© BMA Inc All rights reserved. Value Stream Capacity Understanding Value Stream Decision Making
© BMA Inc All rights reserved. Understanding Value Stream Capacity The production quantity that can be achieved at each step in the value stream or production process. There are usually one or two production steps (cells, machines, or work centers) that constrain the flow through the value stream or business unit. We need to identify the production capacity at each step in the value stream (or production flow) so that we can understand the flow through the entire process. Where is the data required for this analysis? –On the Value Stream Maps
© BMA Inc All rights reserved. Analyzing the capacity Productive capacity Value added activities Provides value to the customer Comes directly from customer pull Non-productive capacity Non-value-added activities Change-overs, unplanned maintenance, making for stock, defects/rework, etc. Also meetings, 5S, improvement activity Available capacity Capacity that is not currently being use for productive or non-productive activities.
© BMA Inc All rights reserved. OEM Value Stream Map SupplierCustomer Kanban Shipping S&OP Demand ForecastsPurchase Forecasts Order SupplierCustomer Shipping Assembly Welding 3,000 per Month Machine Shop Machine Shop Machine Shop Machine Shop Machine Shop Machine Shop Machine Shop Qty = 30,000 C/T = 70s Batch = 1500 Set Up = 10,800s Scrap = 10% Rework = 20% Downtime = 15% Inspection = 10% Insp Time = 120s # cells = 8 Crew Size = 4 # of people = 34 Shifts = 1 Qty = 15,000 C/T = 180s Batch = 600 Set Up = 1200s Scrap = 5% Rework = 10% Downtime = 5% Inspection=100% Insp Time = 30s # cells = 5 Crew Size = 1 # of people = 10 Shifts = 2 Qty = 3,000 C/T = 210s Batch = 20 Set Up = 600s Scrap = 0% Rework = 10% Downtime = 0% Inspection=100% Insp Time = 60s # cells = 2 Crew Size = 5 # of people = 10 Shifts = 1 Qty = 3,000 C/T = 120s Batch = 1 Set Up = 0s Scrap = 0% Rework = 2% Downtime = 0% Inspection=0% Insp Time = 0s # cells = 1 Crew Size = 1 # of people = 1 Shifts = 1 DATA BOXES
© BMA Inc All rights reserved. Cycle Time: How often a part or product is completed by a process. (or: the time taken for an operator to go through all his/her work elements before repeating them.) C/T Cycle time includes all processes VA & NVA Cycle time is measured by tracking it with a stop watch We match the cycle time to the customer takt time The process is under control if the cycle time is consistent Standard Cycle Time
© BMA Inc All rights reserved. Crew size - the number of people in the cell or operation required to produce to the cycle time recorded on the Value Stream Map # of cells = the number of cells running in parallel. Similar cells, working on the same products and performing the same process step. Crew size = 5 # of cells = 1 Crew size and number of cells
© BMA Inc All rights reserved. Calculate the Capacity for the Machine Shop SupplierCustomer Kanban Shipping S&OP Demand ForecastsPurchase Forecasts Order SupplierCustomer Shipping Assembly Welding 3,000 per Month Machine Shop Machine Shop Machine Shop Machine Shop Machine Shop Machine Shop Machine Shop Qty = 30,000 C/T = 70s Batch = 1500 Set Up = 10,800s Scrap = 10% Rework = 20% Downtime = 15% Inspection = 10% Insp Time = 120s # cells = 8 Crew Size = 4 # of people = 34 Shifts = 1 Qty = 15,000 C/T = 180s Batch = 600 Set Up = 1200s Scrap = 5% Rework = 10% Downtime = 5% Inspection=100% Insp Time = 30s # cells = 5 Crew Size = 1 # of people = 10 Shifts = 2 Qty = 3,000 C/T = 210s Batch = 20 Set Up = 600s Scrap = 0% Rework = 10% Downtime = 0% Inspection=100% Insp Time = 60s # cells = 2 Crew Size = 5 # of people = 10 Shifts = 1 Qty = 3,000 C/T = 120s Batch = 1 Set Up = 0s Scrap = 0% Rework = 2% Downtime = 0% Inspection=0% Insp Time = 0s # cells = 1 Crew Size = 1 # of people = 1 Shifts = 1 DATA BOXES
© BMA Inc All rights reserved. Step 1. Calculate the Total Available Employee Time (#employees x #days x Labor Hrs per shift) Step 2. Calculate the Employee Productive Time (Qty per Month x Cycle Time x Crew Size) Step 3. Calculate the Emp. Productive Capacity Percentage. (Employee Productive Time / Total Available Time) Step 4. Calculate the change-over time, scrap & rework time, downtime, inspection time. C/O = (quantity/batch size) x Change-over time Scrap/rework = (Qty produced / (1- (scrap + rework %) ) * (scrap + rework%) x Cycle Time x Crew Size D/T = Downtime% x Total Available Time Inspection= (Total produced + scrap/rework) x Inspection % x Inspection time Over-production = OP Qty x Cycle Time * Crew Size 5S & Clean-up = 5S Time x #Employees x #days Meetings = Meeting Time x #Employees x #days TPM = TPM Time per day * #days Step 5. Calculate the Total Non-Productive Time Sum of Step 4 Step 6. Calculate the Emp. Non-Productive Capacity Percentage Total Non-Prod Time / Total Available Time Step 7. Calculate the Emp. Available Capacity Percentage. 100% - (Prod. Capacity + Non-Prod Capacity) Calculate the employee capacity
© BMA Inc All rights reserved. Machine Shop Capacity - employees
© BMA Inc All rights reserved. Machine Shop Capacity EMPLOYEE CAPACITY Cell output is driven by Employee Time rather than Machine Time. There is more machine capacity than employee capacity MACHINE CAPACITY
© BMA Inc All rights reserved. Capacity Calculations when you have Multiple Product Families Calculate the weighted average of the cycle time, change-over, etc.
© BMA Inc All rights reserved. Value Stream Capacity Value Stream demand = 3,000 units/month Takt Time = 180 sec Average product has 5 welded sub-assy Average sub-assy has 2 machined components Machine Shop makes 30,000 items Welding Shop welds 15,000 sub-assy Assembly assembles 3,000 units Shipping ships 3,000 units Maximum Capacity is 3,000 units because Machine Shop can only make 30,000 parts