RollCalcPython/docs/en/quick_reference.md

RollCalc Quick Reference

1. Before You Start

RollCalc is an engineering support tool for roll geometry, roll weight, and transport capacity assessment. It helps experienced technical users prepare and interpret calculations, but it does not replace production, handling, or shipping approval.

Before using a result operationally, check that the selected article, article data, manually entered values, and transport assumptions match the actual case. The calculated result is only meaningful if the input data is technically plausible.

Use this Quick Reference for the most common workflows. For background, detailed interpretation, and troubleshooting, use the full User Manual.

2. Which Function Should I Use?

Task	Function / Calculation Mode
Calculate the diameter of a planned roll	Direct Calculation → Roll Diameter
Estimate product length from a measured roll	Direct Calculation → Product Length
Determine maximum permitted product length	Direct Calculation → Target Diameter
Estimate a new roll from a reference roll	Extrapolation
Assess transport capacity	Load Optimizer
Understand why a transport result is limited	Capacity Summary and Capacity Analysis
Visually check the geometric arrangement	Front View – Cross-Section

3. Article Selection and Input Data

Use Article Number (optional) when an article is available in the article data. The current application can prefill available article values such as Product Thickness, tolerance data, Area Weight, and Core Diameter when these values are present in the data source.

Prefilled values are starting values, not approvals. The values currently visible in the input fields are decisive for the calculation. You can manually change the populated values before calculating.

Planned article-data extension: future article data may also provide a typical Roll Width for automatic prefilling. Do not assume Roll Width is currently populated by article selection unless it is visibly filled in the UI.

Check before calculation:

• Product Category and Production Site match the intended context.
• Article Number (optional) refers to the correct article.
• Product Thickness is plausible for the product.
• Area Weight is current and product-specific.
• Core Diameter matches the actual core.
• Roll Width is entered when Calculated Weight or Load Optimizer will be used.

4. Direct Calculation – Roll Diameter

Use Direct Calculation with Calculation Mode Roll Diameter when a planned Product Length is known and the expected outer roll size must be assessed.

Required inputs

• Core Diameter (d)
• Product Thickness (t)
• Product Length (L)

Optional weight inputs

• Roll Width
• Area Weight

Main results

• Roll Diameter (D)
• tolerance range when tolerance is entered
• Calculated Weight, when Roll Width, Area Weight, and Product Length are available
• Forklift Check, where applicable

Check before use

• Units: mm for diameters and thickness, m for length and width, g/m² for Area Weight, kg for weight.
• Product Thickness is plausible and belongs to the article.
• Core Diameter matches the actual core type.
• Product Length is realistic for the planned roll.
• Calculated Weight is plausible before using the result in Forklift Check or Load Optimizer.

5. Direct Calculation – Product Length

Use Direct Calculation with Calculation Mode Product Length when a roll has a measured Roll Diameter and the product length on the roll must be estimated.

Required inputs

• Core Diameter (d)
• Roll Diameter (D)
• Product Thickness (t)

Main result

• Product Length (L)

Typical use

• measured roll
• stock check
• quality check
• comparison with a planned or nominal length

Important caution

The accuracy depends directly on the measured Roll Diameter and the assumed Product Thickness. If either value is inaccurate or does not match the actual product, the calculated Product Length will be inaccurate as well.

6. Direct Calculation – Target Diameter

Use Direct Calculation with Calculation Mode Target Diameter to determine the maximum allowed Product Length for one roll under entered diameter and weight limits. This is a limit workflow for a single roll. It is not a transport optimization and does not answer how many rolls fit into a container or vehicle.

Relevant inputs

• Core Diameter (d)
• Product Thickness (t)
• Roll Width
• Area Weight
• Max. Roll Diameter
• Max. Roll Weight
• Minimum Product Length

Main results

• Maximum Allowed Product Length
• Resulting Roll Diameter
• Resulting weight
• Minimum length
• Difference
• Limiting factor
• diameter and weight utilization line

Interpretation

Result situation	Meaning
Limiting factor: Diameter	Max. Roll Diameter is reached before the weight limit.
Limiting factor: Weight	Max. Roll Weight is reached before the diameter limit.
Limiting factor: Diameter + Weight	Both limits are reached at the same practical length.
warning below Minimum length	The requested Minimum Product Length cannot be achieved under the entered limits.

The result describes the maximum allowed single-roll layout under the entered limits. It is not automatically the best roll design.

7. Roll Weight and Forklift Check

Roll Weight depends on Product Length, Roll Width, and Area Weight. Similar Roll Diameter values can therefore produce very different roll weights if width, length, or material weight differ.

Calculated Weight is used as the practical roll weight for downstream assessment. It is relevant for handling, Forklift Check, Max. Roll Weight checks, and the Load Optimizer.

Forklift Check is a technical warning or handling indication. It may show messages such as Forklift Check OK, Heavy Roll – Special Equipment Required, or Weight Limit Exceeded. It is not an operational approval, prohibition, or safety release.

Check first if Forklift Check appears unexpected:

• Calculated Weight
• Core Diameter
• Product Category
• Roll Width
• Area Weight
• article data used for the calculation

8. Extrapolation

Use Extrapolation when a Known Reference Roll exists and a comparable roll with a changed length must be estimated.

Use only when

• a known reference roll exists,
• the same article is used,
• Core Diameter is unchanged,
• material structure and Product Thickness are comparable,
• mainly Product Length changes.

