MPS planning of finished products output
The master production schedule (MPS or MPS project) is formed as a result of reconciliation of the medium-term and short-term sales plans with the medium-term and short-term production possibilities.
MPS plan is formed on the basis of:
- sales forecast
- orders from customers
- finished products on stock
- information of orders put into production
- required amount of reserve stock, etc.
MPS production planning allows to calculate the required product output volumes, production startup and finished products release dates while considering reserve stock. In addition, the MPS plan will evaluate product shipment dates based on SOP quotas for sales and production plan.
In most companies the MPS plan corresponds to product output plan or manufacturing plan for dedicated items of the product (assembly units or parts – the video tutorial at the link below features the latter).
The MPS production plan can be generated according to different positioning strategies:
- Made to order (MTO)
- Assembly to order (ATO)
- Made to stock (MTS)
MPS plan in Clobbi is a rolling one, i.e. new orders are included as soon as available (in practice, normally once or twice a week or on a daily basis) and planning covers the period from the current date to the date of release of all orders accepted for production. Here, the planning horizon is rolling and is continuously moved forward.
Quarterly and monthly rough-cut capacity planning – planning of needs of production in machinery and labor resources (RCCP) is done based on MPS plan.
MRP production scheduling by shops and operations
Once all production orders are introduced into the MPS plan, one can proceed to calculation of the detailed version of the master production schedule with regard to parts and operations i.e. material requirement planning or the MRP plan.
MRP production planning is based on the MPS plan and production technology and includes:
- Parts plans and schedules or parts & operations plans for manufacture and transfer of parts and assembly units between shops/areas, which allow for complex process routes: “loops” – situations when parts return to a shop for another run, outsourcing certain operations to other companies, etc.
- Plans and schedules for requirement, supply, delivery of materials and components to warehouses, shops and areas from the central warehouse.
Operations production plans will normally be created with allowance for materials and components in the shops and areas as well as work-in-process inventory in the shops, with the plans adjusted accordingly.
The most recommended way of MRP planning is single-level rolling job-order production planning intended for making continuous (“rolling”) plans based on production orders. In this approach the plan is continuously replenished and products of the same type, being a part of different orders, are treated as planning and inventory items.
In single-level MRP production planning the company’s master planner plans all transfers and process operations by departments. Depending on production conditions, the single-level planning may employ different tools:
- Constrained MRP production planning
- Constrain-independent MRP and CRP production planning
- Constrained planning and scheduling for optimization by production management (APS/MES planning)
The key element of job-order production planning and accounting is to identify the “orders linkage” points – production stages planned and recorded by orders as well as stages planned and recorded by nomenclature. Clobbi offers flexible settings for linkage of manufacturing (assembly) and blank production shops/areas, allows to select nomenclature (e.g. standard specifications and in-house unification) in order to exclude it from job-order planning. The method of keeping records of production plans execution will depend on the specifics of production and the planning model applied, with the main options here being as follows:
- by direct indication of the production order number in the documents
- by automatic posting of completed parts operations to production orders according to their manufacturing priorities
A convenient way of keeping part plans records is analysis of planned and actual production, where job (production) order content is represented as a so-called job “tree”.
APS/MES optimization production planning prior to work center
APS/MES production planning offers the benefit of effective implementation of MPS and/or MRP production plans by optimization of machinery operation. Optimization leads to timely order delivery with minimum delays or discrepancies, if any, better capacity utilization, reduction of backlog and downtime between operations, overall production cycle time reduction, thus increasing the company’s turnover capacity and financial and material resource turnover .
APS/MES planning is the next level of evolution of CRP capacity planning and scheduling based on limited process utilization. The principal distinctions include:
- Absence of discrete planning intervals. Positioning of all jobs on the time axis with an accuracy to minutes
- Possibility to take account of actual job sequence in the system, changeover downtime, in-process queue time and time for movement between work centers
- Plan formation using one or several optimization criteria
For APS/MES planning one needs to form and maintain updated the information as follows:
- Bills of materials and route processes detailing all work standards and alternative processes
- The list of work centers detailing composition of work centers and work schedules for each of them, load utilization procedures (for single and multiple jobs), capacity calculation method, inventory flow charts, job assignment procedures and other parameters
- Job and work schedules of work stations define the scheduled worktime fund of each work center. In case of breakdown or scheduled maintenance, the work center’s duty hours in respective days should be amended accordingly.
- The time for work centers changeover can be both fixed for each work center and selectable.
