Work-In-Process Flow Carts

Mobile gravity flow carts for routing sub-assemblies, carriers, and WIP containers through production cells and assembly lines — maintaining FIFO sequence, tracking identity, and buffering inter-operation inventory on the move.

Why Choose WIP Flow Carts

WIP flow carts replace flat-shelf staging trolleys with structured, sequenced, gravity-fed lanes — reducing operator search time, preserving build order, and enabling cell-level WIP control without floor space for fixed buffering.

FIFO Sequence Through the Route

Gravity lanes ensure that sub-assemblies leave each operation in the same order they entered. Serial number and lot traceability are maintained end-to-end without operator sorting or re-sequencing.

Carrier and Fixture Compatible

Lane rails and end stops are configured to locate steel carriers, foam-padded fixtures, or custom dunnage trays precisely at the pick face — supporting robotic and operator access without positioning fixtures on each cycle.

Cell-Level WIP Visibility

Lane-full and lane-empty sensors provide real-time WIP level data to the cell controller or MES. Supervisors see buffer levels at a glance without walking the floor to count containers.

Poka-Yoke Integration

Presence sensors in each lane can signal the cell controller to hold the next operation start if the previous operation did not return a container to the lane — preventing skipped operations and missed inspections.

RFID and Barcode Tracking

RFID antenna mounts and barcode scanner brackets at lane entry and exit log each sub-assembly as it moves through the WIP route — providing full genealogy traceability without paper travelers.

Buffer Sized to Your Cycle Time

Lane depth is calculated from the operation cycle times and planned WIP buffer for each cell. Modular Solutions delivers a cart that holds exactly the right number of containers — no over-buffering, no starvation.

Specifications

Frame Profile

45mm or 90mm aluminum T-slot extrusion

Caster Diameter

100mm–150mm swivel with 2 locking brakes

Carrier Compatibility

Steel carriers, foam fixtures, custom dunnage trays

Lane Sensor Options

Photoelectric presence, weight-based, or RFID

Tier Count

1–4 tiers per frame

Load Capacity

Up to 800kg total distributed load

Tracking Options

RFID antenna mount, barcode scanner bracket

WIP Buffer

Sized to operation cycle times and planned buffer level

Finish

Natural anodized aluminum; stainless hardware available

Applications

WIP flow carts support in-process material routing across a wide range of discrete manufacturing, assembly, and quality operations.

Cell-to-Cell Routing

Move sub-assemblies between production cells on a gravity-fed cart, maintaining build sequence and WIP visibility at each handoff point.

Assembly Line Buffering

Buffer inter-operation inventory at the assembly line with a defined lane capacity that prevents over-accumulation and line starvation.

Quality Hold Staging

Stage quality-hold containers in a dedicated flow cart lane with visual red-tag identification, isolated from the main production route.

Rework and Repair Routing

Route rework containers through repair cells on a dedicated WIP cart with FIFO tracking so oldest rework items are processed first.

Frequently Asked Questions

What makes a WIP flow cart different from a standard WIP cart?

A WIP flow cart has gravity-fed lanes on each tier instead of flat shelves. Sub-assemblies or containers are loaded at the rear and gravity-feed to the front pick position. This eliminates the operator reaching past work to retrieve a container and maintains FIFO sequence through the production route — which is especially important for date-coded components, serialized assemblies, or operations with first-fail-first-fix rework tracking.

Can WIP flow carts hold assembly fixtures or carriers in addition to containers?

Yes. WIP flow cart lanes can be configured to hold steel carriers, foam-padded fixtures, or custom dunnage trays. The lane width and rail height are set to match the carrier footprint. Locating pins or end stops position carriers precisely at the pick face for robot or operator access.

How are WIP flow carts identified and tracked through the production route?

Cart ID plates, RFID tag mounts, and barcode label holders are standard T-slot accessories. Scan points can be set at each cell entry and exit to log the cart and its contents through the route. Modular Solutions supplies the mounting hardware; the customer specifies or supplies the scanning and tracking system.

Can WIP flow carts be integrated with poka-yoke or error-proofing systems?

Yes. Presence sensors in the cart lanes can signal the cell controller when a container is removed or returned. If the correct container is not returned to the lane after the operation, the sensor detects the missing item and the cell controller can hold the next operation start. Sensor mounting brackets attach to the T-slot frame without welding.

How many WIP stages can one cart cover?

A three-tier WIP flow cart can typically buffer one to three operations depending on container size and cycle time. Carts are designed for the production cell's target WIP buffer — Modular Solutions calculates the required lane capacity from the operation cycle times and planned WIP levels specified by the customer.

Design Your WIP Flow Cart

Share your cell layout, container types, cycle times, and WIP buffer targets — we will design a cart that fits your route and keeps your production flowing.

Request a Quote