T3_6_FlowRack.vb Detailed Explanation

📖 Overview

This module (FlowRackCalcF) is a form for calculating the design and volume of a Flow Rack system. A flow rack is a gravity-fed (inclined) storage system designed to maximize picking efficiency for high-turnover items. It automatically achieves "First-In, First-Out (FIFO)" by replenishing from the back and picking from the front.

🎯 Main Objectives

Calculate dimensions for a single flow rack (bay width, depth, height, number of tiers, etc.)
Calculate area and volume for the entire layout (rack placement, aisles, required area)
Calculate storage volume (considering the rack fill rate)
Estimate inventory turnover days (comparing inventory days between flow racks and other equipment)

🏗️ Main Classes/Modules

Public Class FlowRackCalcF

A Windows Forms class for calculating the design, layout, and storage capacity of flow racks.

Features:

Calculation of case storage capacity for a single rack (calculates the number of bays and cases from width, depth, height, and tiers)
Layout area calculation (calculates required area from the number of columns, bays, and aisle placement)
Volume efficiency evaluation (effective storage volume considering the fill rate)
Inventory days comparison (compares inventory holding days between flow racks and other equipment)

🔧 Details of Main Functions/Subroutines

1. FlowRackCalc_Load

Private Sub FlowRackCalc_Load(sender As Object, e As EventArgs) Handles MyBase.Load CopyrightL.Text = Company & " Copyright:" & Copyright ValidityPeriodL.Text = "Validity Period:" & TrialVersionExpirationDate SingleRackCalc() End Sub

Process Details:

Displays copyright information and license expiration date upon form loading.
Executes single rack calculation with initial values.

2. SingleRackCalc

Private Sub SingleRackCalc() ' Retrieve rack dimensions ' Calculate bay width, depth, height ' Calculate case dimensions ' Calculate case volume ' Call layout volume and area End Sub

Process Details:

Retrieve basic rack dimensions: Read input values such as flow rack width, rack depth, pillar width, top tier height, etc.
Rack Width Pitch Calculation: Rack Width - Pillar Width = Rack Width Pitch
Bay Width Pitch Calculation: Effective Rack Width ÷ Bays per Tier = Bay Width Pitch
Bay Height Calculation: (Pic Top Tier Height - Min Height 1) ÷ (Rack Tiers - 1) = Bay Height
Input Height Calculation: Pic Top Tier Height + (Min Height 2 - Min Height 1) = Input Height (height of case input position)
Bays/Rack: Bays_Tier × Rack Tiers = Bays_Rack
Cases/Rack: Bays_Rack × Cases_Bay = Cases_Rack
Case Width: Bay Width Pitch - (Guide Width + Bay Width C × 2)
Case Length: Rack Depth ÷ Cases_Bay
Case Height: Bay Height - (Conveyor Thickness + Pic Clearance)
Case Volume (m³): (Case Width × Case Length × Case Height) ÷ 1000³
Case Volume (m³)/Rack: Case Volume × Cases_Rack
Call layout volume and layout area calculations

📐 Main Calculation Formulas:
Rack Width Pitch = Rack Width - Pillar Width
Bay Width Pitch = (Rack Width Pitch - Pillar Width) ÷ Bays per Tier
Bay Height = (Pic Top Tier Height - Min Height 1) ÷ (Rack Tiers - 1)
Input Height = Pic Top Tier Height + (Min Height 2 - Min Height 1)
Case Width = Bay Width Pitch - (Guide Width + Bay Width C × 2)
Case Length = Rack Depth ÷ Cases_Bay
Case Height = Bay Height - (Conveyor Thickness + Pic Clearance)
Case Volume = (Case Width × Case Length × Case Height) ÷ 1000³

3. Layout Volume

Private Sub LayoutVolume() ' Total Racks = Columns × Bays ' Total Bay Count = Total Racks × Bays_Rack ' Consider rack fill rate ' Storage Volume_Rack = Calculated Volume_Rack × Rack Fill Rate ' Total Storage Volume = Storage Volume_Rack × Total Racks End Sub