- Time and methods of movement of semi-finished products between work centers
- Information on current material stocks and constituent semi-finished products
- Information on current release deadlines and priorities from the MPS, MRP plan
- And plenty of other reference and operating data
APS/MES plan is formed according the following three optimization criteria:
- Commercial optimization criteria Minimization of delays in order shipment schedule agreed with the customer or intershop transfers
- Production optimization criteria Maximum capacity utilization
- Other optimization criteria, including optimization according to several criteria simultaneously, with the criteria prioritized
The model of production scheduling based on limited process utilization. Jobs are assigned to machines without any overload at any given moment of time.
- Backward planning – from order delivery back to first process operations
- Forward planning – from current date for uncompleted process operations only
- Bottle neck planning. This approach combines the above approaches.
- Smoothing machinery overloads with assignment of jobs to alternative equipment
- Manual assignment of jobs to machinery
Clobbi features the following capacity utilization scenarios:
- Single-job utilization, when a work center can process only one semi-finished product (product) at a time
- Multiple-job utilization, when a work center can process a certain number of semi-finished products (products) at a time
Types of production planning with regard to materials availability:
- Planning considering current availability of materials and semi-finished products
- Planning considering materials receipt schedule
- Planning with no regard to materials availability and receipt
The method to aggregate jobs to be assigned to machinery include:
- Aggregation by jobs of the same type within a certain period of time For example, aggregation of the same type of product from different production orders to be manufactured within one week or one day
- Aggregation of products of different types shipped to a customer on a same day
- Aggregation of products based on specifics of the manufacturing process, etc.
The methods of selection of alternative work centers to assign jobs from prioritized queues include:
- Selection of a primary and/or alternative work center available first
- Selection of a primary and/or alternative work center that needs no readjustment after its last completed job
- Selection of a primary and/or alternative work center with minimum time till completion of the job to be assigned considering changeover time
- Selection of a primary and/or alternative work center with minimum job completion cost. This method is especially relevant when the production floor is equipped with different types of machinery
Creation of shift tasks and route charts with barcodes
Generation of shift tasks is the final part of the multilevel process of production planning. This is the lowest level of production planning down “on the floor”.
So, we have an optimized in-shop production schedule (MES), created and verified with the involvement of the master scheduler The schedule represents a minute-by-minute work timetable for each work center for several days ahead with due regard to the specifics of the manufacturing process.
The shop foreman creates and issues shift tasks to all workers, normally, before the shift start. To do so in Clobbi the foreman will use the Shift Tasks function on the desktop.
Shift tasks are issued both in the electronic form represented in the mobile application Clobbi.Manufacture and in hard-copy documents printed out from the Clobbi service:
The system starts running production records from the moment material is issued for manufacturing of parts and semi-finished products. In order all participants of the production process had access to information regarding the item flow route, it requires a route chart accompanying each batch of items until completion of the last operation to finish manufacturing for the whole batch.
The route chart is generated at the time of issue of first shift task for production of a job.
For example, the foreman of the blank production shop have issued a shift task for cutting materials (the first operation of the route) for production of two batches of items. At this moment the system has generated two route charts with a complete list of operations for production of these two batches. Then, the mechanical shop foreman issues shift tasks for further operations to produce these two batches. These operations of the shift tasks will be already on the route charts created earlier, so no new route charts will be created for these shift tasks since one batch of products is covered by one route chart only.
One route chart can have several shift tasks assigned, and similarly, one shift task can be linked to several route charts. Shift tasks and route charts are associated to each other via a unique operation number. Therefore, job completion can be recorded not only by operations on the shift task, but also by operations on the route chart.
The diagram above shows connection of shift tasks to route charts. Also, one operations on the route chart may correspond to several shift tasks (not shown in the Figure) if an operation on the route chart is to be performed on a batch by several workers at the same time.
List of operations of the route chart is created based on the item MRP plan.
The worker makes real-time notes of the quantity of actual units produced and elapsed time on the shift task as he completes operations.
He can use ordinary PC connected to the company network equipped with a bar-code scanner or a mobile device running under Android (smartphone or tablet) connected via Wi-Fi as a recording device. Should it be impractical to equip individual workplaces with such devices the recording of actual figures is done by the shop’s foreman.
Production planning should be done in conjunction with design-to-manufacture measures and online production records since preproduction measures are the primary source of information regarding the flow route and time planned for items in production, while production records provide information on the current status of the item for further calculations of the production plan. The production plan also forms the basis for purchasing plan calculations.
Please read our cases on optimal production planning: