Ethylene Vinyl Acetate (EVA) foam also known as poly(ethylene-vinyl acetate) (PEVA), it is a copolymer of ethylene and vinyl acetate, widely used in footwear, sports goods, yoga mats, adhesives , sealants, coatings , orthotics, surfboard and skimboard traction pads, car mats , insulation, and packaging due to its feature of softness, elasticity, and shock absorption to heat.
EVA is like elastomeric polymer which are “rubber-like” in softness and flexibility ,it can be formed from chain-growth polymerization of ethylene and vinyl acetate. There are several techniques of polymerization that can be applied to this polymer, such as solution, suspension, bulk, and emulsion polymerization.
The manufacturing process of EVA foam involves several key stages, from raw material preparation to the final product, utilizing various foam extrusion methods
To make EVA foam ,it need to go through a series of steps that require specialized machinery.
In this blog, Let us explore which speciallized machine needed from raw material mixing to foaming and molding to make EVA foam.
1. Dispersion Kneader / Banbury Internal Mixer
The first step in EVA foam production is the raw material need to be mixed uniformly. A powerful industrial dispersion kneader ,also known as internal Banbury mixer or an intensive lab kneader , which are very essential for blending EVA resin with additives, fillers, and foaming agents etc.
Key Features:
* High-torque mixing
* High-speed
* High-intensity mixing
* High viscosity adaptability
* Temperature control
* Highly efficient mixing
* Uniform mixing results
* Short mixing cycle for mass production
Why it’s important: A well-blended compound kneader machine ensures consistent cell structure and foaming results.
2. Two-Roll Mixing Mill
Two Roll Mill is also named open mixing mill or Two Roll Mixing Mills. it is an abbreviation of open type plastic refining machine . The EVA compound material need to be sheeted out after kneading by using a two-roll open mixing mill, which presses the mixture into even thickness for further processing as per needs.
Key Feature of Two Roll Mill:
* High-precision mixing
* High Efficiency to ensures thorough mixing and compounding of materials
* Consistent Performance
*Adjustable gap between the two rolls
* High accuracy
* Independent and variable speed control for each roll (Optional);
* Sensitively and uniformly temperature control
* Electric or Oil heating
3. Screw Extruder (Optional)
For continuous processing lines, a twin-screw extruder or single-screw extruder machine need to be used for continuous processing and pelletizing ,so that shape EVA compound into sheets or pellets before foaming. This step improves production efficiency for certain grades of EVA.
Key Feature:
* Robust design to ensures reliability and ease of operation
* Efficient material processing to ensure the quality of melting and mixing of materials, leading to uniform output.
* Versatility for EVA , plastics, rubbers, and composites etc
* Enery efficiency to reduce operational costs
4. Hydraulic Vulcanizing Press / Compression Molding Press
Vulcanization process is the most critical curing press machine in EVA foam production. The compound sheets are placed into molds inside a hydraulic vulcanizer press for vulcanization ,where they are subjected to high temperature and pressure, initiating the crosslinking and foaming reaction.
Key Features:
* High adaptability and flexibility
* High-efficiency vulcanization capacity
* Dust-proof and moisture-proof design
* Safety protection function
* Durability and low maintenance costs
* Intelligent PLC operation interface
* Precision mold control
5. Cooling Conveyor & Cutter
At the final step , EVA foam needs to be cooled gradually and then trimmed to size using foam cutters or CNC cutting machines for further shaping and quality inspection.
Whether you’re producing EVA foam sheets, shoe soles, protective packaging, or sports mats, the aboved specialized machine all are important to ensure the quality of foam.
If you’re starting a new EVA foam line or upgrading existing equipment, consider working with experienced machinery suppliers who understand the intricacies of EVA processing ,then welcome to contact with Simptek Machine , we can provide customized solutions as per your needs .
