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50 SMT007 MAGAZINE I MAY 2018 3. Product running line CPH (PRLCPH). This represents the CPH potential of that product on that SMT line configuration when the line is running. PRLCPH = Product running line CPH LineCPH = Line CPH NCLM = Net CPH loss per machine 4. Percentage of line CPH capability (%LCC). This represents the percentage of line CPH capacity a product utilizes on that line config- uration. %LCC = Line CPH capability percentage PRLCPH = Product running line CPH LineCPH = Line CPH 5. Panel volume percentage (PV%). This is percentage of panel volume that product repre- sents relative to the total panel volume (TPV) in that plant. PV% = Panel volume percentage PPV = Product panel volume TPV = Total panel volume 6. CPH Category (CPHC). This is a weight assigned to a product based upon the %LCC that it utilizes when running. a. If %LCC < 25% CPHC = 10 b. If 25% < %LCC < 50% CPHC = 7 c. If 50% < %LCC < 75% CPHC = 3 d. If %LCC > 75% CPHC = 1 %LCC = Line CPH capability percentage CPHC = CPH category 7. Volume category (VC). This is a weight assigned to a product based upon the percent- age of panel volume that it represents. The total panel volume (TPV) is split into three segments: product panel volumes that repre- sent the top 40%, middle 40%, and bottom 20% of the total panel volume for that plant. a. Top 40% VC = 10 b. Middle 40% VC = 4 c. Bottom 20% VC = 1 VC = Volume category 8. (CPHC x VC) product. A product weight ranging from one to 100 that represents the volume and CPH utilization to rank the prod- ucts on that line. This is a prioritization factor; the larger the number the more potential impact relative to improving CPH utilization based on line configuration and its panel volume. 9. Product cycle time ratio (PCTR). A ratio of the observed cycle time (POCT) to the calcu- lated line constraint cycle time (LCCT) for a product. A PCTR greater than 1.0 represents a product running slower than its calculated potential. Ideally, this value would fall between 0.8 and 1.2 which represents the typical error in the model. PCTR = Product cycle time ratio POCT = Product observed cycle time LCCT = Line constraint cycle time Results & Conclusions 1. The machine and line models can be used to quickly evaluate the throughput and CPH utilization for an entire line to select the best machine. With additional tabulations, esti- mates can reflect the return on investment of replacing a machine. When replacing two SMT machines on an existing line, the line model estimated product run time would be reduced by 44 hours per month (32% reduction). 2. Using (CPHC x VC) and the product cycle time ratio (PCTR), an engineer can evaluate an entire plant by line to identify products with greatest improvement opportunity. When used to evaluate a SMT line, eight products with a large product cycle time ratio (PCTR) were identified and optimized, saving 136 hours of product run time per month (30% reduction).