Process Details:

Total Racks: Columns × Bays
Total Bay Count: Total Racks × Bays_Rack
Rack Fill Rate: Convert input fill rate (%) to a decimal
Storage Volume_Rack: Calculated Volume_Rack × Rack Fill Rate
Total Storage Volume: Storage Volume_Rack × Total Racks (rounded to an integer)

📐 Volume Calculation Formulas:
Total Racks = Columns × Bays
Total Bay Count = Total Racks × Bays_Rack
Storage Volume_Rack = Calculated Volume_Rack × (Rack Fill Rate ÷ 100)
Total Storage Volume = Storage Volume_Rack × Total Racks

4. Layout Area

Private Sub LayoutArea() ' Calculate number of aisles ' Calculate W direction (Width direction) ' Calculate L direction (Length direction) ' Calculate various areas End Sub

Process Details:

Rack Width Pitch: Flow Rack Width - Pillar Width
Calculate Number of Aisles:
- Number of Racks = Columns
- Number of Replenishment Aisles = Int(Number of Racks ÷ 2) + 1
- Number of Pic Aisles = Int(Number of Racks ÷ 2 + 0.999)
- Number of Auxiliary Aisles = 2 (Fixed)
W Direction (Width) Calculation:
- W1 = Replenishment Aisle Width
- W2 = Rack Installation Width (Same as Rack Depth)
- W3 = Pic Aisle Width
- Required Width W = W1 × Number of Replenishment Aisles + W2 × Number of Racks + W3 × Number of Pic Aisles
L Direction (Length) Calculation:
- L1 = Auxiliary Aisle Width
- L2 = Rack Installation Length = Rack Width Pitch × Bays + Pillar Width
- Required Length L = L1 × 2 + L2
Calculation of Each Area:
- Rack Installation Area = (W2 × L2) ÷ 1000² × Number of Racks
- Pic Aisle Area = (W3 × L2) ÷ 1000² × Number of Pic Aisles
- Replenishment Aisle Area = (W1 × L2) ÷ 1000² × Number of Replenishment Aisles
- Auxiliary Aisle Area = (W × L1 ÷ 1000²) × Number of Auxiliary Aisles
- Total Required Area = Rack Installation Area + Pic Aisle Area + Replenishment Aisle Area + Auxiliary Aisle Area
After calculation, call ExampleRecalc()

📐 Layout Calculation Formulas:
Number of Aisles:
Number of Replenishment Aisles = Int(Columns ÷ 2) + 1
Number of Pic Aisles = Int(Columns ÷ 2 + 0.999)
Number of Auxiliary Aisles = 2

Required Width / Length:
Required Width W = Replenishment Aisle Width × Number of Replenishment Aisles + Rack Depth × Columns + Pic Aisle Width × Number of Pic Aisles
Required Length L = Auxiliary Aisle Width × 2 + (Rack Width Pitch × Bays + Pillar Width)

Required Area:
Total Required Area = Rack Installation Area + Pic Aisle Area + Replenishment Aisle Area + Auxiliary Aisle Area

5. Example Recalculation

Private Sub ExampleRecalc() ' Calculate Flow Rack Inventory Days ' Calculate Other Equipment Inventory Days End Sub

Process Details:

Flow Rack Inventory Days: Example Flow Rack Storage Volume ÷ Example Shipping Volume (To 1 decimal place)
Other Equipment Inventory Days: Example Total High-Turnover Inventory Days - Example Flow Rack Inventory Days (To 1 decimal place)

📐 Inventory Days Calculation Formulas:
Flow Rack Inventory Days = Flow Rack Storage Volume ÷ Shipping Volume
Other Equipment Inventory Days = Total High-Turnover Inventory Days - Flow Rack Inventory Days

6. RecalculateBt_Click

Private Sub RecalculateBt_Click(sender As Object, e As EventArgs) Handles RecalculateBt.Click SingleRackCalc() If CalcStart_Chk2 = 0 Then LayoutDimensionDetailsTp.BackColor = Color.LightYellow CalcStart_Chk2 = 1 Else LayoutDimensionDetailsTp.BackColor = Color.PowderBlue CalcStart_Chk2 = 0 End If End Sub

Process Details:

Execute SingleRackCalc() when the recalculate button is clicked.
Toggle the background color of the Layout Dimension Details tab (LightYellow ⇔ PowderBlue).
Toggle the calculation start flag (CalcStart_Chk2).

