What Is Material Kitting in SMT Production?
Material kitting is the process of assembling all components required for a specific production job into a single package — a kit — before the job reaches the SMT line. Instead of operators pulling individual reels from storage during setup, they receive a complete, verified set of materials ready to load onto feeders.
In high-mix SMT production, kitting is the bridge between material storage and line-side delivery. When done well, it compresses changeover time, eliminates wrong-component errors, and keeps production lines running. When done poorly — or not done at all — it becomes the bottleneck that every other process waits on.
Why Kitting Matters
The economics are straightforward. In a high-mix environment where changeovers happen 4-8 times per shift, every minute saved during changeover directly translates to additional production time. If a changeover takes 30 minutes without kitting and 15 minutes with pre-kitting, that is 60-120 minutes of recovered production time per shift — enough to produce hundreds or thousands of additional boards daily.
Beyond speed, kitting reduces errors. When operators pull components individually during changeover, the error rate for loading the wrong reel is typically 0.5-2% per pick. With a pre-verified kit, that rate drops to near zero.
Types of Kitting Strategies
Job Kits (Dedicated Kits)
One kit per production job. Contains exactly the components needed for a specific work order, in the exact quantities planned.
- Best for: high-mix, low-volume production where each job uses a different BOM
- Advantage: simple to verify — each kit matches exactly one work order
- Disadvantage: components shared between consecutive jobs must be returned and re-kitted
Family Kits (Group Kits)
One kit covers a group of related products that share common components. The kit includes the superset of all components needed for the product family, and the line program selects which feeders to use for each variant.
- Best for: product families with high component commonality (70%+ shared BOMs)
- Advantage: fewer changeovers between family members — only unique components change
- Disadvantage: more components loaded than any single job needs, increasing feeder count and machine setup complexity
Line-Side Supermarket
Not traditional kitting, but an alternative approach. High-frequency components are stocked permanently at the line-side in a small shelving or carousel system. Kitting is only done for job-specific or low-frequency components.
- Best for: operations where 30-50% of components are common across most jobs
- Advantage: reduces kit size and preparation time; common parts are always available
- Disadvantage: requires discipline to maintain and replenish the supermarket; inventory accuracy at the line-side can drift
The Kitting Process: Step by Step
Step 1: BOM Explosion and Pick List Generation
The process starts when the production schedule triggers a material requirement. The MES or ERP system explodes the Bill of Materials for the scheduled job and generates a pick list — the complete set of components, quantities, and feeder positions needed.
Best practice: generate the pick list at least one job ahead of current production. This gives the kitting team time to prepare without creating a bottleneck.
Step 2: Material Picking
The kitting operator retrieves each component from storage. In manual operations, this means walking to shelves, finding the correct reel, and placing it in a kit container. In automated operations, the storage system retrieves the reels and presents them at an output port.
Best practice: sequence the pick list by storage location (not by feeder position) to minimize walking distance. Automated storage systems handle this optimization automatically.
Step 3: Verification
Every component in the kit must be verified against the BOM. This catches wrong part numbers, wrong values, expired components, and quantity errors before they reach the line.
Verification methods, from least to most reliable:
- Visual check: operator reads labels and compares to the pick list. Error rate: 1-3%.
- Barcode scanning: operator scans each reel barcode; system confirms match against BOM. Error rate: 0.1-0.5%.
- Automated verification: storage system verifies identity at retrieval; kit is inherently correct. Error rate: <0.01%.
Best practice: barcode scanning is the minimum acceptable verification method. Visual-only verification is insufficient for any production that requires traceability.
Step 4: Kit Staging
Completed, verified kits are placed in a staging area, clearly labeled with the work order number, line assignment, and scheduled run time. Kits should be organized in the sequence they will be needed.
Best practice: use a visual management system (kanban cards, colored labels, or a staging board) so production supervisors can see at a glance which kits are ready and which are still being prepared.
Step 5: Line-Side Delivery
Kits are transported from staging to the production line. Timing is critical — deliver too early and the line-side becomes cluttered; deliver too late and the line waits.
Best practice: deliver kits during the current job’s production run, not after it finishes. The next kit should be line-side before the current job completes, enabling immediate changeover start.
