PVC Ball Texture Formation via Two-Stage Rotational Molding
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Solution Overview
Problem
Existing methods struggle to produce PVC balls with predetermined textures and patterns, as they are difficult to achieve during the plasticized shaping process.
Innovation Solution
A method involving two stages of shaping using roto-cast or rotational molding machines, where a PVC film with a predetermined pattern is applied to the first mold, and a gas-charged PVC ball is then shaped in a second mold with a predetermined texture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plasticized shaping is used to produce PVC balls, then the production process is simple, but it is very difficult to produce predetermined texture and pattern on the surface of the PVC ball
Solution Approach 1:
The patent divides the shaping process into two separate stages: first shaping the basic ball form, then separately forming the texture pattern. This segmentation allows each stage to focus on its specific function - the first stage creates the ball shape while the second stage imprints the texture, thereby achieving both manufacturing simplicity and surface precision without requiring complex integrated tooling.
Solution Approach 2:
The patent applies preliminary action by pre-heating the PVC ball to a plasticized state before texture formation. The ball is heated to 40-80°C to make it pliable, then pressed against the textured mold surface. This preliminary heating enables the ball to conform to the texture pattern easily, achieving high surface precision while maintaining a relatively simple overall process.
2Productivity
If a single shaping process is used, then the production time is short, but the ball cannot have both predetermined pattern and texture
Solution Approach 1:
The patent segments the forming process into two distinct operations: first shaping the ball geometry, then separately forming the texture pattern. This allows each operation to be optimized independently - the first shaping maintains productivity while the second texture formation achieves the required surface precision, solving the contradiction between speed and capability.
Solution Approach 2:
The patent changes the temperature parameter of the PVC ball between operations. The ball is heated to 40-80°C during texture formation to increase plasticity, enabling pattern imprinting. After cooling, the ball regains structural stability. This parameter change allows the material to be easily shaped when needed while maintaining form stability during handling, thus enabling both rapid production and precise pattern formation.
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 allows for the successful production of PVC balls with both predetermined patterns and textures, overcoming the limitations of previous technologies.
Implementation Method 1
the internal gas of the PVC ball expands, through the principle of thermal expansion, so that the PVC ball presses against an inner wall of the second mold
Implementation Method 2
placing the first mold into a furnace chamber of the roto-cast machine or the rotational molding machine to heat for heated and plasticized shaping
Data Source
AI summary
The present disclosure provides a method for processing a PVC ball, including: Step A: carrying out a first ball shaping of a PVC paste located inside a first mold using a roto-cast machine or a rotational molding machine, to produce a hollow PVC ball; Step B: charging a gas to an interior of the shaped ball, so that the ball has an external diameter equal to a diameter of an inner cavity of a second mold; and Step C: placing the gas-charged ball into the second mold, then carrying out a second texture shaping of the shaped gas-charged ball located inside the second mold using the roto-cast machine or the rotational molding machine, to produce a texture on a surface of the shaped PVC ball. This method can produce a PVC ball having a predetermined texture and a predetermined pattern.