BATTERY OPERATOR OVER TAKT TIME

RESULTS

❖ Space reduction: five percent reduction in floor space➢ Old: 2,015 in2

➢ New: 1,914 in2

❖ Battery assembly time reduction: ~39 second (5.6%) reduction➢ Cycle time is variable, 39 seconds represents an average reduction

❖ Work flow improvement: new process promotes better ergonomics,less walking and shorter part transport distances.

AGV INTEGRATION

Battery/Tiltback Stations Harness/Motor

Stations

➢ Iteration 3:■ Added boards for schedule

and quality check documents■ Moved drill holders■ Added battery tester holder■ Changed curvature of work

area opening ➢ Iteration 4:

■ Condensed materials into three stacked shelves

■ Moved schedule and documentation board

■ Decreased work area size

➢ Original Mockup: ■ Original design with rounded work

area■ Work area opening for operator■ Small parts shelf

➢ Iteration 2: ■ Tilted part shelves■ Centered tool shadow-board■ Work area size reduction■ Centered drill holders underneath

table■ Larger work area opening

Problem Explanation❖ Based on the Standard Work Distribution Chart, the Battery/EIA operator is over the

takt time❖ Exceeding the takt time can cause major delays and assembly line stoppages❖ Goal: Reduce battery operator cycle time so that he is under the takt time

Data Collection❖ Cycle time data: Observed a 31’48” average cycle time, 1’25” over takt time❖ Work sequence and spaghetti diagram: Identified problem cause - part shelves

and work table were in separate areas, causing the operator to waste valuable time by walking when parts were needed

Proposed Solution❖ Solution: Combined part shelves and work area to eliminate the need for the

operator to walk to retrieve parts❖ Based on collected data, we calculated measureable (target) goals for success

(Table 1).

Implementation❖ Built a wooden mockup workstation in order to validate our design and improve

work station ergonomics for the operator❖ Major iteration changes:

Genie Industries:Aerial Work Platform Assembly Line Improvement

Franklin Chang, Ian Docherty, Sean McElmurry, Hilcois Sunardi, Stephanie Wang | University of Washington

BACKGROUND: GENIE

Genie is a subsection of the Terex corporation that specializes in manufacturing exceptionally safe and reliable material lifts. Our project scope encompasses the Aerial Work Platform (AWP) production line. Specifically, the project revolves around using karakuri devices - structures that automatically unload parts using mechanical advantage - in cooperation with Genie’s Automatic Guided Vehicle (AGV) to deliver parts from material storage to the assembly line.

ANTICIPATED BENEFITS

❖ Reduction in walking distance and cycle time of material handler❖ Increased parts delivery using the AGV without delaying system functions

ACKNOWLEDGEMENTSWe would like to thank the following for their contributions to our project: Allan Baglin, Ankit Sharma, Josh Jasper, Christina Mastrangelo, Genie operators within the AWP production line

RESULTS AND FUTURE RECOMMENDATIONS

❖ Overall, our implemented solutions and proposed changes will help make the AWP line run more efficiently by integrating the AGV into the delivery of more parts and balancing workloads among all operators.

❖ Our functional wooden workstation has been implemented for several weeks. ➢ Battery assembly time has decreased, and the operator is under the current takt time. However, it is important to note that before our validation the takt time increased to 34’43” and resulted in a change of work sequences which made it difficult to accurately compare

work process times before and after the change.➢ In the steel model we intend the workstation to implement a scissor lift for adjustable table height➢ The iterative process of improvement through operator feedback can be applied to workstation layouts in other areas of operation to reduce physical space required and increase process ergonomics

❖ We have added six subassembly stations to the AGV delivery, removing the need for the material handler to manually deliver to one side of the AWP line. ❖ Future projects will include the remaining subassembly stations along the AWP line that currently require manual delivery of parts

➢ Continuing to add karakuri devices to automatically load and unload material from workstations will further reduce the need for manual delivery by the material handler➢ The expected reduction of walking distance if the material handler does not need to leave the material store is approximately 907 ft per cycle

❖ We recommend that Genie continue to monitor improvements by auditing assembly line operator cycle times to ensure that solutions not only reduce the material handler’s walking distance, but do not add significant work for individual operators

Explanation❖ Work area only involved two operators, creating the

simplest test environment for a new karakuri device❖ Goal: Remove the need for manual delivery of parts and

reception of empty bins by implementing a system that does both with minimal human interaction

