manual material handling and ergonomics… two auto assembly case studies ccohs / cre-msd mmh...
TRANSCRIPT
Manual Material Handling and Ergonomics… Two Auto Assembly
Case Studies
CCOHS / CRE-MSD MMH Workshop
March 4, 2008
Wyatt Clark, CAW National Ergonomic Coordinator / Chrysler
Objectives
1) Overview of systemic MMH barriers to ergonomic interventions in the auto industry.
2) Two quick Case Studies of ergonomic “solutions” to some systemic MMH problems
3) Some discussion around how we “Get ‘Er Done”
4) Q&A
Systemic MMH Problems
• Vast majority of MMH barriers have TWO basic driving forces with each of those having a couple of complicating factors
1. Racking / bin design• Who owns the racking?• Transportation
Load density or ‘cubing’ of trucks
2. Real Estate1. Drives capital and fixed costs2. Affects productivity
Case Study 1 – General Part Delivery and Supply
• History lesson– The Old Days: parts arrive by truck in racks or bins
where they are unloaded by jitney and delivered directly to the assembly line or storage.
– The Not-So-Old days: JIT or Just In Time delivery attempted to solve real estate problems
– Today:• Small Lot Containers… an addition to JIT to squeeze more
real estate out of the system• More parts than ever are being shipped in including entire
subassemblies
Case Study 1 – General Parts Delivery
43”
18.5”
New problems Small lot delivery
adds a new level of human interface to a process done previously by machine
Some small lots can still have significant weight
How will this be managed?
Case Study 1 – General Parts Supply
New problems Small lot presentation lends
itself to an increased vertical configuration
Shelving creates hand access constraints
Have we simply shifted from a world of back postures to one of shoulder concerns
How will this be managed?
Case Study 1 - Final Resolve• Ergonomics involvement led to:
– Shelf height guidelines were determined based upon internal benchmarking and container sizes were standardized
– Recommendations provided for:• Generally:
– Totes to be loaded within a 30 lb target– Totes requiring loading beyond 30 lb target automatically trigger further
ergonomic analysis• Delivery Side (delivery dolly & gravity feed racks)
– Dolly shelves to be located at 19” and 43”– Dolly shelves to be no deeper than 25”– Maximum rack loading height is 62 in.– Totes which weigh >25 lb should be delivered to shelves no higher than 40” from
the standing surface• Supply Side (gravity feed racks)
– Assembly operator interface should be tiered ‘away’ to facilitate easy hand access to tote parts
– Bottom rack level is reserved for empty tote return only
Case Study 2 – Exhaust Assemblies
• Problem– Reaches are unacceptable under ergonomic
guidelines– The repetitive back postures to accomplish all
the vertical lifting were problematic– Lack of foot clearance compounds both the
above
Case Study 2 – Exhaust Assemblies
• Solution 1– Easy… redesign the rack!– Sorry… can’t be done!– Why?– The supplier owns the racks.
• Solution 2– OK… Easy… re-rack the parts in our own rack design– Added bonus… can schedule the exhaust assemblies
while re-racking• Minimizes long ‘carries’ of heavy parts• Saves real estate• Saves walking time
Case Study 2 - Final Resolve
• Ergonomics joint involvement led to:– New rack design and incorporation of a lift table for in-plant parts
presentation
• Exhaust assemblies are trucked from supplier to TDF Inc. where they are unloaded, re-racked in sequence, re-loaded and trucked to the assembly plant.– Pros
• New racks resolve ergo hazards• Sequencing allows
– Increased productivity… less walking– Decreased real estate needs
– Cons• Ergonomic hazards were simply transferred to TDF Inc. workers
Get ‘Er Done
• What negotiations were required to achieve the ergonomic resolves in the two case studies?
• Short answer – None!
• You don’t ‘negotiate’ unsafe… you solve it.
• Why don’t we negotiate?
Get ‘Er Done
• Part of the answer is legislation and part of it is contract.– Legislation by way of the H&S Act requires
joint participation– Unions have always desired some control
over their work environment and the decision making that goes on within it and have used labour contracts to achieve varying degrees of that.
• Part of the answer is “economies of scale
Get ‘Er Done
• In relative terms though, those things are the easy part… they simply create opportunities, nothing else
• The real answer to our question of “Why” is “Credibility” – the credibility of the people and processes involved our ergonomic program