Planning in production systems

1. Slovak University of Technology Faculty of Material Science and Technology in Trnava Planning inproduction systems MRP systems, MRP II, JIT

2. Material Requirements Planning (MRP) • MRP is a software based production planning and inventory control system used to manage manufacturing processes. • MRP is a calculation method geared toward determining how much of which raw materials are required and roughly when they should be ordered to fulfill a set of product orders.

3. An MRP system is intended to simultaneously meet three objectives: • Ensure materials and products are available for production and delivery to customers. • Maintain the lowest possible level of inventory. • Plan manufacturing activities, delivery schedules and purchasing activities.

4. MRP generally consists of four steps: • Bill of Materials Explosion - looking backward from each product, determine which intermediates and raw materials are required, and in what quantities. • Netting - compare the above quantities against current inventory. • Lot Sizing - determine how the needed materials will be purchased or produced. • Start Date Determination - based on cycle time information, determine when each order should start production.

5. MRP system structure

6. Level of stock

7. Manufacturing Resource Planning (MRP II) • orientation to production sources planning • all information current, planning function and production control integrate to one logical chain cross material current, • using continuous planning principles - production process hierarchy support.

8. Automated production

9. JIT (Just in Time) • base idea – to optimized buffering stocks, which help us to control supplies level; high supplies level = small effectiveness, • more then supplies control – philosophy based on continual deficit finding out and elimination on all organizations levels.

10. JIT can see as: • philosophy or full access to production • technics which are used for production system design and operation • beam house control system - kanban = dispatch note.

11. Objective of JIT • Produce only the products the customer wants. • Produce products only at the rate that the customer wants them. • Produce with perfect quality • Produce with minimum lead time. • Produce products with only those features the customer wants.

12. JIT Principles • Create flow production • one piece flow • machines in order of processes • small and inexpensive equipment • U cell layout, counter clockwise • multi-process handling workers • easy moving/standing operations • standard operations defined • Establish “TAKT” time • rate at which the customer buys a product • Build Pull Product • use of kanban system

13. By decreasing supplies level we can see hidden problems with two sources: • extern – mistakes in delivery - customers relations • intern – mistakes which reach as consequence of quality deficient (material, production engineering, production process organization, work power, goods and technical documentation design)

14. Solutions • extern problems source - build reliable stable delivers chain and reliable customers • intern problems source - complex quality increasing and monitoring – TQM (Total Quality Management), active production process quality assurance – SPC (Statistical process control); it try to do ZD (zero defects).

15. Aim of JIT • Dodge to generality • Avoid the loss • Continuing improvement

16. 1. Dodge to generality • by the customers – fast change of claim and preferences – although we need to retain adequate costs, offer palette of goods and short delivery dead-lines • by the delivers – first step in production; important in storage nonexistence to achieve quality and right supplies or blank in right time

17. by the workers • absence and another problems can be reduced with right workers motivation, increasing the work claim, work organization, higher work motley and easy identification their portion to making good • workers education - achieve decreasing level of goods mistakes • preference before making simply monotone operations continuously by many workers have to be making complex operations by one workers • by claim of trade – is not anytime constant

18. 2. Avoid the loss • Overproduction • Idle time and production storages • Transporting • Mistakes

19. 3. Continuing improvement • effective increasing, looses elimination, indemnity for reliability, making production discipline etc. (unending process) • KAIZEN philosophy - sense to have trying achieve production without mistakes for all goods, because mistakes destroying continuous production current (continuously increasing process).

20. JIT Advantages • Shortened lead time • Reduced time spent on non-process work • Reduced inventory • Better balance between different processes • Problem clarification

21. Limitations of JIT • Preconditions to JIT • trust must be present • labor/management • suppliers/consumers • recognition of processes • familiarity with problem solving • quality at the source • agreement over value and waste

22. Limitations of JIT • Right Settings • applicable in growth to maturity phases of Product Life Cycle • standard product • Steinway and JIT • standard/fixed pay-rate • problems with piece-rate scheme • Universal agreement that change needed