T3_7_MediumDutyRack.vb Detailed Explanation

📖 Overview

This module (MediumDutyRackCalcF) is a form used to design and calculate the volume and area for a Medium-Duty Rack system. Medium-duty racks are manual storage racks used for piece picking and are the most common warehouse equipment for storing and picking small to medium items at the SKU level.

🎯 Main Objectives

Calculate specifications for a single medium-duty rack (number of tiers, bins, effective dimensions, volume, etc.)
Calculate space for the entire layout (number of columns, bays, aisle placement, required area)
Calculate storage volume (effective storage volume considering fill rate)
Design verification (calculation of required number of sets and storage inventory days)

🏗️ Main Classes/Modules

Public Class MediumDutyRackCalcF

A Windows Forms class to calculate the design, layout, and storage capacity of medium-duty racks.

Features:

Basic specification calculation of the rack (effective bin dimensions, volume calculation)
Layout calculation considering single-row and double-row placements
Area efficiency evaluation (rack installation area + aisle area + building interference increment)
Practical calculation examples (required number of sets, storage inventory days)

🔧 Details of Main Functions/Subroutines

1. SorterCalc_Load

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

Process Details:

Displays copyright information and license expiration date upon form load.
Sequentially executes medium-duty rack specification calculation, space calculation, and calculation procedure and consideration.

2. MediumDutyRackSpecCalc

Private Sub MediumDutyRackSpecCalc() ' Calculate total racks from columns and bays ' Basic rack specs (width, depth, height, tiers, bins per tier) ' Calculate effective bin dimensions ' Calculate effective bin volume ' Calculate calculated volume per rack and per set End Sub

Process Details:

Calculate Number of Racks:
- Medium-Duty Rack Columns × Medium-Duty Rack Bays = Medium-Duty Racks
Calculated Bins per Rack:
- (Medium-Duty Rack Tiers - 1) × Medium-Duty Rack Bins per Tier
- * The top tier is considered a spare and not counted as a bin.
Calculate Effective Bin Width:
- Effective Rack Width = Rack Width - 60mm
- Effective Bin Width = Int((Effective Rack Width - Bins per Tier × 10) ÷ Bins per Tier + 0.5)
- * There are "Bins + 1" places with a 10mm gap between bins.
Effective Bin Depth:
- Effective Bin Depth = Rack Depth
Calculate Effective Bin Height:
- Effective Bin Height = Int((Rack Height - (130 + Rack Tiers × 40)) ÷ Rack Tiers + 0.5)
- * The first tier rack is included in the 130mm.
Effective Bin Volume (m³):
- Effective Bin Volume = (Effective Bin Width × Effective Bin Depth × Effective Bin Height) ÷ 1000³
Calculated Bin Volume (m³):
- Calculated Bin Volume = Effective Bin Volume × (Bin Volume Fill Rate ÷ 100)
Calculated Volume per Rack (m³):
- Calculated Volume per Rack = Calculated Bin Volume × Rack Tiers × Bins per Tier
Volume per Set (m³):
- Volume per Set = Calculated Volume per Rack × Medium-Duty Racks

📐 Main Calculation Formulas:
Racks = Columns × Bays
Calculated Bins per Rack = (Tiers - 1) × Bins per Tier

Effective Rack Width = Rack Width - 60
Effective Bin Width = Int((Effective Rack Width - Bins per Tier × 10) ÷ Bins per Tier + 0.5)
Effective Bin Depth = Rack Depth
Effective Bin Height = Int((Rack Height - (130 + Tiers × 40)) ÷ Tiers + 0.5)

Effective Bin Volume = (Effective Bin Width × Effective Bin Depth × Effective Bin Height) ÷ 1000³
Calculated Bin Volume = Effective Bin Volume × Bin Volume Fill Rate ÷ 100
Calculated Volume per Rack = Calculated Bin Volume × Tiers × Bins per Tier
Volume per Set = Calculated Volume per Rack × Racks

