Manufacturing formulas explained with worked examples.

Manufacturing formulas explained

• Cycle Time Formula. Cycle time = net available time / units produced. See what each variable means, a worked 21.5 s/unit example, and the live cycle time calculator.
• Takt Time Formula. Takt time = net available time / customer demand. See what each variable means, a worked 30 s/unit example, and the live takt time calculator.
• OEE Formula. OEE = availability × performance × quality. See what each variable means, a worked 73.6% OEE example, and the live OEE calculator.
• Throughput Formula. Throughput = good units / available time. See what each variable means, a worked 126.7 units per hour example, and the live throughput calculator.
• Line Balance Efficiency Formula. Line balance efficiency = total work content / (stations × bottleneck time). Variables, a worked 82.1% example, and the live line balance calculator.
• Conveyor Speed Formula. Conveyor speed = parts per minute × part pitch. See what each variable means, a worked 10 ft/min example, and the live conveyor speed calculator.
• Shift Capacity Formula. Shift capacity = planned cycles × units per cycle × uptime × yield. Variables, a worked 1,338-unit example, and the live shift capacity calculator.
• Machine Utilization Formula. Machine utilization = run time / available time. See what each variable means, a worked 81.25% example, and the live machine utilization calculator.
• Unit Cost Formula. Unit cost = material + labor + overhead + setup per unit + scrap allowance. A worked $4.27 per good unit example and the live unit cost calculator.
• Labor Cost Formula. Labor cost per part = operators × loaded rate × cycle time / 3,600. A worked $0.70 per part example and the live labor cost calculator.
• Machine Hour Rate Formula. Machine hour rate = annual ownership cost / available hours. Variables, a worked $7.94 per hour example, and the live machine hour rate calculator.
• Break-Even Quantity Formula. Break-even quantity = fixed cost / (selling price - variable cost per unit). A worked 2,667-unit example and the live break-even quantity calculator.
• Quote Margin Formula. Gross margin % = (selling price - cost) / selling price × 100. See each variable, a worked 28.4% example, and the live quote margin calculator.
• Markup Formula. Markup price = cost × (1 + markup %). See what each variable means, a worked $9.52 selling price example, and the live markup calculator.
• Machining Cost per Part Formula. Cost per part = setup cost / quantity + variable cost per part. A worked $13.40 per part example and the live machining cost per part calculator.
• Welding Cost per Part Formula. Welding cost per part = variable cost per part + setup cost / parts. A worked $6.40 per part example and the live welding cost per part calculator.
• MTBF Formula. MTBF = total operating hours / number of failures. See what each variable means, a worked 600-hour example, and the live MTBF calculator.
• MTTR Formula. MTTR = total repair hours / number of repairs. See what each variable means, a worked 3.5-hour example, and the live MTTR calculator.
• Equipment Availability Formula. Availability = run time / planned production time × 100. Variables, a worked 90.6% example, and the live equipment availability calculator.
• Downtime Cost per Hour Formula. Downtime cost = lost revenue per hour + labor waste + scrap and restart cost. A worked $5,100 an hour example and the live downtime cost per hour calculator.
• Bearing Life Formula. L10 (hours) = basic rating life × speed factor × load factor. See each variable, a worked 4,110-hour example, and the live bearing life calculator.
• Failure Rate Formula. Failure rate = number of failures / total operating hours. A worked 0.000286 failures per hour example and the live failure rate calculator.
• Compressed Air Cost Formula. Annual cost = hp × 0.746 × load factor × run hours × electricity rate. A worked $30,213 per year example and the live compressed air cost calculator.
• First Pass Yield Formula. First pass yield = units passed first time / total units started. Variables, a worked 90.8% example, and the live first pass yield calculator.
• Scrap Cost Formula. Total scrap cost = scrap units × cost per scrapped unit. See what each variable means, a worked $1,020 example, and the live scrap cost calculator.
• Defect Rate and PPM Formula. Defect rate = defects / units inspected. See what each variable means, a worked 0.72% (7,200 PPM) example, and the live defect rate calculator.