7. ExampleRecalcTb_Click

Private Sub ExampleRecalcTb_Click(sender As Object, e As EventArgs) Handles ExampleRecalcTb.Click ExampleRecalc() End Sub

Process Details:

Execute recalculation of inventory days when the example recalculate button is clicked.

8. CoverPb_Click / FlowRackCalcBt_Click

Private Sub CoverPb_Click(sender As Object, e As EventArgs) Handles CoverPb.Click Me.TabControl1.SelectedTab = FlowRackCalcTp End Sub Private Sub FlowRackCalcBt_Click(sender As Object, e As EventArgs) Handles FlowRackCalcBt.Click Me.TabControl1.SelectedTab = FlowRackCalcTp End Sub

Process Details:

Display the Flow Rack Calculation tab when the cover image or flow rack calculation button is clicked.

9. CloseBt_Click

Private Sub CloseBt_Click(sender As Object, e As EventArgs) Handles CloseBt.Click Close() End Sub

Process Details:

Close the form when the close button is clicked.

🔗 Dependencies

Dependency	Description
System.Runtime.Remoting.Messaging	Imported, but unused in the code (can be deleted).
Windows Forms	UI Components (TabControl, TextBox, ComboBox, Button, Label, PictureBox, etc.)
Global Variables	Company, Copyright, TrialVersionExpirationDate, CalcStart_Chk2

📝 Revision History

Version	Date	Changes
1.0	-	Initial creation

💡 Calculation Logic Summary

Configuration of Flow Rack System

Features of Flow Racks:

Inclined FIFO: Replenish from the back, pick from the front (cases flow by gravity).
Suitable for High-Turnover: Ideal for storing frequently picked items.
Space-saving: Can shorten picking aisles compared to regular fixed racks.
Flexible Design of Tiers and Bays: Adjust according to product size and picking frequency.

Calculation Flow

Input Dimensions for a Single Rack: Flow rack width, depth, number of tiers, bays, cases, etc.
Calculate Single Rack:
- Calculate bay width, depth, height.
- Calculate case dimensions (width, length, height).
- Calculate case volume and case volume per rack.
Input Layout Configuration: Number of columns, bays, aisle widths, etc.
Calculate Layout Volume:
- Calculate total number of racks and total number of bays.
- Calculate storage volume taking the fill rate into account.
Calculate Layout Area:
- Calculate the number of aisles (Replenishment, Pic, Auxiliary).
- Calculate required dimensions in width and length directions.
- Sum of various areas (rack installation, aisles).
Compare Inventory Days:
- Flow Rack Inventory Days = Storage Volume ÷ Shipping Volume.
- Other Equipment Inventory Days = Total - Flow Rack.

Aisle Placement Logic

Types and Placement of Aisles:

Pic Aisle (Picking Aisle): Placed at the front (picking side) of the flow rack.
Replenishment Aisle: Placed at the back (replenishment side) of the flow rack.
Auxiliary Aisle: Placed at both ends of the layout (fixed to 2).

