave 0.05–0.10 mm skin, then do a clean final pass to prevent splash-through on small slugs.
Where it wins: rigid-flex (no fibrils), very tight bezels, coated or sensitive assemblies where bending is forbidden.
3.3.7 Rigid-flex, MCPCB, and awkward builds
- Rigid-flex: laser or sharp router only; no V-score across flex. Mask flex zones during handling; fixturing must support both stacks.
- Metal-core / aluminum: router with aluminum-capable bits; collect chips separately; check burrs—edge may need a light chamfer.
- Thick copper / 2+ mm boards: router or laser; V-score forces get high and crack parts.
3.3.8 Stress, debris, and ESD—quick risk table
3.3.9 Symptom → smallest reliable fix
3.3.10 First-article & NPI checks (10-minute routine)
- Method pick agreed (score/router/laser) with edge keepouts validated.
- Strain check at worst refdes during separation (target <500–700 με or per component spec).
- Edge gauge: measure outline vs drawing; record kerf/offsets.
- Debris check: white cloth wipe near cuts, AOI lens check; dial extraction before ramp.
- Cosmetics: compare edge to limit sample; mousebite finish acceptable?
- Recipe saved (bit, rpm, feed, passes / blade pressure / laser power & speed).
3.3.11 Pocket checklists
Design-for-depanel (put on panel drawing)
- Method intended (V-score / tab-route / laser)
- Keepouts from final edge (V-score ≥ 2–3 mm; router/laser ≥ 1–1.5 mm)
- Tab pattern (spacing, web, hole Ø) and don’t place near connectors
- Rails present with tooling holes and fiducials
Router setup
- Bit Ø / type posted; new bit installed; spindle 40–80 krpm
- Feed & finish pass set; nose vacuum + ionizer on
- Fixture clamps secure; test cut, measure kerf
V-score run
- Roller height set; support fingers under seam
- Strain gage at risk part (first lot); parts clear of score line
- No hand snaps on live product unless approved
Laser run
- UV/CO₂ recipe loaded; multi-pass, low HAZ strategy
- Assist gas & vacuum at cut; sample edge inspected
- Char minimal; outline within spec
After depanel
- Deburr mousebites where called out; collect dust; ESD-safe wipe
- Scan SNs if panel → singles; update traveler
BottomWhen
depanelization line:chooseis the depanel method by strain tolerancechosen and edgecontrolled spec,with notintent, habit.it Usebecomes V-scorea seamless step rather than a hidden yield risk. Boards emerge with intact parts, clean edges, and consistent dimensions, ready for speeddownstream when parts sit back from the seam; pick router for clean edgesassembly and lowcustomer stress; pick laser when strain must be near zero or geometry is tight. Control dust, static, and fixtures, and your boards will leave the panel looking as good as they reflowed.