Chapter 6 Handling

6.3 Introduction to Handling

6.3.1 Role of Material Handling

Material handling involves short-distancemovement within the confines of a building or between a building and atransportation vehicle. It utilizes a wide range of manual, semi-automated, andautomated equipment and includes consideration of the protection, storage, andcontrol of materials throughout their manufacturing, warehousing, distribution,consumption, and disposal. Material handling can be used to create time andplace utility through the handling, storage, and control of material, asdistinct from manufacturing, which creates form utility by changing the shape,form, and makeup of material. Material handling is concerned with moving,storing, and controlling material. It covers a wide of range of applications,such as luggage handling at an airport or parcel handling by an overnightdelivery service. However, it is especially associated with parts flow inmanufacturing systems or warehousing/distribution systems, where controllingthe material flow and ensuring that parts (or unit loads) are available iscritical task. In some cases, it can be maintained that manufacturing anddistribution are predominantly materials handling activities (interrupted byprocessing of materials or pars/loads).

Material handling plays an important role inmanufacturing and logistics, which together represent over 20% of theU.S.economy,for instance. Almost every item of physical commerce was transported on aconveyor or lift truck or other type of material handling equipment inmanufacturing plants, warehouses, and retail stores. While material handling isusually required as part of every production worker's job, over 650,000 peoplein the U.S. work as dedicated "material moving machine operators" andhave a median annual wage of $31,530 (May 2012). These operators use materialhandling equipment to transport various goods in a variety of industrialsettings including moving construction materials around building sites ormoving goods onto ships.

6.3.2 Material Handling Systems

(1) Types of material handling

Manual handling. Manual handling refers to the use of aworker’s hands to move individual containers by lifting, lowering, and filling,emptying, or carrying them. It can expose workers to physical conditions thatcan lead to injuries that represent a large percentage of the over half amillion cases of musculoskeletal disorders reported in the U.S. each year, andoften involve strains and sprains to the lower back, shoulders, and upperlimbs. Ergonomic improvements can be used to modify manual handling tasks toreduce injury. These improvements can include reconfiguring the task and usingpositioning equipment like lift/tilt/turn tables, hoists, balancers, and manipulatorsto reduce reaching and bending. Using the exact conditions of the lift (height,distance lifted, weight, position of weight relative to body, asymmetricallifts, and objects that are difficult to grasp), six multipliers are used toreduce the maximum recommended weight for less than ideal lifting tasks.

Automated handling. Whenever technically and economicallyfeasible, equipment can be used to reduce and sometimes replace the need tomanually handle material. Most existing material handling equipment is onlysemi-automated because a human operator is needed for tasks likeloading/unloading and driving that are difficult and/or too costly to fullyautomate, although ongoing advances in sensing, machine intelligence, androbotics have made it possible to fully automate an increasing number ofhandling tasks. A rough guide to determine how much can be spent for automatedequipment that would replace one material handler is to consider that, withbenefits, the median moving machine operator costs a company $45,432 per year.Assuming a real interest rate of 1.7%.and a service life of 5 years for theequipment with no salvage value, a company should be willing to pay up to

(2) Handling systems

Materialhandling technology and equipment offer the potential for substantiallyimproved logistics productivity. Materials handling processes and technologiesimpact productivity by influencing personnel, space, and capital equipmentrequirements. Materials handling is a key logistics activity that can’t beoverlooked. While the technology details of materials handling technology areextensive and beyond the scope of this text, the following section discussesbasic handling considerations and alternative systems.

Handlingsystem can be classified as mechanized, semi-automated, automated, andinformation-directed. A combination of labor and handling equipment is utilizedin mechanized systems to facilitate receiving, processing, and /or shipping.Generally, labor constitutes a high percentage of overall cost in mechanizedhandling. Automated systems, in contract, attempt to minimize labor as much aspossible by substituting equipment capital investment. When a combination ofmechanical and automated systems is used to handle material, the system isreferred to as semi-automated. An information-directed system appliescomputerization to sequence mechanized handling equipment and direct workeffort. Mechanized handling systems are most common, but the use ofsemi-automated and automated systems is increasing. The main drawback toautomated handling is lack of flexibility. One factor contributing to lowlogistical productivity is that information-directed handling has yet toachieve its full potential. This situation has been dramatically changed duringthe first decade of 21st Century. Mechanized systems employ a widerange of handling equipment. The types of equipment most commonly used are lifttrucks, walkie-rider pallet truck, towlines, tractor-trailer device, conveyors,and carousels.