Deliverables❖ New stationary two-tiered karakuri device for

workstation❖ Altered mobile karakuri cart for AGV❖ New part carrying tray for: four small bins, one battery

with cover, one charger, one motor cover

Implementation❖ Created tray designs to minimize space and center

weight❖ Created design sketches of karakuri system to model

delivery mechanisms and size❖ Built wooden mockup of tray, ensured all AWP parts fit❖ Built a functional, creform model of workstation karakuri❖ Altered current AGV cart to deliver/receive parts from

workstation karakuri❖ Tested delivery and reception within karakuri system

using the tray mockup with and without the battery part

Metrics per Cycle Initial Target

Average Operator Cycle Time 31’48” 30’23”

Walking Time(Battery station only)

1’11” 0

Parts Transport Distance Estimate 45.83 ft minimize

Total Walk Time (Battery-EIA) 3’57” 2’46”

Workstation Mockup Iterations

Metrics per Cycle

Initial Future Percent Reduction

Walking Distance 1493.5 ft 1249.5 16.34%

Cycle Time 25’43’’ 23’53’’ 7.13%

Explanation❖ The SWIP (standard work in progress) cart

(detachable cart from AGV carrying parts and materials) is passed through three work areas in every cycle time: Mainline 1, Mainline 2, and Motor stations.

❖ Goal: Remove the need for manual delivery of parts and materials as well as pickup of empty bins by improving and modifying the current SWIP cart.

Deliverables❖ Modified SWIP cart that includes a shelf for the

automated delivery and pickup of materials, and empty bins. This shelf includes two holding trays for bins that carry parts.

Implementation❖ Identified areas on current system to improve or

modify❖ Created designs of holding trays and shelf,

ensured adequate fitting of multiple bin sizes❖ Built wooden mockup of bottom shelf and holding

tray for parts❖ Tested delivery and reception of holding trays on

the SWIP cart

Figure 5. New work sequence.

OPPORTUNITIES

Battery Operator Over Takt TimeAccording to the standard workload distribution chart in Figure 2 below, the Battery/EIA operator’s workload puts him over the takt time. This can cause the operator to get behind on an average cycle, requiring help from other operators or causing delays in the production line. Finding a solution to lower the Battery/EIA operator’s cycle time to takt would create a smoother production flow.

AGV IntegrationGenie currently utilizes an AGV to reduce the walking distance of the material handling operator by automatically delivering certain parts each cycle to select subassembly areas. Materials in small parts bins at each subassembly workstation are restocked through a kanban system that requires the material handler to collect and redistribute these bins manually each cycle. Integrating small parts delivery and increasing the number of subassemblies served by the AGV would further reduce the material handler’s walking distance.

INITIAL STATE OF THE SYSTEMThe AWP assembly line consists of 15 subassembly stations that feed into one main line as seen in

Figure 1 below. These subassembly stations exist to produce specific parts of the AWP which are then installed on the main line.

Each cycle:❖ Takt time: 30’ 23”❖ 11 operators across the assembly line have individual standard work sequences❖ One AGV assists in delivering parts to the assembly line ❖ One operator in the material market:

➢ Loads parts from the market to the AGV➢ Manually delivers additional parts to the assembly line ➢ Walks around the assembly line to restock small parts (screws, bolts, etc)

Figure 1. Layout of the AWP assembly line.

Figure 2. Standard workload distribution (Yamazumi) chart.

Data Collection: ❖ Cycle time of each operator, each subassembly line and main line❖ Layout of the AWP assembly line and AWP market❖ Standard work of each operator❖ Part usage and spaghetti diagrams of targeted areas

Figure 4. Workstation mockups from initial iteration to final implementation

Figure 3. Original work sequence of battery workstation.

Table 1. Target results

Table 2. Anticipated reductions for material handler.

Figure 6. (Left) Initial battery station karakuri device. (Right) Current karakuri device for all battery station parts.

Figure 7. (Left) Initial state of SWIP cart. (Right) Modified state of the SWIP cart for delivery and pickup of materials.

The Standard Workload Distribution bar chart above displays the total amount of time each operator spends during each cycle, as shown with the 6 column model (the most time consuming model). This chart functions as a guide to show how workload is balanced among operators.