 |
 |
 |
 |
 |
 |
 |
 |
MINIMUM INVENTORY VARIABILITY POLICY® (MIVP®) |
|||||||||||||||||||||||||||
|
Three basic ways to reduce cycle time Modeling to demonstrate MIVP® benefits
Minimum Inventory Variability Policy® (MIVP®) MIVP® (US Patent approved November 2004) was invented to implement operations management theories and approaches developed by Donald W. Collins, Ph.D. of ACADZ, Inc. One of these approaches is the Minimum Inventory Variability Scheduling and Release Policy® (MIVP®). The cycle time for a process and its work-in-process (WIP) inventory are linked, so that improvements in the efficiency of a process can be measured by either cycle time or inventory. Managers of production operations are under constant pressure to reduce costs, while at the same time the manufacturing environment is becoming increasingly complex with larger numbers of inter-dependent processes and greater potential for variability being introduced. Using the MIVP® approach minimizes WIP inventory and leads to an increase in the utilization of expensive capital equipment (and other constrained resources) as well as increased production throughput and shorter cycle times. The MIVP® policies eliminate the instantaneous inventory build-ups that develop when there is any unplanned interruption in a manufacturing process. It has been proven quite effective in the semiconductor industry, for example, where a one percent reduction in cycle time can mean additional sales of $200,000 - $300,000 per month in a 6” wafer FAB. After implementing MIVP®, Motorola’s cycle time to make multiple products on one line decreased by 33% over five months. In another case, the cycle time was reduced 50% on a single product production line. In addition, the shipments to customer’s on-time delivery schedule improved from 80% to 95%. In every case these results were obtained without the addition of any personnel or equipment. Three basic ways to reduce cycle time ACADZ, Inc. implements robust scheduling and release policies Ways to reduce cycle time:
Adding resources or equipment at a known bottleneck can be costly as well as time consuming, and the changes still may not reduce the average cycle time. In fact, in some cases this approach merely shifts the bottleneck to some other point in the production process. Re-engineering an already qualified process that is producing an already qualified product can also be quite expensive and time consuming. This method will reduce the cycle time of this product but may not affect the overall average product cycle time in the FAB. Implementing a new scheduling and release policy, however, can be done virtually immediately with minimal costs and no additional personnel or equipment nor any necessity for re-qualifying the process or the product (because they don’t change!). In addition, it is possible to actually observe and confirm the shorter cycle time within 1.5 times of the original cycle. For example, if the overall production cycle time has typically been 35 days then a reduction can be observed within 52 days. Using MIVP®, typical reductions in average cycle time are in the 7% to 45% range for semiconductor manufacturing. And the only costs incurred are the fees to set up and use the MIVP® policy algorithms. There are many optimal scheduling and release approaches (both commercially available and theoretical), which can, in theory, handle the numerous variables and interactions inherent in all but the simplest of manufacturing processes. The problem is the computer time needed to actually run through all the different combinations and then prioritize them to gain the optimal one. This process is very time consuming and expensive. In addition, it is normal for factory conditions to change often and require re-computation of the production schedule and releases. The MIVP® algorithms are distributed throughout the FAB on your local area network to accomplish better results in real time with less expense. Proven at other semiconductor factories Table 1. SEMATECH Model Comparisons of FIFO with 1-Step Ahead MIVP®
The above chart clearly shows that MIVP® reduced the total queueing time (wait time) of both products A and B when4compared with FIFO.
The chart above shows the Total Queueing Time (wait time) percentage reduced for products A and B by MIVP® when compared with FIFO. *click here so see the technical paper that supports these SEMATECH Model cycle time savings Use of modeling to demonstrate MIVP® benefits
These are a few questions that can be answered by a simulation model. ACADZ uses simulation to prove to you, our customer, that MIVP® is better than FIFO and how much better. You will know how much your proprietary scheduling rules improve over FIFO so now a comparison can be made to MIVP®. Once the simulation model is complete and validated using your company’s current set of data, the model can be run using FIFO to gather a set of baseline data for average cycle time and WIP. Next, the same model and data are used to incorporate the MIVP® algorithms, and the simulation is run again and a new cycle time and WIP data are generated. The results from this comparison show the potential to be gained from implementing MIVP® in this specific manufacturing process. This analysis allows management to measure the benefits of implementing MIVP® algorithms compared to the cost of implementation for their factory. Costs for the simulation model and implementation depend upon the amount of data needed to be collected, size of factory, number of process flows, and number of steps in each process flow. All of these activities are accomplished with no interference in the factory’s ongoing production. ACADZ, Inc. wants to be your partner to help improve your bottom line by reducing your average cycle time for now and in the future. Click
here to fill out a service service request form MIVP® system Brochure: ACADZ MIVP® Brochure.PDF* Brochure is in Adobe Acrobat Reader
(.PDF format).
|
|||||||||||||||||||||||||||
