7 Parte 1 Tamaño de Lote

Name: 7 Parte 1 Tamaño de Lote
Uploaded: 2022-08-30T22:23:52.000Z
Duration: 2 h 16 min 18 s

Planning Material Requirements: Lot Sizing Methodologies

Introduction to Lot Sizing

The discussion focuses on planning material requirements and exploring different methodologies for determining lot sizes.

The term "lot-for-lot" is introduced, referencing its notation as "lpl" or "l4" in some literature.

Lot-for-Lot Method

The lot-for-lot method involves ordering exactly what is needed based on demand; for example, if the demand is 150 units, orders are placed for 50 and then 60 units as required.

A significant advantage of this method is that it eliminates holding costs since inventory levels remain at zero.

However, frequent ordering leads to increased ordering costs due to constant replenishment needs.

Cost Calculations in Lot-for-Lot

An example illustrates cost calculations over eight weeks with specific parameters: $10 per unit order cost, $47 per order, a weekly interest rate of 0.5%, and a holding cost of $0.05 per unit weekly.

With an initial inventory of zero, each week incurs an ordering cost of $47 without any holding costs due to the absence of inventory.

Total accumulated costs over the period amount to $376, highlighting how lot-for-lot minimizes inventory but increases ordering frequency.

Limitations of Lot-for-Lot

While minimizing holding costs is beneficial, the continuous need for orders results in higher overall ordering expenses.

Economic Order Quantity (EOQ)

Transitioning to the second methodology: Economic Order Quantity (EOQ), which relates back to concepts from previous production courses regarding optimal order size calculation.

EOQ formula: Q^* = sqrt2DS/H , where D represents demand, S denotes setup or ordering cost, and H signifies holding cost.

Demand Considerations in EOQ

Average demand must be calculated; here it’s noted that average weekly demands will be used for EOQ calculations.

After calculating using given parameters, an optimal order quantity (rounded to 351 units per order) emerges despite fluctuating demand patterns.

Challenges with EOQ

Unlike previous assumptions of constant demand in earlier studies, current scenarios reflect discrete and variable demands complicating the application of EOQ effectively.

Inventory Management and Cost Analysis

Week 1: Initial Inventory Calculations

The initial calculation involves adding 47 to 15.05, resulting in a total of 62.05.

For week 2, the inventory is at 301 units, indicating no need for additional orders; thus, the remaining inventory after fulfilling demand will be 241 units.

No ordering costs are incurred as there are sufficient units (241), leading to a holding cost calculated as $0.05 multiplied by the remaining inventory.

Weeks 3 to 5: Continuing Inventory Management

In week 3, with an inventory of 242 and a demand of 70, the remaining stock drops to 171 without incurring ordering costs.

By week 5, after fulfilling a demand of 95 from an inventory of 111, only 16 units remain; this prompts an order for an additional quantity of 351.

Week-by-Week Cost Analysis

The holding cost for the new total inventory (292 units post-ordering) is calculated at $0.05 per unit.

Total costs are summarized by combining ordering and holding costs; this method proves more efficient than lot-for-lot due to lower overall expenses.

Transitioning Methods: Periodic vs Economic Order Quantity

A shift in methodology introduces periodic review systems instead of economic order quantities; this approach focuses on regular assessments rather than fixed quantities.

The periodic system allows for adjustments based on current needs rather than predetermined amounts.

Demand Calculation and Ordering Strategy

Average demand is computed using historical data; it serves as a basis for future orders.

Orders are placed every five weeks based on average requirements across that period, ensuring adequate supply without excess.

Final Observations on Costs and Inventory Levels

As weeks progress without needing additional orders due to sufficient stock levels, costs associated with ordering and holding drop significantly.

Inventory Management and Cost Analysis

Inventory Planning for Week 6

The speaker discusses the need to maintain a zero inventory by week 6, which necessitates placing orders. Due to limited inventory, only three weeks of orders can be completed instead of five.

Cost Calculations

An order cost is calculated at 190, leading to an inventory total of 290 minus 75. The ordering cost is noted as 47 with a holding cost of 5 for week 67.

Understanding Costs in Inventory Models

The speaker emphasizes that while current calculations show improved costs (140), this may not always hold true due to varying conditions affecting inventory management.

Total Minimum Cost Concept

Introduction of the concept of "total minimum cost," also referred to as balance or lost piece analysis. This involves equating holding costs with ordering costs to minimize overall expenses.

Balancing Holding and Ordering Costs

It’s explained that while holding and ordering costs will never be exactly equal due to discrete distributions, finding a balance point is crucial for effective ordering strategies.

Coverage Period Calculation

A table will be created to assess coverage periods, determining how much should be ordered based on projected needs over specific weeks.

Example Scenario: One Week Coverage

In a one-week scenario where an order of 50 units is placed, the holding cost becomes zero since all units are utilized within the week.

Two Weeks Coverage Analysis

For two weeks, an order totaling 110 units (50 + 60) is analyzed. The holding cost calculation reveals remaining units after fulfilling weekly demands.

