Efficient Material Transportin Lean Production

The Drive & Control Company

Avoiding waste with lean production

The global trend towards “lean production” continues to gain strength.This manufacturing concept provides an optimum framework for efficient,competitive production and is based on a philosophy of consistentwaste avoidance.

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Lean production and automation:a contradiction in terms?

Today, lean production is usually associatedwith manual production systems. Suchsystems are currently in trend and are suc-cessfully integrated into numerous assemblyprocesses and in various sectors of industry.Lean production does not, however, elimi-nate automated transport. Transferringparts manually can cause a drop in quality,for example, or a loss of valuable timeresulting in an increase in per piece costs.Finding the most economically efficienttransport solution depends on the followingproduction factors:• Batch size and variety of models• Production cycle time • Part weight and size• Takt time

How to become “lean”:• Reduce inventory• Eliminate downtime• Reduce space requirements• Avoid errors• Avoid inefficient processes• Avoid overproduction• Shorten transport routes

When does automation make sense?

Automated production or, in other words, the automated transfer of parts, is always the rightchoice if one can cut costs and increase process reliability in comparison to a manual solution.The savings gained through automation must offset the higher investment costs. Of course, inmany situations, the best solution is a combination of manual workstations linked by automaticsystems. Finally, certain production processes are simply economically “unautomatable” – forexample when quantities are too small or the product mix changes too frequently.

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Uncertain quantity requirements

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Automated production cell,not linked

Manualproduction system

Flexible modular system:add automation as needed

Fully automatedcomplete solution

Selecting the most suitable production system: the decisive factors are product quantities and variants as wellas the predictability of these requirements.

Predictable quantity requirements, high quantities

Manual, hourly rate of 30 €Manual, hourly rate of 5 €

Pick & placeTransfer system

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0.02 €

0.01 €

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Efficient transport ensureseconomical production Each production process involvesmaterials or workpieces which aretransported from point A to pointB. However, as no value is addedto the product during transport,investments in this part of theprocess chain are usually ruled outfrom the outset. This is a seriousmistake: the manual forwarding ofparts from one station to the next,as well as the coordination ofindividual production processes,represents a critical factor in termsof time and cost. Therefore, theefficiency of a transfer system isalso a key factor in assessing theeconomic viability of a productionsystem.

Cost comparison of individualsystemsThe diagram above compares thecosts per transfer cycle of a manualmaterial transfer system, a “pick &place” solution and an automatedtransfer system. For both of theautomated solutions, the compari-son assumes a straight-line depre-ciation over a period of five yearsand 3500 operating hours per year(two-shift operation).Under these conditions, with a10 kg part weight, the manualsolution performs well with cycletimes > 35 sec – however, thisapplies only to low-wage countries.Automated transfer systems clearlyrepresent the most cost-effectivesolution when shorter cycle timesare required.

Other advantages of automatedtransfer systemsAvoiding overproduction• Transfer systems can be used to

regulate production cycles, sup-

0 10 s 20 s 30 s 40 s 50 s 60 s 70 s

port lean production flow princi-ples and ensure continuousproduction based on the volumeof customer demand.

Accelerating production• Reduces transfer and handling

time in comparison to manualtransport

Higher, more consistent productquality• Better protection of product sur-

faces and exact precision duringparts processing, due to the stableposition of the workpiece on thepallet

Flexible application range• Able to transport extremely

small, very sensitive, and evenvery large products safely

• Easily integrated into existing –even manual – production lineswithout difficulty

• Easy to expand or adapt tochanging production require-ments

■ Current situation■ Future trend

100 g 1 kg 10 kg 100 kg Product weight

Market

Current manufacturing trends leantoward extremely small, lightweight

products on the one hand, and towardheavy components and modules on

the other. Automated transfersystems can be used effectively in

both areas of production.

Cycle time

Costs per transfer cycle

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Costs dependingon the cycle time

Rexroth – the “lean recipe” for your production

Regardless of industry segment, product, quantity, or manufacturing technique, Rexrothalways offers the most efficient, most cost-effective solution for your production. WhetherManual Production Systems, or automated transfer or handling systems – we have the rightproducts for every situation, and the relevant know-how to make your manufacturing leaner.

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No two systems are the sameFor the reasons mentioned above,there is no easy answer as to whichis the most efficient transportsolution to ensure lean production.A rash decision against automationwithout a careful evaluation of its

potential benefits risks causingwaste – and this is exactly whatlean production seeks to avoid.Individual factors throughout theproduction process must be con-sidered carefully before a decisionis made – whether in favor of

manual parts transport or auto-mated parts forwarding via transferor handling systems.

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Rexroth – everything you need for lean productionWe will gladly help you find the right systemto meet all your requirements by offeringcompletely neutral and objective support.At Rexroth, you can profit from our knowledgethat goes far beyond single-system solutions,

and from a range of products which covers allaspects of lean production. Whether manualproduction or automatic transport systems –we have the solution you need.

Increasing levels of automation in production:From manual workstations to interlinkedworkstations with EcoFlow, to the VarioFlowworkpiece pallet system and the TS 2plustransfer system

US

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