6.3 Material Handling Systems and Equipment

Material Handling Equipment Types

Material handling systems cover all the equipment and methods used to move, store, protect, and control materials throughout a facility. Choosing the right system directly affects throughput, safety, and cost, so understanding the equipment categories and selection criteria is essential for layout design.

Transport and Positioning Equipment

Material handling equipment falls into four main categories: transport, positioning, unit load formation, and storage. Here's what the key transport and positioning types look like in practice:

• Conveyors move bulk materials or unit loads along fixed paths continuously. Belt conveyors work well for loose materials, roller conveyors handle boxes and cartons, and pneumatic conveyors use air pressure to transport powders or granules through enclosed tubes.
• Cranes provide vertical and horizontal movement of heavy loads. Overhead (bridge) cranes span the width of a bay, gantry cranes are freestanding and often used outdoors, and jib cranes rotate around a fixed column for localized lifting.
• Forklifts lift, carry, and stack palletized loads and are among the most versatile equipment in any facility. Counterbalanced forklifts are the standard type, reach trucks extend forks into deep racking, and order pickers elevate the operator to pick items at height.
• Automated Guided Vehicles (AGVs) are computer-controlled, wheel-based carriers that follow predefined paths (magnetic strips, wires, or laser guidance). Common types include tow vehicles, unit load carriers, and automated fork trucks.

Specialized and Auxiliary Equipment

• Industrial robots handle programmable tasks like palletizing, pick-and-place operations, and machine tending. They excel at repetitive, high-speed, or hazardous work.
• Automated Storage and Retrieval Systems (AS/RS) combine storage racks with automated cranes or shuttles to store and retrieve loads without manual intervention, improving inventory accuracy and space utilization.
• Sortation systems automatically divert items to specific destinations based on criteria like size, weight, or barcode data. Tilt-tray and cross-belt sorters are common in distribution centers.
• Vertical Lift Modules (VLMs) use an inserter/extractor to deliver trays of parts to an operator at an ergonomic height, providing high-density storage in a small footprint.
• Auxiliary equipment supports transfers between systems and includes dock levelers, pallets, containers, and stretch wrappers for load unitization.

Factors for System Selection

Picking the right material handling system isn't just about what moves the fastest. You need to balance product requirements, operational goals, and budget constraints.

Product and Operational Considerations

• Product characteristics drive equipment choices more than anything else. Size, shape, weight, and fragility all matter. A fragile glass component needs different handling than a steel billet.
• Throughput requirements set the needed capacity and speed. If a facility must move 500 pallets per shift, a single forklift won't cut it, but an AGV fleet or conveyor loop might.
• Flexibility matters when a facility handles a wide product mix or expects changing production volumes. Forklifts and AGVs adapt more easily than fixed conveyors.
• Environmental factors like temperature extremes, humidity, or hazardous materials restrict which equipment is suitable. Cold storage warehouses, for example, require specialized forklift batteries and lubricants.
• Ergonomics and safety should be evaluated early. Lifting aids, ergonomic workstations, and guarding around automated equipment all reduce worker strain and accident risk.

Economic and Facility Factors

• Total Cost of Ownership (TCO) goes beyond the purchase price. You need to account for maintenance, energy consumption, operator training, and downtime costs over the equipment's life.
• Return on Investment (ROI) compares the savings from improved efficiency against the initial capital outlay and ongoing expenses.
• Facility layout and space constraints directly influence what fits. A narrow-aisle warehouse might require reach trucks instead of standard counterbalanced forklifts.
• Integration with existing systems is often overlooked. New equipment needs to work with current conveyors, WMS software, and building infrastructure.
• Future expansion should factor into the decision. Choosing modular or scalable systems avoids costly replacements when volumes grow.

Efficient System Design

Layout and Flow Optimization

Good material handling design doesn't happen in isolation; it's tightly linked to facility layout. Several tools help you get this right:

1. Systematic Layout Planning (SLP) is a structured method that relates material flow volumes between departments to develop an optimal layout. Material handling paths are designed alongside the layout, not after it.
2. Material flow analysis uses tools like From-To charts (which quantify flow volumes between workstations) and spaghetti diagrams (which trace actual movement paths) to identify inefficiencies such as backtracking or excessive travel distances.
3. Unit load design determines the optimal load size and configuration. Moving 40 parts on one pallet is far more efficient than moving them individually, but oversized loads create their own problems.
4. Cross-docking and staging areas reduce storage time by transferring inbound materials directly to outbound shipping, minimizing handling steps.
5. Integration of handling equipment with storage systems (like connecting conveyors to AS/RS) creates seamless material flow and eliminates manual transfer points.

Design Tools and Principles

• Simulation modeling lets you test design alternatives digitally before committing capital. You can model throughput, identify bottlenecks, and compare scenarios using software tools.
• Lean manufacturing principles guide system design toward minimizing waste and excess inventory. Just-In-Time (JIT) delivery and kanban systems pull materials through the facility only as needed.
• Value Stream Mapping (VSM) charts every step in the material handling process, distinguishing value-added activities from waste, so you know where to focus improvement efforts.
• Warehouse Management Systems (WMS) coordinate and optimize material flow in real time, directing equipment and operators to the right locations.
• Modular design allows you to add capacity or reconfigure systems as production needs change, without replacing the entire setup.

Automation Impact on Operations

Productivity and Safety Enhancements

Automation in material handling replaces or assists manual tasks, and the effects show up across several dimensions:

• Labor productivity increases because automated systems handle higher throughput rates with fewer operators. An AGV fleet, for instance, can run multiple shifts without fatigue.
• Safety improves by removing workers from heavy lifting, repetitive motions, and close proximity to moving equipment. Injury rates in automated facilities tend to be significantly lower.
• Overall Equipment Effectiveness (OEE) can rise because automated systems operate continuously and consistently, reducing idle time and variability.
• Data collection from automated systems feeds continuous improvement. Real-time tracking of cycle times, error rates, and equipment utilization enables faster, better decisions.

Operational Considerations

• Capital costs for automated systems are typically much higher upfront than manual alternatives, but long-term labor savings and efficiency gains often offset this within a few years.
• Flexibility varies by system type. AGVs can be reprogrammed for new routes relatively easily, while a fixed conveyor sortation system is harder to reconfigure.
• Workforce impact is real. Automation shifts job roles from manual labor toward system operation, monitoring, and maintenance, which usually requires retraining.
• Reliability and uptime become critical. When an automated system goes down, there's often no manual backup, so preventive maintenance programs are essential.
• Integration challenges frequently arise when layering automation onto existing manual processes. Phased implementation and thorough testing help manage this transition.