Planning inproduction systems
MRP systems, MRP II, JIT
Slovak University of TechnologyFaculty of Material Science and Technology in Trnava
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.
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.
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.
MRP system structure
Level of stock
Manufacturing Resource Manufacturing Resource PlanningPlanning (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.
Automated production
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.
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.
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.
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
By decreasing supplies level we cansee 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)
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).
Aim of JIT
1. Dodge to generality
2. Avoid the loss
3. Continuing improvement
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
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
2. Avoid the loss Overproduction Idle time and production storages Transporting Mistakes
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).
JIT Advantages Shortened lead time Reduced time spent on non-process work Reduced inventory Better balance between different processes Problem clarification
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
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
