Work-In-Process Carts
Work-in-process staging and transport carts that carry sub-assemblies, partially complete units, and in-process materials between production operations while maintaining part identity, status visibility, and lot traceability throughout the production flow. T-slot aluminum construction provides the flexibility to configure each cart for the specific part geometry, tracking system, and visual management requirements of your WIP control program.
Why Choose Modular Solutions for Work-In-Process Carts?
WIP control starts at the cart — part identity, status, and traceability should be built in, not improvised.
WIP Identity Built Into the Cart
Traveler document holders, build status boards, RFID tag mounts, and barcode scan positions are integrated into the T-slot frame as designed elements — not clipped-on, taped, or improvised. Every WIP cart in the fleet carries the same identity provisions at the same location for consistent scanning and verification.
Part-Specific Nesting and Support
Sub-assemblies and in-process parts are staged in custom-designed nesting positions that hold the part in the correct orientation for the next operation. Correct orientation at staging eliminates re-fixturing time at the next workstation and reduces rework from part damage during transport.
Visual WIP Status Management
Color-coded status flag systems, job traveler display windows, and build stage indicators are built into the T-slot upright frame for clear WIP status visibility from the aisle without approaching the cart. Aisle-visible status reduces supervisor walk time and supports lean visual management programs.
Supports One-Piece-Flow Architecture
WIP carts sized for one or a small number of units support one-piece-flow production designs where WIP is minimized and each unit moves through production as soon as it is complete. Cart-per-unit assignment in one-piece-flow systems maintains part identity and traceability without batch staging.
Compatible with MES and ERP Tracking
RFID, barcode, and QR code scan provisions at standardized cart positions support MES, ERP, and WIP tracking system integration. Cart movement triggers at work center entry and exit points update production status automatically without manual data entry.
Flexible for Process Variation
T-slot frame nesting positions, document holder locations, and accessory provisions are all reconfigurable when production processes change or new product lines are introduced. WIP cart reconfiguration does not require new cart purchases — only bracket repositioning and new inserts.
Key Features & Benefits
Structural and functional features that make WIP carts effective in controlled production flow environments.
Custom Part Nesting Positions
Nesting cradles, support rails, locating pins, and pad materials are fabricated and mounted to the T-slot frame based on the part geometry and the operation sequence. Parts are presented in the correct orientation for the next operation — not just supported to prevent damage during transit.
Job Traveler Document Display
Document display windows and traveler clip holders mount to T-slot upright faces at aisle-visible positions. Travelers, build instructions, inspection records, and non-conformance tags are accessible and visible without opening a container or moving the cart.
RFID and Barcode Provisions
RFID antenna brackets, barcode label holders, and QR code display panels are integrated at standardized cart positions for automatic identification and tracking as carts move through work center entry and exit scan points.
Status Flag and Andon Integration
Color-coded status flag brackets, Andon signal light mounts, and electronic status display provisions are built into the T-slot upright frame for aisle-visible WIP status communication.
Ergonomic Access to All Part Positions
Nest positions are located at heights that allow access from a standing or seated position without excessive bending or reaching. For heavy sub-assemblies, nest heights are set to minimize lift distance and ergonomic risk during part transfer to and from the cart.
Corrosion-Resistant, Clean-Room Compatible Options
T-slot aluminum frames with anodized finish are compatible with clean-room and low-contamination environments. All-aluminum hardware is available for applications requiring non-magnetic or non-ferrous construction.
Common Applications
WIP carts are used wherever sub-assemblies, partially complete units, or in-process materials must move between operations with maintained identity and traceability.
- Sub-Assembly Staging Between Operations - WIP carts staging partially assembled units between welding, machining, assembly, inspection, and test operations with part identity and build status visible throughout the flow.
- Rework and Non-Conformance Staging - Dedicated WIP cart configurations for non-conforming units moving through rework, repair, and re-inspection operations with NCR documentation display and segregated staging to prevent return to production flow before approval.
- Single-Unit Build Tracking - WIP carts assigned per unit in low-volume, high-value manufacturing environments — capital equipment, defense systems, aerospace assemblies — where individual unit identity and complete operation history must be maintained from first operation to final acceptance.