3. MediumDutyRackSpaceCalcAreaCalc

Private Sub MediumDutyRackSpaceCalcAreaCalc() ' Calculate space in width direction (single row, double row, pick aisle) ' Calculate space in depth direction (added bays, auxiliary aisle) ' Calculated space area ' Required space area (add building interference increment) End Sub

Process Details:

Calculation in Space Width Direction

Single Row: Rack Depth
Number of Single Rows:
- If Columns is an integer: 2 (single rows at both ends)
- If Columns is a decimal: 1 (single row on one side only)
Double Row: Rack Depth × 2 (back-to-back placement)
Number of Double Rows: (Columns - Number of Single Rows) ÷ 2
Number of Pick Aisles: Number of Double Rows + 1
Number of Adjacent Horizontal Clearances: Number of Single Rows
Space Width (m):
- (Single Row × Number of Single Rows + Double Row × Number of Double Rows + Pick Aisle Width × Number of Pick Aisles + Adjacent Horizontal Clearance × Number of Adjacent Horizontal Clearances) ÷ 1000

Calculation in Space Depth Direction

Single Rack Unit: Rack Width
Number of Single Units: 1
Added Bays: Rack Width - 60mm (Shared pillar)
Number of Added Bays: Bays - 1
Number of Auxiliary Aisles: Input value (usually 1-2)
Number of Adjacent Vertical Clearances: 1
Space Depth (m):
- (Single Unit × Number of Single Units + Added Bays × Number of Added Bays + Auxiliary Aisle Width × Number of Auxiliary Aisles + Adjacent Vertical Clearance × Number of Adjacent Vertical Clearances) ÷ 1000

Area Calculation

Calculated Space Area (m²): Space Width × Space Depth
Required Space Area (m²): Calculated Space Area × (1 + Building Interference Increment ÷ 100)

📐 Space Calculation Formulas:
Width Direction:
Space Width = (Single Row × Number of Single Rows + Double Row × Number of Double Rows + Pick Aisle Width × Number of Pick Aisles + Adjacent Horizontal Clearance × Number of Adjacent Horizontal Clearances) ÷ 1000

Depth Direction:
Space Depth = (Single Unit × Number of Single Units + Added Bays × Number of Added Bays + Auxiliary Aisle Width × Number of Auxiliary Aisles + Adjacent Vertical Clearance × Number of Adjacent Vertical Clearances) ÷ 1000

Area:
Calculated Space Area = Space Width × Space Depth
Required Space Area = Calculated Space Area × (1 + Building Interference Increment ÷ 100)

4. CalcProcedureAndConsideration

Private Sub CalcProcedureAndConsideration() ' Calculate racks and bins per set ' Calculate required number of sets (based on 4351 items) ' Calculate medium-duty rack storage volume ' Calculate storage inventory days End Sub

Process Details:

Racks per Set: Medium-Duty Racks
Bins per Rack: Medium-Duty Rack Calculated Bins per Rack
Bins per Set: Racks × Calculated Bins per Rack
Required Sets: 4351 ÷ Bins per Set
Medium-Duty Rack Storage Volume (m³): Volume per Set × Required Sets
Average Shipping Volume (m³): 13 + 10 + 10 = 33 (Fixed value)
Medium-Duty Rack Storage Inventory Days: Medium-Duty Rack Storage Volume ÷ Average Shipping Volume

📐 Practical Calculation Formulas:
Bins per Set = Racks × Calculated Bins per Rack
Required Sets = 4351 ÷ Bins per Set
Medium-Duty Rack Storage Volume = Volume per Set × Required Sets
Medium-Duty Rack Storage Inventory Days = Medium-Duty Rack Storage Volume ÷ Average Shipping Volume

5. RecalcBt_Click_1

Private Sub RecalcBt_Click_1(sender As Object, e As EventArgs) Handles RecalcBt.Click MediumDutyRackSpecCalc() MediumDutyRackSpaceCalcAreaCalc() CalcProcedureAndConsideration() If CalcStart_Chk2 = 0 Then MediumDutyRackCalcTp.BackColor = Color.LightYellow CalcStart_Chk2 = 1 Else MediumDutyRackCalcTp.BackColor = Color.PowderBlue CalcStart_Chk2 = 0 End If End Sub

Process Details:

Re-execute all calculations when the recalculate button is clicked.
Toggle the background color of the Medium-Duty Rack Calculation tab (LightYellow ⇔ PowderBlue).
Toggle the calculation start flag (CalcStart_Chk2).