Rules for Calculating the Number of Aisles:

Number of Replenishment Aisles = Int(Columns ÷ 2) + 1 (Between racks and at both ends)
Number of Pic Aisles = Int(Columns ÷ 2 + 0.999) (Between racks)
Number of Auxiliary Aisles = 2 (Fixed at both ends of the layout)

🎓 Usage Instructions and Design Guide

Basic Usage

Input basic flow rack specifications:
- Flow rack width, rack depth, rack tiers, bays per tier, cases per bay.
- Structural parameters like pillar width, guide width, conveyor thickness.
- Height settings like Min Height 1, Min Height 2, Pic Top Tier Height.
Click the Recalculate button: Check the calculation results for a single rack.
Input Layout Configuration:
- Columns, Bays.
- Replenishment Aisle Width, Pic Aisle Width, Auxiliary Aisle Width.
- Rack Fill Rate (%).
Check Layout Calculation Results:
- Required Width, Required Length, Required Area.
- Total Storage Volume.
- Breakdown of various areas.
Check Inventory Days with Example:
- Input flow rack storage volume, shipping volume.
- Compare flow rack inventory days and other equipment inventory days.

Design Points

⚠️ Notes during Design:

Case Size Compatibility: Flow racks are suitable for items with uniform case sizes. If sizes vary, adjustments per bay are necessary.
Incline Angle: In actual design, the incline angle of the flow lane must be considered (simplified in this calculation).
Separation of Replenishment and Picking: Because Pic aisles and Replenishment aisles are separate, interference in work lines can be avoided.
Aisle Width Optimization: Set the aisle width according to the size of forklifts or picking carts.
Setting the Fill Rate: In actual operation, about 80-90% is realistic (100% is a theoretical value).
Inventory Turnover Rate: Flow racks are for high-turnover items, so it is effective to place items with short inventory days (= high turnover rate).

Comparison with Other Warehouse Systems

Item	Flow Rack	Fixed Rack	Automated Warehouse
Picking Method	Front Picking (Auto FIFO)	In-front-of-rack Picking	Automated Retrieval
Replenishment Method	Replenish from Rear	Replenish from Same Side	Automated Storage
Turnover Suitability	Optimal for High Turnover	Medium to Low Turnover	General
Initial Cost	Medium	Low	High
Space Efficiency	High (Shortened Aisles)	Medium	Very High
FIFO Management	Automatically Guaranteed	Manual Management	System Management

🔍 Differences between Flow Racks and Case AS/RS

Features of Flow Racks:

Manual Picking: Workers pick directly from the front.
Gravity FIFO: Cases automatically move forward due to the incline.
Replenishment Work: Replenish from the rear manually or by forklift.
For High-Turnover Items: Handles frequent picking.
Visibility: Products are easy to see, facilitating inventory checks.

Features of Case Automated Warehouses:

Full Automation: Storage and retrieval are fully automated.
High-Density Storage: Minimizes aisles to maximize storage density.
Inventory Management: Integrates with WMS for real-time inventory management.
Initial Investment: Equipment costs are high.
Flexibility: Can store all items regardless of turnover rate.

📊 Utilizing the Calculation Example

Inventory Days Comparison Feature:

This module includes an "Example" feature to compare inventory days between flow racks and other equipment. This helps in determining how much of the high-turnover items should be placed in the flow racks.

Example:

Total High-Turnover Inventory Days: 10 days
Flow Rack Storage Volume: 200 cases
Shipping Volume per Day: 50 cases
→ Flow Rack Inventory Days: 200 ÷ 50 = 4.0 days
→ Other Equipment Inventory Days: 10 - 4 = 6.0 days

From this result, it can be judged appropriate to place 40% of high-turnover items in flow racks and the remaining 60% in other equipment.

🚀 Summary

T3_6_FlowRack.vb is a design support tool for flow rack systems that improve the picking efficiency of high-turnover items. It provides comprehensive design support, from calculating dimensions of a single rack to calculating the volume and area of the entire layout. Its biggest features are the ability to separate replenishment and picking lines, and the ease of inventory management through gravity-fed FIFO.

By using this module, you can:

✅ Design optimal dimensions for a flow rack system.
✅ Accurately calculate the required area for the layout.
✅ Evaluate storage volume considering fill rates.
✅ Optimize the allocation of storage between flow racks and other equipment.
✅ Build an efficient storage and picking system for high-turnover items.