• Rework Cost Formula. Rework cost = reworked units × rework time × loaded labor rate + extra material. A worked $782 example and the live rework cost calculator.
• Rolled Throughput Yield Formula. RTY = step 1 yield × step 2 yield × ... × step N yield. See each variable, a worked 85.8% example, and the live rolled throughput yield calculator.
• Sigma Level Formula. DPMO = defects / (units × opportunities per unit) × 1,000,000, then look up the sigma level. A worked 3.76 sigma example and the live sigma level calculator.
• Process Capability Cpk Formula. Cpk = min((USL - mean) / 3 sigma, (mean - LSL) / 3 sigma). A worked Cpk 1.11 example and the live process capability Cpk calculator.
• Packaging Cost per Unit Formula. Packaging cost per unit = total packaging cost / units packed. A worked $1.50 per unit example and the live packaging cost per unit calculator.
• Cartons per Pallet Formula. Cartons per pallet = cartons per layer × layers per pallet. Variables, a worked 48-carton example, and the live cartons per pallet calculator.
• Pallet Utilization Formula. Pallet utilization = load cube used / pallet cube available. Variables, a worked 80% example, and the live pallet utilization calculator.
• Dimensional Weight Formula. DIM weight = (length × width × height) / DIM divisor. Variables, a worked 22 lb billed weight example, and the live dimensional weight calculator.
• Freight Cost per Unit Formula. Freight cost per unit = total freight cost / units shipped. A worked $1.43 per unit example and the live freight cost per unit calculator.
• CNC Feed Rate Formula. Feed rate = spindle speed × number of flutes × chip load per tooth. A worked 96 IPM example and the live CNC feed rate calculator.
• CNC Spindle Speed Formula. Spindle speed (RPM) = surface speed × 12 / (pi × tool diameter). A worked 2,673 RPM example and the live CNC spindle speed calculator.
• Material Removal Rate Formula. MRR = width of cut × depth of cut × feed rate. See what each variable means, a worked 7.2 in³/min example, and the live material removal rate calculator.
• Chip Load Formula. Chip load = feed rate / (spindle speed × number of flutes). Variables, a worked 0.00267 in/tooth example, and the live chip load calculator.
• Weld Heat Input Formula. Heat input (kJ/in) = volts × amps × 60 / (travel speed × 1,000). A worked 21.6 kJ/in example and the live weld heat input calculator.
• Weld Deposition Rate Formula. Deposition rate = wire feed speed × wire weight factor × deposition efficiency. A worked 11.7 lb/hr example and the live weld deposition rate calculator.
• Setup Cost Formula. Setup cost = setup time × (labor rate + machine rate) + outside setup cost. A worked $435 example and the live setup cost calculator.
• Energy Cost per Part Formula. Energy cost per part = machine kW × run hours × $/kWh / good units produced. A worked $0.015 per part example and the live energy cost per part calculator.
• Compressed Air Leak Cost Formula. Annual leak cost = leak CFM × energy cost per CFM × operating hours. A worked $3,240 per year example and the live compressed air leak cost calculator.
• Motor Efficiency Savings Formula. Annual savings = kW × hours × (1/old efficiency - 1/new efficiency) × $/kWh. A worked $2,016 a year example and the live motor efficiency savings calculator.
• Equipment Lifecycle Cost Formula. Lifecycle cost = purchase cost + annual operating cost × years - residual value. A worked $388,000 example and the live equipment lifecycle cost calculator.
• Safety Stock Formula. Safety stock = Z × standard deviation of demand × square root of lead time. A worked 396-unit example and the live safety stock calculator.
• Economic Order Quantity Formula. EOQ = square root of (2 × annual demand × ordering cost / holding cost rate). A worked 894-unit order example and the live batch size calculator.
• Inventory Turns Formula. Inventory turns = cost of goods sold / average inventory. Variables, a worked 6.0 turns per year example, and the live inventory turns calculator.
• Reorder Point Formula. Reorder point = average daily demand × lead time + safety stock. See each variable, a worked 1,090-unit example, and the live reorder point calculator.