- Paint and Surface Treatment Staging - WIP cart configurations with FIFO lane order and surface-protection nests for staging pre-treatment, treatment, and post-treatment parts through surface finishing operations in correct process sequence.
- Test and Inspection Hold Areas - WIP carts in hold areas at test and inspection work centers, with status flags and traveler display visible to quality engineers and supervisors for rapid WIP status assessment during floor walks.
- Kitting and Pre-Assembly Staging - WIP carts staging completed kits and pre-assembled sub-components at final assembly work centers, with nest positions for each kit component and visual verification provisions for kit completeness checking.
Specifications & Configurations
Standard design ranges. All specifications are configurable to your part geometry, WIP control system, and production flow requirements.
| Specification | Detail |
|---|---|
| Frame Profile | 45 Series or 90 Series T-slot aluminum depending on part weight |
| Nesting Material | Aluminum, steel, urethane, or closed-cell foam per application |
| Part Positions per Cart | 1 to 8 per cart depending on part size and configuration |
| Document Display | Job traveler window, clip holder, or enclosed document pouch options |
| Tracking Integration | RFID bracket, barcode label holder, QR code panel provisions |
| Status Indicators | Color-coded flag bracket, Andon light mount, or electronic display provision |
| Cart Footprint | Custom to part envelope; standard ranges 24 in. x 36 in. to 48 in. x 72 in. |
| Caster Diameter | 4 in. or 5 in.; swivel with 2 brake casters standard |
| Clean Room Compatibility | Anodized finish and all-aluminum hardware option available |
| Lead Time | 4 to 6 weeks from approved drawings |
Frequently Asked Questions
Common questions about work-in-process carts from Modular Solutions.
How do WIP carts support lean and one-piece-flow production?
WIP carts in one-piece-flow systems carry a single unit or a small batch between adjacent operations. Because each cart holds only one unit, the WIP level is physically limited by the number of carts in the system. When a downstream operation is delayed, WIP accumulates on carts in the staging lane between operations, making the bottleneck visible. This is the core principle of lean WIP control — making inventory visible and physical rather than invisible in a system queue.
What information is typically displayed on a WIP cart?
Standard WIP cart displays include: part number and serial or lot number, current operation status, next operation destination, inspection or test results, and non-conformance or hold status flags. Document display windows hold paper travelers, build records, or inspection sheets. Electronic tracking provisions support MES or ERP integration for digital status updates.
Can WIP carts be tracked automatically without manual scanning?
Yes. RFID-based tracking systems using cart-mounted transponders and fixed reader antennas at work center entry and exit points automatically record cart movement and update WIP status in MES or ERP systems without operator action. Barcode and QR code systems require a scan action but provide similar functionality. Modular Solutions integrates the antenna bracket or scan target provisions into the cart frame at the positions required by your tracking system.
How do WIP carts differ from component transport carts?
Component transport carts carry incoming parts or sub-assemblies between storage and production. WIP carts carry partially assembled units through the production sequence while maintaining build identity and status. WIP carts typically include document display, status flag, and tracking provisions that are not required on component transport carts. The nesting geometry on a WIP cart reflects the in-process part state — which changes as assembly progresses — whereas a component cart nest reflects the incoming part state only.
Can WIP carts be used in regulated industries with lot traceability requirements?
Yes. WIP carts for pharmaceutical, medical device, aerospace, and automotive Tier 1 environments are designed with full lot traceability provisions: document holders for batch records and travelers, RFID or barcode tracking for automated MES integration, and status flag systems for visual hold and quarantine indication. Cart design can be reviewed against your quality system requirements to confirm compliance with 21 CFR Part 11, AS9100, IATF 16949, or other applicable standards.
Ready to Design Your WIP Cart System?
Share your part geometry, production flow, tracking requirements, and WIP control objectives. Our engineers will design WIP carts that make your in-process inventory visible and controlled.
Modular Solutions - 4280 Giddings Rd, Auburn Hills, MI 48326