Once you are happy with the calendar and want to generate (or adjust) the level schedule for each part, click one of the major tabs labeled Shift 1, Shift 2, … All Shifts. An example of one of the frames is shown above.
Initially the scheduling frames in the Level Mix Workbench will show only the already scheduled work for the process. Click the Recalculate button, however, and the system will calculate a leveled schedule for each of the items. Only those periods that are beyond the Time Fence Days will be scheduled.
Each date from the current date through the end of the selected horizon is shown on the left. In the header row above these dates you can see the individual items that have been scheduled. In each cell, you can see the quantity scheduled, and to the right is the summary (hours and quantity) by date and at the bottom, the quantity scheduled for each item against the target schedule.
You can override the schedule by maintaining it directly. The cells in the display above that are shaded yellow are open to change. After changing the schedule, click Recalculate Totals Only and the system will update totals by part and by date.
This allows you to do the necessary fine-tuning and tweaking. And once you’ve done that, you can push that information back down, into flow schedules that will drive supplier schedules.
Scheduling Logic in the Level Mix Workbench
The level scheduling logic in the system has several parts:
• Scheduling at takt time.
• Quantity scheduled based on EPE Interval.
• Sequencing of work based on product wheel considerations or the number of operators required to meet takt time.
Product wheel sequencing handles situation where there’s a fixed processing sequence for products. For example, color or flavor based sequencing is a type of product wheel. In chemical plants producing polyester film, the product wheel might be based on product type (polymer), film width, film thickness.
When the number of operators in the cell varies based on the work content, it doesn’t typically make sense to float operators in and out too frequently. Consequently, an alternative might be to base the sequencing on the number of operators with all the five operator jobs first and then the ones that require four, and then three, and then two, and then one. Alternatively, you can sequence it the other way around, where you want the fewest number of operators first and the higher number of operators last. If you have a well cross-trained workforce, you might set up two different processes with the opposite rules for sequencing: one with ascending operators and the other with descending operators. This way, one process will free up operators just as the other needs them.
The workbench is a tremendous help in leveling both mix and volume. However, many times users have already invested a lot of time and effort into building their own Excel spreadsheets to provide these same functions. Here there can be similar, comfortable tools but no easy way to get the data from the core ERP system into the spreadsheet, or back out when the leveling is over.
QAD Lean provides functions to help with this problem. Specifically, the system provides an export program that you can export the data and load that into your Excel spreadsheets, and an import program to get the data out of the Excel spreadsheet and import it back into QAD Enterprise Applications.To use these functions, all that is required is that you modify your spreadsheets to:
• Read the imported data from a specifically formatted comma delimited format.
• Write data that is coming back to QAD Lean to a specifically formatted comma delimited format.
Supermarket Workbench
The Supermarket Workbench provides a picture of inventory performance into the future. In effect, it allows you to evaluate the amount of inventory that you're carrying at the supermarket compared to the future demand and your planned level schedule for material coming into that supermarket. If future demand is level, the leveled production schedule will be able to cover it with minimal inventory. However, if the future demand for an item is spiky—perhaps because of the nature of your customers and markets, or perhaps because you create the condition through promotions or other marketing initiatives—you’ll need to verify that the amount of inventory is sufficient to absorb peak demand without backorders. Having a perfectly leveled schedule and minimum variability in manufacturing is a fine objective, but if it ends up causing missed deliveries, backorders, and upset customers then it’s hard to put a positive spin on it.
Leveling is just one part of effective master scheduling. The other part is supply/demand
balancing. To give the best customer service, supply and demand must be in balance. To achieve maximum profitability with minimum disruption in manufacturing, the schedule must be level, at least in terms of volume, and ideally in terms of mix of product to be produced. The Level Mix Workbench provides a mechanism to ensure that the schedule has been leveled and meets demand over the leveling horizon. The Supermarket Workbench is one tool in the system to help verify that supply meets demand by date.