Equipment Availability Analysis Fred Schenkelberg, FMS Reliability Angela Lo, Kaiser Permanente
Overview• Bottling line – Multiple bottle sizes – Multiple flavors• Build to finished goods inventory – Mixed shipments of FG to distribution centers – Daily shipments – Broad variation in demand of bottle size and flavor
Introduction• Throughput directly related to inventory size• Inventory is expensive• Goal is to improve the throughput to equipment capabilities seen over long runs to short runs. How much inventory reduction is possible?
Existing Analysis• The filler (bottleneck) has the following values Given a 400 bottles / min equipment average capability
Desired Improvement• (Anecdotally) the line runs better over time• Improve the analysis to calculate MTBF over various length runs• Make the calculations time dependant
General Renewal Process• Assumptions – Time to first failure is known (Weibull) – Time to repair is negligible relative to runtime.• Permit modeling of repairs that are between – As good as new – As bad as old
New MTBF Values Length of run 120 240 480 960 1440 (minutes) Cumulative 7.17 9.29 11.56 13.26 14.16 MTBFInstantaneou s 20.75 26.53 32.57 37.45 34.72 MTBFThe long term MTBF value is 45.6, resulting in approximate2.63 minutes to build 1000 units. Building the same inventoryfaster, permits the inventory reduction.
Results Length of run 120 240 480 960 1440 (minutes)Time to build 3.53 3.33 3.19 3.12 3.09 1000 units%Improveme nt 25.5 20.9 17.5 15.6 14.7with 380/minFor a 4 hour run (240 minutes) if the equipment is improved toa 380/minute throughput, there is at least a20% inventory reduction
Summary & Conclusion• Using the GPP model to estimate MTBF for various run time and calculate throughput• The possible throughput improvement costs can now be balanced with potential cost savings• The improved performance visibility encouraged a study of the shift change and restart behavior
Contact InformationFred SchenkelbergReliability and Management Consultantwww.email@example.com+1 (408) 710-8248