Common Kitting Errors and Their Impact
| Error Type | Cause | Production Impact |
|---|---|---|
| Wrong part number | Similar labels, adjacent storage locations | Wrong component on board → rework or scrap |
| Wrong quantity | Miscounted reels, partial reels not tracked | Line stops mid-run for additional material |
| Expired MSD | Floor life not checked during picking | Moisture-related solder defects, J-STD-033 violation |
| Missing component | Reel not found in storage, pick list incomplete | Changeover delayed until component is located |
| Wrong feeder position | Kit organized by storage location, not feeder slot | Setup time increases as operator re-sorts components |
| Late kit delivery | Kitting started too late, storage bottleneck | Line waits for materials during changeover |
How Automated Storage Transforms Kitting
The traditional kitting process — walking to shelves, searching for reels, manually scanning each one — is inherently slow and error-prone. Intelligent storage systems like the Neotel SMD BOX transform kitting by automating the most time-consuming and error-prone steps:
BOM-Based Auto-Retrieval
The production scheduler sends the upcoming job’s BOM to the storage system. The system automatically retrieves all required reels in sequence and presents them at the output port. No walking, no searching, no wrong picks.
Automatic Verification
Every reel retrieved by the system is inherently verified — the system knows exactly which reel it is retrieving from which slot. Barcode scanning at the output port provides a second verification layer.
MSD Compliance Built In
The system checks floor life remaining for every MSD reel at retrieval time. Reels with insufficient floor life for the planned production run are flagged, and alternative reels are offered — all automatically.
Parallel Kitting
While the current job runs on the line, the storage system prepares the next kit in background. The kit is ready at the output port before the current job finishes, enabling zero-wait changeovers.
Measuring Kitting Performance
| Metric | Definition | Manual Benchmark | Automated Benchmark |
|---|---|---|---|
| Kit preparation time | Time from pick list to completed, verified kit | 20-45 minutes | 5-10 minutes |
| Kitting accuracy | Percentage of kits with zero errors | 95-98% | 99.9%+ |
| Kit availability | Percentage of kits ready before changeover starts | 70-85% | 95-99% |
| Components per hour | Kitting throughput (picks per hour per operator) | 40-80 | 150-300 |
| Return processing time | Time to return unused materials to tracked storage | 15-30 minutes | 5-10 minutes |
Pre-Kitting vs. Just-in-Time Kitting
Pre-Kitting
Materials are assembled into kits well in advance — hours or even a full shift ahead of production. Kits are staged and waiting when the line needs them.
- Advantage: maximum buffer against delays; line never waits for materials
- Disadvantage: MSD floor life clocks are running on pre-kitted components; large staging area required; schedule changes may orphan prepared kits
Just-in-Time Kitting
Materials are kitted immediately before they are needed — typically starting when the previous job enters its final boards.
- Advantage: minimal MSD exposure; adapts to schedule changes; small staging footprint
- Disadvantage: requires fast, reliable kitting process; any delay directly impacts the line
The Right Balance
With manual kitting, pre-kitting is often necessary because the process is too slow for just-in-time execution. With automated storage, just-in-time becomes feasible because kit preparation takes 5-10 minutes instead of 30-45. The optimal approach depends on your changeover frequency and MSD content:
- Low MSD content, infrequent changeovers: pre-kit 2-3 jobs ahead
- High MSD content, frequent changeovers: just-in-time kitting with automated storage
- Mixed: pre-kit non-MSD components, just-in-time kit MSD components
Best Practices Checklist
- ☐ Generate pick lists at least one job ahead of current production
- ☐ Sequence picks by storage location to minimize walking (or use automated retrieval)
- ☐ Verify every component against the BOM using barcode scanning at minimum
- ☐ Check MSD floor life during kitting, not after delivery to the line
- ☐ Label kits clearly with work order, line assignment, and scheduled time
- ☐ Deliver kits to the line-side before the current job finishes
- ☐ Track kit preparation time and accuracy as KPIs
- ☐ Process material returns promptly — unused reels sitting on carts are untracked inventory
- ☐ Integrate kitting with production scheduling for demand-driven preparation
- ☐ Review and optimize kit organization: by feeder position for fast setup, not by storage location
Key Takeaways
- Kitting is the critical link between storage and production — get it right and changeovers accelerate; get it wrong and lines starve
- Choose your kitting strategy (job kits, family kits, or supermarket) based on your product mix and BOM commonality
- Verification is non-negotiable — barcode scanning is the minimum standard for any traceable production
- Automated storage systems cut kit preparation time by 60-80% and virtually eliminate picking errors
- Measure kitting performance (time, accuracy, availability) and treat it as a first-class production KPI