6. CoverPb_Click / MediumDutyRackCalcBt_Click

Private Sub CoverPb_Click(sender As Object, e As EventArgs) Handles CoverPb.Click Me.TabControl1.SelectedTab = MediumDutyRackCalcTp End Sub Private Sub SorterCalcBt_Click(sender As Object, e As EventArgs) Handles MediumDutyRackCalcBt.Click Me.TabControl1.SelectedTab = MediumDutyRackCalcTp End Sub

Process Details:

Display the Medium-Duty Rack Calculation tab when the cover image or Medium-Duty Rack Calculation button is clicked.

7. 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 Medium-Duty Rack System

Features of Medium-Duty Racks:

For Piece Picking: Storage and picking in item units (pieces).
Manual Storage System: Workers retrieve products directly from the racks.
Flexible Bin Design: The number of tiers and bins can be adjusted according to product size.
Single/Double Row Placement: Single rows facing the aisle and double rows placed back-to-back.
Connected Structure: Cost reduction by connecting multiple racks sharing pillars.

Calculation Flow

Input Medium-Duty Rack Specifications: Width, depth, height, tiers, bins, etc.
Calculate Medium-Duty Rack Specifications:
- Calculate effective bin dimensions (width, depth, height)
- Calculate effective bin volume
- Calculated bin volume considering fill rate
- Calculated volume per rack and per set
Input Layout Configuration: Columns, bays, aisle widths, etc.
Space Calculation:
- Width direction (single row, double row, pick aisle, clearance)
- Depth direction (single unit, added bays, auxiliary aisle, clearance)
- Calculated space area + building interference increment
Practical Calculation:
- Required number of sets (based on accommodating 4351 items)
- Medium-duty rack storage volume
- Medium-duty rack storage inventory days

Logic for Single/Double Row Placement

Placement Patterns:

Single Row: Racks where only one side faces an aisle (at the ends of the layout)
Double Row: Two racks placed back-to-back (rack faces on both sides of the aisle)

Interpretation of Columns:

If Columns is an integer (e.g., 4.0 columns): Single rows placed at both ends (Number of Single Rows = 2)
If Columns is a decimal (e.g., 3.5 columns): Single row on one side only (Number of Single Rows = 1)
Number of Double Rows = (Columns - Number of Single Rows) ÷ 2

Aisle Placement:

Number of Pick Aisles = Number of Double Rows + 1 (between double rows and at the ends)
Auxiliary Aisles: Placed at the front and back of the layout (specified by Number of Auxiliary Aisles)

Concept of Connected Structure (Added Bays)

Cost Reduction through Connection:

Single Rack Unit (1st bay): Requires pillars at both ends (Width = Rack Width)
Added Bay Rack (2nd bay onwards): Shares a pillar on one side (Width = Rack Width - 60mm)
Example: For 3 bays
- 1st bay: 1800mm (Single unit)
- 2nd bay: 1740mm (Added bay, shares 60mm pillar)
- 3rd bay: 1740mm (Added bay, shares 60mm pillar)
- Total: 1800 + 1740 + 1740 = 5280mm

