Cutting Rigid P(M)I Foam Panels Without Material Loss

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Solution Overview

Problem

Existing methods for cutting rigid foams, such as P(M)I foams, result in significant material loss and dust formation, and are unable to produce thin sheets or foils efficiently due to mechanical stress and blade limitations, especially for hard and brittle foams.

Innovation Solution

A method that involves making the rigid foam flexible by storing it in water or heating it to a specific temperature range below its foaming temperature, allowing for cutting with a knife to minimize material loss and thermal damage, and enabling the production of thin plates and foils without sawdust accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If sawing is used to cut rigid foams, then cutting capability is achieved, but significant material loss and dust formation occur

Engineering Contradiction:
Improvecutting capabilityVSAvoidmaterial loss
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent changes the physical state parameter of the rigid foam by controlling temperature and humidity. By storing foam at temperatures below its foaming temperature (e.g., room temperature or refrigerated) and exposing it to humidity before cutting, the foam transitions to a more flexible state that can be cut cleanly with a knife, eliminating sawdust and material loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical sawing system with a simple knife cutting system. Instead of using a saw blade that generates dust and material loss, the invention uses a knife to cut the conditioned foam, achieving clean separation without the harmful mechanical action of sawing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Loss of substance

If saw blade thickness is reduced to produce thin sheets, then material loss decreases, but blade sagging and thickness variations increase

Engineering Contradiction:
Improvematerial lossVSAvoidthickness uniformity
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

By changing the physical state of the foam through temperature and humidity control, the foam becomes flexible and can be cut with a thin knife edge. This eliminates the need for thick saw blades, allowing precise cutting of thin sheets without blade sagging while maintaining thickness uniformity.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If heated wires are used to cut foams, then cutting capability is achieved, but thermal damage occurs

Engineering Contradiction:
Improvecutting capabilityVSAvoidthermal damage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the thermal cutting method (heated wire) with a mechanical knife cutting system. The foam is first conditioned to become flexible through temperature and humidity control, then cut with a simple knife, eliminating thermal damage while maintaining cutting capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Strength

If rigid foam is cut while hard and brittle, then structural integrity is maintained, but panel breakage occurs during cutting

Engineering Contradiction:
Improvestructural integrityVSAvoidcutting processability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent temporarily changes the physical state parameter of the foam by controlling temperature and humidity before cutting. The foam is stored at lower temperatures and exposed to humidity to increase flexibility, making it easier to cut without breakage. After cutting, the foam returns to its original hard state, maintaining structural integrity.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method significantly reduces material loss and thermal damage, allowing for the production of thin foils and plates with precise thickness control, including those less than 3 mm, and prevents panel breakage during cutting, making the process more economical and efficient.

Implementation Method 1

the rigid foam is heated or set to a temperature that is at least 15 °C and at most 1 °C below the foaming temperature of the rigid foam

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

the rigid foam is stored in water to make it flexible before cutting

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3221101B1Splitting of thick hard foam panels
Publication Date: 2020.10.14 EVONIK OPERATIONS GMBH

AI summary

The present invention relates to a method for cutting hard foams, in particular P(M)I foam blocks. A method is provided which allows cutting these hard foams without any loss of material, produced for example in the form of relevant amounts of sawdust during sawing, even when cutting into layers of greater thickness, for example of more than 3 mm.