Three Weeks Coverage Strategy

When planning for three weeks, an order of 180 units is necessary. Detailed calculations are provided regarding leftover stock from previous weeks and their associated costs.

Four Weeks Coverage Evaluation

Inventory Management and Cost Analysis

Initial Inventory Calculations

The speaker discusses the initial inventory calculations for a period of five weeks, determining that the total order size needed is 335 units.

For week 1, after consuming 50 units, the remaining inventory is calculated to be 285 units.

In week 2, with a consumption of 60 units, the inventory decreases to 225 units.

By week 3, after consuming another 70 units, the remaining inventory drops to 155 units.

Week 4 sees a further reduction in inventory to 95 units after consuming another 60.

Cost of Positioning

The cost of positioning is calculated as follows: 285 times 0.05 + 225 times 0.05 + 155 times 0.05 + 95 times 0.05, resulting in a total cost of exposure at this stage being compared against ordering costs.

When extending calculations to six weeks, an order size of 410 is determined based on projected consumption rates.

Weekly Consumption and Inventory Tracking

The final inventories for each week are tracked:

Week 1: 360

Week 2: 300

Week 3: 230

Week 4: 170

Week 5: 75

Week6: 0 (after consumption).

Further Cost Analysis

A detailed calculation for costs over six weeks shows increasing holding costs due to higher ending inventories leading up to week six.

The difference between holding costs and ordering costs indicates that adjustments are still necessary as they remain unbalanced.

Decision Making on Order Sizes

After analyzing differences in costs between various weeks, it’s concluded that ordering sizes should align closely with demand forecasts; thus choosing week five's order size appears optimal at this point.

As demand fluctuates weekly, decisions on whether or not to place orders depend heavily on current inventory levels and expected future needs.

Adjustments Based on Demand Forecasting

The speaker emphasizes recalibrating orders based on actual versus forecasted demand; if there’s sufficient stock from previous orders, new orders may not be necessary immediately.

Analyzing two-week coverage reveals potential adjustments needed for upcoming demands while ensuring minimal excess stock remains.

Final Recommendations and Conclusions

A comprehensive review suggests requesting additional quantities when necessary but also highlights maintaining balance between supply chain efficiency and cost management strategies over time.

Cost Analysis and Inventory Management

Understanding Cost Components

The speaker discusses having 55 units remaining with no opposition or ordering costs, while possession cost is noted as 2.75. This leads to a calculation of inventory adjustments.

A total minimum cost is calculated, emphasizing the importance of estimating costs accurately for effective inventory management.

Unit Cost Calculation Methodology

The speaker introduces a method for determining unit costs by calculating the cost per unit for each order, aiming to find the lowest possible unit cost.

A table is created to analyze various costs including position and ordering costs, leading to an understanding of how these affect total expenses.

Weekly Inventory Planning

For week one, an order of 50 units incurs zero possession cost; thus, only ordering costs are considered in total calculations.

The discussion shifts to planning for two weeks where the total order increases to 110 units (50 + 60), affecting inventory levels significantly.

Extended Planning Over Multiple Weeks

As planning extends over three weeks, the need arises to calculate orders based on cumulative requirements (50 + 60 + 70 = 180).

The speaker highlights that after fulfilling demands over three weeks, there would be no remaining inventory left at the end of week three.

Analyzing Costs Over Four and Five Weeks

For four-week planning, a comprehensive breakdown shows how position and ordering costs contribute to overall expenses.

In five-week analysis, cumulative needs lead to an order totaling 335 units. Each week's consumption impacts subsequent inventory levels significantly.

Final Considerations on Cost Efficiency

Cost Analysis and Inventory Management

Cost of Ownership Calculation

The cost of ownership is calculated by summing the products of inventory quantities and their respective costs, resulting in a total cost of 1,375 with a unit cost of 0.25.

Weekly Inventory Adjustments

The analysis continues to evaluate costs over seven weeks, revealing that the total needed for week seven is 50 units.

A detailed breakdown shows weekly inventory adjustments: starting with 470 units, reducing to 420 in week one after taking out 50 units.

Further reductions are tracked through subsequent weeks, leading to a final count of zero by week seven.

Total Cost Assessment

The unique possession cost accumulates from each week's remaining inventory multiplied by the holding cost rate (0.05), totaling approximately 149.75.

The overall ordering cost is noted as 47, leading to a total estimated cost of around 196.75 with a unit cost calculated at approximately 0.40.

Order Quantity Decisions

For six-week orders, it’s determined that sufficient inventory should be ordered based on the lowest unit costs identified earlier.

As calculations progress into weeks seven and eight, similar methodologies are applied to maintain optimal inventory levels without incurring additional ordering costs.

Final Calculations and Methodologies

In week seven, an order for 60 units results in zero remaining stock; thus, the holding cost remains at zero while maintaining an ordering expense of 47.

The final unit cost for this period is calculated at approximately 0.43 per unit when considering total expenses against ordered quantities (115).

Various methods for determining order sizes are discussed: lot-by-lot ordering versus economic order quantity (EOQ), emphasizing balancing protection costs with leasing expenses for minimal total costs.