3.3 Depanelization Choices

Separating boards from their panelsDepanelization is the lastfinal mechanical stepprocess beforethat separates individual Printed Circuit Boards (PCBs) from the large manufacturing array after assembly and soldering are complete. The choice of method is a productcritical isDesign trulyfor finished,Manufacturability (DFM) decision, directly trading off production volume and itcost carriesagainst morethe riskmechanical thanstress itapplied appears.to Thesensitive wrongcomponents depanelingand methodsolder joints. Failure to manage stress during this step can silentlylead introduceto hidden failures like micro-cracks in brittleceramic components, leave edges out of tolerance,capacitors or contaminateweakened surfacesBGA with fiber dust. V-scoring delivers speed at the cost of higher stress, routers trade dust for cleaner outlines, and lasers offer precision with minimal strain but higher cost. Success depends on aligning method with board fragility, cosmetic requirements, and throughput goals—while managing dust, static, and fixture stability to keep reliability intact.joints.

3.3.1 Panel Connection Methods

The problemmethod of panelization defines the required depanelization tool. This decision must be locked in one minute

You’ve got good panels. Now you need good singles—without cracking MLCCs, snowingduring the roomdesign 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).phase.

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3.3.2 Three main methods (what each is best at)

Connection Method	Design Features	Best Use Case	Stress Profile
V-Scoring (V-Cut)	V-shaped groove cut into the top and bottom of the panel (leaving ≈ 1/3 thickness).	High-Volume production with straight-line cuts (rectangular/square boards).	High Stress near the score line; requires careful component spacing.
Tab Routing (Mouse Bites)	Individual boards milled out, connected only by thin perforated break-away tabs.	Irregular shapes and designs requiring high mechanical support during assembly.	Low Stress in the board center; stress is localized at the tab break point.

3.3.2 Depanelization Technologies: Stress vs. Throughput

The technology chosen must minimize stress near sensitive components (e.g., fine-pitch SMT, ceramic capacitors, BGAs). A general corporate limit for acceptable stress near a component is often 200 microstrain (µε).

Method	How it worksMechanism	Edge qualityAdvantages	Disadvantages & Stress on PCA	Debris/ESD	Where it shines	Watch-outs
V-score + “pizza cutter”Router/Milling	Factory-scoredUses groovesa snappedrotating orbit rolledto apartmill away the tab material between boards.	Low Stress transmission; ideal for complex contours and non-straight lines.	Fair;Slower slightcycle knifetime burr	Higherthan (board bending)	Low dust; static from rollers	Fast, cheap,V-cut; high volume,maintenance straight(bit seams	Keepwear); partsgenerates ≥2–3 mm from score; rails helpdust.
Tab-routePizza (routerCutter +/ mousebites)Shearing	MilledA outline + perforated tabs snappedfixed or milledpowered rotary blade separates V-scored boards.	Good–very good	Low–mediumFast (ifcycle well-fixtured)time; low equipment cost; suitable for medium-volume straight cuts.	GlassHigh dustStress; managenear withthe vaccut &line; ionizerlimited to straight cuts only.
Punching/Die Cutting	Uses custom die blades to punch out the board in a single press.	Highest ThroughputCurvy outlines,for tightmass bezels,production; metal-coreexcellent speed.	High Fixture CostBit wear(NRE); =introduces burrs;high, noise;localized keepmechanical guards onstress.
Laser Cutting (UV/CO₂)CO2)	AblatesUses outlinea withoutfocused forcelaser beam (UV preferred) to ablate the material.	ExcellentNon-Contact (UVzero best)mechanical stress); highest precision; ideal for thin/flexible boards.	VeryHighest low	Char/soot minimal with UV, more with CO₂	Thin/flex/rigid-flex, tiny gaps, tight keepouts	Slower; capex; heat-affected edge if overdone

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.

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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 mmCapEx; 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; planlimited to sand/polishthin after.
• Score geometrymaterials (if≤ V-score)
• • Blade1 angles 30°/45° common; residual web 0.30–0.50 mm.
  • Straight lines only; don’t score into cutouts or tight radii.

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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.

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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.

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3.3.6 Laser depaneling (cleanest edges, lowest force)

Pick the wavelength

• UV (355 nm): crisp edge, tiny heat-affected zonemm); bestthermal forresidue 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.

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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.

