Pulp Tray Compression Moulding for Smooth Inner Surfaces
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Solution Overview
Problem
Existing fibrous pulp containers face challenges in achieving a smooth inner surface while forming external protrusions for stacking, which can compromise lamination integrity and aesthetics.
Innovation Solution
A compression moulding tool with female mould elements featuring recessed portions of decreasing size and a smooth male mould element, allowing for the formation of external protrusions without corresponding impressions on the inner surface, facilitated by a water permeable filter and drainage channels to ensure solid protrusions and efficient dewatering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a compression moulding tool uses traditional male and female mould elements with corresponding features, then external protrusions can be formed on the tray, but corresponding impressions are created on the inner surface compromising lamination integrity and aesthetics
Solution Approach 1:
The mould system is segmented into three distinct elements: a first female mould element with larger recessed portions for initial shaping, a second female mould element with smaller recessed portions for final protrusion formation, and a male mould element with a smooth surface. This segmentation allows each element to perform a specific function without creating unwanted impressions on the inner surface.
Solution Approach 2:
The male mould element has a smooth surface specifically at locations corresponding to where external protrusions need to be formed, while other areas may have different surface characteristics. This local quality ensures that only the necessary external features are created without compromising the inner surface quality.
2Manufacturing precision
If the male mould element has a smooth surface profile at locations corresponding to recessed portions, then the inner surface remains smooth for better lamination, but additional female mould elements with decreasing recess sizes are required
Solution Approach 1:
The mould system is divided into multiple female mould elements with progressively smaller recessed portions, allowing the formation of solid external protrusions without requiring complex features on the male mould element. This segmentation distributes the shaping function across multiple specialized components.
Solution Approach 2:
The first female mould element with larger recessed portions performs preliminary shaping of the pulp material before the second female mould element with smaller recessed portions creates the final external protrusions. This preliminary action ensures that the pulp is properly positioned and pre-compressed before final shaping.
3Ease of operation
If external protrusions are formed using traditional moulding methods, then stacking capability is improved, but lamination integrity is compromised due to impressions on the inner surface
Solution Approach 1:
The mould system separates the functions of creating external stacking features from maintaining internal surface quality by using multiple female mould elements with progressively smaller recessed portions and a smooth male mould element.
Solution Approach 2:
The male mould element maintains a smooth surface profile specifically at locations where external protrusions are formed, ensuring that the inner surface remains suitable for lamination while still enabling external features for stacking.
4Shape
If recessed portions of decreasing size are used in successive compression steps, then solid external protrusions are formed without inner surface impressions, but the moulding process becomes more complex
Solution Approach 1:
The moulding process is segmented into successive compression steps using female mould elements with progressively smaller recessed portions, allowing complex external shapes to be formed through a series of simpler, specialized operations rather than a single complex step.
Solution Approach 2:
Earlier compression steps use larger recessed portions to perform preliminary shaping and material distribution, preparing the pulp for final protrusion formation in later steps with smaller recessed portions, making the overall process more manageable.
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
The tool enables trays with external protrusions for easy stacking and improved lamination integrity, reducing the risk of film damage and enhancing the usability of fibrous pulp containers.
Implementation Method 1
a water permeable filter arranged in the first female mould element and configured to follow the surface of the female mould element, the filter being configured to retain pulp fibers
Implementation Method 2
at least one male mould element configured to press against the first and second female mould element to compress a fibrous pulp product located therebetween
Data Source
Figure 1
Figure 2A
Figure 2B~3A
AI summary
A compression moulding tool for manufacturing a fibrous pulp tray (600) having a floor portion (602) and walls (604) extending from the floor portion. The tool comprises a first female mould element (102) comprising a plurality of first recessed portions (112), a water permeable filter (202) arranged in the first female mould element and configured to follow the surface of the female mould element, a second female mould element (104) comprising a plurality of second recessed portions (306) at locations corresponding to the first recessed portions and smaller than the first recessed portions, and a male mould element (106) configured to press against the first and second female mould elements to compress a fibrous pulp product located therebetween, the male mould element having a smooth surface profile at locations corresponding to the first and second recessed portions of the first and second female mould.