Question

KRM 6.12 Figure 6.15 provides a new current state value stream map for the family of retainers at the Jensen Bearings, Inc. firm described in Example 6.1. This map depicts the value stream after Kline Steel agrees to accept daily orders for steel sheets and Jensen Bearings continues to deliver the finished goods on a daily basis. Operators work 5 days/week, one shift/day, 8 hours per shift with two 30 minute lunch breaks. Figure 6.15 New Current State Value Stream Map at Jensen Bearings, Inc. 180/90/60/30/day 4-week Forecast Forecasts Kline Steel Co. PRODUCTION CONTROL GNK Enterprises 7 Daily Order Daily Order Weekly Schedule 2.500 pieces week -1,500 "L" -1,000 "S" Tray 50 pieces 1 shift 1x/Day Daily Ship Schedule 1x/Day PRESS PIERCE & FORM FINISH GRIND SHIPPING Staging Sheets 1 day 1050 "L 1200 "S" 250 "L" 1500 "S" 500 "L" 1200 "S" CT = 3 seconds C/O 2 hours Uptime = 100% 25,200 sec, avail 1 Shift CT = 22 seconds C/O = 30 minutes Uptime = 100% 1 Shift 25,200 sec avail. C/T = 35 seconds C/O 45 minutes Uptime - 100% 1 Shift 25,200 sec, avail Production b d Lead Time 3 seconds 22 seconds 35 seconds Processing Time Calculate each component of the new value stream's reduced lead time. 1. Takt time is ? 2. Press utilization is ? 3. Pierce & Form utilization is? 4. Finish Grind utilization is?

Answer 1

1. Customer's daily demand = 2500/5 = 500 pieces per day (since only 5 working days are available in a week)

Time available for production per day = 8 - 0.5*2 hrs = 7 hrs (only 1 shift per day with two 0.5 hr breaks)

Takt Time = (Net Time Available for Production)/(Customer’s Daily Demand)

= 7/500 = 0.014 hrs = 0.84 min = 50.4 sec

2. Utilization = (Planned Production time + changeover time) / Available time

Since we have to changeover from from "L" to "S" or vice-versa. There would be one change over per shift.

Changeover time = 2 hours = 2*60*60 = 7200 sec

Press Planned production time per day = cycle time * number of units per day = 3 * 500 sec =1500 sec

therfore, Press utilization = (7200+1500)/25200 = 0.3452 = 34.52%

3. Pierce & Form Planned production time per day = cycle time * number of units per day = 22 * 500 = 11000 sec

Changeover time = 30 min = 30*60 = 1800 sec

therfore, Pierce & Form utilization = (11000+1800)/25200 = 0.5079 = 50.79%

4. Finish Grind Planned production time per day = cycle time * number of units per day = 35*500 = 17500 sec

Changeover time = 45 min = 45*60 = 2700 s

therfore, Finish grind utilization = (17500+2700)/25200 = 0.8015 = 80.15%