🎓 Usage Instructions and Design Guide

Basic Usage

Input basic specifications for the medium-duty rack:
- Medium-Duty Rack Width, Depth, Height (Select from ComboBox)
- Medium-Duty Rack Tiers, Bins per Tier (Select from ComboBox)
- Bin Volume Fill Rate (%)
Input layout configuration:
- Medium-Duty Rack Columns, Bays
- Pick Aisle Width, Auxiliary Aisle Width, Number of Auxiliary Aisles
- Adjacent Horizontal Clearance, Adjacent Vertical Clearance
- Building Interference Increment (%)
Click the Recalculate button: Update all calculation results.
Check calculation results:
- Effective bin dimensions and volume
- Volume per rack and per set
- Space width, depth, and area
- Required sets, storage volume, and storage inventory days

Design Points

⚠️ Notes during Design:

Reserve the top tier as a spare rack: The calculated bins per rack is computed as "(Tiers - 1) × Bins per Tier".
Optimization of Bin Count: If the number of bins is too small compared to the number of items, multiple SKUs will be mixed in the same bin, lowering picking efficiency.
Securing Aisle Width: Ensure the pick aisle width is wide enough for workers and picking carts to pass comfortably (typically 1000-1200mm).
Realistic Setting of Fill Rate: A bin volume fill rate of around 70-80% is realistic (100% is a theoretical value).
Economy of Connection: Increasing the number of bays reduces costs by sharing pillars, but note that the distance to auxiliary aisles becomes longer.
Building Interference Increment: Estimate about 5-10% to account for interference from pillars and walls, and future expansion space.

Comparison with Other Storage Systems

Item	Medium-Duty Rack	Flow Rack	Case AS/RS
Storage Unit	Piece (Loose)	Case	Case/Pallet
Picking Method	Manual Picking	Front Picking (FIFO)	Automated Retrieval
Turnover Suitability	Medium to Low	High	General
Initial Cost	Low	Medium	High
Space Efficiency	Medium	High	Very High
Flexibility	Very High	Medium	Depends on system design
Optimal Use	High-mix piece picking	High-turnover case picking	Mass storage/Automation

🔍 Practical Example of Medium-Duty Rack Design

Design Example: Medium-Duty Rack System for Storing 4351 Items

This module includes a practical calculation for storing 4351 items under "Calculation Procedure and Consideration".

Calculation Flow:

Calculate Bins per Set:
- Example: 6 racks, 35 calculated bins per rack → Bins per set = 6 × 35 = 210 bins
Calculate Required Sets:
- Required Sets = 4351 ÷ 210 ≒ 20.72 sets
Calculate Medium-Duty Rack Storage Volume:
- Medium-Duty Rack Storage Volume = Volume per set × 20.72 sets
Calculate Storage Inventory Days:
- Average Shipping Volume = 33m³/day (Fixed value)
- Medium-Duty Rack Storage Inventory Days = Storage Volume ÷ 33

Through this calculation, you can evaluate how many days' worth of inventory the designed medium-duty rack system can store.

📊 Concept of Bin Design

Relationship between Bin Count and Item Count:

Ideal: 1 SKU per bin (clear inventory management, fewer picking errors)
Reality: If there are fewer bins than items, store multiple SKUs in one bin (improves fill rate but increases management difficulty)
Recommended Ratio: Bin Count = Item Count × 1.2 to 1.5 (allow for a margin)

Optimization of Tiers and Bins:

Increase tiers → Vertical space efficiency goes up, workability goes down (working at heights)
Increase bins per tier → Horizontal storage capacity goes up, bin width becomes narrower

🚀 Summary

T3_7_MediumDutyRack.vb is a design support tool for medium-duty rack systems handling high-mix piece shipping. It provides comprehensive design verification, from calculating the specifications of a single rack to calculating the space for the entire layout, and further to practical calculations of the required number of sets and storage inventory days. It is particularly characterized by realistic space calculations considering single/double row placements and connected structures (added bays).

By using this module, you can:

✅ Design optimal specifications for a medium-duty rack system.
✅ Accurately calculate the required area for the layout (including building interference increments).
✅ Evaluate storage volume taking the fill rate into account.
✅ Verify the design based on the required number of sets and storage inventory days.
✅ Enable economical designs utilizing single/double row placements and connected structures.