SeedTactic: Planning supports four different manufacturing strategies that can be divided into two types:
Assembly or labor-limited process: In an assembly line or a labor-limited process, you purchase enough machines and tools to keep the assembly line moving or the labor busy. The main question is how many machines are needed so that you purchase enough but not too much capacity.
Machine-limited process: A machine-limited process is more complicated, since there are capital vs labor trade-offs as a result of material handling increasing station efficiency. Automated handling can increase station efficiency, lower the number of machines required, and reduce labor but create management and overhead costs.
In Stage 2, various strategies are investigated and compared and by the end of Stage 2, a manufacturing strategy is selected.
Manufacturing Strategy Card
The Manufacturing Strategy card lists the four manufacturing strategies supported by SeedTactics: Planning. The outcome of Stage 2 is to select one of the four strategies. If you are investigating an existing system and already know the manufacturing strategy, you can just select it and move to Stage 3. If you have a machine-limited process but want to compare the three possible machine-limited strategies, click the "Help me choose" button and for now can leave the manufacturing strategy unselected.
Assembly or labor-limited process: If you have an assembly or labor-limited process, you can just select it here and move on to Stage 3, where the details of the process will be investigated.
Machine-limited process with manual operation: In this strategy, parts are manually moved from machine to machine and manually loaded and unloaded into each machine.
Machine-limited process with an automated handling system: This strategy consists of an automated robotic cart which loads and unloads the machines and maintains a buffer of pallets. Operators interact with the handling system via a dedicated load/unload station.
Machine-limited process with an automated handling system and robotic loading: This strategy also uses an automated robotic cart which loads and unloads the machines and maintains the buffer of pallets (typically the same automated system as the previous strategy). Instead of manually loading and unloading material into the automated handling system, a separate robot loads and unloads material into and out of the automated handling system.
Ideal Manufacturing Cost Card
The Ideal Manufacturing Cost card contains inputs that will be used below to compare manufacturing strategies. For each strategy below, we use the costs entered in this card to compute an ideal manufacturing cost for the specific scenario.
- Cost/Year: The cost/year for each workcenter is the depreciation cost of a single station. The cost/year is multiplied by the number of stations and then scaled to the project horizon to obtain the station cost component of the ideal cost.
- Cost/Operating Hour: The cost/hour for each workcenter is the cost of operating a station for an hour. The total production and part flow times from Stage 1 are multiplied by the cost/hour to obtain the operating component of the ideal cost. The cost/hour can include electricity, consumables, or even an average tool cost.
- Wage/Hour: The wage per hour per operator is the total cost of a single operator for one hour. It is multiplied by the number of operators, the number of hours per day, and the total days to obtain the labor component of the ideal manufacturing cost.
Horizon in Scenarios 1, 2, and 3
The horizon is the number of operating days and the number of hours/day. They are initially set from the horizon chosen from Stage 1 but you can vary them here independently for each manufacturing scenario. Machines come in big chunks of capacity so you can be in a situation where five machines is not enough capacity and six machines is too much, but by altering the horizon slightly (e.g. skip weekends or only two shifts/day) you can make effective use of all stations. The variety of manufacturing scenarios provides even more ability to tune station utilization, so each scenario can use a slightly different horizon.
Workcenters and Stations in Scenarios 1, 2, and 3
In each scenario, there is a list of workcenters (located on the right under the heading Labor Assignment). For each workcenter, you can enter a count. Each station is assumed to be identical and parts will visit exactly one of the stations. (In Stage 3, parts can be assigned to specific stations.) The workcenter also lists the utilization, which is the percentage of time that each station is busy. The utilization is calculated using Little's Law. From our experience working with existing systems, about 60-65% Little's law utilization is realistic for manual handling, 80-85% utilization for an automated handling system, and about 90% for robotic loading.
The utilization can be influenced in several ways: change the station count, change the number of hours per day, change the total number of work days, change the part goals in Stage 1, or finally change the cycle times in the part flow. The goal is to adjust station quantities and the horizon to target 60%-65% utilization for manual handling, 80%-85% for automated handling, and 90% for robotic loading.
Labor Assignment in Scenarios 1, 2, and 3
In each scenario, there is a list of labor teams and the ability to assign labor teams to stations (located under the heading Labor Assignment). A labor team is a group of operators who work together; any operator in the team can perform any task assigned to the team. To assign a labor team to a station, use the dropdown box in the list of workcenters. Each labor team shows the utilization, which is the percentage of time that a single operator is working at an assigned station. The labor utilization is calculated by summing of station utilizations and dividing by the number of operators.
The utilization can be influenced by changing the station utilization, changing the number of operators, or changing the labor assignment. The goal is to adjust the team assignment so that each team is loaded at around 60%-80% utilization (to allow for breaks and other tasks).
Ideal Manufacturing Cost in Scenarios 1, 2, and 3
The header of each scenario card shows the calculated ideal manufacturing cost. The ideal manufacturing cost has several components:
- Station Yearly Cost: take the cost/year times the station count for each workcenter, and scale this from a yearly cost to the project horizon.
- Station Operating Cost: take the total time the station is actually busy and multiply it by the cost/operating hour
- Labor Cost: for Scenarios 1 and 2, take the total number of operators times the wage rate/hour times the hours per day times the total days. For Scenario 3, the wage rate/hour is not used because robots are used instead.
- Automation Cost: for Scenarios 2 and 3, you can enter a cost/year of the handling system (located inside the Scenario card). This cost is scaled from a yearly cost to the project horizon.
The result is an ideal manufacturing cost which is the cost of capital and labor for the project horizon. We encourage you to not read too much into this cost (a more detailed cost-study is in Stage 4). The ideal manufacturing cost is primarily intended to be used to compare between the three scenarios.