Required inputs

• Core Diameter (d)
• Known Roll Diameter (D₀)
• Known Roll Length (L₀)
• New Roll Length (L₁)

Main result

• Extrapolated Roll Diameter (D₁)
• optional min/max range when Tolerance (optional) is entered

Do not use when

• the article changes,
• Product Thickness changes,
• Core Diameter changes,
• reference data is uncertain,
• a full technical roll layout is required.

The quality of the result depends on the quality and comparability of the reference roll.

9. Load Optimizer

Use Load Optimizer – Transport Capacity Calculator after the roll has already been defined. The Load Optimizer evaluates an existing roll in a selected transport space. It does not redesign the roll and does not automatically select the best transport mode.

Required roll data

• Roll Diameter
• Roll Width
• Roll Weight

These values are taken from the completed Direct Calculation workflow. Roll data must be plausible before the transport calculation is meaningful.

Required transport data

• Preset Transport Type:
• or Custom with Length (m), Width (m), Height (m), and Max. Load (kg)
• Loading Clearances
• Side Wall Clearance (one side)
• Ceiling Clearance (top only)

Loading Clearances reduce the effective loading space. They can change the number of rolls that fit geometrically and may change the Governing Constraint.

10. Reading the Transport Results

Read transport results in this order:

1. Read Capacity Summary.
2. Check Total Rolls.
3. Identify the Governing Constraint.
4. Review Remaining Capacity.
5. Check Front View – Cross-Section.
6. Use Capacity Analysis to understand the technical limit.

Capacity Summary

Capacity Summary shows the actual transport result. It is divided into:

• Governing Constraint
• Transport Result
• Remaining Capacity

Transport Result includes Total Rolls, Weight Utilization, Volume Utilization, and the transported product area. Use these values together; a single utilization value does not explain the transport limit by itself.

Use this area first because it shows the result that can actually be reached under the entered assumptions.

Governing Constraint

Governing Constraint	Meaning
Geometry	No additional roll fits into the actual arrangement. Payload or volume may remain unused.
Weight	The permitted payload is reached before geometric capacity is exhausted.
Volume	The calculated transport volume is reached before another constraint becomes decisive.

Governing Constraint is not a recommendation. It is the technical constraint that determines the final Total Rolls.

Remaining Capacity

Remaining Capacity shows reserves after the actual loading result:

• Remaining Payload
• Unused Payload
• Unused Volume

Remaining values do not automatically mean that another roll fits. They must be read together with Governing Constraint and Front View – Cross-Section.

Capacity Analysis

Capacity Analysis is a constraint analysis, not a list of alternative loading solutions. Its rows show theoretical capacity limits for:

• Weight
• Volume
• Geometry

The smallest applicable limit determines the actual Total Rolls. The governing row is marked with → Governing Constraint.

The table columns are:

• Constraint
• Max Rolls
• Total Weight
• Transported Area [m²]
• Payload Util. % — indicates the percentage of the permitted payload that is used.

Front View – Cross-Section

Front View – Cross-Section visualizes the actual geometric loading configuration. Use it to check whether the geometric arrangement is plausible, especially when Geometry is the Governing Constraint.

Important interpretation rules

• Remaining Payload does not automatically mean that another roll fits.
• Unused Volume does not automatically mean that another roll fits.
• Capacity Analysis does not show alternative loading solutions.
• Weight, Volume, and Geometry are theoretical capacity limits.
• The smallest applicable limit determines the actual Total Rolls.

11. Final Plausibility Check

Before using a result for production, handling, or transport planning, check:

• Correct article selected
• Product Thickness checked
• Area Weight checked
• Core Diameter checked
• Roll Width checked
• Product Length or Roll Diameter checked
• Roll Weight plausible
• Calculated Weight plausible
• Transport dimensions correct
• Max. Load (kg) correct
• Loading Clearances realistic
• Governing Constraint understandable
• Remaining Payload and Volume Utilization plausible
• Front View – Cross-Section plausible
• Result compared with experience or a reference case

12. Common Problems

Observation	Check first
Roll Diameter is unexpectedly high or low	Product Thickness, Product Length, Core Diameter, units
Product Length is much larger or smaller than expected	measured Roll Diameter, Product Thickness, Core Diameter
Roll Weight appears incorrect	Product Length, Roll Width, Area Weight
Similar Roll Diameter values have very different weights	Roll Width, Area Weight, Product Length
Forklift Check appears unexpected	Calculated Weight, Core Diameter, Product Category, article data
Extrapolation result appears implausible	Known Roll Diameter (D₀), Known Roll Length (L₀), New Roll Length (L₁), comparability of both rolls
Fewer rolls fit than expected	roll data, Loading Clearances, transport dimensions, Governing Constraint
Remaining Payload is available but no additional roll fits	Geometry, Front View – Cross-Section
Capacity Analysis appears contradictory	governing row, Capacity Summary, Remaining Capacity, Front View – Cross-Section
Similar calculations produce different results	article data, roll geometry, transport data, Loading Clearances

Recalculate completely after changes to article data, roll geometry, or transport parameters. Old results should not be interpreted after changing values such as Product Thickness, Area Weight, Core Diameter, Roll Width, Max. Load (kg), or Loading Clearances.

13. Key Rule

The calculated result is only as reliable as the entered article data, roll data, and transport assumptions. Always perform a technical plausibility check before operational use.