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3.3.8 Stress, debris, and ESD—quick risk table

Risk	V-score	Router	Laser	Mitigations
Mechanical strain	High	Low–Med	Lowest	Add rails, use roller, move parts back; router/laser if crackspossible.
Fiber/particulateHand Breaking (Snapping)	LowManual bending along a V-score or perforated tab.	Lowest cost; simple; suitable for prototyping or low volume.	High (glass dust)	Low–Med (char)	Vac + HEPA; ionized air; wipe benches; post-clean if needed
ESD	Low	Medium (static)	Low	Ground spindles, ionizers, ESD mats, wrist straps
Edge cosmetics	Fair	Good–Excellent	Excellent (UV)	Finish pass, brush; laser multi-pass
Throughput/cost	Fast, cheap	Medium	Slower, higher capex	Choose by volumeHighest and riskleast controllable stress; operator inconsistency; risks cracking ceramic capacitors.

3.3.3 Design for Depanelization (DFD) Mandates

The decision on the separation method must be made at the DFM stage (Chapter 1.1) to ensure component placement accommodates the mechanical risk.

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• Component Keepout: Critical components (BGAs, ceramic capacitors ≤ 0603 size) must be placed away from the separation line. A minimum clearance of 3 mm from the cut line (V-cut or tab) is typically mandated. Placing capacitors parallel to the edge reduces the risk of cracking compared to perpendicular placement.
• V-Cut Depth: The V-groove depth must be consistent, typically ≈ 1/3 of the PCB thickness, to ensure clean separation without excessive force.
• Tooling Holes: The final individual PCB must include tooling holes near the edges to allow for post-depanelization alignment during ICT/FCT (In-Circuit Test/Functional Test).

3.3.4 Stress Reduction Strategy

If mechanical methods (routing, V-cut) must be used on sensitive boards, specific process controls are mandatory to reduce the strain profile.

• Support and Fixturing: Use custom, rigid fixtures to support the panel during separation, preventing flexing or warping that transfers stress to the components.
• Speed Control: For routing, reducing the feed rate (cutting speed) decreases vibration and the resulting mechanical stress transferred to the board edges.
• Stress Monitoring: On high-risk NPI builds, use strain gauges (per IPC/JEDEC-9702) near sensitive components to qualify the chosen depanelization method against a 200 to 250µε limit.

3.3.9Final SymptomChecklist: →Depanelization smallestDFM reliable fixAudit

SymptomParameter	Likely causeMandate	First moveRationale
CrackedConnection MLCCs near edgeMethod	Method (V-scoreCut snapor strainTab Route) must be chosen based on board shape and volume.	SwitchV-Cut tofor router/laser;straight addhigh rails;volume; pushTab keepoutRoute tofor ≥3complex mm; use roller not hand snapcontours.
Fuzzy/burredComponent edgesClearance	DullCritical bit;SMT toocomponents fast(BGAs, feed≤ 0603 chips) placed ≥ 3 mm away from the separation line.	New bit; addPrevents finishcomponent passcracking; lowerand feedsolder 20%;joint brush/deburrmicro-fractures wheelfrom mechanical stress.
MousebiteSeparation teeth uglyTool	TabsRouter tooor wide/few;Laser nomust finishbe selected for sensitive or irregularly shaped PCBs.	SmallerAvoids websuncontrolled, (0.3–0.4high-stress mm),methods morelike tabs;Hand quickBreaking, end-millwhich nibblecauses orhidden sand paddefects.
CharredTooling laser edgeIntegrity	PowerRouter toobits, high;punches, slowor passV-cut blades must be maintained and sharpened on a PM schedule.	MoreDull passestools atincrease lowermechanical power;stress N₂and assist;result finalin “polish”rough passedges or burrs.
DustPost-Process everywhere / AOI hazeCheck	WeakBoards extractionmust be inspected (AOI/microscope) for burrs or micro-cracks after separation.	Nose-vacEnsures upgrade;dimensional HEPAaccuracy check;and ionizedprevents airenclosure atfitting cutter; wipe & tack-roll after
Outline out-of-tolerance	Tool deflection, kerf error	Slower feed; thicker bit; comp kerf in CAM; verify fixture clampissues.

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3.3.10 First-article & NPI checks (10-minute routine)

1. Method pick agreed (score/router/laser) with edge keepouts validated.
2. Strain check at worst refdes during separation (target <500–700 με or per component spec).
3. Edge gauge: measure outline vs drawing; record kerf/offsets.
4. Debris check: white cloth wipe near cuts, AOI lens check; dial extraction before ramp.
5. Cosmetics: compare edge to limit sample; mousebite finish acceptable?
6. Recipe saved (bit, rpm, feed, passes / blade pressure / laser power & speed).
   

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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

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When depanelization is chosen and controlled with intent, it becomes a seamless step rather than a hidden yield risk. Boards emerge with intact parts, clean edges, and consistent dimensions, ready for downstream assembly and customer inspection.